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...

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Main Authors: Z. Dong, L. Shi, M. Lin, Y. Jia, T. Zeng, S. Wu
Format: Article
Language:English
Published: Copernicus Publications 2023-03-01
Series:The Cryosphere
Online Access:https://tc.copernicus.org/articles/17/1389/2023/tc-17-1389-2023.pdf
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author Z. Dong
Z. Dong
L. Shi
L. Shi
M. Lin
M. Lin
Y. Jia
Y. Jia
T. Zeng
T. Zeng
S. Wu
author_facet Z. Dong
Z. Dong
L. Shi
L. Shi
M. Lin
M. Lin
Y. Jia
Y. Jia
T. Zeng
T. Zeng
S. Wu
author_sort Z. Dong
collection DOAJ
description <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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spelling doaj.art-fb3cdb811319422f9f29dcaab6009df02023-03-31T12:16:20ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242023-03-01171389141010.5194/tc-17-1389-2023Feasibility of retrieving Arctic sea ice thickness from the Chinese HY-2B Ku-band radar altimeterZ. Dong0Z. Dong1L. Shi2L. Shi3M. Lin4M. Lin5Y. Jia6Y. Jia7T. Zeng8T. Zeng9S. Wu10College of Oceanography, Hohai University, Nanjing, 210003, ChinaNational Satellite Ocean Application Service, Beijing, 100081, ChinaNational Satellite Ocean Application Service, Beijing, 100081, ChinaKey Laboratory of Space Ocean Remote Sensing and Application (MNR), Ministry of Natural Resources, Beijing, 100081, ChinaNational Satellite Ocean Application Service, Beijing, 100081, ChinaKey Laboratory of Space Ocean Remote Sensing and Application (MNR), Ministry of Natural Resources, Beijing, 100081, ChinaNational Satellite Ocean Application Service, Beijing, 100081, ChinaKey Laboratory of Space Ocean Remote Sensing and Application (MNR), Ministry of Natural Resources, Beijing, 100081, ChinaNational Satellite Ocean Application Service, Beijing, 100081, ChinaKey Laboratory of Space Ocean Remote Sensing and Application (MNR), Ministry of Natural Resources, Beijing, 100081, ChinaNational Satellite Ocean Application Service, Beijing, 100081, China<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>https://tc.copernicus.org/articles/17/1389/2023/tc-17-1389-2023.pdf
spellingShingle Z. Dong
Z. Dong
L. Shi
L. Shi
M. Lin
M. Lin
Y. Jia
Y. Jia
T. Zeng
T. Zeng
S. Wu
Feasibility of retrieving Arctic sea ice thickness from the Chinese HY-2B Ku-band radar altimeter
The Cryosphere
title Feasibility of retrieving Arctic sea ice thickness from the Chinese HY-2B Ku-band radar altimeter
title_full Feasibility of retrieving Arctic sea ice thickness from the Chinese HY-2B Ku-band radar altimeter
title_fullStr Feasibility of retrieving Arctic sea ice thickness from the Chinese HY-2B Ku-band radar altimeter
title_full_unstemmed Feasibility of retrieving Arctic sea ice thickness from the Chinese HY-2B Ku-band radar altimeter
title_short Feasibility of retrieving Arctic sea ice thickness from the Chinese HY-2B Ku-band radar altimeter
title_sort feasibility of retrieving arctic sea ice thickness from the chinese hy 2b ku band radar altimeter
url https://tc.copernicus.org/articles/17/1389/2023/tc-17-1389-2023.pdf
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