- Created by Unknown User (rricker), last modified by Stefan Hendricks on Nov 03, 2021
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Main Improvements and changes in v204
- We updated the CS2SMOS processing to the latest input data versions (SMOS: L1C 724, CryoSat-2: ICE L1B baseline-D until April 2021 and ICE L1B baseline-E from October 2021 and later)
- We adapted the CS2SMOS processing to changes due to the update to CryoSat-2 sea ice thickness product version v2.4 (updated auxiliary data and change of sea ice concentration mask from 70% to 15%)
Main Improvements and changes in v203
- We adapted the CS2SMOS processing to changes due to the update to CryoSat-2 sea ice thickness product version v2.3.
Main Improvements and changes in v202
- The time coverage resolution has been changed from 7 days to 1 day, meaning that the weekly averaged product is updated every day from now on.
- We adapted the CS2SMOS processing to changes due to the update to CryoSat-2 sea ice thickness product version v2.2.
- We adapted the CS2SMOS processing to changes due to the update to SMOS sea ice thickness product version v3.2, which is now processed and provided by AWI.
- An ocean mask is applied to allow for a consistent land/ocean mask throughout the entire data record in order to overcome inconsistencies due to switches of the land masks in the OSI SAF ice concentration products.
- We now use different sea ice concentration products for the operational mode and for the reprocessing mode. In the operational mode, we use the operational OSI-401 ice concentration product, while in the reprocessing mode, the reprocessed OSI -430-b ice concentration product is used. Both are provided by OSI SAF.
- Changes in the NetCDF variable names, fulfilling CF 1.6 conventions.
Version | Date | Comments |
---|---|---|
v204 | 19.10.2021 | Update to version 204 (system evolution) |
v203 | 07.10.2020 | Update to version 203 (system evolution) |
v202 | 01.10.2019 | Update to version 202 (system and algorithm evolution) |
v201 | 10.01.2019 | Official ESA release |
Product Description Overview
Parameter | Sea ice thickness |
Spatial covergae | N: 90°, S:16.6°, E:180°, W:-180° |
Spatial Resolution | 25 km x 25 km |
Temporal coverage of the data record: | November 2010 to present |
Time coverage resolution | 1 day |
Time coverage duration | 7 days |
Data Format(s) | NetCDF |
Platforms | CryoSat-2, SMOS |
Version | v202 |
File naming convention
NetCDF files are named using the following convention:
<convention-prefix>_<regional code>- <institution>,<platform(s)>,<grid>_<time>_<mode>_<product version>_<file version>.nc
convention-prefix | World Meteorological Organization: W |
regional code | European: XX |
institution | European Space Agency: ESA |
processing level/parameter | level 4 sea ice thickness: l4sit |
Platform(s) | satellites: SMOS, CS2 |
grid | 25 km EASE2 grid, Northern Hemisphere: NH_25KM_EASE2 |
time | time span: yyyymmdd - yyyymmdd |
mode | reprocessing: r, operational: o |
product version | version 2.0.2: v202 |
file version | version 1: 01 |
Example NetCDF naming for operationally processed data:
W_XX-ESA,SMOS_CS2,NH_25KM_EASE2_20190304_20190310_o_v202_01_l4sit.nc
Example NetCDF naming for reprocessed data:
W_XX-ESA,SMOS_CS2,NH_25KM_EASE2_20190304_20190310_r_v202_01_l4sit.nc
File Format
The weekly grids are given in standardized binary data format (Network common data form: NetCDF v4). Global attributes are given in Table 1. The variables are given as grid arrays, see Table 2. NetCDF files are formatted according to CF conventions: CF-1.6 ACDD-1.3. We use a scaling factor of 10^-3 and a fillvalue = -2147483647.
Table 1: Global attributes from an example NetCDF file, covering the week from March 04 to March 10, 2019.
