| Based on TIMESAT3.2 platform for 2000—2015 MODIS NDVI data of Qaidam basin fitting,using the method of dynamic threshold to extract three main vegetation phenological parameters including the start of growth season,the end of growth reason and the length of growth season.Qaidam basin are analyzed respectively the space differentiation characteristics of vegetation phenology and climate factors,the change trend of time and space,and conducted partial correlation analysis between them,the conclusions are as follows:(1)The start of growth season of Qaidam basin is mainly delayed as a whole.It is roughly equal between the areas delayed and advanced in the end of growth season,and the growth season overall is shortened.(2)With the trend of the start of growth season to delay and the length of growth season to shorten,in some areas such as the mountain valley around the basin edge,the core area of alluvial fan and pluvial fan in the central and eastern,the eastern and northern mountain basin and other places,the start of growth season to advance,the end of growth to postpone and the length of growth season to extend.(3)The temperature and precipitation distribute like a ring or a semi-ring in Qaidam basin.The temperature in vegetation coverage areas overall rise,but the trend is not significant.The amount of precipitation in the east significantly increases,but it decreases in the central and western regions.(4)In Qaidam Basin,it is obvious to the response of the phenology to the temperature and precipitation changes,which is not obvious in the more humid part with water distribution at the low elevation regions.And in these areas,the start of growth season arrives early and the end of growth season delay.As while,in the upper part of the mountain located at high elevation regions,with temperature rising the start of growth season delay,and the end of growth season arrives early,and with precipitation increasing,the start of growth season arrives early,and the end of growth season delays. |
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