区域干旱过程模拟和农业干旱风险评价及应对研究

Abstract:This fund takes Liaoning Province as research area, which is a region seriously affected by agricultural drought disasters. By means of certain-point experiment, site observation, remote sensing refutation and crop-grown model, a drought disaster forecast model is established from the perspective of precipitation-evaporation-runoff yield of hydrologic cycle angle to simulate the development process of drought in a condition of lower precipitation, based on the support of grid distributed hydrographical model. At the same time, in order to reveal the space-time evolution rule and the dominant influence factors of drought developemnt, a soiltilth simulation model based on soil moisture balance simulation modesl and a soiltilth forecast model based on GFS precipitation prediction imformation were put forward, and a dynamic indicator system and a drought comprehensive assessment method reflect major characteristic of drought development were further proposed. Considering all the characteristics of drought risk such as danger, openness, vulnerability and drought disaster prevention and mitigation capacity, the fuzzy variable set approach and projection pursuit technique were applied to comprehensive assessment of agricultural drought disasters risk, and agricultural drought risk planning charts were made.We conduct the analysis on the suitability of corn planting in the summer, and make decision on the corn planting arrangement in the study area based on the risk assessment.Through the research of basic issues, such as the formation mechanism of drought disaster risk, risk identification and estimation model, drought risk assessment index system, drought disaster risk model, crop growth simulation model and so on. Analyzing regional agricultural drought risk response plans of different drought scene and different risk level and combining with the inducement mechanism of regional agricultural drought risk, regional agricultural drought risk avoidance scheme in the macroscopic level was put forward in this paper.

本基金以受旱灾影响严重的辽宁省为研究区，通过定点实验、站点观测、遥感反演以及作物生长模型等手段，从降水－蒸发－产汇流等流域水循环角度，构建改进的PDSI的辽宁省干旱发展过程模拟模型、基于土壤水量平衡模型的土壤墒情模拟模型和基于GFS降水预报信息的土壤墒情预报模型，揭示干旱发展的时空演变规律，提出干旱特性动态指标体系及旱情综合评估方法。通过对干旱灾害风险机理、风险识别及估测模型、干旱风险指标、干旱灾害风险模型等基础问题的研究，考虑危险性、暴露性、脆弱性及抗旱减灾能力，将可变模糊集和投影寻综技术应用于农业干旱风险评价中，形成风险区划图。根据风险评价结果对夏玉米种植适宜度进行分析，确定研究区玉米种植布局。结合未来变化条件下干旱灾害演变趋势，分析不同干旱情景、不同风险水平下区域农业旱灾风险应对预案。从水土资源调控方面提出干旱灾害的整体、分类型与分区域的风险应对策略，并分析风险应对策略的实施效果。

在气候变化和人类活动的影响下，干旱在我国呈现出广发和频发态势。干旱不仅对工农业生产造成影响，波及城乡居民生活用水安全，严重时还会给生态环境带来重大危害，影响经济社会可持续发展。本基金利用数据较为完整的黄淮海流域历年气象、水文、土壤湿度、干旱灾害等资料对帕默尔干旱指数进行改进，基于建立的黄淮海流域帕默尔干旱指数从干旱时空演变规律以及历史典型旱情特征等角度对该地区进行系统分析。以辽宁西北部为典型示范区，基于辽西北地区40个代表站的基础数据应用经验正交函数分解法归纳了辽西北地区降雨时空演变特征，且采用周期叠加模型、均生函数模型及时间序列分析模型，预测了辽西北地区未来降水趋势；基于土壤水量平衡模型、BP神经网络及Penman-Monteith公式，分析了土壤墒情对作物ET变化的响应，发现作物ET变化对土壤墒情的变化影响并不很大，而降水是影响土壤墒情变化的主要因子。从干旱的危险性、暴露性、脆弱性和抗旱能力角度出发，综合考虑区域气象水文条件、土壤状况、作物种植情况、农田灌溉能力、区域抗旱减灾能力等指标，建立了农业干旱风险评价体系；以模糊综合评价法为理论基础，结合区域干旱特点，建立了适用于辽西北部地区的干旱风险综合评价模型，编制了辽西北地区主要农业县的干旱风险图。在此基础上，通过修正Z指数综合评价了区域旱情，发现辽西北干旱指数总体呈上升趋势，区域上呈现由东南向西北递减；结合可变模糊评价法、经验正交函数分解法将辽西北地区划分为4个干旱等级区域，并预测未来辽西北地区旱情将持续发生。结合干旱灾害演变规律及趋势预测，对华北、西南、西北及东北地区抗旱中存在的问题进行探讨，从水土资源调控方面提出干旱灾害整体、分类型与分区域的风险应对策略和应对策略的实施效果，以期为实现区域干旱有效治理提供科学依据。