安徽省燃气炮人工增雨作业效果综合评估

Comprehensive Evaluation of Rainfall Enhancement of Gas Cannon in Anhui Province

选取2021—2023年安徽省81次燃气炮作业的双偏振天气雷达、雨量计等多源观测数据,综合评估燃气炮作业增雨效果并分析可能机理。结果显示:在降水开始前作业个例增雨效果较好,并伴有水平反射率因子Z_(H)、差分反射率Z_(DR)的增加和共极化相关系数ρ_(hv)的减少;降水开始后作业增雨效果欠佳。使用携带暖云催化剂的燃气炮作业后云体变化主要在零度层以下,且维持时间较短;使用携带冷云催化剂的燃气炮作业后暖云区和冷云区均有明显变化,且作业影响持续时间更长。燃气炮作业过程中雷达速度谱宽增大,可能是作业引起气流涡旋的增加所导致。统计结果显示:增雨的显著性与作业时长呈负相关,作业时长与Z_(DR)增量呈负相关,过量播撒会导致减雨;增雨的显著性与作业前影响区雨量呈负相关;增雨量与Z_(H)、中低层风速、风切变呈正相关,与高层风速呈负相关。

Gas cannon is a new type of equipment used for rainfall enhancement operating which comprehensively utilizes the influence of shock waves,sound waves,and catalysts to interfere with and catalyze local weather.At present,the use of gas cannons to conduct artificial weather operations in China is still in the experimental stage.Based on multi-source observations from dual-polarization weather radar,rain gauges and other equipment,the rainfall enhancement effect and the possible physical mechanism are comprehensively analyzed for 81 gas cannon operation cases in Anhui Province from 2021 to 2023.Observations of typical cases show that the effect of rainfall enhancement is better when the gas cannon is operated prior to the onset of rainfall,accompanied by an increase in the horizontal reflectivity factor Z_(H)and the differential reflectivity Z_(DR),and the decrease in the co-polarization correlation coefficientρ_(hv).However,the effectiveness is poor when the operation is after the start of rainfall.It is observed that the cloud undergoes significant changes primarily in the sub-zero layer following the use of warm cloud catalyst,and the cloud changes rapidly but effects are short-lived.On the other hand,when a cold cloud catalyst is used,the cloud undergoes obvious changes in both the warm cloud region and the cold cloud region with a greater effecting range and longer duration of effects.This may be attributed to the impact of the cold cloud catalyst on the ice phase microphysical processes within the cloud.The increase in radar velocity spectrum width(S_(W))during the operation of a gas cannon may be caused by the increase in air vortex.Statistical results of hourly rainfall enhancement show that the number of cases of significant rainfall enhancement from the gas cannon is slightly higher than that of significant rainfall reduction.Among the three different types of operation timing,the rainfall enhancement effect is best for Type 2(rainfall operation at the beginning).The significance of rainfall enhancement is negatively correlated with the duration of the operation,while the duration of the operation is negatively correlated with the increment of Z_(DR).Excessive sowing can lead to a reduction in rainfall.The significance of rainfall enhancement is negatively correlated with the amount of rainfall in the affected area prior to the operation.After the beginning of rainfall,the operational effectiveness of the gas cannon is poor.The rainfall enhancement is positively correlated with Z_(H),as well as with middle and low-level wind speed and wind shear.However,the enhancement of rainfall is negatively correlated with high-level wind speed.The high wind speed in the middle and high levels is not conducive to enhancing the rainfall through gas cannon operation.These results provide physical evidence for the effect of a gas cannon on cloud microphysical structure and rainfall.