Effects Of Climate Change And Human Activities On Dust Weather In Hotan,Xinjiang

Dust weather is a kind of disastrous weather frequently occurring in arid areas,which not only seriously harms the sustainable improvement of ecological environment quality in the region,but also seriously affects social and economic development,people's production and living standards and health conditions in the region.Under the background of rapid global climate change,the climate change in China is also more intense,and various meteorological disasters arising from climate change also emerge endlessly.Xinjiang is located in the interior of the mainland of China,and the climate change in the region is complex.Hotan area in the south of Xinjiang is one of the areas where sand and dust weather occurs most frequently in China.The ecological environment is harsh and the social and economic development level in the region is low.Therefore,it is of great significance to deeply understand and analyze the spatio-temporal variation of climate and dust weather in this region,and to discuss the influence of climate change and human activities on dust weather in the region.This study provides scientific reference and theoretical basis for understanding regional wind-blown sand environment,improving wind-proof and sand-fixing ability,promoting vegetation conservation and ecological restoration,and guaranteeing economic and social production of oasis in arid area.Hotan area is selected as the study area,and the meteorological,sand and dust days and human activity data of 7 meteorological stations in the region are selected.By collecting Populus euphratica tree-ring samples from the downstream of Yulongkashi River and Cele River,Wavelet analysis,M-K mutation test and Inverse Distance Weight were used to analyze the spatio-temporal variation characteristics of main meteorological elements and dust days in Hotan area from 1960 to 2019.The tree-ring chronology was established to analyze the response of poplar growth to climate and the influence of dust weather on it.The bivariate correlation method was used to analyze the correlation between dust weather and climate and human activities,then the influence of the two factors on dust weather is discussed.Research shows that:1)The climate change in Hotan region has obvious response to global climate change,showing a trend of"warming and humidification".The spatial microclimate of each county in Hotan region has some regional differences.The temperature shows a spatial distribution pattern of high in the Midwest and low in the East.The precipitation is concentrated in Pishan in the west and surrounding areas centered on Yutian.The precipitation is relatively low in surrounding areas centered on Hotan and minfeng in the east,and the spatial distribution of relative humidity is consistent with precipitation.The spatial distribution of wind speed is larger in the east and west and smaller in the middle.The average annual temperature in Hotan showed a rising trend,and the overall regional temperature increase rate was 0.3?/10a.Precipitation and atmospheric relative humidity fluctuated greatly and increased to a certain extent.The regional precipitation increase rate was 3.6mm/10a,the atmospheric relative humidity increase rate was 0.5%/10a,and the wind speed showed a decreasing trend.The deceleration rate was 0.1 m.s^-1/10a.2)The main meteorological elements in all counties in Hotan area fluctuated greatly and had abrupt changes,and the abrupt changes almost occurred in the late1990s and early 21st century.At the same time,the temperature,precipitation and wind speed in hotan county have obvious periodic changes in recent decades,in which the temperature and precipitation generally have 25 years,7 years and 3-5years variation cycles nested with each other,and the wind speed has a common variation cycle of about 15 years.3)From 1960 to 2019,the total number of dust days in Hotan area decreased with uneven spatial distribution.Minfeng has a high incidence of sandstorm and floating dust days,followed by Pishan and Hotan and Cele,while Moyu,Luopu and Yutian have relatively fewer sandstorm days.The overall spatial distribution pattern shows that there are more sandstorm days in the east and the west,but less dust days in the middle.The monthly variation trend of the three kinds of dust days at different stations is basically consistent,the number of sandstorm days mainly occurs in April-July,the number of floating dust days occurs all year round,and the number of blowing sand days mainly occurs in March to August.4)There is a significant correlation between human activities and dust weather in the region.The Population,artificial afforestation area,shelterbelt area,per capita GDP,agricultural output value,livestock number with three kinds of sand dust days mainly showed a negative correlation,the correlation between arable land area and dust days is not obvious,forest area and dust days basic was a positive correlation.It can be seen that different human activities have different degrees of influence on dust weather,reasonable human activities play a positive role in dust weather intervention,and conversely become the inducing factor of dust weather.5)Under the background of global warming,the climate in Hotan presents a trend of warming and humidification,the number of dust days in the region keeps decreasing.The monthly variation of dust weather is strongly influenced by climatic factors.The number of three kinds of dust days at different stations changes positively with air temperature,precipitation and wind speed,but negatively with atmospheric relative humidity.In terms of annual time variation,the three kinds of dust days showed extremely significant positive correlation at the level of 0.01,but there were differences among the main meteorological elements at each station.The number of dust days has a significant negative correlation with average annual temperature,a positive correlation with wind speed,but a relatively small correlation with precipitation and atmospheric relative humidity.6)The growth of P.euphratica in the desert areas surrounding the lower reaches of the Yulongkashi River basin and Cele River Basin was limited by similar climatic factors,but climate is not the main factor affecting its growth.Generally,during1980-2019,the tree-ring width index of P.euphratica at the two sampling sites was negatively correlated with air temperature,but the correlation was not significant and mainly in P.euphratica growth season relatively obvious.The correlation was not significantly correlated with precipitation and atmospheric relative humidity.In terms of monthly variation,the growth of P.euphratica was affected by local climate factors with a certain lag and the response of P.euphratica around cele River basin to climate factors was stronger than that in Yulongkashi River basin.There was a negative correlation between the three kinds of dust days and the ring width index of P.euphratica,and it was obvious in the growing season,that is,P.euphratica grew well and could play a good windbreak and sand-fixation effect,the occurrence of dust weather would hinder the growth of P.euphratica.