Feasibility of retrieving Arctic sea ice thickness from the Chinese HY-2B Ku-band radar altimeter
<p>With the continuous development of the China ocean dynamic environment satellite series (Haiyang-2, HY-2), it is urgent to explore the potential application of HY-2B in Arctic sea ice thickness retrievals. In this study, we first derive the Arctic radar freeboard and sea ice thickness durin...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-03-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/17/1389/2023/tc-17-1389-2023.pdf |
| Summary: | <p>With the continuous development of the China ocean dynamic
environment satellite series (Haiyang-2, HY-2), it is urgent to explore the
potential application of HY-2B in Arctic sea ice thickness retrievals. In
this study, we first derive the Arctic radar freeboard and sea ice thickness
during two cycles (from October 2019 to April 2020 and from October 2020 to
April 2021) using the HY-2B radar altimeter and compare the results with the
Alfred Wegener Institute (AWI) CryoSat-2 (CS-2) products. We evaluate our
HY-2B sea ice freeboard and thickness products using Operation IceBridge
(OIB) airborne data and Ice, Cloud, and land Elevation Satellite 2 (ICESat-2) products. Finally, we estimate the uncertainties in the HY-2B sea ice freeboard and sea ice thickness. Here, we
derive the radar freeboard by calculating the difference between the
relative elevation of the floe obtained by subtracting the mean sea surface
(MSS) height and sea surface height anomaly (SSHA) determined by an average
of the 15 lowest points method. The radar freeboard deviation between HY-2B
and CS-2 is within 0.02 m, whereas the sea ice thickness deviation between
HY-2B and CS-2 is within 0.2 m. The HY-2B radar freeboards are generally
thicker than AWI CS-2, except in spring (March and April). A spring segment
likely has more floe points than an early winter segment. We also find that
the deviations in radar freeboard and sea ice thickness between HY-2B and
CS-2 over multiyear
ice (MYI) are larger than those over first-year ice (FYI). The correlation between HY-2B
(CS-2) sea ice freeboard retrievals and OIB values is 0.77 (0.84), with a
root mean square error (RMSE) of 0.13 (0.10) m and a mean absolute error
(MAE) of 0.12 (0.081) m. The correlation between HY-2B (CS-2) sea ice
thickness retrievals and OIB values is 0.65 (0.80), with an RMSE of 1.86
(1.00) m and an MAE of 1.72 (0.75) m. The HY-2B sea ice freeboard
uncertainty values range from 0.021 to 0.027 m, while the uncertainties in
the HY-2B sea ice thickness range from 0.61 to 0.74 m. The future work
will include reprocessing the HY-2B L1 data with a dedicated sea ice
retracker, and using the radar waveforms to directly identify leads to
release products that are more reasonable and suitable for polar sea ice
thickness retrieval.</p> |
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| ISSN: | 1994-0416 1994-0424 |