PRODUCT USER MANUAL For Sea Level SLA products

PRODUCT USER MANUAL For Sea Level SLA products
PRODUCT USER MANUAL
For Sea Level SLA products
SEALEVEL_ARC_PHY_L3_NRT_OBSERVATIONS_008_038
SEALEVEL_BS_PHY_L3_NRT_OBSERVATIONS_008_039
SEALEVEL_BS_PHY_L3_REP_OBSERVATIONS_008_040
SEALEVEL_EUR_PHY_ASSIM_L3_NRT_OBSERVATIONS_008_043
SEALEVEL_GLO_PHY_L3_NRT_OBSERVATIONS_008_044
SEALEVEL_GLO_PHY_L3_REP_OBSERVATIONS_008_045
SEALEVEL_MED_PHY_ASSIM_L3_NRT_OBSERVATIONS_008_048
SEALEVEL_MED_PHY_L3_REP_OBSERVATIONS_008_049
SEALEVEL_BS_PHY_ L4_NRT_OBSERVATIONS_008_041
SEALEVEL_BS_PHY_ L4_REP_OBSERVATIONS_008_042
SEALEVEL_GLO_PHY_ L4_NRT_OBSERVATIONS_008_046
SEALEVEL_GLO_PHY_ L4_REP_OBSERVATIONS_008_047
SEALEVEL_MED_PHY_ L4_NRT_OBSERVATIONS_008_050
SEALEVEL_MED_PHY_ L4_REP_OBSERVATIONS_008_051
SEALEVEL_GLO_NOISE_L4_NRT_OBSERVATIONS_008_032
SEA_LEVEL_GLO_NOISE_L4_REP_OBSERVATIONS_008_033
Issue: 1.1
Contributors: Françoise Mertz (CLS), Vinca Rosmorduc (CLS), Caroline Maheu (CLS), Yannice Faugère (CLS)
CMEMS version scope : Version 3.0
Approval Date : April 19 2017
PUM for products
Ref: CMEMS-SL-PUM-008-032-051
SEALEVEL_*_PHY_*_OBSERVATIONS_008_0*
Date : 17th March 2017
Issue : 1.1
CHANGE RECORD
Issue
Date
1.0
1.1
§
Description of change
Author
Validated by
2017/01/01 all
First version of document for V3
products
F. Mertz
Y. Faugère
2017/03/17 all
Review from Mercator
F. Mertz
Y. Faugère
c EU Copernicus Marine Service - Public
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PUM for products
Ref: CMEMS-SL-PUM-008-032-051
Date : 17th March 2017
SEALEVEL_*_PHY_*_OBSERVATIONS_008_0*
Issue : 1.1
C ONTENTS
I. Introduction
6
II. Altimetry Principle
8
II.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
II.1.1. Variables used in SL-TAC products . . . . . . . . . . . . . . . . . . . . . . . . . . 8
II.2. CMEMS and Aviso+ Disseminations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
III.COPERNICUS SL-TAC Products
III.1. Near Real Time Products . . . . .
III.1.1. Delay of the products . . .
III.1.1.1. Along-track products
III.1.1.2. Gridded products . .
III.2. Delayed Time Products . . . . . .
III.2.1. Delay of the products . . .
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IV. Description of the product specification
IV.1. General information . . . . . . . . . . . . . . .
IV.1.1. Along-track products . . . . . . . . . .
IV.1.2. Gridded Sea Level Anomalies . . . . .
IV.1.3. Gridded Noise on Sea Level Anomalies
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V. Nomenclature of files
V.1. Nomenclature of files downloaded through the CMEMS Web Portal download Service
V.1.1. Nomenclature of the Along Track products . . . . . . . . . . . . . . . . . . .
V.1.1.1. Nomenclature of the datasets . . . . . . . . . . . . . . . . . . . . . . . .
V.1.1.2. Nomenclature of the NetCdf files . . . . . . . . . . . . . . . . . . . . . .
V.1.2. Nomenclature of the Gridded products . . . . . . . . . . . . . . . . . . . . . .
V.1.2.1. Nomenclature of the datasets . . . . . . . . . . . . . . . . . . . . . . . .
V.1.2.2. Nomenclature of the NetCdf files . . . . . . . . . . . . . . . . . . . . . .
V.1.3. Nomenclature of the Gridded noise of Sea Level Anomalies . . . . . . . . . .
V.1.3.1. Nomenclature of the datasets . . . . . . . . . . . . . . . . . . . . . . . .
V.1.3.2. Nomenclature of the NetCdf files . . . . . . . . . . . . . . . . . . . . . .
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VI. Data format
VI.1. NetCdf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VI.2. Structure and semantic of NetCDF along-track (L3) files . . . . . . . . . . .
VI.2.1. Example of classic along-track L3 file . . . . . . . . . . . . . . . . .
VI.2.2. Example of along-track L3 file dedicated to assimilation . . . . . . .
VI.3. Structure and semantic of NetCDF maps (L4) files . . . . . . . . . . . . . . .
VI.3.1. Example of classic gridded L4 file . . . . . . . . . . . . . . . . . . .
VI.4. Structure and semantic of NetCDF Gridded Noise on Sea Level Anomaly files
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VII.How to download a product
VII.1.Download a product through the CMEMS Web Portal Directgetfile Service . . . . . . . . .
VII.2.Download a product through the CMEMS Web Portal Ftp Service . . . . . . . . . . . . . .
VII.3.Download a product through the CMEMS Web Portal Subsetter Service . . . . . . . . . . .
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c EU Copernicus Marine Service - Public
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Page 2
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PUM for products
Ref: CMEMS-SL-PUM-008-032-051
Date : 17th March 2017
SEALEVEL_*_PHY_*_OBSERVATIONS_008_0*
Issue : 1.1
L IST OF TABLES
1
2
3
4
5
6
Liste of variables in the SL-TAC products . . . .
Description of variables in the SL-TAC products .
List of the time varying products in NRT . . . . .
List of the time invariant product in NRT . . . . .
List of the time varying products in Delayed Time
List of the time invariant product in Delayed Time
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9
10
12
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L IST OF F IGURES
1
2
3
Altimetry Principle . . . . . . . . . . . . . . . . . . . .
Data delivery flow for Global NRT SL-TAC products . .
Three merged maps are produced daily: final map (d-6),
liminary map (d0) . . . . . . . . . . . . . . . . . . . . .
c EU Copernicus Marine Service - Public
. . . . . . . . . .
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intermediate map
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Page 3
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(d-3)
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. . . . . . 8
. . . . . . 14
and pre. . . . . . 15
PUM for products
SEALEVEL_*_PHY_*_OBSERVATIONS_008_0*
Ref: CMEMS-SL-PUM-008-032-051
Date : 17th March 2017
Issue : 1.1
L IST OF ACRONYMS
AL
ATP
ADT
AVISO
BGLO
Cal/Val
CERSAT
C2
DAC
DT
DTU
DUACS
E1
E2
EN
ENN
ECMWF
ENACT
G2
GIM
GDR
HY-2A
IERS
IGDR
J1
J1N
J1G
J2
J2N
J3
JPL
LAS
LWE
MADT
MDT
MOE
MP
MSLA
MSS
NRT
OE
OER
Opendap
PO.DAAC
AltiKa
Along-Track Product
Absolute Dynamic Topography
Archiving, Validation and Interpretation of Satellite Oceanographic data
Biais Grande Longueur d’Onde
Calibration - Validation
Centre ERS d’Archivage et de Traitement
Cryosat-2
Dynamic Atmospheric Correction
Delayed Time
Mean Sea Surface computed by Technical University of Danemark
Data Unification and Altimeter Combination System
ERS-1
ERS-2
Envisat
Envisat on its non repetitive orbit (since cycle 94)
European Centre for Medium-range Weather Forecasting
ENhanced ocean data Assimilation and Climate prediction
Geosat Follow On
Global Ionospheric Maps
Geophysical Data Record(s)
Haiyang-2A
International Earth Rotation Service
Interim Geophysical Data Record(s)
Jason-1
Jason-1 on its interleaved orbit (since cycle 262)
Jason-1 on its geodetic orbit (since May 2012)
OSTM/Jason-2
OSTM/Jason-2 on its interleaved orbit
Jason-3
Jet Propulsion Laboratory
Live Access Server
Long Wavelength Errors
Map of Absolute Dynamic Topgraphy
Mean Dynamic Topography
Medium Orbit Ephemeris
Mean Profile
Map of Sea Level Anomaly
Mean Sea Surface
Near-Real Time
Orbit Error
Orbit Error Reduction
Open-source Project for a Network Data Access Protocol
Physical Oceanography Distributed Active Archive Centre
c EU Copernicus Marine Service - Public
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Date : 17th March 2017
Issue : 1.1
POE
RD
S3A
SAD
SARAL
SLA
SL TAC
SSALTO
SSH
TAC
T/P
TPN
Precise Orbit Ephemeris
Reference Document
Sentinel-3A
Static Auxiliary Data
Satellite with ARgos and ALtika
Sea Level Anomaly
Sea Level Thematic Assembly Centre
Ssalto multimission ground segment
Sea Surface Height
Thematic Assembly Centre
Topex/Poseidon
Topex/Poseidon on its interleaved orbit (since cycle 369)
c EU Copernicus Marine Service - Public
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SEALEVEL_*_PHY_*_OBSERVATIONS_008_0*
Ref: CMEMS-SL-PUM-008-032-051
Date : 17th March 2017
Issue : 1.1
I. I NTRODUCTION
The Sea Level TAC (Thematic Assembly Centre) is one of the five TAC of the Copernicus Marine Environment Monitoring Service (CMEMS) project. The aim of this document is to describe the products
delivered by the Sea Level TAC.
