Hurricane Forecasters Using Long Range Lightning DataJuly 21, 2008
The National Hurricane Center is evaluating data from Vaisala's long-range lightning detection network to examine the link between lightning activity and the strength and structure of tropical cyclones.
TUCSON, AZ--(Marketwire) - Vaisala's Long Range Lightning Detection Network (LLDN) data are of increasing interest to the National Hurricane Center (NHC). The LLDN provides detection capability far offshore into the Atlantic Ocean and eastern Caribbean Sea which assists in a better understanding of hurricane intensity changes.
Vaisala provides real-time, long range lightning data to the NHC as part of its contract to provide lightning data to the National Weather Service (NWS). NHC began displaying LLDN data in its operations in April 2007. NHC tropical cyclone and marine forecasters have been evaluating the data since then, making use of the ability to overlay lightning data on visible and infrared satellite imagery. Operational tropical meteorologists conduct analyses and forecasts over very large but data-sparse oceans, and the LLDN data provide a new data source to help assess the structure of tropical cyclones and other weather systems at sea.
To better understand the relationships between lightning activity and tropical cyclone strength and structure, scientists from Vaisala's applications and technology team conducted a study in 2004 that linked lightning trends near the center of hurricanes to hurricane intensity. The study combined data reported by NHC in strong hurricanes with eyewall lightning data gathered by Vaisala's LLDN, which measures lightning strikes from cloud to ground.
Shortly after this study, Vaisala scientists began interacting with NHC forecasters to examine a larger number of tropical cyclones during the 2005 through 2007 hurricane seasons. As a result of the interaction, Vaisala developed a web-based product for real-time use by NHC forecasters to monitor eyewall lightning within tropical cyclones. As time has permitted, NHC forecasters have been viewing these products during operational shifts, to evaluate how the lightning data may complement other tools used to analyze tropical cyclone strength and structure.
These evaluations reveal that enhanced lightning activity in tropical cyclones appears to occur at certain times within their life cycle, such as when strong tropical storms are on the verge of reaching hurricane status, and when strong hurricanes undergo significant changes in their internal structure. It has also become apparent that tropical cyclones are more prolific lightning producers than previously thought, and that periods of enhanced lightning do not occur randomly. Further research will assess the value that long range lightning data may provide for improved tropical cyclone track and intensity forecasts.
"Based on the interest expressed by some NHC forecasters, Vaisala has expanded sensor technology into the Caribbean to increase detection for coastal and tropical storms. Forecasters now have more frequent and reliable lightning information from within the eyewalls of hurricanes over a larger portion of the Atlantic basin. As a result, continuous information on the tropical cyclone's inner structure can now be monitored that is obscured on visible and infrared satellite imagery," noted Nicholas W.S. Demetriades, manager of applications and technology for Vaisala.
Vaisala Dropsonde is another tool that has been used for hurricane measurement by different weather and research authorities for several years. A dropsonde is released from an aircraft flying above a hurricane. It descents through the hurricane by a special parachute, transmitting meteorological data.
Vaisala is a global leader in environmental and industrial measurement, providing services, products and solutions for meteorology, environmental sciences, aviation, traffic and industry. Built on science-based innovation, advanced technology and over 70 years of experience, Vaisala is committed to providing a better quality of life through environmental measurement. Headquartered in Finland, Vaisala employs over 1100 professionals and is listed on the Nordic Exchange, Helsinki.
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