TC The Cryosphere TC The Cryosphere 1994-0424 Copernicus Publications Göttingen, Germany 10.5194/tc-8-915-2014 Weekly gridded Aquarius L-band radiometer/scatterometer observations and salinity retrievals over the polar regions – Part 2: Initial product analysis Brucker L. 1 2 Dinnat E. P. 3 1 Koenig L. S. 1 NASA GSFC, Cryospheric Sciences Laboratory, Code 615, Greenbelt, MD 20771, USA Universities Space Research Association, Goddard Earth Sciences Technology and Research Studies and Investigations, Columbia, MD 21044, USA Chapman University, School of Earth and Environmental Sciences, Orange, CA 92866, USA 16 05 2014 8 3 915 930 Copyright: © 2014 L. Brucker et al. 2014 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://tc.copernicus.org/articles/8/915/2014/tc-8-915-2014.html The full text article is available as a PDF file from https://tc.copernicus.org/articles/8/915/2014/tc-8-915-2014.pdf

Following the development and availability of Aquarius weekly polar-gridded products, this study presents the spatial and temporal radiometer and scatterometer observations at L band (frequency ~1.4 GHz) over the cryosphere including the Greenland and Antarctic ice sheets, sea ice in both hemispheres, and over sub-Arctic land for monitoring the soil freeze/thaw state. We provide multiple examples of scientific applications for the L-band data over the cryosphere. For example, we show that over the Greenland Ice Sheet, the unusual 2012 melt event lead to an L-band brightness temperature (TB) sustained decrease of ~5 K at horizontal polarization. Over the Antarctic ice sheet, normalized radar cross section (NRCS) observations recorded during ascending and descending orbits are significantly different, highlighting the anisotropy of the ice cover. Over sub-Arctic land, both passive and active observations show distinct values depending on the soil physical state (freeze/thaw). Aquarius sea surface salinity (SSS) retrievals in the polar waters are also presented. SSS variations could serve as an indicator of fresh water input to the ocean from the cryosphere, however the presence of sea ice often contaminates the SSS retrievals, hindering the analysis. The weekly grided Aquarius L-band products used are distributed by the US Snow and Ice Data Center at <a href=" http://nsidc.org/data/aquarius/index.html "target="_blank"> http://nsidc.org/data/aquarius/index.html </a> , and show potential for cryospheric studies.

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