The data produced in the frame of this TAC are generated by the processing system including data from
all altimeter missions: Sentinel-3A, Jason-3, HY-2A, Saral/AltiKa, Cryosat-2, OSTM/Jason-2, Jason-1,
Topex/Poseidon, Envisat, GFO, ERS-1&2.
The products described in this user manual are the following:
1)
SEALEVEL_GLO_PHY_L3_NRT_OBSERVATIONS_008_044
SEALEVEL_MED_PHY_ASSIM_L3_NRT_OBSERVATIONS_008_048
SEALEVEL_BS_PHY_L3_NRT_OBSERVATIONS_008_039
SEALEVEL_EUR_PHY_ASSIM_L3_NRT_OBSERVATIONS_008_043
SEALEVEL_ARC_PHY_L3_NRT_OBSERVATIONS_008_038
and
SEALEVEL_GLO_PHY_L3_REP_OBSERVATIONS_008_045
SEALEVEL_MED_PHY_L3_REP_OBSERVATIONS_008_049
SEALEVEL_BS_PHY_L3_REP_OBSERVATIONS_008_040
are Sea Surface Heights observations from the altimeters.
The data provided to users have a global coverage (SEALEVEL_GLO_*_OBSERVATIONS_008_*) and
regional products are also computed over specific areas:
Mediterranean Sea (SEALEVEL_MED_*_OBSERVATIONS_008_*)
and Black Sea (SEALEVEL_BS_*_OBSERVATIONS_008_*).
The following two regional products are available only in Near Real time:
Europe (SEALEVEL_EUR_PHY_ASSIM_L3_NRT_OBSERVATIONS_008_043)
and Arctic (SEALEVEL_ARC_PHY_L3_NRT_OBSERVATIONS_008_038).
Specific features of dedicated assimilation product (*ASSIM*):
Those products are added to existing Sea Level TAC products to address the needs of data assimilation and
validation in regional models, following the TAPAS (Tailored Altimeter Product for Assimilation System)
initiative launched by MyOcean project with all the Modeling and Forecasting Centers (MFCs). Those products are not filtered and not sub-sampled, contrary to the other SEA LEVEL along-track products. Their
resolution is thus 7 km. Those products propose several variables: the SLA that is usually contained in SL
TAC products which in unfiltered, the filtered SLA, but also, the MDT (Mean Dynamic Topography), the
DAC (Dynamic Atmospheric Correction), the oceanic tide and the LWE (Long Wavelength Error) correction. The description is detailed in section II.
2)
SEALEVEL_GLO_PHY_L4_NRT_OBSERVATIONS_008_046
SEALEVEL_MED_PHY_L4_NRT_OBSERVATIONS_008_050
SEALEVEL_BS_PHY_L4_NRT_OBSERVATIONS_008_041
and
SEALEVEL_GLO_PHY_L4_REP_OBSERVATIONS_008_047
SEALEVEL_MED_PHY_L4_REP_OBSERVATIONS_008_051
SEALEVEL_BS_PHY_L4_REP_OBSERVATIONS_008_042
are merged Maps of Sea Surface Heights and derived variables observations from the altimeters. Those
products were previously distributed by Aviso+ and the scientific content has not changed.
c EU Copernicus Marine Service - Public
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Date : 17th March 2017
Issue : 1.1
3)
SEALEVEL_GLO_NOISE_L4_NRT_OBSERVATIONS_008_032
SEALEVEL_GLO_NOISE_L4_REP_OBSERVATIONS_008_033
are gridded products containing the noise of filtering of SLA Global Ocean products and are described in the
QUID http://marine.copernicus.eu/documents/QUID/CMEMS-SL-QUID-008-032-051.
pdf
c EU Copernicus Marine Service - Public
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Ref: CMEMS-SL-PUM-008-032-051
Date : 17th March 2017
Issue : 1.1
II. A LTIMETRY P RINCIPLE
II.1. Definitions
• The Altimetry gives access to the Sea Surface Height (SSH)
above the reference ellipsoïd (see figure 1)
SSH = Orbit - Altimetric Range
• The Mean Sea Surface (MSS) is the temporal mean of
the SSH over a period N. It is a mean surface above
the ellipsoïd and it includes the Geoid. See the detailed
computation in QUID http://marine.copernicus.eu/
documents/QUID/CMEMS-SL-QUID-008-032-051.pdf
MSSN =<SSH>N
• The dynamical part of the signal: Sea Level Anomaly (SLA)
is deduced from the SSH using a Mean Sea Surface
(MSS):
Figure 1: Altimetry Principle
SLAN = SSH - MSSN
• The Mean Dynamic Topography (MDT) is the temporal mean
of the SSH above the Geoid over a period N.
MDTN = MSSN - Geoid
• The dynamical part of the absolute signal: Absolute Dynamic Topography (ADT) is deduced from the
SLA using a Mean Dynamic Topography (MDT):
ADT= SLAN + MDTN = SSH - MSSN + MDTN
II.1.1. Variables used in SL-TAC products
This part gives an overview of the variables used in the SL-TAC products and their signification. The complete processing to calculated the variables is described in the QUID http://marine.copernicus.
eu/documents/QUID/CMEMS-SL-QUID-008-032-051.pdf.
c EU Copernicus Marine Service - Public
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Date : 17th March 2017
Issue : 1.1
Name of products
SEALEVEL_GLO_PHY_L3_NRT_OBSERVATIONS_008_044
SEALEVEL_ARC_PHY_L3_NRT_OBSERVATIONS_008_038
SEALEVEL_MED_PHY_ASSIM_L3_NRT_OBSERVATIONS_008_048
SEALEVEL_EUR_PHY_ASSIM_L3_NRT_OBSERVATIONS_008_043
physical variables
sla_filtered
adt_filtered
sla_filtered
sla_unfiltered
mdt
dac
lwe
ocean_tide
SEALEVEL_BS_PHY_L3_NRT_OBSERVATIONS_008_039
sla_filtered
SEALEVEL_GLO_PHY_L3_REP_OBSERVATIONS_008_045
sla_filtered and
adt_filtered for filtered datasets
sla_unfiltered and
adt_unfiltered for unfiltered datasets
SEALEVEL_MED_PHY_L3_REP_OBSERVATIONS_008_049
SEALEVEL_BS_PHY_L3_REP_OBSERVATIONS_008_040
sla_filtered for filtered datasets
sla_unfiltered for unfiltered datasets
SEALEVEL_GLO_SLA_MAP_L4_NRT_OBSERVATIONS_008_046
sla
err
adt
ugosa
vgosa
ugos
vgos
SEALEVEL_GLO_SLA_MAP_L4_REP_OBSERVATIONS_008_047
SEALEVEL_MED_SLA_MAP_L4_NRT_OBSERVATIONS_008_050
SEALEVEL_MED_SLA_MAP_L4_REP_OBSERVATIONS_008_051
SEALEVEL_BS_SLA_MAP_L4_NRT_OBSERVATIONS_008_041
SEALEVEL_BS_SLA_MAP_L4_REP_OBSERVATIONS_008_042
sla
err
ugosa
vgosa
Table 1: Liste of variables in the SL-TAC products
c EU Copernicus Marine Service - Public
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Issue : 1.1
Name of variable
description/comment
sla_filtered
sla_unfiltered
described in II.1. Note that for assimilation products, the sla is filtered but not subsampled
contrary to other L3 products.
adt_filtered
adt_unfiltered
described in II.1. Note that for assimilation products, the adt variable is not in the product
but can be obtained with adt_filtered=sla_filtered + mdt
ugosa and vgosa
ugos and vgos
described in the QUID
http://marine.copernicus.eu/documents/QUID/
CMEMS-SL-QUID-008-032-051.pdf
mdt
Mean Dynamic Topography, described in II.1.
dac
This correction allows for the removal of high frequency variability induced by the atmospheric forcing and aliased by the altimetric measurements. The high frequency part
is based on a barotropic model simulation forced by atmospheric pressure and winds
(MOG2D; Carrère and Lyard 2003[7]); the low frequency part is an inverse barometer response. A 20-day cutoff-period was chosen because it corresponds to the Nyquist period
of T/P-Jason reference altimeters sampling and because the variability is mostly barotropic
in this high frequency band. This correction is already included in the SLA so if the user
wants to uncorrect it or to use another correction instead, he must add it to the SLA from
the product:
sla_filtereduncorrected = sla_filteredfrom product + dac.
sla_unfiltereduncorrected = sla_unfilteredfrom product + dac.
lwe
This correction allows correcting along track altimeter signals from long wavelengths errors remaining in the signal. LWE are defined to be orbit errors (very long spatial scales)
and residual high-frequency signals (short time scale and large spatial scales); LWE are assumed to be uncorrelated between tracks and cycles. The LWE estimation is similar to the
optimal interpolation technique described in Le Traon et al.[1998][41]; the main difference
is that along-track LWE are estimated instead of the ocean signal. This correction is already
included in the SLA but it is stored with opposite sign compared to the other corrections
so if the user wants to uncorrect it or to use another correction instead, he must subtract it
from the SLA in the product:
sla_filtereduncorrected = sla_filteredfrom product - lwe.
sla_unfiltereduncorrected = sla_unfilteredfrom product - lwe.
ocean_tide
The oceanic tide combines the ocean tide model and the loading tide model. The models
are described in the QUID http://marine.copernicus.eu/documents/QUID/
CMEMS-SL-QUID-008-032-051.pdf. This correction is already included in the SLA
so if the user wants to uncorrect it or to use another correction instead, he must add it to the
SLA from the product:
sla_filtereduncorrected = sla_filteredfrom product + oceanic_tide.
sla_unfiltereduncorrected = sla_unfilteredfrom product + oceanic_tide.
