• Transition of L1C data from v620 to v724: In v3.3, v724 L1C data is used instead of v620 L1C.
  • Polar stereographic projection update: Following NSIDC we consider the EPSG 3411 and 3412 as deprecated and replaced this with 3413 and 3976 in v3.3 (https://nsidc.org/data/polar-stereo/ps_grids.html).
  • NetCDF format update: Furthermore, the output of L3 data in updated to NetCDF v4.



Version

Date

Comments

v3.2

15.10.2018

Official ESA release

v3.303.11.2021Official ESA release



Product Description

Overview

Table 1: Overview of SMOS Product

Parameter

Sea ice thickness

Spatial covergae

Northern hemisphere, poleward of 50°N, -180°E to 180°E

Spatial Resolution

12.5 km x12.5 km

Temporal Coverage:

since 15. Oct. 2010

Temporal Resolution

1 day

Data Format(s)

NetCDF v4

Platforms

SMOS

Version

v3.3

File name

NetCDF files are named as:

SMOS_Icethickness_v3.3_north_<date>.nc

File Format

Daily mean SMOS sea ice thickness is given in NetCDF v4 format. Global attributes are given in Table 2. The variables are given as grid arrays as listed in Table 3.

Table 2: Global attributes from an example NetCDF file.

Attribute

Value

title

Daily gridded sea-ice thickness and auxiliary parameters from satellite L-band radiometry data

project

CS2SMOS PDS CR-1: SMOS Sea Ice Data Product Processing and Dissemination Tasks, supported by ESA

institution

Alfred-Wegener-Institut Helmholtz Zentrum für Polar und Meeresforschung (AWI), http://www.awi.de

contributor_name

Xiangshan Tian-Kunze, Lars Kaleschke, Stefan Hendricks

publisher_email

xiangshan.tiankunze@awi.de

platform

“ESA Soil Moisture and Ocean Salinity (SMOS) mission”

sensor

“Microwave Imaging Radiometer using Aperture Synthesis (MIRAS)”

source

SMOS v724 L1C brightness temperature

product_version

v3.3

Processing level

L3c

grid

NSIDC polar stereographic projection. https://nsidc.org/data/polar-stereo/ps_grids.html

tracking id

08533af0-7656-4f35-b0a8-7ae4081a2c9a

naming authority

de.awi

history

Product generated with SMOS sea ice thickness retrieval Algorithm v3.3

summary

This dataset contains Level-3 daily sea ice thickness products from satellite observations in the northern hemisphere. Northern hemisphere sea ice thickness coverage is limited to the winter month between October and April. 100% sea ice coverage is assumed, which leads to underestimation of sea ice thickness.

topiccategory

Oceans Climatology Meteorology Atmosphere

keywords

Earth Science > Cryosphere > Sea Ice > Ice Depth/Thickness, Earth Science > Oceans > Sea Ice > Ice Depth/Thickness, Earth Science > Climate Indicators > Cryospheric Indicators > Ice Depth/Thickness, Geographic Region > Northern Hemisphere, Vertical Location > Sea Surface, Institutions > AWI > Alfred Wegener Institute for Polar and Marine Research

id

 ​awi-cs2smos-l3c-sithick-smos-nh_12p5_km_polstereo-YYMMDD-fv3p3

doi

none

Date_created

e.g. “Tue Mar 24 17:37:59 2020”

spatial_resolution

12.5 km grid spacing

time_coverage_duration

P1D

time_coverage_start

yyyy-mm-ddT00:00:00

time_coverage_end

yyyy-mm-ddT23:59:59

time_coverage_resolution

P1D

geospatial_bounds_crs

EPSG:3413

geospatial_lat_max

90.0

geospatial_lat_min

50.0

geospatial_lon_max

180.0

geospatial_lon_min

-180.0

geospatial_vertical_max

0.0

geospatial_vertical_min

0.0

references

1) Kaleschke, L., X. Tian-Kunze, N. Maass, M. Maekynen, and M. Drusch (2012), Sea ice thickness retrieval from SMOS brightness temperatures during the Arctic freeze-up period, Geophys. Res. Lett., 39, L05501, doi:10.1029/2012GL050916. (2) Tian-Kunze, X., Kaleschke, L., Maass, N., Maekynen, M., Serra, N., Drusch, M., and Krumpen, T., SMOS-derived sea ice thickness: algorithm baseline, product specifications and initial verification, The Cryosphere, 8, 997-1018, doi:10.5194/tc-8-997-2014, 2014 (3) Kaleschke, L., Tian-Kunze, X., Maass, N., Beitsch, A., Wernecke, A., Miernecki, M. and others, SMOS sea ice product: operational application and validation in the Barents Sea marginal ice zone, Remote Sensing of Environment 180 (2016), 264-273. doi: 10.1016/j.rse.2016.03.009 (4) Tietsche, S., Alonso-Balmaseda, M., Rosnay, P., Zuo, H., Tian-Kunze, X., and Kaleschke, L.: Thin Arctic sea ice in L-band observations and an ocean reanalysis, The Cryosphere, 12, 2051-2072, https://doi.org/10.5194/tc-12-2051-2018, 2018.



Table 3: NetCDF file content.

VariableDescriptionUnitTypeDimension
latitudelatitude coordinatedegrees_northfloat32896 x 608
longitudelongitude coordinatedegrees_eastfloat32896 x 608

x

Projection_x_corordinatekmfloat32608
yProjection_y_corordinatekmfloat32896
sea_ice_thicknessSMOS sea ice thicknessmfloat321 x 896 x 608
ice_thickness_uncertaintysea ice thickness total uncertaintym

float32

1 x 896 x 608

saturation_ratio

ratio of retrieved ice thickness and maximal retrievable ice thickness

%int161 x 896 x 608
TB

brightness temperature intensity (TBh+TBv)/2

Kfloat321 x 896 x 608
TB_uncertainty

brightness temperature uncertainty defined as one standard deviation of TB devided by the sqrt(nPair)

Kfloat321 x 896 x 608
Tsurf

SMOS derived snow surface temperature

Kfloat321 x 896 x 608
Sice

Bulk ice salinity

psufloat321 x 896 x 608
nPair

number of TBh and TBv pairs available


int161 x 896 x 608
RFI_ratio

percent of RFI-contaminated measurements in total measurements

%float321 x 896 x 608
land

land_binary_mask


int8896 x 608
time

hours since 2010-01-01 00:00:00

hourdouble1



Grid

Table 4: Northern Hemisphere Grid Coordinates of NSIDC Polar Stereographic Grids

(ref.: https://nsidc.org/data/polar-stereo/ps_grids.html)

X (km)

Y (km)

Latitude (deg)

Longitude (deg)

position

-3850

5850

30.98

168.35

corner

0

5850

39.43

135.00

midpoint

3750

5850

31.37

102.34

corner

3750

0

56.35

45.00

midpoint

3750

-5350

34.35

350.03

corner

0

-5350

43.28

315.00

midpoint

-3850

-5350

33.92

279.26

corner

-3850

0

55.50

225.00

midpoint