Thursday, 26 January 2012: 11:45 AM
Satellite Data Applications for Nowcasting of Cloud-to-Ground Lightning Initiation
Room 245 (New Orleans Convention Center )
Cloud-to-ground lightning represents a considerable safety threat for aviation operations, particularly at the airport terminals. Baggage-handlers, aircraft refuelers, food caterers, and emergency personnel are all exposed to the risk of being struck by lightning. Lightning forecasts at US airports are typically based upon a combination of data from lightning detection networks and in situ electric field measurements. This poster will address the feasibility of using GOES satellite data to produce 0-1 hr cloud-to-ground lightning initiation (LI) nowcasts over the Southeastern U.S. and near-shore regions along the Gulf of Mexico. The initiation of lightning is thought to occur as a result of charge separation in the mixed-phase region of a convective cloud where graupel and supercooled water co-exist. A sufficiently strong updraft is also required to maintain the particle interactions required for charge separation. NASA's SATellite Convection AnalySis and Tracking (SATCAST) convective initiation nowcasting system has been modified to infer these LI mechanisms from geostationary satellite data. A novel aspect of this study is the use of the GOES 3.9 micron band reflectivity and its trend to detect clouds that have recently undergone glaciation. In addition to glaciation, a sharp drop in cloud top temperature detected by the 15-minute trend in the GOES 10.7 micron brightness temperature is also an important indication that the storm cloud is rapidly growing upward, suggesting a very recent and large flux of water and ice in the mixed-phase region of the cloud. The SATCAST system produces additional indicators from the GOES 6.7 and 13.3 micron bands that infer cloud growth rate and vertical extent, and these indicators may also help to identify LI. This poster will address the feasibility of using the satellite-based indicators to nowcast cloud-to-ground LI and discuss possible applications of the nowcasts for airport terminal safety.
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