气候变暖背景下中国农业干旱灾害致灾因子、风险性特征及其影响机制研究

发布时间：2017-12-30 23:11

本文关键词：气候变暖背景下中国农业干旱灾害致灾因子、风险性特征及其影响机制研究　出处：《兰州大学》2016年博士论文　论文类型：学位论文

【摘要】：干旱是我国发生频次最高、影响范围最广、造成损失最严重的自然灾害之一。随着气候变暖,我国干旱发生了显著的变化,不仅原本一直干旱的北方地区干旱灾害加重,而且,南方的极端干旱事件也呈增加趋势,干旱灾害风险不断加剧。在全球气候变暖背景下,干旱灾害正以新的气候常态发生在中国各个区域,对社会经济和农业生产造成了严重损失。由于干旱灾害风险影响因素及其机制复杂且具有区域差异性,而且风险因子之间相互作用,导致干旱灾害风险区域差异性更明显。我国气候类型复杂多样,属于全球气候变暖的敏感区之一。而且,农业是气候变暖的敏感行业,也是干旱灾害风险的主要承灾对象。在气候变暖背景下,干旱灾害对中国农业生产造成更加严重的影响,农业干旱灾害风险不断扩大。本研究以我国干旱灾害致灾因子、风险性特征及其影响机制为研究切入点,以气象综合干旱指数(MCI)为干旱致灾因子表征指标,研究我国干旱时空分布特征及其区域差异性。基于风险因子耦合模拟和历史干旱灾损概率统计两种风险评估方法,研究中国农业干旱灾害风险性特征。阐述不同时段关键气候物理要素对风险的影响,揭示气候变暖对农业干旱灾害损失的影响,明确中国干旱灾害风险关键影响期。研究成果为提升我国干旱灾害风险评估、防灾减灾能力和风险管理水平提供科学依据,主要结论如下:(1)充分认识了中国干旱时空变化特征、演变规律和区域差异性。基于1961-2014年逐日MCI,系统分析了我国干旱时空变化特征。研究表明,气候变暖背景下,中国干旱范围扩大、程度加剧和频次增加。同时,干旱发生的范围发生了明显的转移,北方干旱加剧的同时,南方干旱明显加重,尤其是大旱范围明显增加。中国上世纪90年代中后期-21世纪初期干旱范围最广、持续时间最长,造成的损失最严重。中国干旱主要发生在黄河流域以南和长江以北地区。干旱频次北方高于南方,东部高于西部,长江流域以北干旱频次较高,黄河流域干旱频次大于30%。但不同年代,干旱发生范围、程度、频次和持续时间有一定的差异性。(2)基于风险因子耦合法,构建了综合农业干旱灾害风险评估模型,并在中国西南地区进行案例研究。基于gis和rs技术,融合气象综合干旱指数(mci)、遥感反演的土壤湿度、植被指数、干旱灾情和农业统计等多源数据。综合考虑干旱灾害致灾因子、承灾体、孕灾环境和防灾减灾能力,构建农业干旱灾害风险评估模型。在gis平台下,实现了西南地区干旱灾害风险精细化评估。同时,根据历史干旱灾害损失概率统计计算干旱灾害综合损失率。将风险因子耦合模拟和历史灾损统计法相结合,系统分析西南农业干旱灾害风险特征及其影响机制。研究表明,西南农业干旱灾害综合风险具有明显的地带性。农业干旱灾害高风险区主要位于西南东部,北部高于南部。不同的致灾因子、承灾体、孕灾环境和防灾减灾能力差异导致农业干旱综合风险格局复杂。(3)系统分析了中国农业干旱灾损率变化特征、南北区域差异及其对气候变暖的响应。基于历史干旱灾损构建干旱灾害受灾率、成灾率、绝收率和综合损失率,分析近50多年中国干旱灾害损失及南北差异性。研究表明,气候变暖背景下,中国干旱受灾率、成灾率、绝收率和综合损失率都呈增加趋势。农业干旱灾害损失的范围和程度均明显增加,风险显著加大,尤其是成灾以上干旱损失增速更快。受气候变暖的影响,中国南方和北方农业干旱灾害损失差异明显。气候突变后,北方农业干旱灾害损失明显高于南方,增幅也比南方快,北方灾害损失增幅是南方的3~4倍,而且干旱损失越重,增幅越快。北方干旱灾害损失主要依赖降水,而南方对温度的依赖程度比北方大。不同时段降水和温度对农业干旱损失的影响不同,只有关键时段的降水和气温对农业干旱灾害损失率具有更显著的影响。中国7月下旬、9月中旬降水量和6月上旬气温对农业干旱损失至关重要。(4)阐明中国七个子区域干旱灾害损失变化特征。在气候变暖背景下,不同等级干旱灾害损失变化具有明显的区域差异性。东北综合损失率多年平均值最大(9.6%),其次为华北(9.3%)和西北(8.4%),华东最小(2.4%)。华北综合损失率增幅最大,为1.4%/10a。气候突变后,西北、华北和西南受灾率呈增加趋势,而东北、华中、华南和华东降低;成灾率和绝收率各区域均增加;综合损失率除华中外,其它区域均增加。气候变暖背景下,中国各区域干旱灾害损失呈增加趋势,越重的灾害对气候变暖越敏感。综合损失率在气候空间的分布区域差异性显著。(5)系统分析了干旱对中国主要粮食作物产量的影响。气候变暖总体不利于中国主要粮食作物产量增加,但不同作物对气候变暖的响应略有差异。气候变暖对夏粮、玉米和稻谷不利,尤其是玉米,平均减产0.9kg/10a。中国粮食作物随气象干旱程度的增加趋于减产,尤其是秋粮作物。冬小麦和稻谷随着气象干旱程度加重趋于减产,而夏粮、春小麦、玉米和马铃薯与气象干旱的响应不明显。(6)明确了中国农业干旱灾害风险关键影响期。中国干旱灾害风险关键影响期为春末、夏季和秋季前中期,8月达到峰值。北方干旱灾害风险关键影响期与中国一致,南方为夏季和秋季前中期,8月关键期的作用最突出。北方关键影响期较南方长,作用比南方更突出。中国各子区域干旱灾害风险关键影响期的长短和作用具有显著的区域差异性。西北、东北、华北、华中和华东为单峰型,西南和华南为双峰型。华北、东北和华南。东北、华南和华北关键影响期较长。华北、东北、华中和华东夏季关键影响期作用最突出,西北和华南为春季,西南为夏季和冬季中后期。关键影响期不仅与干旱发生时间有关,更与作物种植结构、类型、生育期和抗旱能力有关。
[Abstract]:Drought is China's highest frequency, the most affected area, one of the most serious losses caused by natural disasters. With climate warming, significant changes have taken place in China's arid northern region, not only the drought disaster had been drought and extreme drought events increased, the South also showed an increasing trend, increasing drought disaster risk. Under the background of global warming, drought disaster is a new climate normal occurred in each region China, caused serious damage to the social economy and agricultural production. Because of the influence of drought disaster risk factors and its mechanism is complex and has regional differences, and the interaction between risk factors, differences in regional drought disaster risk is more obvious the climate types in China. One of the complex, belongs to sensitive area of global warming. Moreover, agriculture is a sensitive industry climate warming, and drought disaster risk The main disaster object. Under the background of climate warming, drought disasters caused more serious impact on agricultural production Chinese, agricultural drought disaster risk is expanding. In this study, China's drought disaster factors, characteristics and influence mechanism of risk as the research point to gas as comprehensive drought index (MCI) of disaster factor index for drought, temporal and spatial distribution of