Synthesis Analysis of SWOT KaRIn‐Derived Water Surface Heights and Local Cross‐Calibration of the Baseline Roll Knowledge Error Over Lake Baikal

Abstract

Abstract The upcoming Surface Water and Ocean Topography (SWOT) mission provides a promising opportunity for retrieval of high spatiotemporal resolution water surface height (WSH) over inland water bodies. To investigate the accuracy of SWOT derived WSH, the observations over Lake Baikal are simulated and a comprehensive evaluation is conducted in this study. Firstly, compared with Jason‐class altimeter WSH and in situ WSHs, the accuracy of SWOT KaRIn‐derived monthly WSHs and their spatiotemporal characteristics are analyzed. Secondly, a local cross‐calibration method is used to reduce the short wavelength roll error over lakes. The results show that, though SWOT has more observations than Jason‐class altimeter, the accuracy of the SWOT KaRIn‐derived monthly WSHs is difficult to be equivalent with those from Jason‐class altimeter, and varies with the number of duplicated observations, the spatial location and the time interval due to the effect of systematic erros and random errors, but can be significantly improved by local cross‐calibration method, especially at higher spatial resolutions after cross‐calibration associate with external nadir altimeter.

Keywords

• SWOT
• radar altimetry
• water surface height
• Lake Baikal
• local cross‐calibration