农业干旱与气象干旱关联性——以淮河蚌埠闸以上地区为例

基于淮河蚌埠闸以上地区60个站点1961—2015年气象数据,计算作物水分亏缺指数（Crop Water Deficit Index,CWDI）与相对湿润度指数（Relative Moisture Index,M）,以冬小麦干旱作为农业干旱的代表,分析生育期内冬小麦干旱与气象干旱时空特征,并通过游程理论识别30场主要干旱事件的历时、烈度及重现期频率,展开农业干旱与气象干旱关联性研究,结果表明：（1）时间上,冬小麦生育期内农业干旱旱情年占比均高于气象干旱,年际差最多年份均发生在冬前生长期;（2）空间上,全生育期和各个生育期内的冬小麦干旱和气象干旱呈纬向分布,由南至北旱情逐渐加重,冬小麦干旱75%以上中旱占比发生在越冬期至灌浆成熟期,气象干旱仅在越冬期出现;（3）冬小麦干旱相较气象干旱存在延时,且烈度大于气象干旱,平均历时分别为18.8旬和17.3旬,平均烈度分别为12.2和9.9;（4）气象干旱历时达到1.28旬或干旱烈度达到3.35时,便会引发冬小麦干旱,且冬小麦干旱历时、烈度重现期频率大于气象干旱,农业干旱较气象干旱持续周期更长、频率及强度更大,气象干旱加剧农业干旱旱情。

Agricultural drought and its association with meteorological drought: A case study of the Huaihe River Basin above the Bengbu Sluice,China

Based on the meteorological data of 60 stations above the Bengbu Sluice of Huaihe River from 1961 to 2015, crop water deficit index (CWDI) and relative moisture index (M) were calculated. By taking winter wheat drought as the representative of agricultural drought, the temporal and spatial characteristics of winter wheat drought and meteorological drought during the growth period were analyzed. The duration, severity and frequency of 30 major drought events were identified through the run theory, and the correlation between agricultural drought and meteorological drought was studied. The results showed that: (1) In terms of time, the proportion of agricultural drought in winter wheat growth period was higher than that of meteorological drought, and the years with the largest interannual difference occurred in the pre-winter growth period; (2) In terms of space, the winter wheat drought and meteorological drought in the whole growth period and each growth period were distributed by zonal mode structure, and the drought gradually increases from south to north. More than 75% of the drought of winter wheat occurs from over-wintering period to filling and mature period, while meteorological drought only occurred during over-wintering period; (3) Winter wheat drought was delayed compared with meteorological drought, and its intensity was greater than that of meteorological drought. The average duration was 18.8 dekad and 17.3 dekad, respectively, and the average severity was 12.2 and 9.9, respectively; (4) When the duration of meteorological drought reached 1.28 dekad or the drought severity reached 3.35, the drought of winter wheat will be triggered, and the frequency of the duration and severity return period of winter wheat drought was greater than that of meteorological drought. Agricultural drought has a longer duration, greater frequency and greater severity than meteorological drought and meteorological drought aggravates agricultural drought.