Table 2: Description of variables in the SL-TAC products
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Issue : 1.1
II.2. CMEMS and Aviso+ Disseminations
• The along-track and maps SLAs and ADTs for Global ocean, Mediterranean Sea, Black Sea, Arctic Ocean and European Seas are distributed by CMEMS but they are in the Aviso+ Catalogue and
can be visualized via the Live Access Server (LAS) http://www.aviso.altimetry.fr/en/
data/data-access/las-live-access-server.html
• The Gridded Sea Level Anomalies Climatologies are available via the Aviso+ dissemination (with
registration) http://www.aviso.altimetry.fr/en/data/products/sea-surface-height-pr
global/msla-mean-climatology.html
• The along-track and maps SLAs and ADTs for Mozambique Area are distributed by Aviso+ http:
//www.aviso.altimetry.fr/en/data/products/sea-surface-height-products/
regional/msla-mozambique-area.html
• The MSS is available via the Aviso+ dissemination (with registration) http://www.aviso.altimetry.
fr/en/data/products/auxiliary-products/mss.html
• The MDT is available via the Aviso+ dissemination (with registration) http://www.aviso.
altimetry.fr/en/data/products/auxiliary-products/mdt.html
• Other altimetry products are available via the Aviso+ dissemination (with registration), see http:
//www.aviso.altimetry.fr/en/data/products.html
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Issue : 1.1
III. COPERNICUS SL-TAC P RODUCTS
The CMEMS SL-TAC produces two components: one REPROCESSING (REP) component and on Nearreal-Time (NRT) component described in this part.
III.1. Near Real Time Products
The purpose of the NRT CMEMS component is the acquisition of altimeter data from various altimeter
missions in
• near-real-time (IGDRs) or in short time critical (L2P STC for Sentinel-3A) i.e. within a few days at
most and
• in fast delivery: real time (OGDRs) or near real time (L2P NRT for Sentinel-3A),
the validation and correction of these altimeter data sets (i.e edition and selection, update of corrections and
homogenization, orbit error reduction) in order to produce each day along-track and gridded products.
Exploitation of real time OGDR or L2P NRT Sentinel-3A data allows the DUACS system to produce multimission maps with 0-day and 3-day delay and NRT (IGDR-based) or L2P STC Sentinel-3A production has
a 6-day delay see III.1.1.2..
The quality measurements in the NRT SL-TAC CMEMS component is more sensitive to the number of
altimeter missions involved in the system. This is mainly due to the orbit error and the non-centered processing time-window (in NRT case, "future" data are not available; the computation time window takes into
account only the 6 weeks before the date).
If two altimeters are acknowledged as the bare minimum needed to observe mesoscale signals in DT maps,
three or even four missions are needed to obtain equivalent accuracy in NRT (Pascual et al., 2006[51]).
Along-track Sea surface height
Along-track Sea level anomaly
Gridded Sea Surface Height and
for assimilation
derivated variables
NRT PHY L3
NRT PHY ASSIM L3
NRT PHY L4
(SEALEVEL_*_PHY_L3_NRT
_OBSERVATIONS_008_*)
(SEALEVEL_*_PHY_ASSIM_L3_NRT
_OBSERVATIONS_008_*)
(SEALEVEL_*_PHY_L4_NRT
_OBSERVATIONS_008_*)
delivered
-
delivered
-
delivered
delivered
Black Sea
delivered
-
delivered
Arctic
delivered
-
-
Europe
-
delivered
-
Global
Sentinel-3A dataset is produced
under EUMETSAT responsibility
and disseminated by CMEMS
Mediterranean
Table 3: List of the time varying products in NRT
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A time invariant product SEALEVEL_GLO_NOISE_L4_NRT_OBSERVATIONS_008_032 is also delivered: it describes the noise level of along-track measurements. This is a gridded product. One file is provided
for the global ocean and those values must be applied for Arctic and Europe products. For Mediterranean
and Black seas, one value is given in the QUID http://marine.copernicus.eu/documents/
QUID/CMEMS-SL-QUID-008-032-051.pdf.
Gridded Noise on SLA
NRT NOISE SLA
(SEALEVEL_GLO_NOISE_L4_NRT
_OBSERVATIONS_008_*)
Global
delivered
Mediterranean
see QUID
Black Sea
see QUID
Arctic
Same as global
Europe
Same as global
Table 4: List of the time invariant product in NRT
III.1.1. Delay of the products
III.1.1.1. Along-track products
As described in Figure 2 below, there is a nominal run of the SL-TAC chain each day, combining IGDR or
L2P STC and OGDR or L2P NRT data. This run produces every day along-track products 3 to 12 hours after
the last measurement. Moreover, several times per day a secondary run for GLOBAL area only takes into
account the last Saral, Cryosat-2, Jason-2 and Jason-3 OGDRs or L2P NRT Sentinel-3A files. This allows
producing GLOBAL along-track files within 2 hours for the last measurement. This was implemented in
order to allow downloading the latest measurement available whenever during the day.
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The delivery data flow is described below with an example on a real situation. The consolidated data are in
green and will not be updated in the future processing. The files in yellow are computed with IGDRs or L2P
STC input data and the files in orange and red are produced with OGDRs or L2P NRT data. Once a day,
the nominal processing is run with all the input data available. Several times per day, the global processing
is run and integrates the available fast delivery products leading to increase the number of measurements
available to users.
The situation A/ describes the available data after a nominal processing (processing date is 20160621) and
several secondary processings. In the situation B/, after a new secondary processing, the consolidated files
are the same as in A/, the yellow files are the same as in A/, the file of day 20 is the same as in A/ and the file
of day 21 contains the measurements as in situation A/ plus the measurements acquired in the meanwhile
(in red). Each time new data is ingested, the resultant file (of day 21) is overwritten with the attribute
"date_created" updated.
In the situation C/ the day after A/ and B/, another file has been consolidated (day 31). The yellow, orange
and red files have been updated with a new production date (20160622) and new measurements have been
ingested (in red).
Figure 2: Data delivery flow for Global NRT SL-TAC products
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III.1.1.2. Gridded products
The availability of the gridded products in near real time is day-0 , day-3 and day-6 days. Those products
are delivered every day.
Three merged maps are produced daily, each with a different delay and quality:
• A 6-day delay, which represents a final NRT map production,
• A 3-day delay, which represents an intermediate map production,;
• and a 0-day delay, which represents a preliminary map production, based on IGDR+OGDR production.
Then, these maps are replaced when a better quality data is available:
• At d0+6 , the final NRT map replaces the preliminary map which was produced at d0 .
Figure 3: Three merged maps are produced daily: final map (d-6), intermediate map (d-3) and preliminary
map (d0)
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III.2. Delayed Time Products
The Delayed Time (DT) component of SL-TAC system is responsible for the production of processed Jason3, HY-2A, Saral/AltiKa, Cryosat-2, Jason-1, Jason-2, T/P, Envisat, GFO, ERS1/2 data in order to provide a
homogeneous, inter-calibrated and highly accurate long time series of SLA and MSLA altimeter data .
DT products are more precise than NRT products. Two reasons explain this quality difference. The first one
is the better intrinsic quality of the POE orbit used in the GDR processing. The second reason is that in the
DT processing, the products can be computed optimally with a centred computation time window for OER,
LWE and mapping processes (6 weeks before and after the date). On the contrary in NRT case, "future"
data are not available so the computation time window is not centred and therefore not optimal. As for NRT
products, improved altimeter corrections and processing algorithms are used: ocean tide model to correct
altimeter data, improved methods for orbit error reduction and mapping.
Along-track Sea surface height
Gridded Sea surface height and
derivated variables
Global filtered
REP PHY L3
REP PHY L4
(SEALEVEL_*_PHY_L3_REP
_OBSERVATIONS_008_*)
(SEALEVEL_*_PHY_L4_REP
_OBSERVATIONS_008_*)
delivered
delivered
Sentinel-3A dataset is produced
under EUMETSAT responsibility
and disseminated by CMEMS
delivered
Global unfiltered
-
Sentinel-3A dataset is produced
under EUMETSAT responsibility
and disseminated by CMEMS
Mediterranean filtered
delivered
delivered
Mediterranean unfiltered
delivered
-
Black Sea filtered
delivered
delivered
Black Sea unfiltered
delivered
-
Table 5: List of the time varying products in Delayed Time
A time invariant product SEALEVEL_GLO_NOISE_L4_REP_OBSERVATIONS_008_033 is also delivered: it describes the noise level of along-track measurements. This is a gridded product delivered only
on global ocean. For each mission two files are provided: one for filtered products and one for unfiltered products. For Mediterranean and Black seas, one value is given, as described in the QUID http:
//marine.copernicus.eu/documents/QUID/CMEMS-SL-QUID-008-032-051.pdf.
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Gridded Noise on SLA
REP NOISE SLA
(SEALEVEL_GLO_NOISE_L4_REP
_OBSERVATIONS_008_*)
Global filtered
delivered
Global unfiltered
delivered
Mediterranean filtered
see QUID
Mediterranean unfiltered
see QUID
Black Sea filtered
see QUID
Black Sea unfiltered
see QUID
Table 6: List of the time invariant product in Delayed Time
III.2.1. Delay of the products
Daily products are delivered. The availability of the products in delayed time is at the best two months after
the date of the measurement. The product generation needs all the GDR data of all the missions to take into
account the best corrections as possible. The time delay can be longer in the case of a missing mission.
The merged products were obtained with the satellites given in QUID. Moreover, the global attribute in the
gridded file called "platform" gives the list of satellites used to compute the map.
