Pseudo Geostationary Lightning Mapper (PGLM) Product Details
RESEARCH DETAILS
Pseudo Geostationary Lightning Mapper 8km Flash Extent Density
SPoRT is a collaborator in the GOES-R Proving Ground for several projects. In particular, SPoRT has a leading role preparing end users for the Geostationary Lightning Mapper (GLM) thanks to the program's expertise in utilizing total lightning data operationally. The initial emphasis was for SPoRT to provide traning and transition expertise for the Algorithm Working Group's (AWG) GLM proxy product. However, this proxy product is not yet ready for evaluation by end users. To help support the GOES-R Proving Ground until the GLM proxy is available, SPoRT has produced a series of demonstration products called the Pseudo Geostationary Lightning Mapper (PGLM). One of these products is the PGLM Flash Extent Density (FED), which shows how many flashes are observed in a given grid box.
Like the GLM proxy, the PGLM products are derived from ground-based total lightning networks. However, the PGLM products are a very simple product compared to the GLM proxy. The proxy attempts to use coincident observations from the polar orbiting Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) along with the ground-based total lightning observations. This is because the TRMM LIS is the closest on orbit instrument to what the future GLM instrument will be. The AWG's proxy is designed to transform ground- based total lightning observations into a close reproduction of what the GLM will eventually see. Conversely, the PGLM products, do not use this space-based optical data. Without this, the PGLM is, at best, a tool to demonstrate the basic capabilities of total lightning data at the GLM spatial and temporal resolution.
While not as sophisticated as the GLM proxy, the PGLM is still an important tool in preparing end users for the eventual launch of the Geostationary Lightning Mapper. Unlike the AWG's proxy product, the PGLM products can easily be adapted to any ground-based total lightning network. Currently, SPoRT is producing the PGLM flash extent density product for the networks in North Alabama, Washington D.C., Kennedy Space Center, and Norman, Oklahoma. This ease of product allows the PGLM to be used over a wider area, providing more opportunities for the GOES-R Proving Ground to train forecasters. Although a simple product, the PGLM is a very useful tool. It provides a way to train forecasters about total lightning and its applications. Also, the PGLM flash extent density prepares end users for the basic spatial and temporal resolution the GLM data will have. Lastly, by providing the PGLM to end users now, these end users have the ability to provide developers valuable information on the best products to develop, such as this flash extent density, and how best to visualize these products in the AWIPS II environment. Ultimately, these lessons will be used to transition the AWG's proxy product, when it is available, and provide Day 1 readiness for the GLM data when the GOES-R satellite is launched.
The PGLM Flash Extent Density product is one variant of the basic Pseudo Geostationary Lightning Mapper products. It is produced by first taking the raw, observations from a ground-based total lightning network. These raw observations, or sources, are the individual components of a lightning flash, namely the stepped leaders. Using a flash creation algorithm, the sources are recombined into lightning flashes. These flashes are then placed on to an 8x8 km grid, similar to the GLM's resolution. Next, each grid box sums the number of flashes within it, counting each flash only once. This sum is what is now called the flash extent density. The extent part of the name refers to the fact that the product shows the horizontal, spatial coverage of lightning within the domain. The higher values most closely correspond to the cores of thunderstorms. End users look for rapid increases in this observation to indicate that a storm is rapidly strengthening and may produce severe weather. The spatial coverage provided, allows end users to monitor the overal threat of where lightning may occur and potential produce a cloud-to-ground strike.
RESEARCH DETAILS
Pseudo Geostationary Lightning Mapper 8km Flash Initiation Density
SPoRT is a collaborator in the GOES-R Proving Ground for several projects. In particular, SPoRT has a leading role preparing end users for the Geostationary Lightning Mapper (GLM) thanks to the program's expertise in utilizing total lightning data operationally. The initial emphasis was for SPoRT to provide traning and transition expertise for the Algorithm Working Group's (AWG) GLM proxy product. However, this proxy product is not yet ready for evaluation by end users. To help support the GOES-R Proving Ground until the GLM proxy is available, SPoRT has produced a series of demonstration products called the Pseudo Geostationary Lightning Mapper (PGLM). One of these products is the PGLM Flash Extent Density (FED), which shows how many flashes are observed in a given grid box.
Like the GLM proxy, the PGLM products are derived from ground-based total lightning networks. However, the PGLM products are a very simple product compared to the GLM proxy. The proxy attempts to use coincident observations from the polar orbiting Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) along with the ground-based total lightning observations. This is because the TRMM LIS is the closest on orbit instrument to what the future GLM instrument will be. The AWG's proxy is designed to transform ground- based total lightning observations into a close reproduction of what the GLM will eventually see. Conversely, the PGLM products, do not use this space-based optical data. Without this, the PGLM is, at best, a tool to demonstrate the basic capabilities of total lightning data at the GLM spatial and temporal resolution.
While not as sophisticated as the GLM proxy, the PGLM is still an important tool in preparing end users for the eventual launch of the Geostationary Lightning Mapper. Unlike the AWG's proxy product, the PGLM products can easily be adapted to any ground-based total lightning network. Currently, SPoRT is producing the PGLM flash extent density product for the networks in North Alabama, Washington D.C., Kennedy Space Center, and Norman, Oklahoma. This ease of product allows the PGLM to be used over a wider area, providing more opportunities for the GOES-R Proving Ground to train forecasters. Although a simple product, the PGLM is a very useful tool. It provides a way to train forecasters about total lightning and its applications. Also, the PGLM flash extent density prepares end users for the basic spatial and temporal resolution the GLM data will have. Lastly, by providing the PGLM to end users now, these end users have the ability to provide developers valuable information on the best products to develop, such as this flash extent density, and how best to visualize these products in the AWIPS II environment. Ultimately, these lessons will be used to transition the AWG's proxy product, when it is available, and provide Day 1 readiness for the GLM data when the GOES-R satellite is launched.
The PGLM Flash Initiation Density product is one variant of the basic Pseudo Geostationary Lightning Mapper products. This was requested by end users during the 2010 Spring Program and has been created for use during the 2011 Spring Program for the GOES-R Proving Ground. It is produced much like the PGLM flash extent density. First the raw observations from a ground-based total lightning network are taken. These sources are the individual components of a lightning flash, namely the stepped leaders. Using a flash creation algorithm, the sources are recombined into lightning flashes. From there, the first source of each flash (based on when it occurred) is selected. These flash initiation points are then placed on to an 8x8 km grid, similar to the GLM's resolution. Next, each grid box sums the number flash initiation points within it. This sum is what is now called the flash initiation density. The PGLM flash initiation density was requested as a way to create a product that only focuses on the main lightning production regions in a storm. Additionally, this product can show whether or not flashes are initiating in the stratiform region of a storm or are expanding into this region from a flash initiating closer to the storm's core. Like the PGLM flash extent density product higher values most closely correspond to the cores of thunderstorms. End users look for rapid increases in this observation to indicate that a storm is rapidly strengthening and may produce severe weather. Unlike the PGLM flash extent density product the PGLM flash initiation density product gives no estimate as to the spatial extent of the lightning activity. This makes it far less useful for lightning safety, but allows end users to focus on the storm cores themselves.
