| Under the background of global warming, China’s climate and environment is also changed significantly. Weather disasters caused by climate warming (drought, heavy rain, hail, typhoons, and these disasters caused by secondary disasters) to the country’s socio-economic development and people’s life happiness caused serious damage. Loess Plateau is the second largest plateau, a vast territory, has a very rich mineral resources. Loess Plateau sensitive areas as climate change and vulnerable areas, is one of the world’s most serious soil erosion areas, serious soil erosion area of about27X104km2, there are11×104km2particularly serious area. As fragile ecological function areas, the study area is also particularly sensitive to climate change, the impact of adverse changes in the study area which will become more profound, more incalculable loss. So on the Loess Plateau depth analysis of climate change, and to determine the trend for the local economic and social development, the government and policy makers Disaster Prevention and Reduction of great significance for its droughts and floods.This paper selects61years Loess Plateau1961-2012National Meteorological base year, the monthly average temperature, precipitation and other meteorological data, through the use of linear regression, Mann-kendall mutation test, ordinary Kriging interpolation, rainfall Z index, a common degree calculation methods and wavelet analysis of regional climate change at different spatial scales background Plateau, droughts and evolution, droughts and floods and droughts occur Year tendency to judge the impact factor for system analysis. Combination of the above analysis results and the actual local situation, and ultimately make relevant disaster prevention and mitigation measures to reduce the adverse effects of droughts and floods to the study area, production and life brings. The main results are as follows:(1)1960-2012Loess Plateau different spatial scales showed a range of climate warming and drying trend. Different spatial scales in the study area in four seasons climate change, spring, summer and autumn showed a warming and drying trend, winter rains are different degrees of increase, and gradually showed the tendency of warm.(2) The average temperature of the study area, the spatial distribution of the overall distribution is not uniform, the overall performance was "elevated temperature decreases with latitude, longitude increases with increasing" feature. Most areas of the Loess Plateau, the temperature change rate and an average annual temperature is inversely proportional to the level, the higher the temperature, the slower regional warming, the lower the temperature, the faster the relative areas of the temperature increase.(3) Spatial distribution of rainfall in the study area showing an overall average "precipitation decreases with increasing latitude, longitude increases with increasing" feature. Most areas of the Loess Plateau, precipitation variability and inversely proportional to the level of annual precipitation, precipitation decreases the higher rainfall areas of relatively faster the greater the increase in precipitation in the lower rainfall areas of relatively faster. Northeast region study area became the center of the high value decreased precipitation, variable rate61.5mm/10a, should consider the impact of floods; throughout the Guanzhong area, decrease in precipitation have different ranges, should prevent the occurrence of drought.(4) The overall situation in the Loess Plateau showing partial drought in nearly53years. Spring droughts and floods and droughts are on the rise in the current trend. Summer droughts and floods generally more stable. Autumn droughts and floods inverted "V" shaped the development of the region in the1960s wet period in the1970s tended to be normal, the fall of the1980s drought-prone Loess Plateau, and continued until the1990s, after2000, the region’s drought Disasters return to normal; winter in the study area in the1990s of frequent droughts(5) The scope of the Loess Plateau is a large-scale studies in recent years of drought, floods and disasters determine the future trend of the results are as follows: drought, autumn flood,and winter drought’s time window are2013and2016,2013and2014,2013and2014. Scale ranges from studies in recent years in the future in Semi-humid areas, drought, spring drought, autumn drought, winter drought time window are2014,2014,2013and2014,2015; Semi-arid region in the spring floods,summer floods time window are2017,2013and2014;2013and2015within the year winter drought in arid areas of the future for the time window. Range from small-scale studies, Yan’an City, autumn floods, drought and winter time window of2013and2015,2013and2014respectively.(6) Since53years, the Loess Plateau drought index and sunspot correlation can be drawn about1960to1965, the number of sunspots and the drought index in the study area is completely inversely correlated, ie, the greater the number of sunspots, droughts Index, the smaller the likelihood of drought; since1965-so far, only2002,2006years near sunspot number and anti-drought index showed a correlation between sunspot number average remaining years of the study area drought index showed a good positive correlation between the presence of1-2years and the drought index lag. Loess Plateau in solar activity minimum years of the previous year (m-1) are more likely to floods, more droughts occurred in year after year minimum (m+1), sunspot maximum years (M) more drought.This study attempts to determine trends in research methods rich disasters, recognizing the Loess Plateau Occurrence of droughts and floods, increased experience in disaster prevention and mitigation scenarios, as well as droughts and floods Disaster Prevention and Mitigation Measures providing research for local decision-making department. |
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