| Based on the surface phenology observation data of Fukang city in Xinjiang,MODISEVI satellite remote sensing data and surface meteorological observatio-n data,this paper analyzed the spatiotemporal dynamic change characteristics of vegetation phenology and key climate factors affecting vegetation development in Tianshan Mountains,Xinjiang from 2001 to2017.To further explore the relationship bet--ween vegetation phenology and key climatic factors and elevation in Tianshan Mountains,Xinjiang,we hope to elucidate the response mechanism of vegetation phenology in Xinjiang Tianshan Mountains to climate change and predict its largescale change trend under the background of global warming in the future.This research on ecosystem carbon-process simulation and prediction of water circulation and to deal with the global change,ecological security protection policy is of great signif-icance,the results for the xinjiang tianshan ecological barrier function protection,restoration of vegetation ecosystem function and to develop and perfect the agroforestry will provide a scientific basis for policy to respond to climate change.The main conclusions are as follows:(1)From 2001 to 2017,the vegetation growth season in the Tianshan Mountains,Xinjiang averaged 89 to 105 DOY at the start,235 to 256 DOY at the end,and 222 to 236 days at the end.Phenological parameters with most vegetation phenology characteristics under the background of global climate change trends,on the other hand,the growing season initial period was significantly delayed trend(p<0.05),the interannual trend rate of 3.9d·(10a)-1,the end of the growing season as a whole is not significant trends in advance(p>0.05),the annual tendency at a rate of 4.9d·(10a)-1,length of growing season as a whole has grown significantly shorten the trend(p<0.01),the interannual trend rate of 5.9d·(10a)-1.(2)Spatially,the start of the growing season was earlier in the Northern Slope than in the southern slope,earlier in the plain area than in the alpine mountain area,and earlier in the desert area of the Tianshan Mountains,Xinjiang than in the agricultural area.The agricultural area and desert area showed a later trend,but the grassland area showed an earlier trend.At the end of the growing season,the Northern Slope was later than the southern slope,the plain area was later than the high mountain area,the desert area and the low altitude grass area were later than the agricultural area and the high altitude grass area,the agricultural area showed an advanced trend,and the high mountain area and the grass area showed a delayed trend.The length of the growing season was longer on the Northern Slope than on the southern slope,longer in the plain area than in the high mountain area,longer in the desert area and low altitude grassland area on the Northern Slope of the Tianshan Mountains,Xinjiang than in the agricultural area and high altitude gra-ss area,the agricultural area showed a shortening trend,and the high altitude mountain area and grassland showed a lengthening trend.(3)From 2001 to 2017,the interannual variation trends of the four climatic elements in the Tianshan Mountains,Xinjiang showed no significant increasing trend,and their significance did not pass the level of 0.1.In space,the high mountain area showed a cooling trend while the plain area showed a warming trend.The sunshine hours showed a decreasing trend in the northeast and an increasing trend in the southwest.The precipitation in the high altitude mountainous area showed an increasing trend with a higher rate,while the plain area showed a slow decreasing trend.The spatial distribution of annual moisture index and its variation trend is basically consistent with that of precipitation.(4)When the altitude was lower than 1500m,the vegetation phenology fluctuated greatly with altitude and had no obvious change rule.When the altitude was between 1500m and3500m,the start of the growing season showed a significantly delayed trend,the end of the growing season showed a significantly advanced trend,and the length of the growing season showed a significantly shortened trend.When the altitude was greater than 3500m,with the increasing of the altitude,the start of the growing season was still significantly delayed,and the end of the growing season was significantly delayed,and the length of the growing season was significantly prolonged.When the altitude was greater than 1500m,the rate of change at the start and end of the growing season did not show a continuous increase or decrease with the increase of altitude,except that the rate of change at the start and end of the growing season showed a continuous increase or decrease with the increase of altitude.(5)Correlation analysis and partial correlation analysis showed that each climate factor had opposite effects on the beginning of the growing season and the length of the growing season,that is,the effects of annual mean temperature and annual mean sunshine on the beginning of the growing season were mainly negatively correlated,while the effects of annual accumulative precipitation and annual humidity index on the beginning of the growing season were mainly positively correlated.The influence of annual mean temperature and annual mean sunshine on the length of the growing season is mainly positive correlation,while the influence of annual accumulated precipitation and annual humidity index on the beginning of the growing season is mainly negative correlation.However,the effects of various climatic factors on the end of the growing season are different,and the effects of annual mean sunshine and annual accumulated precipitation on the end of the growing season are still uncertain.Annual mean sunshine duration was the most important climatic factor at the beginning and length of the growing season,and annual mean temperature was the most important climatic factor at the end of the growing season. |
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