Lake Ice Phenology Variations and Influencing Factors in the Qinghai-Xizang Plateau During 1978-2016
The change in lake ice phenology is a sensitive indicator reflecting climate change.Lake ice phenology over the Qinghai-Xizang Plateau(QXP)is however rarely observed and recorded.The numerous lakes in the QTP have significant functions within the climate system,influencing the balance of water and energy in the region,and are additionally viewed as key indicators of local climate change.Based on lake ice phenology dataset from 126 lakes on the QXP and meteorological data,this article analyzes the changes of lake ice phenology and influencing factors in the QXP from 1978 to 2016.Some conclusions can be drawn as follows.(1)The freeze-up start(FUS)and freeze-up end(FUE)of lake ice appears in mid-November,and mid-December,respectively.The time of break-up start(BUS)and break-up end(BUE)of lake ice is relatively dispersed,and appears in early April and early June,respectively.The average freezing duration(IceD,between BUE and FUS),complete freezing duration(CID,between BUS and FUE)were 168 days and 114 days,respectively.(2)The spatial difference of the change trend of the lake ice phenology in the QXP is relatively significant.The freezing time,melting time and duration of the ice period of most lakes show an obvious trend of advancing,delaying and shortening,while some lakes have no obvious trend of change.(3)The spatial distribution characteristics of lake ice phenology in the QXP have obvious regional differences,but the spatial distribution characteristics of each index are relatively similar,that is,there is a spatial distribution pattern of early lake ice formation date,delayed ice melting date,and extended ice period duration from the south to the north.(4)The spatiotemporal variability of lake ice phenology is the result of the combined effects of climate change and lake conditions.Temperature is a key factor affecting lake ice phenology,while precipitation,latitude,and lake area are the main factors influencing the dates of ice-on and ice-off.On the other hand,the dates of beginning and complete ice melting are mainly influenced by wind speed,latitude,and altitude.Wind speed,precipitation,latitude,and altitude are the main factors affecting the duration of the ice period and complete ice cover.In summary,under the background of global warming,the formation,melting,and duration of the ice period in the lakes on the QXP are undergoing significant changes.
lake ice phenologyspatial-temporal variationinfluencing factorsQinghai-Xizang Plateau
NETL
NSTL
万方数据
