气候条件对气象干旱与农业干旱耦合关系的影响

以多时间尺度SPEI干旱指数代表气象干旱,农业气象观测站观测的多层土壤体积含水量历史数据作为农业干旱的代表因子,在中国东部亚热带季风气候区、中部大陆性季风气候区和西部中温带干旱气候区探究了气象干旱和农业干旱间的耦合关系,并结合时间延迟进行分析。结果显示：中部地区整体相关性最好,西部最差,其中高相关区域在不同气候区有所差异,越干旱的地区与土壤水分更相关的是越长时间尺度的SPEI,西、中、东部站点最优时间尺度分别为9月、6月、4月尺度。土壤表层的降水在一月内即可下渗至50 cm深度并储存在此深度附近,待干旱时补充表层土壤水分。气象干旱和农业干旱均是水分亏缺现象,但是响应时间并不相同,探究其耦合关系对于提升对干旱机理的认识、提高干旱监测水平、助力防旱抗旱具有重要意义。

Climate Conditions: Effects on Coupling Relationship Between Meteorological Drought and Agricultural Drought

Based on multi-time scale SPEI representing meteorological drought, and the historical multi-layers soil volumetric water content data from agro-meteorological stations as representative factors for agricultural drought, we explored the coupling relationship between meteorological drought and agricultural drought in subtropical monsoon climate region in eastern China, continental monsoon climate region in central China and moderate temperature arid climate region in western China, and conducted the analysis in combine with time delay as well. The results showed that: the overall correlation in the central region was the best, the worst was in the west, among them, the high correlation region had differences in different climatic regions, the longer time-scale of SPEI was more relevant with soil moisture in drier regions, the optimal time scale in western, central and eastern regions was September, June, April, respectively; precipitation infiltrated from soil surface to 50 cm depth within a month and then stored near that depth, to replenish surface soil moisture in the event of drought. Meteorological drought and agricultural drought are both water shortage phenomena, but the response time is not the same. Exploring the coupling relationship between the two is significant for enhancing the awareness of drought mechanism, as well as improving the ability of drought monitoring and mitigating and preventing drought.