The Physical and Meteorological Characteristics Associated with Lightning Flashes

9806189奥维尔我们批准使用来自国家闪电探测网络(NLDN)的数据以及来自雷达和卫星观测的支持信息，延长美国国家科学基金会ATM-92 13787的三年。我们将同时进行这项拟议研究的两个部分。首先，我们建议继续调查与云对地闪电有关的物理和气象条件。这将包括以下领域的继续分析：a)美国的NLDN闪电记录，包括峰值电流、极性和多重性及其随季节、月份、风暴和风暴内的年际变化，b)德克萨斯州中尺度对流复合体中闪电的研究，c)活跃闪电日数的预报，d)冬季闪电的特征。其次，我们将通过确定云对地闪电中正闪电次数增加和年平均峰值电流降低背后的原因来调查NLDN的可靠性。我们将使用最近安装的高级闪电方向探测仪和布鲁克波形数字化记录系统来获取德克萨斯农工大学几百公里范围内的闪电波形。我们还建议在德克萨斯州的大学站测量NLDN的检测效率。这项研究将有助于直接参与拟议研究的几名研究生的教育，其中将包括他们在数据获取和分析方面的分享。这项建议包括对研究生的支持，他们将撰写论文和论文，并在研讨会和专业会议上展示他们的结果，并撰写手稿描述他们的研究。研究成果将被纳入云物理和中尺度现象的高级课程。本科生将来自气象系、电气工程系和计算机科学系。

9806189 Orville We grant a three-year continuation of NSF ATM-92 13787 using data from the National Lightning Detection Network (NLDN) with supporting information from radar and satellite observations. There are two parts to the proposed research that we will simultaneously pursue. First, we propose to continue our investigations into the physical and meteorological conditions associated with cloud-to-ground lightning flashes. This will include continued analysis in the following areas, a) NLDN lightning records in the United States, to include peak currents, polarity, and multiplicity and their variation from year to year, with seasons, from month to month, from storm to storm, and within storms, b) research on the lightning in mesoscale convective complexes in Texas, c) the forecasting of active lightning days, and d) the characteristics of winter lightning. Second, we will investigate the NLDN reliability by determining the reasons behind the increased positive flash counts and lowering of the annual mean peak current in cloud-to-ground flashes. We will do this by using a recently installed Advanced Lightning Direction Finder and a Brook waveform digitizing recording system to obtain waveforms on lightning within a few hundred kilometers of Texas A&M University. We propose, also, to measure the detection efficiency of the NLDN at College Station, Texas. This research will contribute to the education of several graduate students who will directly participate in the proposed research, which will include their sharing in data acquisition and analysis. Included in this proposal is support for graduate students who will write theses and dissertations and present their results at seminars and professional meetings, and write manuscripts describing their research. Research results will be incorporated into advanced courses on cloud physics and mesoscale phenomena. Undergraduates will be involved from the Departments of Meteorology, Electrical Engineering, and Computer Science.