Lake Level Variations Of Baikal From Satellite Altimetry

With the development of satellite altimetry,its application field gradually expanded from the ocean to inland waters.At present,domestic and foreign scholars have proposed a variety of waveform retracking algorithm,each has advantages and disadvantages.This paper attempts to find the most suitable algorithm for Lake Baikal,to provide reference for the study of lake level variance and climate change in Lake Baikal area.Based on the previous research results,three kinds of traditional retracking algorithm a sub-waveform extraction algorithm and extreme method are used to deal with the waveform data of Lake Baikal,to correct the error caused by contamination of the waveform.Then,combine the result with GRACE,GLADS,temperature and precipitation data to analysis of its internal relationship.The main contents and conclusions are as follows:1.Taking one pass of Jason-1 over the Lake Baikal as an example,analysis the change of waveform from land to the lake center.The waveform change from peaks,cascade,like brown to brown.Affected by land topography,the trailing edge of waveform changes violently,the amplitude is higher than normal waveform.This paper puts forward that eliminate waveform which the median of last ten bins is less than 5%of the amplitude.2.Using five waveform retracking algorithm to correct the result.The 15 years'monthly water level anomaly(2002-2016)of Lake Baikal is calculated.The IMP,in-situ data is used to find the retracking algorithm suit Lake Baikal best.Take one pass as an example,the IMP values of the 5 algorithms are-14.24,12.06,14.07,17.76,and 26.80,respectively,therefore,it is concluded that the OCOG is affected by terrain and the precision is worse than that without correction,the other four algorithms is greatly improved.Compared with the in-situ data,the extreme method is best suit the Lake Baikal.3.The water level anomaly of Baikal from satellite altimetry is compared with the result of GRACE and GLDAS to analysis their relationship.The temperature and precipitation data is also compared to analysis the relationship between lake level change and climate.Least square,wavelet analysis is used to research the cycle of water level anomaly time series.The anniversary is the main cycle of Lake Baikal.