基于作物水分亏缺指数的湖北赤壁农业干旱特征及人工增雨需求分析

Analysis of agricultural drought characteristics and artificial precipitation enhancement demand in Hubei Chibi City based on crop water deficit index

摘要:

摘要：为了有效发挥人工增雨在农业抗旱中的重要作用，以湖北赤壁为研究区，利用2014—2023年逐日气温、降水观测资料，基于作物需水量公式和作物水分亏缺指数（Crop water deficit index，CWDI），确定了农作物干旱过程的识别和等级标准，构建了人工增雨需求指数及等级标准，深入分析了作物需水量、农业干旱以及人工增雨需求的时空分布特征。结果表明：（1）赤壁市作物需水量呈单峰型分布，峰值为7月下旬；旬作物需水量超过20 mm的时段集中于4月初至10月初；其累计作物需水量呈“X”形高低交错的空间分布，740～800 mm的高值区分布在中伙铺、官塘驿和新店等乡镇。（2）轻、中、重度干旱过程平均为8～10 d、18～20 d、25～35 d，特旱过程则在60 d以上，轻旱多发于12—5月，中等以上的干旱多发于6—10月；乡镇区域间干旱的频次和强度差异明显，极高强度区分布在赤壁、柳山湖、中伙铺等乡镇。（3）人工增雨需求的季节性特征明显，冬春季（12—5月）的等级低且频次少，夏秋季（6—11月）的等级高且频次多；需求程度呈现“边角高、中部低”的空间分布，东北角、西北角和西南角为高至极高需求区。（4）低等级人工增雨需求的出现是触发人工增雨作业的重要信号，低等级向中高等级的发展期是人工增雨的有效作业期；实践多次证明了人工增雨需求指标能帮助作业单位更有效、合理地安排农业抗旱的人工增雨作业计划。

Abstract:

Abstract: In order to effectively play the important role of artificial precipitation enhancement in agricultural drought resistance, taking Chibi city in Hubei Province as the research area,using the daily temperature and precipitation observation data from 2014 to 2023, based on the crop water requirement formula and crop water deficit index (CWDI),determined the identification and grade standard of crop drought process,and constructed the artificial precipitation enhancement demand index and grade standard. We deeply analyzed the spatial and temporal distribution characteristics of crop water requirement, agricultural drought and artificial precipitation demand. The results showed that:(1) The crop water requirement in Chibi City showed a unimodal distribution, with a peak in late July. The period during which the crop water requirement exceeds 20 mm is concentrated from early April to early October.The cumulative crop water requirement showed an 'X'-shaped high - and - low - scattered spatial distribution.The high - value area between740 mm and 800 mm was distributed in the towns such as Zhonghuopu, Guantangyi, Xindian, etc. (2) The light, medium and heavy crop drought processes last an average of 8 - 10days, 18 - 20days, 25 - 35days respectively, and the extreme drought process is more than 60days. Light drought occurs from December to May, and moderate and above -level droughts mostly occur in June - October. The frequency and intensity of drought among townships are significantly different; and the extremely high intensity areas are distributed in Chibi,Liushanhu,Zhonghuopu and other towns.(3)The seasonal characteristics of artificial precipitation demand are obvious. In winter to spring ( December-May ), the grade is low and the frequency is low. In summer to autumn (June-November), the grade is high and the frequency is high. The demand degree shows a spatial distribution of ' high in the angle area and low in the middle area ', with high to extremely high demand areas are distributed in the northeast, northwest and southwest angle areas.(4) The emergence of low level artificial precipitation enhancement demand is an important signal to trigger the artificial precipitation enhancement operation, and the development period of demand degree from low level to medium and high level is the effective operation period of artificial rain enhancement. The practice has proved many times that the artificial precipitation enhancement demand index can help the operation unit make the artificial precipitation enhancement operation plan for agricultural drought resistance more effectively and reasonably.