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IV. D ESCRIPTION OF THE PRODUCT SPECIFICATION
IV.1. General information
IV.1.1. Along-track products
Product Specification
SEALEVEL_GLO_PHY_L3_NRT_OBSERVATIONS_008_044
SEALEVEL_GLO_PHY_L3_REP_OBSERVATIONS_008_045
Geographical coverage
global
Variables
latitude
longitude
sla_filtered (Sea level anomaly)
adt_filtered (Absolute dynamic topography)
sla_unfiltered (Sea level anomaly) for unfiltered REP datasets
adt_unfiltered (Absolute dynamic topography) for unfiltered REP datasets
track
time in days since 1950-01-01 00:00:00 UTC
flag
cycle
Near Real time
Yes
Reanalysis
Yes
Available time series
see QUID
Temporal resolution
Daily
Target delivery time
3-4 months for REP and up to 10 times a day for NRT
Delivery mechanism
CMEMS Information System
Horizontal resolution
14km for filtered, 7km for unfiltered
Number of vertical levels
1
Format
Netcdf CF1.6
SEALEVEL_GLO_PHY_L3_NRT_OBSERVATIONS_008_044 and
SEALEVEL_GLO_PHY_L3_REP_OBSERVATIONS_008_045 Product Specification
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Product Specification
SEALEVEL_MED_PHY_ASSIM_L3_NRT_OBSERVATIONS_008_048
Geographical coverage
6˚W-37˚E ; 30˚N-46˚N
Variables
time in days since 1950-01-01 00:00:00 UTC
latitude
longitude
cycle
track
sla_filtered (Sea level anomaly)
sla_unfiltered (Sea level anomaly)
dac (Dynamic Atmospheric correction)
lwe (Long wavelength correction)
ocean_tide
mdt (Mean dynamic topography)
Near Real time
Yes
Reanalysis
No
Available time series
see QUID
Temporal resolution
Daily
Target delivery time
Daily
Delivery mechanism
CMEMS Information System
Horizontal resolution
7km
Number of vertical levels
1
Format
Netcdf CF1.6
SEALEVEL_MED_PHY_ASSIM_L3_NRT_OBSERVATIONS_008_048 Product Specification
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Product Specification
SEALEVEL_MED_PHY_L3_REP_OBSERVATIONS_008_049
Geographical coverage
6˚W-37˚E ; 30˚N-46˚N
Variables
latitude
longitude
sla_filtered (Sea level anomaly)
adt_filtered (Absolute dynamic topography)
sla_unfiltered (Sea level anomaly) for unfiltered REP datasets
adt_unfiltered (Absolute dynamic topography) for unfiltered REP datasets
track
time in days since 1950-01-01 00:00:00 UTC
flag
cycle
Near Real time
No
Reanalysis
Yes
Available time series
see QUID
Temporal resolution
Daily
Target delivery time
3-4 months for REP
Delivery mechanism
CMEMS Information System
Horizontal resolution
14km for filtered, 7km for unfiltered
Number of vertical levels
1
Format
Netcdf CF1.6
SEALEVEL_MED_PHY_L3_REP_OBSERVATIONS_008_049 Product Specification
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Product Specification
SEALEVEL_BS_PHY_L3_NRT_OBSERVATIONS_008_039
SEALEVEL_BS_PHY_L3_REP_OBSERVATIONS_008_040
Geographical coverage
27˚E-42˚E ; 40˚N-47˚N
Variables
latitude
longitude
sla_filtered (Sea level anomaly)
sla_unfiltered (Sea level anomaly) for unfiltered REP datasets
track
time in days since 1950-01-01 00:00:00 UTC
flag
cycle
Near Real time
Yes
Reanalysis
Yes
Available time series
see QUID
Temporal resolution
Daily
Target delivery time
3-4 months for REP and daily for NRT
Delivery mechanism
CMEMS Information System
Horizontal resolution
7km for filtered, 7km for unfiltered
Number of vertical levels
1
Format
Netcdf CF1.6
SEALEVEL_BS_PHY_L3_NRT_OBSERVATIONS_008_039 and
SEALEVEL_BS_PHY_L3_REP_OBSERVATIONS_008_040 Product Specification
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Product Specification
SEALEVEL_EUR_PHY_ASSIM_L3_NRT_OBSERVATIONS_008_043
Geographical coverage
25˚W-42˚E ; 21˚N-66˚N
Variables
time in days since 1950-01-01 00:00:00 UTC
latitude
longitude
cycle
track
sla_filtered (Sea level anomaly)
sla_unfiltered (Sea level anomaly)
dac (Dynamic Atmospheric correction)
lwe (Long wavelength correction)
ocean_tide
mdt (Mean dynamic topography)
Near Real time
Yes
Reanalysis
No
Available time series
see QUID
Temporal resolution
Daily
Target delivery time
daily
Delivery mechanism
CMEMS Information System
Horizontal resolution
7km
Number of vertical levels
1
Format
Netcdf CF1.6
SEALEVEL_EUR_PHY_ASSIM_L3_NRT_OBSERVATIONS_008_043 Product Specification
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Product Specification
SEALEVEL_ARC_PHY_L3_NRT_OBSERVATIONS_008_038
Geographical coverage
0˚W-360˚E ; 50˚N-82˚N
Variables
latitude
longitude
sla_filtered (Sea level anomaly)
adt_filtered (Absolute dynamic topography)
track
time in days since 1950-01-01 00:00:00 UTC
flag
cycle
Near Real time
Yes
Reanalysis
No
Available time series
see QUID
Temporal resolution
Daily for NRT
Target delivery time
daily for NRT
Delivery mechanism
CMEMS Information System
Horizontal resolution
14km for filtered
Number of vertical levels
1
Format
Netcdf CF1.6
SEALEVEL_ARC_PHY_L3_NRT_OBSERVATIONS_008_038 Product Specification
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IV.1.2. Gridded Sea Level Anomalies
Product Specification
SEALEVEL_GLO_PHY_L4_NRT_OBSERVATIONS_008_046
SEALEVEL_GLO_PHY_L4_REP_OBSERVATIONS_008_047
Geographical coverage
global
Variables
time in days since 1950-01-01 00:00:00 UTC
latitude
longitude
sla (Sea level anomaly)
err (Formal mapping error)
adt (Absolute dynamic topography)
ugosa (Geostrophic velocity anomalies: zonal component)
vgosa (Geostrophic velocity anomalies: meridian component)
ugos (Absolute geostrophic velocity: zonal component)
vgos (Absolute geostrophic velocity: meridian component)
Near Real time
Yes
Reanalysis
Yes
Available time series
see QUID
Temporal resolution
Daily
Target delivery time
3-4 months for REP and daily for NRT
Delivery mechanism
CMEMS Information System
Horizontal resolution
0.25˚x0.25˚
Number of vertical levels
1
Format
Netcdf CF1.6
SEALEVEL_GLO_PHY_MAP_L4_NRT_OBSERVATIONS_008_046 and
SEALEVEL_GLO_PHY_MAP_L4_REP_OBSERVATIONS_008_047 Product Specification
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Product Specification
SEALEVEL_MED_PHY_L4_NRT_OBSERVATIONS_008_050
SEALEVEL_MED_PHY_L4_REP_OBSERVATIONS_008_051
Geographical coverage
6˚W-37˚E ; 30˚N-46˚N
Variables
time in days since 1950-01-01 00:00:00 UTC
latitude
longitude
sla (Sea level anomaly)
err (Formal mapping error)
adt (Absolute dynamic topography)
ugosa (Geostrophic velocity anomalies: zonal component)
vgosa (Geostrophic velocity anomalies: meridian component)
ugos (Absolute geostrophic velocity: zonal component)
vgos (Absolute geostrophic velocity: meridian component)
Near Real time
Yes
Reanalysis
Yes
Available time series
see QUID
Temporal resolution
Daily
Target delivery time
3-4 months for REP and daily for NRT
Delivery mechanism
CMEMS Information System
Horizontal resolution
0.125˚x0.125˚
Number of vertical levels
1
Format
Netcdf CF1.6
SEALEVEL_MED_PHY_L4_NRT_OBSERVATIONS_008_050 and
SEALEVEL_MED_PHY_L4_REP_OBSERVATIONS_008_051 Product Specification
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Product Specification
SEALEVEL_BS_PHY_L4_NRT_OBSERVATIONS_008_041
SEALEVEL_BS_PHY_L4_REP_OBSERVATIONS_008_042
Geographical coverage
27˚E-42˚E ; 40˚N-47˚N
Variables
time in days since 1950-01-01 00:00:00 UTC
latitude
longitude
sla (Sea level anomaly)
err (Formal mapping error)
ugosa (Geostrophic velocity anomalies: zonal component)
vgosa (Geostrophic velocity anomalies: meridian component)
Near Real time
Yes
Reanalysis
Yes
Available time series
see QUID
Temporal resolution
Daily
Target delivery time
3-4 months for REP and daily for NRT
Delivery mechanism
CMEMS Information System
Horizontal resolution
0.125˚x0.125˚
Number of vertical levels
1
Format
Netcdf CF1.6
SEALEVEL_BS_PHY_L4_NRT_OBSERVATIONS_008_041 and
SEALEVEL_BS_PHY_L4_REP_OBSERVATIONS_008_042 Product Specification
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IV.1.3. Gridded Noise on Sea Level Anomalies
Product Specification
SEALEVEL_GLO_NOISE_L4_NRT_OBSERVATIONS_008_032
SEALEVEL_GLO_NOISE_L4_REP_OBSERVATIONS_008_033
Geographical coverage
global
Variables
lat
lon
