| All kinds of natural disasters occur frequently in China, and meteorological disasters is at the top of the list. Drought and flood, as the most important meteorological disasters, have the big scope, deep impact, weight loss and other significant characteristics. In the background of global warming, drought and flood disaster will become more frequent and serious. The three provinces of northeast China, as the typical mid-high climate vulnerable zone, have strong response to the climate change and drought-flood disasters occur frequently. Besides, as our country’s important agricultural and animal husbandry and commodity grain production base, climate change is bound to cause many adverse effects on local agriculture, so judgment in spatial and temporal evolution of in-depth study of the geographic unit and the future trend of drought, waterlogging years appear very important, providing theoretical foundation and basis for the local disaster prevention and mitigation.Based on the annual and monthly mean temperature and precipitation data of70meteorological stations from1961to2012in three provinces of northeast China, using the linear regression, M-K mutation test, Kriging interpolation, Z index, EOF, REOF, Morlet wavelet analysis and so on, this paper has found the background of climate change, evolution of the drought and judging the trend of drought and flood years. Based on the above analysis results and local actual situation, put forward relevant countermeasures for disaster prevention and mitigation to answer the adverse effects brought by the local response of drought and flood disaster. The main conclusions of this paper are as follows:(1) The annual average temperature appears a steadily rising trend from1961, and the increase rate is0.33℃/10a, occurring a significant mutation in1993. Heating rate is the lowest in summer, and the spring, autumn, winter temperature rise rate is higher than the national level. The distribution of temperature presents low in the North and high in the South. Annual temperature change and tendency are on the contrary. The strong heating center is in northwest of Heilongjiang, and weak heating center is in the central Liaoning province.(2) Precipitation is slightly downward trend and the average reduction rate is5.9mm/10a, occurring a significant mutation in1967. Precipitation increases slightly in spring and winter, and reduces in autumn. The spatial distribution of precipitation presents low in the North and high in the South, central much and east and west less. The high value area is in the eastern part of Liaoning and the southeastern part of Jilin, and the low value zone is located in the adjacent area of Jilin and Western Heilongjiang. Precipitation change and tendency are on the contrary. The precipitation variability of low center is in the coastal area of Jilin province, and the high value center is located in northwestern Liaoning and southwestern Jilin.(3) There are signs of waterlogging to drought, and drought and waterlogging appear a significant stage characteristics. The change is different among the four seasons. The region has changed from drought to flood in spring and autumn. Summer drought grade rose slightly and has obvious alternation. It gradually turned into a flood stage in winter.(4) The cumulative variance contribution rate of four EOF spatial vector fields of the Z index is up to58.05%. According to the distribution of each feature vector field, the space structure of drought and flood has consistency, north and south, east and west and the northwestern and southeastern negative region, central and southwest positive regional style. Based on REOF analysis, the drought and flood spatial distribution structure is divided into the following five areas:I southeast district; II southwest area; III northeast district; IVmid-west division; V northwest area.(5) Drought and waterlogging prediction results in recent years in future are as follows:the spring floods, autumn waterlogging, autumn drought and winter floods maybe happen in2015,2014,2014and2013. The situation of five typical flood and drought areas is different. The drought of first zone, the severe drought of second zone, the flood of third area, the drought of third area, the severe flood of fourth area and the flood of fifth zone have larger possibility in2013,2013,2016,2014,2015and2013.(6) There are significant correlation between annual and summer drought-flood change and sunspot, and drought increases in case of solar activity. The flood year is easily occured in the low value area of sunspots. At the same time there are more times in the flood in the twenty-second and twenty-fourth period, while more times in the drought in the twenty-first and twenty-third period. It is prone to drought conditions in El Nino/La Nina. Compared with El Nino years, droughts and floods occur at relatively high frequencies in La Nina years, and the flood occurs more easily. |
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