为了定量评估气候变化背景下中国西北地区作物干旱灾害损失,本研究以甘肃省春玉米为例,构建了用于春玉米干旱灾损评估的生物气象指标——DI指数,该指标由CI指数和水分适宜度构成,前者反映中长期降水和热量条件的作用,后者表征作物供水与生理需水的关系。在对该指标进行了验证分析和可行性评价的基础上,以干旱减产和生长季降水量为依据对DI指数进行了等级划分,分别表示轻、中、重、特重干旱。利用气象台站逐日降水量和气温、玉米单产和总产、发育期和生理需水量资料反演了历史逐日DI指数,计算了累积DI指数,给出玉米种植区代表站春玉米DI指数时空变化规律,对农业种植制度调整、作物布局和防灾减灾具有一定的实际意义。

In order to quantitatively evaluate the crop disaster losses caused by drought in northwest of China in the context of climate change, a Bio-meteorological Index-DI, that is used to quantitatively evaluate the drought loss of spring corn in Gansu Province, China, is built. The DI index consists of CI index and water fitness. The former reflects the role of the medium- and long-term precipitation and heat condition; the latter represents the relationship between the water supply and physiological water demand of corp. According to the drought-reduced and growing season precipitations, the DI index is divided into four degrees, that is, mild drought, moderate drought, serious drought, and particular heavy drought, respectively based on the verification analysis and feasibility evaluation of the DI index. The historical daily DI index and accumulated DI index are backward calculated by using the materials of daily precipitation and temperatures collected from the meteorological stations, the corn yields and total productions, developmental and physiological water demand. The temporal and spatial variations of spring corn DI index for the representative stations in the growing areas have some practical significance on the agricultural crop system adjustment, crop allocation, and disaster prevention and mitigation.