noise
lat_bnds
lon_bnds
crs
Near Real time
Yes
Reanalysis
Yes
Available time series
They are time invariant
Temporal resolution
/
Target delivery time
/
Delivery mechanism
CMEMS Information System
Horizontal resolution
2˚x2˚
Number of vertical levels
1
Format
Netcdf CF1.6
SEALEVEL_GLO_NOISE_L3_NRT_OBSERVATIONS_008_032 and
SEALEVEL_GLO_NOISE_L3_REP_OBSERVATIONS_008_033 Product Specification
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V. N OMENCLATURE OF FILES
V.1. Nomenclature of files downloaded through the CMEMS Web Portal
download Service
V.1.1. Nomenclature of the Along Track products
V.1.1.1. Nomenclature of the datasets
The nomenclature used is: dataset-duacs-<delay>-<zone>-<mission>-<variable>-l3-v3 where the fileds in
"<>" are described below:
delay
zone
mission
variable
nrt
rep
global
medsea
blacksea
arctic
europe
e1
e2
tp
tpn
g2
j1
j1n
j1g
j2
j2n
j3
en
enn
c2
al
alg
h2
s3a
phy
phy-assim
phy-unfiltered
near-real time products
delayed time products
global geographic coverage product
Mediterranean products
Black Sea products
Arctic products (only for nrt)
Europe products (only for nrt)
ERS-1 (only for rep)
ERS-2 (only for rep)
TOPEX/Poseidon (only for rep)
TOPEX/Poseidon on its new orbit (only for rep)
GFO (only for rep)
Jason-1 (only for rep)
Jason-1 on its new orbit (only for rep)
Jason-1 on its geodetic orbit (only for rep)
Jason-2 (only for rep)
Jason-2 on its interleaved orbit
Jason-3
Envisat (only for rep)
Envisat on its new orbit (only for rep)
Cryosat-2
Saral/AltiKa
Saral/AltiKa on its geodetic orbit (only for rep)
HY-2A (only for rep)
Sentinel-3A
contains sla and adt (REP and NRT)
contains sla and some corrections (assimilation products, only NRT)
non filtered sla and adt (only REP)
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V.1.1.2. Nomenclature of the NetCdf files
The nomenclature used is:
<delay>_<zone>_<mission>_<variable>_<date>_<dateprod>.<format> where the fileds in "<>" are described below:
delay
nrt
dt
global
med
blacksea
arctic
europe
e1
e2
tp
tpn
g2
j1
j1n
j1g
j2
j2n
j3
en
enn
c2
al
alg
h2
s3a
phy-vfec
phy-vxxc
zone
mission
variable
date
dateprod
format
phy-assim
YYYYMMDD
YYYYMMDD
.nc.gz
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near-real time products
delayed time products
global geographic coverage product
Mediterranean products
Black Sea products
Arctic products (only for nrt)
Europe products (only for nrt)
ERS-1
ERS-2
TOPEX/Poseidon
TOPEX/Poseidon on its new orbit
GFO
Jason-1 (only for rep)
Jason-1 on its new orbit (only for rep)
Jason-1 on its geodetic orbit (only for rep)
Jason-2 (only for rep)
Jason-2 on its new orbit
Jason-3
Envisat (only for rep)
Envisat on its new orbit (only for rep)
Cryosat-2
Saral/AltiKa
Saral/AltiKa on its geodetic orbit (only for rep)
HY-2A (only for rep)
Sentinel-3A
filtered and sub-sampled sla and adt (REP and NRT)
non filtered and non sub-sampled sla and adt (only for
REP)
sla and some corrections (assimilation products, only NRT)
date of the dataset
production date of the dataset
compressed NetCdf CF1.6
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V.1.2. Nomenclature of the Gridded products
V.1.2.1. Nomenclature of the datasets
The nomenclature used is:
dataset-duacs-<delay>-<zone>-merged-allsat-phy-l4-v3
where the fileds in "<>" are described below:
delay
nrt
rep
global
medsea
blacksea
zone
near-real time products
delayed time products
global geographic coverage products
Mediterranean products
Black Sea products
V.1.2.2. Nomenclature of the NetCdf files
The nomenclature used is:
<delay>_<zone>_allsat_phy_l4_<datemap>_<dateprod>.<format> where the fileds in "<>" are described
below:
delay
zone
datemap
dateprod
format
nrt
dt
global
med
blacksea
YYYYMMDD
YYYYMMDD
.nc.gz
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near-real time products
delayed time products
global geographic coverage products
Mediterranean products
Black Sea products
date of the map
production date of the map
compressed NetCdf CF1.6
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V.1.3. Nomenclature of the Gridded noise of Sea Level Anomalies
V.1.3.1. Nomenclature of the datasets
The nomenclature used is:
dataset-duacs-<delay>-<zone>-<mission>-<type of sla>-l4-v4
where the fileds in "<>" are described below:
delay
zone
mission
type of sla
nrt
rep
global
e1
e2
tp
tpn
g2
j1
j1n
j1g
j2
en
enn
c2
al
alg
h2
j3
j2n
s3a
sla
sla_unfiltered
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near-real time products
delayed time products
global geographic coverage product
ERS-1 (only for rep)
ERS-2 (only for rep)
TOPEX/Poseidon (only for rep)
TOPEX/Poseidon on its new orbit (only for rep)
GFO (only for rep)
Jason-1 (only for rep)
Jason-1 on its new orbit (only for rep)
Jason-1 on its geodetic orbit (only for rep)
Jason-2
Envisat (only for rep)
Envisat on its new orbit (only for rep)
Cryosat-2
Saral/AltiKa
Saral/AltiKa on its geodetic orbit (only for rep)
HY-2A
Jason-3
Jason-2 new orbit
Sentinel-3A
filtered sla
non filtered sla (only for rep products)
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V.1.3.2. Nomenclature of the NetCdf files
The nomenclature used is:
<delay>_<zone>_<mission>_sla_noise_<variable>.<format> where the fileds in "<>" are described below:
delay
zone
mission
variable
format
nrt
dt
global
e1
e2
tp
tpn
g2
j1
j1n
j1g
j2
en
enn
c2
al
alg
h2
j3
j2n
s3a
vfec
vxxc
.nc.gz
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near-real time products
delayed time products
global geographic coverage product
ERS-1
ERS-2
TOPEX/Poseidon
TOPEX/Poseidon on its new orbit
GFO
Jason-1
Jason-1 on its new orbit
Jason-1 on its geodetic orbit
Jason-2
Envisat
Envisat on its new orbit
Cryosat-2
Saral/AltiKa
Saral/AltiKa on its geodetic orbit (only for rep)
HY-2A
Jason-3
Jason-2 new orbit
Sentinel-3A
filtered and sub-sampled sla
non filtered and non sub-sampled sla (only for rep)
compressed NetCdf CF1.6
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VI. DATA FORMAT
This chapter presents the data storage format used for CMEMS products.
VI.1. NetCdf
The products are stored using the NetCDF format. NetCDF (network Common Data Form) is an interface
for array-oriented data access and a library that provides an implementation of the interface. The netCDF
library also defines a machine-independent format for representing scientific data. Together, the interface,
library, and format support the creation, access, and sharing of scientific data. The netCDF software was
developed at the Unidata Program Center in Boulder, Colorado. The netCDF libraries define a machineindependent format for representing scientific data. Please see Unidata NetCDF pages for more information,
and to retreive NetCDF software package on:
http://www.unidata.ucar.edu/packages/netcdf/index.html.
NetCDF data is:
• Self-Describing. A netCDF file includes information about the data it contains.
• Architecture-independent. A netCDF file is represented in a form that can be accessed by computers
with different ways of storing integers, characters, and floating-point numbers.
• Direct-access. A small subset of a large dataset may be accessed efficiently, without first reading
through all the preceding data.
• Appendable. Data can be appended to a netCDF dataset along one dimension without copying the
dataset or redefining its structure. The structure of a netCDF dataset can be changed, though this
sometimes causes the dataset to be copied.
• Sharable. One writer and multiple readers may simultaneously access the same netCDF file.
The NetCDF SEA LEVEL TAC files are based on the attribute data tags defined by the Cooperative
Ocean/Atmosphere Research Data Service (COARDS) and Climate and Forecast (CF) metadata conventions. The CF convention generalises and extends the COARDS convention but relaxes the COARDS constraints on dimension and order and specifies methods for reducing the size of datasets.
