Comprehensive Evaluation of Rainfall Enhancement of Gas Cannon in Anhui Province
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 comprehen-sively 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 ZH and the differential reflectivity ZDR,and the decrease in the co-polarization correlation coefficient ρhv.However,the effective-ness is poor when the operation is after the start of rainfall.It is observed that the cloud undergoes signifi-cant changes primarily in the sub-zero layer following the use of warm cloud catalyst,and the cloud chan-ges rapidly but effects are short-lived.On the other hand,when a cold cloud catalyst is used,the cloud un-dergoes 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(Sw)during the operation of a gas cannon may be caused by the increase in air vortex.Statistical results of hour-ly rainfall enhancement show that the number of cases of significant rainfall enhancement from the gas can-non is slightly higher than that of significant rainfall reduction.Among the three different types of opera-tion 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 ZDR.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 effective-ness of the gas cannon is poor.The rainfall enhancement is positively correlated with ZH,as well as with middle and low-level wind speed and wind shear.However,the enhancement of rainfall is negatively corre-lated with high-level wind speed.The high wind speed in the middle and high levels is not conducive to en-hancing the rainfall through gas cannon operation.These results provide physical evidence for the effect of a gas cannon on cloud microphysical structure and rainfall.
gas cannonartificial rainfall enhancementdual polarization weather radarmulti-source ob-servation
NETL
NSTL
万方数据
维普
