Urban Influences on Clouds, Precipitation and Lightning

在该奖项下，首席研究员将继续研究城市环境对云和降水的影响。在美国国家科学基金的支持下，敏感性实验的结果表明，城市热岛是主要城市地区下风深层潮湿对流的一个诱发因素。由城市热岛驱动的地表辐合在城市背风侧增强。城市动量阻力与城市热岛的非线性相互作用导致城市顺风对流，降水增加。地形也会影响风暴的发展。根据目前的合同，首席研究员将进行以下活动：-模拟增强云凝结核和巨大云凝结核浓度对对流的影响。-城市地区对中尺度对流系统影响的理想模式和案例研究。-参与休斯顿环境气溶胶雷暴项目（HEAT）。HEAT正处于规划阶段，是一个由多个研究者组成的项目，旨在调查城市环境对天气的影响。首席研究员的建模工作将有助于本项目的规划。-模拟城市对有利于闪电的对流和云结构的影响。这项研究将有助于从根本上了解主要城市中心对对流风暴、闪电和降水的影响。这项研究将对城市土地利用规划产生更广泛的影响。这项工作的教育效益是，其成果将立即纳入第一年的课程内容和云物理和云动力学高级课程，以及由首席研究员合著的教科书“人类对天气和气候的影响”。

Under this award, the Principal Investigator will continue research on the influence of the urban environment on clouds and precipitation. Under prior NSF support, which was focused on dynamical influences, results of sensitivity experiments have shown that the urban heat island is a factor in inducing deep, moist convection downwind of a major urban area. Surface convergence driven by the urban heat island is enhanced on the leeward side of the city. The nonlinear interaction between urban momentum drag and the urban heat island causes convection downwind of the urban area with a concomitant increase in precipitation. Topography is also shown to impact storm development.Under the current award, the Principal Investigator will undertake the following activities:-Modeling the effects of enhanced cloud condensation nuclei and giant cloud condensation nuclei concentrations on convection.-Idealized modeling and a case study of impacts of an urban area on mesoscale convective systems.-Participation in the Houston Environmental Aerosol Thunderstorm Project (HEAT). HEAT is in the planning stages and is a multi-investigator program designed to investigate the influence of the urban environment on weather. The Principal Investigator's modeling work will be helpful in the planning of this project.-Modeling urban impacts on convection and cloud structures favorable for lightning.This research will contribute to fundamental understanding of the influence of major urban centers on convective storms, lightning, and precipitation. The broader impacts of this research will be on urban land-use planning. The educational benefit is that results of this work will be immediately incorporated in the course content of first year and advanced courses in cloud physics and cloud dynamics, as well as in the textbook "Human Impacts on Weather and Climate" co-authored by the Principal Investigator.