A wide range of software is available to write or read NetCDF/CF files. API are made available by
UNIDATA (http://www.unidata.ucar.edu/software/netcdf):
• C/C++/Fortran
• Java
• MATLAB, Objective-C, Perl, Python, R, Ruby, Tcl/Tk
In addition to these conventions, the files are using a common structure and semantic as described below
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VI.2. Structure and semantic of NetCDF along-track (L3) files
VI.2.1. Example of classic along-track L3 file
netcdf dt_global_al_phy_vxxc_l3 {
dimensions:
time = 51327 ;
variables:
double time(time) ;
time:axis = "T" ;
time:calendar = "gregorian" ;
time:long_name = "Time of measurement" ;
time:standard_name = "time" ;
time:units = "days since 1950-01-01 00:00:00" ;
int longitude(time) ;
longitude:add_offset = 0. ;
longitude:long_name = "Longitude of measurement" ;
longitude:scale_factor = 1.e-06 ;
longitude:standard_name = "longitude" ;
longitude:units = "degrees_east" ;
int latitude(time) ;
latitude:add_offset = 0. ;
latitude:long_name = "Latitude of measurement" ;
latitude:scale_factor = 1.e-06 ;
latitude:standard_name = "latitude" ;
latitude:units = "degrees_north" ;
short cycle(time) ;
cycle:coordinates = "longitude latitude" ;
cycle:long_name = "Cycle the measurement belongs to" ;
cycle:units = "1" ;
short track(time) ;
track:coordinates = "longitude latitude" ;
track:long_name = "Track in cycle the measurement belongs to" ;
track:units = "1" ;
short sla_unfiltered(time) ;
sla_unfiltered:_FillValue = 32767s ;
sla_unfiltered:add_offset = 0. ;
sla_unfiltered:coordinates = "longitude latitude" ;
sla_unfiltered:long_name = "Sea level anomaly not-filtered not-subsampled" ;
sla_unfiltered:scale_factor = 0.001 ;
sla_unfiltered:standard_name = "sea_surface_height_above_sea_level" ;
sla_unfiltered:units = "m" ;
sla_unfiltered:comment = "The sea level anomaly is the sea surface height above mean
sea surface; it is referenced to the [1993, 2012] period; see the product user
manual for details" ;
short adt_unfiltered(time) ;
adt_unfiltered:_FillValue = 32767s ;
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adt_unfiltered:add_offset = 0. ;
adt_unfiltered:coordinates = "longitude latitude" ;
adt_unfiltered:long_name = "Absolute dynamic topography not-filtered not-subsampled" ;
adt_unfiltered:scale_factor = 0.001 ;
adt_unfiltered:standard_name = "sea_surface_height_above_geoid" ;
adt_unfiltered:units = "m" ;
adt_unfiltered:comment = "The absolute dynamic topography is the sea surface height
above geoid; the adt is obtained as follows: adt=sla=mdt where mdt
is the mean dynamic topography; see the product user manual for details" ;
// global attributes:
:Conventions = "CF-1.6" ;
:Metadata_Conventions = "Unidata Dataset Discovery v1.0" ;
:cdm_data_type = "Swath" ;
:comment = "Sea Surface Height measured by altimeters referenced to the [1993, 2012]
period" ;
:contact = "servicedesk.cmems@mercator-ocean.eu" ;
:creator_email = "servicedesk.cmems@mercator-ocean.eu" ;
:creator_name = "CMEMS - Sea Level Thematic Assembly Center" ;
:creator_url = "http://marine.copernicus.eu" ;
:date_created = "2016-11-14T14:08:44Z" ;
:date_issued = "2016-11-14T14:08:44Z" ;
:date_modified = "2016-11-14T14:08:44Z" ;
:geospatial_lat_max = 66.143568 ;
:geospatial_lat_min = -66.146391 ;
:geospatial_lat_resolution = 0.00395950000000056 ;
:geospatial_lat_units = "degrees_north" ;
:geospatial_lon_max = 359.998892 ;
:geospatial_lon_min = 0.004494 ;
:geospatial_lon_resolution = 0.0312305000000208 ;
:geospatial_lon_units = "degrees_east" ;
:geospatial_vertical_max = 0. ;
:geospatial_vertical_min = 0. ;
:geospatial_vertical_positive = "down" ;
:geospatial_vertical_resolution = "point" ;
:geospatial_vertical_units = "m" ;
:history = "2016-11-14T14:08:44Z: Created by DUACS DT V2.0.3" ;
:institution = "CLS, CNES" ;
:keywords = "Oceans > Ocean Topography > Sea Surface Height" ;
:keywords_vocabulary = "NetCDF COARDS Climate and Forecast Standard Names" ;
:license = "http://marine.copernicus.eu/web/27-service-commitments-and-licence.php" ;
:platform = "AltiKa" ;
:processing_level = "L3" ;
:product_version = "5.7" ;
:project = "COPERNICUS MARINE ENVIRONMENT MONITORING SERVICE
(CMEMS)" ;
:references = "http://marine.copernicus.eu" ;
:source = "AltiKa measurements" ;
:ssalto_duacs_comment = "The reference mission used for the altimeter inter-calibration
processing is Topex/Poseidon between 1993-01-01 and 2002-04-23,
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Jason-1 between 2002-04-24 and 2008-10-18, OSTM/Jason-2 since 2008-10-19." ;
:standard_name_vocabulary = "NetCDF Climate and Forecast (CF) Metadata Convention
Standard Name Table v37" ;
:summary = "SSALTO/DUACS Delayed-Time Level-3 sea surface height measured by
AltiKa altimetry observations over Global Ocean." ;
:time_coverage_duration = "P24H15M37.646370S" ;
:time_coverage_end = "2016-05-05T23:29:24Z" ;
:time_coverage_resolution = "P1S" ;
:time_coverage_start = "2016-05-04T23:13:46Z" ;
:title = "DT AltiKa Global Ocean Along track SSALTO/DUACS Sea Surface Height L3
product" ;
}
VI.2.2. Example of along-track L3 file dedicated to assimilation
netcdf nrt_med_al_phy_assim_l3 {
dimensions:
time = 382 ;
variables:
double time(time) ;
time:axis = "T" ;
time:calendar = "gregorian" ;
time:long_name = "Time of measurement" ;
time:standard_name = "time" ;
time:units = "days since 1950-01-01 00:00:00" ;
int longitude(time) ;
longitude:add_offset = 0. ;
longitude:long_name = "Longitude of measurement" ;
longitude:scale_factor = 1.e-06 ;
longitude:standard_name = "longitude" ;
longitude:units = "degrees_east" ;
int latitude(time) ;
latitude:add_offset = 0. ;
latitude:long_name = "Latitude of measurement" ;
latitude:scale_factor = 1.e-06 ;
latitude:standard_name = "latitude" ;
latitude:units = "degrees_north" ;
short cycle(time) ;
cycle:coordinates = "longitude latitude" ;
cycle:long_name = "Cycle the measurement belongs to" ;
cycle:units = "1" ;
short track(time) ;
track:coordinates = "longitude latitude" ;
track:long_name = "Track in cycle the measurement belongs to" ;
track:units = "1" ;
short dac(time) ;
dac:_FillValue = 32767s ;
dac:add_offset = 0. ;
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dac:coordinates = "longitude latitude" ;
dac:long_name = "Dynamic atmospheric correction" ;
dac:scale_factor = 0.0001 ;
dac:units = "m" ;
dac:comment = "The sla in this file is already corrected for the dac; the uncorrected sla
can be computed as follows: [uncorrected sla] = [sla from product] + [dac];
see the product user manuel for details" ;
int ocean_tide(time) ;
ocean_tide:_FillValue = 2147483647 ;
ocean_tide:add_offset = 0. ;
ocean_tide:coordinates = "longitude latitude" ;
ocean_tide:long_name = "Ocean tide model" ;
ocean_tide:scale_factor = 0.0001 ;
ocean_tide:units = "m" ;
ocean_tide:comment = "The sla in this file is already corrected for the ocean_tide; the
uncorrected sla can be computed as follows:
[uncorrected sla] = [sla from product] + [ocean_tide];
see the product user manuel for details" ;
short lwe(time) ;
lwe:_FillValue = 32767s ;
lwe:add_offset = 0. ;
lwe:coordinates = "longitude latitude" ;
lwe:long_name = "Long wavelength error" ;
lwe:scale_factor = 0.001 ;
lwe:units = "m" ;
lwe:comment = "The sla in this file is already corrected for the lwe; the uncorrected sla can
be computed as follows: [uncorrected sla] = [sla from product] - [lwe];
see the product user manuel for details" ;
short flag(time) ;
flag:_FillValue = 32767s ;
flag:comment = "The origin of the data is determined by the types of geophysical data record
(GDR) used in computation of the SLA: 1 for the Interim GDR (IGDR) or Short Time
Critical (STC) and 0 for Operational GDR (OGDR) or Near Real Time (NRT)." ;
flag:coordinates = "longitude latitude" ;
flag:long_name = "data origin" ;
flag:meaning = "OGDR_or_NRT, IGDR_or_STC" ;
flag:units = "1" ;
flag:values = 0s, 1s ;
short sla_unfiltered(time) ;
sla_unfiltered:_FillValue = 32767s ;
sla_unfiltered:add_offset = 0. ;
sla_unfiltered:coordinates = "longitude latitude" ;
sla_unfiltered:long_name = "Sea level anomaly not-filtered not-subsampled with dac,
ocean_tide and lwe correction applied " ;
sla_unfiltered:scale_factor = 0.001 ;
sla_unfiltered:units = "m" ;
sla_unfiltered:comment = "The sea level anomaly is the sea surface height above mean sea
surface; the uncorrected sla can be computed as follows:
[uncorrected sla] = [sla from product]+[dac]+[ocean_tide]-[lwe];
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see the product user manuel for details" ;
sla_unfiltered:standard_name = "sea_surface_height_above_sea_level" ;
short sla_filtered(time) ;
sla_filtered:_FillValue = 32767s ;
sla_filtered:add_offset = 0. ;
sla_filtered:coordinates = "longitude latitude" ;
sla_filtered:long_name = "Sea level anomaly filtered not-subsampled with dac, ocean_tide
and lwe correction applied" ;
sla_filtered:scale_factor = 0.001 ;
sla_filtered:units = "m" ;
sla_filtered:comment = "The sea level anomaly is the sea surface height above mean sea
