Collaborative Research: Understanding Relationships between First Lightning, In-cloud Microphysics and Satellite-Observed Cumulus Cloud-top Properties

本研究的重点是加强对地球静止运行环境卫星（GOES）和中分辨率成像光谱仪（MODIS）卫星观测、总闪电信息和与对流云中闪电（所谓的第一次闪电）引发机制相关的极化雷达场之间相互关系的理解。一个有待检验的假设是，人们可以在一个地区的对流云中估计闪电事件的发生、强度和特征（即，根据一段时间内的闪电率，预计闪电的相对数量）。在对流云中闪电远不是无处不在，因此存在相当大的不确定性，为什么某些风暴是多产的闪电产生者，而附近的其他风暴可能不是。该项目的目标是：(1)开展基础研究，将GOES卫星观测到的（红外）对流云生长特性与这些云中的闪电特征（云内与云对地）和强度，以及与云内双极化多普勒雷达观测到的微物理分布的关系联系起来；(2)通过描述卫星和双极化多普勒雷达在不同环境下观测到的闪电和对流云发展的一般特征，加强对对流状态的理解；(3)利用GOES和MODIS将当前能力扩展到临近预报（0-90分钟）闪电事件。知识价值：这项研究将有助于人们更好地理解闪电、云微物理和不断增长的积云的卫星观测之间的相互关系。这项研究将利用现有的气象试验台，包括双极化雷达、闪电测绘阵列、GOES、MODIS和热带降雨测量任务（TRMM）观测，以及一个移动雷达。闪电密度将在空间和时间上与霰、冻结高度和冰分布相关（所有这些都是从极化雷达推断的），并与GOES云顶冷却速率进行比较，作为云内垂直质量通量、积云生长和云顶微物理的估计。对积云电气化、充电和闪电类型的见解将随后从这项研究中发展出来。更广泛的影响：目前由主要研究人员开发的对流启动（CI）预报技术已经在联邦航空管理局的航空天气研究计划和国家气象局进行评估。因此，这些机制已经到位，使这项研究能够立即影响到广泛的操作社区。此外，与其他大学科学家和研究生的合作将进一步将这项研究扩展到更大的学术和教育界。

This research focuses on enhancing understanding of the inter-relationships between the Geostationary Operational Environmental Satellite (GOES) and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations, total lightning information, and polarimetric radar fields related to the mechanisms that initiate lightning within convective clouds (so-called first lightning). A hypothesis to be tested is that one can estimate the onset, intensity and character of lightning events (i.e. the relative amount of lightning expected, in terms of flash rates over time) in convective clouds across a region. Lightning within convective clouds is far from ubiquitous, and therefore considerable uncertainty exists as to why certain storms are prolific lightning producers, while others nearby may not be. The project goals are: (1) Perform basic research to relate GOES satellite-observed (infrared) convective cloud growth properties to the character (intra-cloud versus cloud-to-ground) and intensity of lightning in these clouds, and to the relationship to in-cloud dual-polarimetric Doppler radar-observed microphysical distributions; (2) Enhance understanding of convective regimes by describing the general characteristics of lightning and convective cloud development as observed by satellite and dual-polarimetric Doppler radar in various environments; (3) Extend current ability to nowcast (0-90 minutes) lightning events using GOES and MODIS. Intellectual Merit: The research will lead to an improved understanding of the interrelationships between lightning, cloud microphysics, and of satellite observations of growing cumulus. This research will take advantage of an exiting meteorological testbed that includes dual-polarimetric radar, lightning mapping array, GOES, MODIS and Tropical Rainfall Measuring Mission (TRMM) observations, and a mobile radar. Density of lightning will be correlated in space and time to graupel, freezing altitudes and ice distributions (all inferred from polarimetric radar), and compared to GOES cloud-top cooling rates as an estimate of in-cloud vertical mass flux, cumulus cloud growth, and cloud-top microphysics. Insights into cumulus cloud electrification, recharge, and lightning types will be subsequently developed from this research. Broader Impact: A current CI (convective initiation) forecasting technique developed by the Principal Investigators is already being evaluated within the Federal Aviation Administration's Aviation Weather Research Program and the National Weather Service. The mechanisms, therefore, are in place for this research to immediately impact a broad operational community. In addition, collaboration with other university scientists and graduate students will further extend this research to the larger academic and educational community.