NASA Goddard Scientists Head to Africa to Study Birth of Hurricanes
Scientists from NASA's Goddard Space Flight Center, Greenbelt, Md. and Wallops Flight Facility, Wallops Island, Va. will join scientists from several other NASA centers off the West African coast this August in a month-long expedition to see how hurricanes are born.
Image to right: The Islands known as Cape Verde, will be the base for the NAMMA mission. Depicted here are all of the islands that comprise Cape Verde, which is off the west coast of Africa. Credit: NASA
The mission, called the NASA African Monsoon Multidisciplinary Analyses 2006 (NAMMA), is a series of experiments using advanced NASA technology in space, on the ground and in the air. NAMMA will be based in the Cape Verde Islands, 350 miles off the coast of Senegal. NAMMA is targeting those tropical cyclones that develop off the west coast of Africa and may eventually reach the U.S. mainland. A tropical cyclone is the general name given to tropical depressions, storms and hurricanes.
This mission leverages the African Monsoon Multidisciplinary Analyses (AMMA), an international project aimed at improving the knowledge and understanding of the West African Monsoon. AMMA will study the impact of the West African Monsoon on weather and climate. NASA's contribution to this larger experiment will focus on the evolution of the birth of tropical cyclones.
The major research topics of this mission examine the formation and evolution of tropical hurricanes in the eastern and central Atlantic and their impact on the U.S. east coast, and the composition and structure of the Saharan Air Layer, and whether aerosols affect cloud precipitation and influence cyclone development.
Image to left: Researchers utilize high-flying planes to drop temperature-taking instruments into tropical cyclones from about 3 miles above them. Sensors called "dropsondes" are dropped into tropical cyclones to obtain temperature, pressure, moisture and wind readings throughout different locations in the storm. During the NAMMA mission dropsondes will be dropped over storms from the DC-8 plane. Click image to view animation. Credit: NASA
Several scientists from Goddard and Wallops are heading to Africa this summer. Those scientists are responsible for overseeing the mission, operating one of the instruments on the DC-8 aircraft and conducting studies using both weather observations and computer models. NASA is also partnering with the National Oceanic and Atmospheric Administration (NOAA) to fly coordinated aircraft missions.
Gerry Heymsfield from Goddard and Jeff Halverson, a former NASA Goddard Hurricane Scientist consulting with the NAMMA science team, are two of the four mission scientists helping to direct the field campaign. They will be working with Larry Belcher from Science Systems and Applications, Inc., Lanham, Md., to study early stages of development of tropical storms.
Image to right: The NAMMA mission will also include the use of satellite data. This is an image of Hurricane Katrina on Sunday, August 28, 2005 at 5:30 PM EDT (21:33 UTC) as seen by the Tropical Rainfall Measuring Mission (TRMM) satellite's PR (Precipitation Radar), VIRS (Visible Infrared Scanner), TMI (Tropical Microwave Imager) and the GOES spacecraft. TRMM looks underneath of the storm's clouds to reveal the underlying rain structure. Blue represents areas with at least 0.25 inches of rain per hour. Green shows at least 0.5 inches of rain per hour. Yellow is at least 1.0 inches of rain and red is at least 2.0 inches of rain per hour. TRMM is a joint mission between NASA and the Japan Aerospace Exploration Agency (JAXA). + High resolution TIF imageCredit: NASA/JAXA
One of the instruments Belcher will be using is a dropsonde, a device dropped from an aircraft to measure and track tropical storm conditions as it falls to the surface. It measures air temperature, humidity, wind speed, air pressure and wind direction. The dropsonde is released when the plane flies over the rainbands and the eye, normally at around 40,000 feet, and is attached to a parachute. It typically relays these data to a computer in the airplane.
Two scientists from Wallops will study the structure of the atmosphere and the potential for rain from the atmosphere by looking at the amount of water produced when all the water vapor in a column of air condenses. Frank Schmidlin and Brian Morrison will use radiosondes to do this. A radiosonde is just like a dropsonde, except it is not dropped from an airplane, it is launched upward into the atmosphere using a balloon, and provides the same measurements as it climbs through the sky.
William Lau from Goddard will be studying the link between tropical cyclone development and West Africa rainfall. This study will use the GEOS-5 computer model from the Goddard Modeling Analysis Office (GMAO).
D. Allen Chu, Chung-Lin Shie, Xiaowen Li, Ruei-Fong Lin of the Goddard Earth Sciences and Technology Center (GEST) will be studying the effects of African dust on precipitation using NASA satellite measurements and several computer models. They study dust properties by using data from several instruments on the Terra, Aqua, and Aura satellites, a cloud resolving computer model and weather readings from the DC-8 aircraft and surface instruments. GEST is located at the University of Maryland, Baltimore County and is associated with NASA Goddard Space Flight Center.
Liguang Wu of Goddard will study the birth of tropical cyclones using aircraft and satellite observations. Jiundar Chern, and Wei-Kuo Tao, both of Goddard, are on the Instrument Team that will be studying precipitation and cloud microphysics and dynamics. Christina Hsu of Goddard and the University of Maryland, College Park, will work on near-real time broadcasts of satellite data.
Image to left: The NASA DC-8 aircraft is a four-engine jet with a range in excess of 5000 nautical miles (9,200 Kilometers), a ceiling of 41,000 feet (12,500 meters), and an experimental payload of 30,000 lbs. (13,600 kilograms). The aircraft is managed by the Airborne Science Program at Dryden Flight Research Center. Credit: NASA Dryden
Si-Chee Tsay, of NASA Goddard; MJ Jeong, of Goddard and the University of Maryland, College Park; and Dave Augustine of Goddard and George Mason University, Fairfax, Va., will work on ground-based operations. They will work with the Surface-sensing Measurements for Atmospheric Radiative Transfer/Chemical, Optical, & Microphysical Measurements of In-situ Troposphere instruments. These instruments help put together a total picture of the atmosphere in a given location.
+ NAMMA hurricane field mission
+ NASA's Hurricane Resource page
Goddard Space Flight Center