Estimate the fluctuation of Poyang Lake water level using Cryosat-2 data

Abstract

Poyang Lake is the largest freshwater lake in China and one of the world's sites recognized in the RAMSAR Convention on Wetlands. The wetlands provide an important range of ecosystem services. Poyang Lake is subject to seasonal fluctuations, with changes in water levels apparent in seasonal, yearly and multi-year patterns. However, the lake is shallow, and the pronounced changes in water levels could lead to the large alterations in the wetlands landscape. Satellite radar altimetry has effectively been used for monitoring the water level change in recent years. This article focuses on the estimation of the fluctuation of Poyang Lake water level using level 2 geophysical data record (GDR) altimeter datasets from Cryosat-2/Siral in recent 6 years from 2010 to 2015. The altimeter datasets were extracted according the MODIS water product image. The abnormal water levels data were eliminated according to the Pauta criterion and Lomnaofski norm. The final water level results were interpolated using B-Spline to get the water level change trend and compared to the 6 hydrology stations' record. At last, the fluctuation trend in the past 6 years was analyzed using long-term trend estimation methods.