drought and its regional differences in China. The evaluation method of risk factors and historical drought disaster damage coupling simulation of two kinds of risk probability and statistics based on the study of China agricultural drought disaster risk characteristics are described. The effects of different periods of physical key climate elements of risk, reveal the impact of climate warming on agricultural drought disaster, drought disaster risk Chinese key clear effect. Research results to improve the drought disaster risk assessment in China, disaster prevention and mitigation capacity and risk management Providing a scientific basis, the main conclusions are as follows: (1) to fully understand the Chinese arid spatial and temporal variation characteristics, evolution and regional differences. 1961-2014 daily MCI based on the systematic analysis of the temporal and spatial variation features of drought in China. The results show that under the background of global warming, drought China scope, intensification and increasing frequency. At the same time, obviously the transfer range of drought, severe drought in northern and southern drought was aggravated, especially drought in the area was significantly increased. The late last century in 90s China -21 century drought scope, the longest, the most serious losses. China drought occurred mainly in the south of the Yellow River and the area north of the Yangtze River. The drought frequency is higher in the north than in the south, the east than the west, in the north of Yangtze River Basin drought frequency in the Yellow River basin drought frequency is greater than 30%. but not the same year, the drought The scope, extent, duration and frequency have certain difference. (2) based on risk factor coupling, comprehensive agricultural drought disaster risk assessment model is constructed, and a case study is conducted in the southwest region of China. GIS and RS technology based on the integration of comprehensive drought index (MCI), soil moisture, vegetation remote sensing inversion index, multi-source data of drought disaster and agricultural statistics. Considering the drought disaster factors, disaster mitigation, disaster environment and disaster prevention, agricultural drought disaster risk assessment model is constructed. Under the GIS platform, the Southwest drought disaster risk fine assessment. At the same time, according to the historical drought disaster loss probability the statistical calculation of comprehensive loss rate of drought disaster. Combining the risk factor and historical disaster damage coupled simulation statistics, system analysis of southwest agricultural drought disaster risk characteristics and its influence mechanism. The research shows that the Southwest Comprehensive agricultural drought risk has obvious zonality. The high risk areas of agricultural drought disaster are mainly located in the southwest of the East, the north is higher than the south. Different disaster causing factors, hazard bearing body, the difference ability of disaster environment and disaster prevention and mitigation in the agricultural drought risk comprehensive pattern complex. (3) analyzed the variation characteristics of agricultural China rate drought disaster, spatial differences and its response to climate warming. The historical drought disaster construction of drought disaster disaster rate, based on the hazard rate, rate of crops and comprehensive loss rate, nearly 50 years of drought disaster losses and China differences between the southern and Northern analysis. Research shows that, under the background of global warming, Chinese drought disaster disaster rate, rate. The rate of crops and comprehensive loss rate increased. The range and extent of the losses of agricultural drought