Study of the ability of SWOT to detect sea surface height changes caused by internal solitary waves  

作　　者：Hao Zhang Chenqing Fan Lina Sun Junmin Meng 

机构地区：[1]First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China [2]Technology Innovation Center for Ocean Telemetry,Ministry of Natural Resources,Qingdao 266061,China [3]College of Oceanography and Space Informatics,China University of Petroleum(Huadong),Qingdao 266580,China

出　　处：《Acta Oceanologica Sinica》2024年第5期54-64,共11页海洋学报（英文版）

基　　金：The National Natural Science Foundation of China under contract Nos U2006207 and 42006164.

摘　　要：Surface Water and Ocean Topography(SWOT)is a next-generation radar altimeter that offers high resolution,wide swath,imaging capabilities.It has provided free public data worldwide since December 2023.This paper aims to preliminarily analyze the detection capabilities of the Ka-band radar interferometer(KaRIn)and Nadir altimeter(NALT),which are carried out by SWOT for internal solitary waves(ISWs),and to gather other remote sensing images to validate SWOT observations.KaRIn effectively detects ISW surface features and generates surface height variation maps reflecting the modulations induced by ISWs.However,its swath width does not completely cover the entire wave packet,and the resolution of L2/L3 level products(about 2 km)cannot be used to identify ISWs with smaller wavelengths.Additionally,significant wave height(SWH)images exhibit blocky structures that are not suitable for ISW studies;sea surface height anomaly(SSHA)images display systematic leftright banding.We optimize this imbalance using detrending methods;however,more precise treatment should commence with L1-level data.Quantitative analysis based on L3-level SSHA data indicates that the average SSHA variation induced by ISWs ranges from 10 cm to 20 cm.NALTs disturbed by ISWs record unusually elevated SWH and SSHA values,rendering the data unsuitable for analysis and necessitating targeted corrections in future retracking algorithms.For the normalized radar cross section,Ku-band and four-parameter maximum likelihood estimation retracking demonstrated greater sensitivity to minor changes in the sea surface,making them more suitable for ISW detection.In conclusion,SWOT demonstrates outstanding capabilities in ISW detection,significantly advancing research on the modulation of the sea surface by ISWs and remote sensing imaging mechanisms.

关 键 词：internal solitary waves Surface Water and Ocean Topography(SWOT) Ka-band radar interferometer(KaRIn) Nadir altimeter(NALT) sea surface height anomaly(SSHA) normalized radar cross section(NRCS) 

分 类 号：P714.1[天文地球—海洋科学]