I'm at the 63rd Interdepartmental Hurricane Conference
(IHC) in St. Petersburg, Florida this week, catching up on the latest hurricane research results and plans. About 150 scientists and administrators from all the major U.S. hurricane research agencies are here, and I'll present a few of the highlights of the conference in my next few posts.
One new technology discussed involves the release of hundreds of "superpressure" helium balloons into the atmosphere surrounding an approaching hurricane. Justyna Nicinska and Alexander MacDonald of the Oceanic and Atmospheric Research branch of the National Oceanic and Atmospheric Administration (NOAA) presented a talk on this concept--the WISDOM project (Weather In Situ Deployment Optimization Method). The WISDOM project uses hundreds of "superpressure" balloons (Figure 1) to take data around the periphery of a hurricane. These balloons carry a 100 gram GPS receiver and satellite radio transmitter, and are launched from the ground. The balloons quickly rise to an altitude of 12,000 or 26,000 feet, where they remain for a period of 2 - 5 days. They are designed to stay at a constant pressure as they blow across the Atlantic, radioing back their GPS position every 15 - 30 minutes. This position information can then be used to derive the winds in the vicinity of the balloon. This wind information can then be fed into computer forecast models, and the hundreds of new data points over the data-poor ocean regions surrounding the hurricane should help to make improvements in hurricane track and intensity forecasts. The system was tested in November 2008 during Hurricane Paloma, when 57 balloons were launched from locations in the Caribbean and along the U.S. coast. The balloons remained in the air for up to a week, successfully transmitting their position and providing wind information. The data was not ingested in real time into any computer forecast models, though.Figure 1.
Launch of a WISDOM balloon from Miami. Image credit: NOAA
For 2009, a full-scale test launch of hundreds of balloons into the atmosphere surrounding a high-impact hurricane is planned. Again, the data will not be ingested in real time into hurricane forecast models, but will be available for "hindcast" studies to see how the additional data helps forecasts. The balloons cost several thousand dollars each. Additional costs include the deployment of eight trained student teams (two people per team via commercial air transport) to potential launch sites:
* Barbados, Cayman Islands, St. Croix, and Mexico in the Caribbean
* Cape Verdes Islands in the far eastern Atlantic
* U.S. East Coast: Miami FL, Charleston SC, Morehead City, NC
* Central U.S.: Denver CO, Twin Cities MN, Wilmington OH, Dodge City KS
* Western Gulf Coast: Jackson MS, Corpus Christi TX
The current costs of a WISDOM deployment are similar to the costs of flying the Hurricane Hunters for two days into a hurricane. The thought is that costs will fall a factor of ten, to several hundred dollars per balloon, once the project moves into production mode. The WISDOM project is currently funded (by the Department of Homeland Security) through 2014. The WISDOM team hopes to develop a new data package which will carry a temperature and humidity sensor for future work. It is unknown how much improvement the WISDOM project might make for hurricane track forecasts. The NOAA jet can improve hurricane track forecasts by 25% when it flies one of its dropsonde missions around a hurricane, but these dropsondes provide a more 3-dimensional picture of the atmosphere than the WISDOM balloons will provide, and it is unlikely that the WISDOM balloons wil be able to affect hurricane track forecasts to that degree. Wind data similar to the WISDOM data come from cloud tracking by the GOES satellites, and this data has been shown to improve hurricane track forecasts by 7% to 24% in one model study
. It is uncertain how much additional improvement might result from using the WISDOM data, since GOES is already providing some data of a similar nature.
I'll have more Thursday from the Interdepartmental Hurricane Conference.