disaster was significantly increased, the risk increased significantly, especially in the above drought loss growth faster. Affected by climate change Warm effect, Chinese South and North agricultural drought disaster losses significantly. Climate change after the northern agricultural drought disaster loss was significantly higher than that of the south, also increased than in the south, the North disaster loss is 3~4 times increase in the south, and more severe drought loss, increase more quickly. The north drought disaster losses mainly depends on precipitation, and the temperature dependence on the South than in the north. The effects of different periods of precipitation and temperature on agricultural drought losses of different precipitation and temperature only the key period has more significant influence on agricultural drought disaster loss rate. China temperature in late July, mid September and early June precipitation is crucial to agricultural drought damage. (4) stated the change of seven sub regional drought disaster losses Chinese characteristics. Under the background of climate warming, have significant regional differences in different grades of drought disaster losses. The loss rate of Northeast The annual average maximum (9.6%), followed by China (9.3%) and Northwest (8.4%), East (2.4%). The minimum comprehensive loss rate of the largest increase in North China, 1.4%/10a. climate change, northwest, North and southwest disaster rate showed an increasing trend, while the northeast, central, East Southern China and reduce the disaster rate of crops; and the rate of each area increased; comprehensive loss rate in China and other regions, were increased. Under the background of global warming, the regional drought disaster China showed an increasing trend, the more heavy disasters more sensitive to climate warming. The difference distribution of regional comprehensive loss rate in climate space significantly. (5) analyzed the influence drought on main grain crop yield. Chinese climate warming is not conducive to the overall China main grain crop yield increased, but the response of different crops to climate warming is slightly different. Climate warming on summer corn and rice, unfavorable, especially corn, the average yield of 0.9 Kg/10a. China grain crop production with the degree of drought weather tends to increase, especially for grain crops. Wheat and rice with meteorological drought severity tends to cut, and summer, spring wheat, corn and potato and the meteorological drought response is not obvious. (6) defined the agricultural drought disaster risk China key period. Effects of drought Chinese effect disaster risk critical period for late spring, summer and autumn before mid August peak. The drought disaster risk North key influence period and Chinese, South for the summer and autumn before the mid August, the most prominent key role. The North South long period is the key influence, more prominent role than the south. Chinese sub drought disaster regional risk key influence period and has significant differences between different regions. In the northwest, northeast, north, central and East China is unimodal, southwest and Southern China to Shuangfeng. The North China and Northeast China. South. The northeast, North China and Southern China key influence over a long period of time. In North China, northeast, central and East China in summer, the most prominent key influencing period, northwest and Southern China in spring, summer and winter in the southwest. The late period of drought and the key influence not only on time, and crop planting structure, type, growth period and related the ability of drought resistance.

【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S423

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