Study On The Response Of Lake Ice Phenology To Climate Change In Plateau Region

Lake ice phenology is a sensitive indicator of climate change.The plateau area is a key research area for lake ice phenology,and the plateau lake ice phenology data is often used to reflect and record climate change.At present,there are not many studies on lake ice phenology in plateau areas,and most of them are concentrated in the Qinghai-Tibet Plateau and the middle and high latitudes of Europe and America.This paper uses MOD10 A1 daily snow cover data as the lake ice phenology data source,extracts the lake ice parameter values of the Qinghai-Tibet Plateau and Mongolia Plateau,and analyzes the spatial distribution characteristics,changing laws and models,and finally discusses the effects of phenological parameters and phenological models on climate change The response law.First,by studying the adaptability of different cloud removal methods in plateau areas,a series of cloud removal processes suitable for plateau areas are obtained,including 7 cloud removal algorithms.The cloud removal processes are all completed on the cloud computing platform Google Earth Engine.Using the daily data after cloud pollution removal and the lake vector boundary data,the daily lake ice coverage rate was obtained,and the lake ice phenology parameter values of the two plateau lakes from 2000 to 2019 were extracted according to the threshold value 10%-90%defined by the lake ice phenology.A study on the temporal and spatial distribution characteristics of the five parameter values of lake ice phenology found that the lake ice phenology parameter value ranges of the Qinghai-Tibet Plateau and the Mongolian Plateau are basically the same,but the Tibetan Plateau phenological parameter values have a larger span;the lake ice ages of the Qinghai-Tibet Plateau are less than the Mongolian Plateau,about30 day.Research findings on the multi-year trend of five parameter values from 2000 to 2019.The phenological parameters of lake ice in the Qinghai-Tibet Plateau and the Mongolian Plateau are mostly advanced and delayed.Among them,the complete melting of the Mongolian Plateau and the lake ice age only have an early trend.The change trend of lake ice phenological parameters is basically consistent with the spatial distribution of parameter values.The lake ice age also showed obvious spatial distribution.According to the characteristics of various parameters of lake ice phenology,the lake ice phenology of plateau lakes is divided into three types,namely ideal phenology model,unstable type and non-freezing period type.Analyzing the change trend of ice phenology patterns of plateau lakes and lakes,a total of 9 different phenological patterns change trends were found,of which the Mongolian Plateau only contains 5 of them.In the model change trends of the two plateaus,lakes with phenological parameters showing a trend of "delayed,delayed,advanced," phenological model of change accounted for more than 50% of the total number of lakes on the plateau.