论河南“75.8”特大暴雨的研究:回顾与评述

“75.8”河南特大暴雨的发生已经过去40年了,它在人们的记忆中留下深刻的印象。这场暴雨在1975年8月5—7日3 d之内在河南南部的局部地区降下了1605 mm的总雨量,1、3、6、12 h雨量均破中国降水的历史记录。由于水库垮坝,洪水夺走了该区约2万6千人的生命,经济损失巨大。在这40年间,中国的暴雨研究和预报都取得了重大的进展。其中一个重要原因是中国的气象和水文部门从这场空前强烈的大暴雨和大洪水事件中吸取了宝贵的经验教训,多年来,以这场超级大暴雨洪水为借鉴,不断促进和鼓励中国气象学家向暴雨研究和预报发展的更高目标前进。有感于此,回顾和评述了当年老一辈科学家在比较艰苦的条件下所进行的这次大暴雨的研究活动,以及所获得的卓越科学成果。即使从今天来看,其中不少成果也具有创新性的意义,在中国暴雨研究的发展史上,占有十分重要甚至里程碑式的地位。文中重点对其中的关键科学问题进行了评述,包括:(1)“75.8”特大暴雨的雨情和极值;(2)“75.8”特大暴雨发生的原因;(3)“75.8”特大暴雨的动力诊断;(4)暴雨中尺度分析;(5)地形对暴雨的增幅作用。希望以此纪念河南“75.8”特大暴雨发生40周年,并表达对参与此次研究活动的老一辈科学家深深的怀念和敬意。

On the study of the unprecedented heavy rainfall in Henan Province during 4-8 August 1975: Review and assessment

The occurrence of the unprecedented heavy rainfall in Henan Province during 4-8 August 1975 ("75.8" rainstorm in short hereafter) has passed for 40 years. It has made a deep imprint for us. This event of heavy rainfall produced downpour of the total amount of precipitation of 1605 mm during three days (5-7 August 1975) in a local area of southern part of Henan Province, with rainfall intensity within 1, 3, 6 and 12 h breaking historical records in China. Due to collapse of dams of many reservoirs, about 26000 people were killed by the abrupt floods and huge economic losses were made. During the past 40 years, the research and prediction of heavy rainfalls have made significant progress, one important cause, among others, is the impetus of valuable experiences and lessons that we learnt from this unusually strong rainstorm. For many years, with this event of mega-rainstorm and flood as reference, we have been continuously promoted and encouraged to endeavor toward a higher goal in the areas of research and prediction of heavy rainfalls. For this purpose, the present author has made this review and assessment to memorize the follow-up research activities undertaken in hard conditions during that time period by the old generation of Chinese meteorologists and excellent achievement derived by them. Even for today, many of them are of innovative significance and can be regarded as a substantial or milestone success. The paper will assess the following five key scientific issues: (1) the observed precipitation amount and extreme values of the "75.8" rainstorm, (2) causes of occurrence of the "75.8"rainstorm, (3) dynamical and diagnostic analysis, (4) mesoscale analysis and its important role, and (5) topographic amplification effect. It is my hope to commemorate the 40th anniversary of the occurrence of the "75.8" rainstorm with the paper, and to pay tribute and memory to all predecessor scientists who engaged in research activities of the "75.8" rainstorm.