Attribute | Value |
---|---|
title | Sea Ice Thickness derived from merging CryoSat-2 and SMOS ice thickness |
description | Weekly Arctic sea-ice thickness derived from CryoSat-2 and SMOS using an optimal interpolation scheme |
summary | Weekly Arctic sea-ice thickness derived from CryoSat-2 and SMOS using an optimal interpolation scheme |
keywords | Cryosphere > Sea Ice > Sea Ice Thickness |
product_version | 202 |
processing_mode | r |
time_of_creation | Fri Oct 11 09:04:06 2019 |
history | Fri Oct 11 09:04:06 2019 creation |
Conventions | CF-1.6 |
spatial_resolution | 25.0 km grid spacing |
geospatial_lat_min | 16.623929977416992 |
geospatial_lat_max | 90.0 |
geospatial_lon_min | -180.0 |
geospatial_lon_max | 180.0 |
geospatial_vertical_min | 0.0 |
geospatial_vertical_max | 0.0 |
time_coverage_start | 2019-03-04T00:00:00Z |
time_coverage_end | 2019-03-11T00:00:00Z |
time_coverage_duration | P7D |
time_coverage_resolution | P1D |
platform | CryoSat-2, SMOS |
project | CS2SMOS PDS: SMOS & CryoSat-2 Sea Ice Data Product Processing and Dissemination Service |
institution | Alfred-Wegener-Institut Helmholtz Zentrum für Polar und Meeresforschung (AWI), http://www.awi.de |
creator_name | Alfred-Wegener-Institut Helmholtz Zentrum für Polar und Meeresforschung (AWI), http://www.awi.de |
creator_type | institution |
creator_url | |
publisher_email | |
references | Ricker, R., Hendricks, S., Kaleschke, L., Tian-Kunze, X., King, J., and Haas, C.: A weekly Arctic sea-ice thickness data record from merged CryoSat-2 and SMOS satellite data, The Cryosphere, 11, 1607-1623, https://doi.org/10.5194/tc-11-1607-2017, 2017. |
_CoordSysBuilder | ucar.nc2.dataset.conv.CF1Convention |
Table 2: NetCDF file content. Note, that we use a scaling factor of 10^-3 and a fillvalue = -2147483647.
Variable | Description | Unit | Type | Dimension |
---|---|---|---|---|
Lambert_Azimuthal_Grid | proj4_string: +proj=laea +lon_0=0 +datum=WGS84 +ellps=WGS84 +lat_0=90.0 | - | int | - |
time_bnds | start and end time of the weekly retrieval | seconds since 1978-01-01 00:00:00 | double | 2 |
analysis_sea_ice_thickness | CS2SMOS weekly merged sea ice thickness | m | int | 1,432,432 |
background_sea_ice_thickness | background field, interpolation using CS2 and SMOS sea ice thickness data | m | int | 1,432,432 |
weighted_mean_sea_ice_thickness | weighted mean of weekly CS2 and SMOS ice thickness retrievals | m | int | 1,432,432 |
innovation | difference between background and analysis ice thickness | m | int | 1,432,432 |
sea_ice_concentration | sea ice concentration | % | int | 1,432,432 |
sea_ice_type | sea ice type | - | int | 1,432,432 |
correlation_length_scale | correlation length scale of background ice thickness | m | int | 1,432,432 |
analysis_sea_ice_thickness_unc | uncertainty of the merged sea ice thickness | m | int | 1,432,432 |
smos_sea_ice_thickness | weekly averaged SMOS ice thickness | m | int | 1,432,432 |
cryosat_sea_ice_thickness | weekly averaged CryoSat-2 ice thickness | m | int | 1,432,432 |
time | reference time of product (middle of the week) | seconds since 1978-01-01 00:00:00 | double | 1 |
xc | x coordinate of projection (eastings) | km | float | 432 |
yc | y coordinate of projection (northings) | km | float | 432 |
lon | longitude coordinate | degrees_north | float | 432,432 |
lat | latitude coordinate | degrees_east | float | 432,432 |
Grid
All grids are projected onto the 25 km EASE2 Grid, which is based on a polar aspect spherical Lambert azimuthal equal-area projection (Brodzik et al., 2012). The grid dimension is 5400 km x 5400 km, equal to a 432 x 432 grid. The grid is centered on the geographic Pole, meaning that the Pole is located at the intersection of center cells (Figure 1).
Figure1: Specifications of the EASE2 25 km grid, which is used for the merged product.
Links
ESA Websites:
Visualization of NetCDF data:
Points of Contacts
Responsible Scientists
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