surface; the uncorrected sla can be computed as follows:
[uncorrected sla] = [sla from product]+[dac]+[ocean_tide]-[lwe];
see the product user manuel for details" ;
sla_filtered:standard_name = "sea_surface_height_above_sea_level " ;
short mdt(time) ;
mdt:_FillValue = 32767s ;
mdt:add_offset = 0. ;
mdt:coordinates = "longitude latitude" ;
mdt:long_name = "Mean dynamic topography" ;
mdt:scale_factor = 0.001 ;
mdt:units = "m" ;
mdt:comment = "The mean dynamic topography is the sea surface height above geoid; it is
used to compute the absolute dynamic tyopography adt=sla+mdt" ;
// global attributes:
:Conventions = "CF-1.6" ;
:Metadata_Conventions = "Unidata Dataset Discovery v1.0" ;
:cdm_data_type = "Swath" ;
:comment = "Sea surface height measured by altimeters referenced to the [1993, 2012]
period; with additional corrections; the proposed sla is already corrected for dac,
ocean_tide and lwe;
[uncorrected sla] = [sla from product]+[dac]+[ocean_tide]-[lwe]" ;
:contact = "servicedesk.cmems@mercator-ocean.eu" ;
:creator_email = "servicedesk.cmems@mercator-ocean.eu" ;
:creator_name = "CMEMS - Sea Level Thematic Assembly Center" ;
:creator_url = "http://marine.copernicus.eu" ;
:date_created = "2016-11-20T23:50:50Z" ;
:date_issued = "2016-11-20T23:50:50Z" ;
:date_modified = "2016-11-20T23:50:50Z" ;
:geospatial_lat_max = 42.976056 ;
:geospatial_lat_min = 31.678771 ;
:geospatial_lat_resolution = 0.0481970000000018 ;
:geospatial_lat_units = "degrees_north" ;
:geospatial_lon_max = 29.194464 ;
:geospatial_lon_min = 1.110606 ;
:geospatial_lon_resolution = 0.0319119999999984 ;
:geospatial_lon_units = "degrees_east" ;
:geospatial_vertical_max = 0. ;
:geospatial_vertical_min = 0. ;
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:geospatial_vertical_positive = "down" ;
:geospatial_vertical_resolution = "point" ;
:geospatial_vertical_units = "m" ;
:history = "2016-11-20T23:50:50Z: Created by DUACS NRT V2.1.0" ;
:institution = "CLS, CNES" ;
:keywords = "Oceans > Ocean Topography > Sea Surface Height" ;
:keywords_vocabulary = "NetCDF COARDS Climate and Forecast Standard Names" ;
:license = "http://marine.copernicus.eu/web/27-service-commitments-and-licence.php" ;
:platform = "Altika Drifting Phase" ;
:processing_level = "L3" ;
:product_version = "17.0" ;
:project = "COPERNICUS MARINE ENVIRONMENT MONITORING SERVICE
(CMEMS)" ;
:references = "http://marine.copernicus.eu" ;
:source = "Altika Drifting Phase measurements" ;
:ssalto_duacs_comment = "Jason-3 is the reference mission used for the altimeter
inter-calibration processing" ;
:standard_name_vocabulary = "NetCDF Climate and Forecast (CF) Metadata Convention
Standard Name Table v37" ;
:summary = "SSALTO/DUACS Near-Real-Time Level-3 sea surface height measured by
Altika Drifting Phase altimetry observations over Mediterranean Sea." ;
:time_coverage_duration = "P9H56M23.20437S" ;
:time_coverage_end = "2016-11-16T19:04:32Z" ;
:time_coverage_resolution = "P1S" ;
:time_coverage_start = "2016-11-16T09:08:09Z" ;
:title = "NRT Altika Drifting Phase Mediterranean Sea Along track SSALTO/DUACS Sea
Surface Height L3 product" ;
}
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VI.3. Structure and semantic of NetCDF maps (L4) files
VI.3.1. Example of classic gridded L4 file
netcdf nrt_global_allsat_phy_l4 {
dimensions:
time = 1 ;
latitude = 720 ;
longitude = 1440 ;
nv = 2 ;
variables:
int crs ;
crs:comment = "This is a container variable that describes the grid_mapping used by the
data in this file. This variable does not contain any data; only information
about the geographic coordinate system." ;
crs:grid_mapping_name = "latitude_longitude" ;
crs:inverse_flattening = 298.257 ;
crs:semi_major_axis = 6378136.3 ;
float time(time) ;
time:axis = "T" ;
time:calendar = "gregorian" ;
time:long_name = "Time" ;
time:standard_name = "time" ;
time:units = "days since 1950-01-01 00:00:00" ;
float latitude(latitude) ;
latitude:axis = "Y" ;
latitude:bounds = "lat_bnds" ;
latitude:long_name = "Latitude" ;
latitude:standard_name = "latitude" ;
latitude:units = "degrees_north" ;
latitude:valid_max = 89.875 ;
latitude:valid_min = -89.875 ;
float lat_bnds(latitude, nv) ;
lat_bnds:comment = "latitude values at the north and south bounds of each pixel." ;
lat_bnds:units = "degrees_north" ;
float longitude(longitude) ;
longitude:axis = "X" ;
longitude:bounds = "lon_bnds" ;
longitude:long_name = "Longitude" ;
longitude:standard_name = "longitude" ;
longitude:units = "degrees_east" ;
longitude:valid_max = 359.875 ;
longitude:valid_min = 0.125 ;
float lon_bnds(longitude, nv) ;
lon_bnds:comment = "longitude values at the west and east bounds of each pixel." ;
lon_bnds:units = "degrees_east" ;
int nv(nv) ;
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nv:comment = "Vertex" ;
nv:units = "1" ;
int sla(time, latitude, longitude) ;
sla:_FillValue = -2147483647 ;
sla:coordinates = "lon lat" ;
sla:grid_mapping = "crs" ;
sla:long_name = "Sea level anomaly" ;
sla:scale_factor = 0.0001 ;
sla:standard_name = "sea_surface_height_above_sea_level" ;
sla:units = "m" ;
sla:comment = "The sea level anomaly is the sea surface height above mean sea surface;
it is referenced to the [1993, 2012] period; see the product user manual for details" ;
int err(time, latitude, longitude) ;
err:_FillValue = -2147483647 ;
err:comment = "The formal mapping error represents a purely theoretical mapping error.
It mainly traduces errors induced by the constellation sampling capability and
consistency with the spatial/temporal scales considered, as described in
Le Traon et al (1998) or Ducet et al (2000)" ;
err:coordinates = "lon lat" ;
err:grid_mapping = "crs" ;
err:long_name = "Formal mapping error" ;
err:scale_factor = 0.0001 ;
err:units = "m" ;
int ugosa(time, latitude, longitude) ;
ugosa:_FillValue = -2147483647 ;
ugosa:coordinates = "lon lat" ;
ugosa:grid_mapping = "crs" ;
ugosa:long_name = "Geostrophic velocity anomalies: zonal component" ;
ugosa:scale_factor = 0.0001 ;
ugosa:standard_name =
"surface_geostrophic_eastward_sea_water_velocity_assuming_sea_level_for_geoid" ;
ugosa:units = "m/s" ;
ugosa:comment = "The geostrophic velocity anomalies are referenced to the [1993, 2012]
period" ;
int vgosa(time, latitude, longitude) ;
vgosa:_FillValue = -2147483647 ;
vgosa:coordinates = "lon lat" ;
vgosa:grid_mapping = "crs" ;
vgosa:long_name = "Geostrophic velocity anomalies: meridian component" ;
vgosa:scale_factor = 0.0001 ;
vgosa:standard_name =
"surface_geostrophic_northward_sea_water_velocity_assuming_sea_level_for_geoid" ;
vgosa:units = "m/s" ;
vgosa:comment = "The geostrophic velocity anomalies are referenced to the [1993, 2012]
period" ;
int adt(time, latitude, longitude) ;
adt:_FillValue = -2147483647 ;
adt:coordinates = "lon lat" ;
adt:grid_mapping = "crs" ;
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adt:long_name = "Absolute dynamic topography" ;
adt:scale_factor = 0.0001 ;
adt:standard_name = "sea_surface_height_above_geoid" ;
adt:units = "m" ;
adt:comment = "The absolute dynamic topography is the sea surface height above geoid;
the adt is obtained as follows: adt=sla=mdt where mdt is the mean dynamic
topography; see the product user manual for details" ;
int ugos(time, latitude, longitude) ;
ugos:_FillValue = -2147483647 ;
ugos:coordinates = "lon lat" ;
ugos:grid_mapping = "crs" ;
ugos:long_name = "Absolute geostrophic velocity: zonal component" ;
ugos:scale_factor = 0.0001 ;
ugos:standard_name = "surface_geostrophic_eastward_sea_water_velocity" ;
ugos:units = "m/s" ;
int vgos(time, latitude, longitude) ;
vgos:_FillValue = -2147483647 ;
vgos:coordinates = "lon lat" ;
vgos:grid_mapping = "crs" ;
vgos:long_name = "Absolute geostrophic velocity: meridian component" ;
vgos:scale_factor = 0.0001 ;
vgos:standard_name = "surface_geostrophic_northward_sea_water_velocity" ;
vgos:units = "m/s" ;
// global attributes:
:Conventions = "CF-1.6" ;
:Metadata_Conventions = "Unidata Dataset Discovery v1.0" ;
:cdm_data_type = "Grid" ;
:comment = "Sea Surface Height measured by Altimetry and derivated variables" ;
:contact = "servicedesk.cmems@mercator-ocean.eu" ;
:creator_email = "servicedesk.cmems@mercator-ocean.eu" ;
:creator_name = "CMEMS - Sea Level Thematic Assembly Center" ;
:creator_url = "http://marine.copernicus.eu" ;
:date_created = "2016-11-20T23:45:46Z" ;
:date_issued = "2016-11-20T23:45:46Z" ;
:date_modified = "2016-11-20T23:45:46Z" ;
:geospatial_lat_max = 89.875 ;
:geospatial_lat_min = -89.875 ;
:geospatial_lat_resolution = 0.25 ;
:geospatial_lat_units = "degrees_north" ;
:geospatial_lon_max = 359.875 ;
:geospatial_lon_min = 0.125 ;
:geospatial_lon_resolution = 0.25 ;
:geospatial_lon_units = "degrees_east" ;
:geospatial_vertical_max = 0. ;
:geospatial_vertical_min = 0. ;
:geospatial_vertical_positive = "down" ;
:geospatial_vertical_resolution = "point" ;
:geospatial_vertical_units = "m" ;
:history = "2016-11-20 23:45:46Z: Created by DUACS NRT V2.1.0" ;
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:institution = "CLS, CNES" ;
