Estimating the snow depth, the snow–ice interface temperature, and the effective temperature of Arctic sea ice using Advanced Microwave Scanning Radiometer 2 and ice mass balance buoy data
<p>Mapping sea ice concentration (SIC) and understanding sea ice properties and variability is important, especially today with the recent Arctic sea ice decline. Moreover, accurate estimation of the sea ice effective temperature (<span class="inline-formula"><i>T</i&g...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-04-01
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| Series: | The Cryosphere |
| Online Access: | https://www.the-cryosphere.net/13/1283/2019/tc-13-1283-2019.pdf |
| Summary: | <p>Mapping sea ice concentration (SIC) and understanding sea ice properties and
variability is important, especially today with the recent Arctic sea ice
decline. Moreover, accurate estimation of the sea ice effective temperature
(<span class="inline-formula"><i>T</i><sub>eff</sub></span>) at 50 GHz is needed for atmospheric sounding applications
over sea ice and for noise reduction in SIC estimates. At low microwave
frequencies, the sensitivity to the atmosphere is low, and it is possible to
derive sea ice parameters due to the penetration of microwaves in the snow
and ice layers. In this study, we propose simple algorithms to derive the
snow depth, the snow–ice interface temperature (<span class="inline-formula"><i>T</i><sub>Snow−Ice</sub></span>) and
the <span class="inline-formula"><i>T</i><sub>eff</sub></span> of Arctic sea ice from microwave brightness temperatures
(TBs). This is achieved using the Round Robin Data Package of the ESA sea ice
CCI project, which contains TBs from the Advanced Microwave Scanning
Radiometer 2 (AMSR2) collocated with measurements from ice mass balance buoys
(IMBs) and the NASA Operation Ice Bridge (OIB) airborne campaigns over the
Arctic sea ice. The snow depth over sea ice is estimated with an error of
5.1 cm, using a multilinear regression with the TBs at 6, 18, and 36 V. The
<span class="inline-formula"><i>T</i><sub>Snow−Ice</sub></span> is retrieved using a linear regression as a function
of the snow depth and the TBs at 10 or 6 V. The root mean square errors
(RMSEs) obtained are 2.87 and 2.90 K respectively, with 10 and 6 V TBs.
The <span class="inline-formula"><i>T</i><sub>eff</sub></span> at microwave frequencies between 6 and 89 GHz is
expressed as a function of <span class="inline-formula"><i>T</i><sub>Snow−Ice</sub></span> using data from a
thermodynamical model combined with the Microwave Emission Model of Layered Snowpacks. <span class="inline-formula"><i>T</i><sub>eff</sub></span> is estimated from the <span class="inline-formula"><i>T</i><sub>Snow−Ice</sub></span>
with a RMSE of less than 1 K.</p> |
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| ISSN: | 1994-0416 1994-0424 |