| Sandstorm,which is a disastrous weather with great harm,will cause a series of ecological and environmental problems and threaten human's life and property security.Sandstorm mainly occurs in arid and semi-arid areas where sufficient source of sands is provided due to aggravated desertification caused by severe loss of water.In an arid area,sandstorm is likely to happen once there is strong cold air.Therefore,it's a hotspot to research the relation between sandstorm and drought.In this article,the sandstorm intensity index was extracted from FY-3B data;the temperature vegetation drought index in growing season was calculated with MOD13A2 and MOD11A2 data;the number of non-snowy days in non-growing season was extracted from MOD10A1.The result fully demonstrated the latest factual characteristics of time-space distribution of sandstorm in Xilingol League during a drought.On this basis,the time-space consistency of sandstorm and drought was furthered expounded and law of response of local sandstorm to drought was discussed.The main research result is as follows:The research result about sandstorm:(1)during 2011-2019,the sand-dust in Xilingol League were mainly sandstorms and blowing sand followed by strong sandstorms,with least frequency of floating dust.Within the research period,the frequency of sand-dust at all levels exhibited a fluctuated decline.(2)The annual accumulated sand-dust area in Xilingol League was increased with increased frequency of sand-dust while decreased with decreased frequency.As to sand-dust at all levels,the law of change of its area was basically consistent with that of change of frequency.(3)Within a year,the frequency of sand-dust at all levels suggested a trend toward peak values in Spring(March,April and May)and reached the maximum value in May.However,the change of area was slightly different:the area influenced by sand-dust at all four levels was the greatest in April every year.(4)Overall,the sand-dust in Xilingol League was distributed more in southwest than in northeast in terms of spatial distribution.Where,floating dust was special.Although it appeared in all researched areas,it was not distributed continuously in large area.Rather,it influenced less area,with less frequency which was generally once or twice.Blowing sand,sandstorm and strong sandstorm were all distributed more in Southwest area and less in Northeast area.The research result about drought:(1)During 2010-2018,the drought is growing season in Xilingol League was mainly mild one,followed by moderate drought and severe drought.Where,severe drought mainly occurred in the East area but not occurred in large area in west.Nonetheless,it was distributed more in Southwest and less in Northeast overall in growing season.(2)Within the same period,the distribution of drought in non-growing season was contrary to that in growing season: severe drought occurred the most with the greatest range of occurrence;moderate drought occurred less frequency,followed by mild drought.Where,both mild drought and moderate drought occurred more frequently in Northeast and less frequently in Southwest,while severe drought occurred more frequently in Southwest and less frequently in Northeast.Overall,drought occurred more frequently in Southwest and less frequently in Northeast in non-growing season.(3)During the research period of 9 years,drought occurred frequently in Xilingol League,covering almost all areas in the league.The research result about relation between sand-dust and drought:(1)There was high consistency between occurrence of sand-dust of all four levels and the occurrence of drought in Xilingol League.Drought occurred in all areas where there was sand-dust and the only difference was the severity.(2)In growing season,floating dust was mainly highly consistent with moderate and severe drought,with less occurrence frequency.In non-growing season,it was mainly highly consistent with severe drought and moderately consistent with moderate drought.(3)In growing season,both blowing sand and sandstorm were highly consistent with mild drought.In growing season,mild drought occurred quite frequently in areas where there are frequent blowing sand and sandstorm.In non-growing season,blowing sand and sandstorm were mainly consistent with severe drought.(4)In Xilingol League,the areas with high frequency of strong sandstorm mainly concentrated near Sunite Right Banner.Except this place,strong sandstorm was highly consistent with mild,moderate and severe drought in growing season.In non-growing season,it was almost totally consistent with severe drought. |
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