:keywords = "Oceans > Ocean Topography > Sea Surface Height" ;
:keywords_vocabulary = "NetCDF COARDS Climate and Forecast Standard Names" ;
:license = "http://marine.copernicus.eu/web/27-service-commitments-and-licence.php" ;
:platform = "Altika OSTM/Jason-2 interleaved Cryosat-2 Jason-3" ;
:processing_level = "L4" ;
:product_version = "17.0" ;
:project = "COPERNICUS MARINE ENVIRONMENT MONITORING SERVICE
(CMEMS)" ;
:references = "http://marine.copernicus.eu" ;
:source = "Altimetry measurements" ;
:ssalto_duacs_comment = "Jason-3 is the reference mission used for the altimeter
inter-calibration processing" ;
:standard_name_vocabulary = "NetCDF Climate and Forecast (CF) Metadata Convention
Standard Name Table v37" ;
:summary = "SSALTO/DUACS Near-Real-Time Level-4 sea surface height and derivated
variables measured by multi-satellite altimetry observations over Global Ocean." ;
:time_coverage_duration = "P1D" ;
:time_coverage_end = "2016-11-21T00:00:00Z" ;
:time_coverage_resolution = "P1D" ;
:time_coverage_start = "2016-11-21T00:00:00Z" ;
:title = "NRT merged all satellites Global Ocean Gridded SSALTO/DUACS Sea Surface
Height L4 product and derivated variables" ;
}
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VI.4. Structure and semantic of NetCDF Gridded Noise on Sea Level
Anomaly files
Example of a NetCDF noise sla file:
netcdf dt_global_al_sla_noise_vfec {
dimensions:
lat = 89 ;
lon = 180 ;
nv = 2 ;
variables:
float lat(lat) ;
lat:long_name = "Latitude" ;
lat:standard_name = "latitude" ;
lat:units = "degrees_north" ;
lat:bounds = "lat_bnds" ;
lat:axis = "Y" ;
lat:valid_min = -90. ;
lat:valid_max = 90. ;
float lat_bnds(lat, nv) ;
float lon(lon) ;
lon:long_name = "Longitude" ;
lon:standard_name = "longitude" ;
lon:units = "degrees_east" ;
lon:bounds = "lon_bnds" ;
lon:axis = "X" ;
lon:valid_min = 0. ;
lon:valid_max = 360. ;
float lon_bnds(lon, nv) ;
int crs ;
crs:grid_mapping_name = "latitude_longitude" ;
crs:semi_major_axis = 6371000. ;
crs:inverse_flattening = 0 ;
int noise(lat, lon) ;
noise:_FillValue = -2147483647 ;
noise:long_name = "Sea Level Anomalies measurement noise" ;
noise:standard_name = "sea_surface_height_above_sea_level" ;
noise:units = "m" ;
noise:scale_factor = 0.0001 ;
// global attributes:
:history = "2013-12-17 16:15:38:creation" ;
:comment = "Surface product;" ;
:institution = "CLS/CNES";
:Conventions = "CF-1.6" ;
:cdm_data_type = "Grid" ;
:geospatial_lat_min = -90. ;
:geospatial_lat_max = 88. ;
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:geospatial_lon_min = -1. ;
:geospatial_lon_max = 359. ;
:geospatial_vertical_min = "0.0" ;
:geospatial_vertical_max = "0.0" ;
:geospatial_lat_units = "degrees_north" ;
:geospatial_lon_units = "degrees_east" ;
:geospatial_lat_resolution = 2. ;
:geospatial_lon_resolution = 2. ;
:title = "SSALTO/Duacs Altimetric Level4 product: SARAL/AltiKa sea level anomalies
measurement noise on global area" ;
:summary = "This dataset contains the measurement noise for filtered SARAL/AltiKa
1-Hz measurements." ;
:product_version = "5.0" ;
:project = "CNES SSALTO/DUACS" ;
:references = "http://www.aviso.altimetry.fr" ;
:contact = "aviso@altimetry.fr" ;
:license = "http://www.aviso.altimetry.fr/fileadmin/documents/data/License_Aviso.pdf" ;
:date_created = "2013-12-17 16:15:38" ;
:standard_name_vocabulary =
"http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/12/cf-standard-n
}
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VII. H OW TO DOWNLOAD A PRODUCT
VII.1. Download a product through the CMEMS Web Portal Directgetfile
Service
You first need to register. Please find below the registration steps:
http://marine.copernicus.eu/web/56-user-registration-form.php
Once registered, the CMEMS FAQ
http://marine.copernicus.eu/web/34-products-and-services-faq.php#2 will guide
you on How to download a product through the CMEMS Web Portal Directgetfile Service.
VII.2. Download a product through the CMEMS Web Portal Ftp Service
You first need to register. Please find below the registration steps:
http://marine.copernicus.eu/web/56-user-registration-form.php
Once registered, the CMEMS FAQ
http://marine.copernicus.eu/web/34-products-and-services-faq.php#2 will guide
you on How to download a product through the CMEMS Web Portal FTP Service.
VII.3. Download a product through the CMEMS Web Portal Subsetter Service
You first need to register. Please find below the registration steps:
http://marine.copernicus.eu/web/56-user-registration-form.php
Once registered, the CMEMS FAQ
http://marine.copernicus.eu/web/34-products-and-services-faq.php#2 will guide
you on How to download a product through the CMEMS Web Portal Subsetter Service.
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R EFERENCES
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[2] Andersen, O. B., Knudsen P., Stenseng L., "The DTU13 MSS and MDT from 20 years of satellite
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documents/OSTST/2011/oral/01_Wednesday/Splinter%201%20IP/06%20%
20Boy%20CPP%20Presentation.pdf
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OSTST2015
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tx_ausyclsseminar/files/29Red1100-2_ppt_OSTST2014_FES2014_LC.pdf
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27,(3-4), 345-372
[19] Dorandeu, J., M. Ablain, P.-Y. Le Traon, 2003: Reducing Cross-Track Geoid Gradient Errors around
TOPEX/Poseidon and Jason-1 Nominal Tracks: Application to Calculation of Sea Level Anomalies.
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mean sea level changes from TOPEX/Poseidon. J. Atmos. Oceanic Technol., 16, 1279-1283.
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Reducing altimetry small-scale errors to access (sub)mesoscale dynamics, OSTST 2013
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Dufau_PresentationError_FINAL.pdf
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altimètres TOPEX et POSEIDON. Technical note 96/018 of CNES Contract 95/1523, 1996.
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altimetric data (OPR version 6). Report of task 2 of IFREMER Contract n˚ 96/2.246 002/C, 1996.
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radar altimeter measurements of seal level, J. Atmos. Oceanic Technology, 19, 1690-1707.
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Current using TOPEX/POSEIDON and ERS-1 altimetry, together with hydrographic and Lagrangian
measurements. Journal of Geophysical Research, 100, 24995-25006.
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[30] Guibbaud, M., A. Ollivier and M. Ablain, A new approach for dual-frequency ionospheric correction
filtering, ENVISAT Altimetry Quality Working Group (QWG), 2015 available in the Section 8.5 of
the 2012 Envisat annual activity report: http://www.aviso.altimetry.fr/fileadmin/
documents/calval/validation_report/EN/annual_report_en_2012.pdf
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CLS/DOS/NT/00.313, 40 pp. CLS Ramonville St Agne.
[33] Iijima, B.A., I.L. Harris, C.M. Ho, U.J. Lindqwiste, A.J. Mannucci, X. Pi, M.J. Reyes, L.C. Sparks,
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Task 2 - SSB estimation for RA2 altimeter. Contract 17293/03/I-OL. CLS-DOS-NT-07-198, 53pp.
CLS Ramonville St. Agne
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newsstand/Newsletter/aviso_users_news09.pdf
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with support from Cnes (http://www.aviso.altimetry.fr/)".
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of the altimeter performances unsing NSOAS S-IGDR data, OSTST 2013 in Boulder,
http://www.aviso.altimetry.fr/fileadmin/documents/OSTST/2013/oral/
Picot_OSTST_HY2_inside_Duacs.pdf
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Ocean from satellite altimetry. Submitted to Marine Geodesy.
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20-year reference period for SSALTO/DUACS products, OSTST, 2013 http://www.aviso.
altimetry.fr/fileadmin/documents/OSTST/2013/oral/pujol_ChgtRef.pdf
[57] Pujol, M.-I., Faugère, Y., Taburet, G., Dupuy, S., Pelloquin, C., Ablain, M., and Picot, N., 2016:
DUACS DT2014: the new multi-mission altimeter data set reprocessed over 20 years, Ocean Sci.,12,
1067-1090, doi:10.5194/os-12-1067-2016 . http://www.ocean-sci.net/12/1067/2016/
[58] Ray, R., 1999: A Global Ocean Tide model from TOPEX/Poseidon Altimetry, GOT99.2. NASA Tech.
Memo. NASA/TM-1999-209478, 58 pp. Goddard Space Flight Center, NASA Greenbelt, MD, USA.
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ocean from altimetry, in-situ measurements and a geoid model. J. Geophys. Res., 109, C12032,
doi:10.1029/2003JC002226.
[60] Rio, M.-H. and F. Hernandez, 2003: High frequency response of wind-driven currents measured by
drifting buoys and altimetry over the world ocean. J. Geophys. Res., 108, 39-1.
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c EU Copernicus Marine Service - Public
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