| With the strengthening of the impact for climate change, the drought events areshowing frequency trend on a global scale. and the time distribution of time and spacehas also changed significantly,are they some time scales presenting cyclical changes inbasin, if they are, the drought trends can be distinguished on different time scales,andidentify the drought regions, area centroid,foucus areas and other characteristics of thespatial distribution.It is the key issue ander climate change response to drought thatanalysis the drought Spatial and temporal characteristics depthly. The main contents areas follows:Firstly, the drought trend is briefly staged of the Yellow River Basin usinghistorical climate meteorological data. combined with the droughts value of the wholebasin,the cycle and point mutations can be identifyied by wavelet analysis and M-K test.500-year-time rules: It can be seen that the drought of the Yellow River basin is inperiods of drought overall pattern,and it also in warm periods from nearly300yearswarm and cold phases, there are some cycles scale,such as125years,40years,11yearsand7years.and then there are some time point mutations,such as the1498a,1614a,1670a,1695a,1714a,1795a,1875a,1980a;500-year-space rules:the drought centroidlongitude range is located108.2°~110.1°, latitude range is located35.2°~36.9°inCentennial-scale,and the drought centroid is located in the northwest of the basin.It canbe seen that the percentury drought frequency and intensity are showing a trend fromsouth to north and from west to east, from the century scale in the period1470-1800, thefrequency and intensity are showing a decreasing trend increasing from Southeast tonorthwest in the period1801-2000,so the drought-prone areas high incidence has beendivided,of the Yellow River basin hundred years scale, and then explore its variouspartitions variation drought centroidSecondly, it makes a preliminary analysis about drought and causes evolution ofthe Yellow River combined with meteorological and hydrological data, in the past60years. meteorological drought rules: the drought area is622,000Km2,and is78%of thetotal Yellow River basin in the1960s; the drought area is377,000Km2,and is47%ofthe total Yellow River basin in the1970s; the drought area is526,000Km2,and is66% of the total Yellow River basin in the1980s; the drought area is471,000Km2,and is78%of the total Yellow River basin in the1990s; the drought area is528,000Km2,andis66%of the total Yellow River basin after2000s;the analysis of Hydrological drought:The precipitation, land-use change and water conservancy projects reduced tonatural runoff, but evaporation increased natural runoff from the whole basin,amongwhich four major factors precipitation is greatest contribution to the natural runoff, thechanges of land use Regulating factors and water conservancy project are differences inthe region. such as C zone, land use contribution rate factor is only6.21%, thecontribution rate of water conservancy Regulating factor reached41.24%;but the F zone,land use factor contribution rate is up to60.94%, the Regulating Hydraulic contributionrate is only factor10.7%.Drought rules:The1960s affected area showed a weakdecreasing trend, but showed an increasing trend disaster area compared to1950s;the1970s affected area is showing double the growth trend an increasing trend, the disasterarea has been enhanced compared to1960s; The1980s affected disaster area showed adecreasing trend, but disaster area was still showing an upward trend compared to1970s;the1990s affected area showed an increasing trend once again, ompared to1980s;Afterthe21century the the affected area showed a downward trend, the disaster area isreducing trend for the first time. compared to1990s.The reason for such a change maybe as water conservancy construction is perfected, and strengthen the regional capacityto deal with drought,so that reducing losses caused by drought is more and moreobvious.Finally, for the next four years drought will be evoluted of the Yellow River basincombining regional climate model climate change scenario data RegCM4.0/RCP4.5future, Combined with the estimated results,While the future drought trend alleviatelyof the Yellow River, However, there is uncertainty, Supply and demand still exists,Forthe drought and the facing problems of the Yellow River basin,we can propose theoverall framework for the drought of Yellow River basin basin and esTablelish missioncritical response to the current drought in the Yellow River Basin. |
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