利用耦合了碘化银催化过程的WRF(Weather Research and Forecast)模式,对2014年8月16日南京青奥会开幕式当天实施的人工催化作业开展数值模拟,评估催化效果并通过敏感性数值试验调查低空环境干层对催化效果的影响.结果表明,催化作业产生了减雨效果,低空干区的存在是影响催化效果的关键.当低空存在深厚的相对湿度很小的干层时,催化导致减雨效果;当增加低层的相对湿度即弱化低空干层,催化减雨效果减弱甚至出现增雨效果.催化增强了雪的形成过程但减弱了雪的增长过程尤其是凝华增长,导致雪粒子浓度增加但粒径减小,融化产生更多的小雨滴增强了蒸发过程,最终导致地面降水减少.
Numerical Simulation of the Effect of the Subcloud Dry Layer on Cloud Seeding for Rain Suppression
To study the cloud-seeding effects during the opening ceremony of the Nanjing 2014 Youth Olympics Games,a silver iodide cloud-seeding parameterization was implemented to the Thompson microphysics scheme of the Weather Research and Forecast(WRF)model.The results revealed that surface precipitation was decreased due to seeding,and the subcloud dry layer played a key role in modifying seeding effects.Furthermore,a low relative-humidity environment was favorable for rain suppression by cloud seeding;however,under a high relative-humidity environment,the opposite effect was observed.Cloud seeding enhanced the formation of snow,but weakened its growth,specifically deposition growth.Thus,the concentration of snow increased,but its size decreased.The snow melted and turned into a large number of small raindrops,which evaporated easily;hence,the precipitation on the ground was less.
Cloud seeding operation for rain suppressionSilver iodide seedingSubcloud dry layerMelting of snowEvaporation of rain
万方数据
维普
