By using data from the NASA Tropical Rainfall Measuring Mission (TRMM) satellite, researchers identified the regions on Earth that experience the most intense thunderstorms. Their study was published in the August 2006 issue of the Bulletin of the American Meteorological Society. The strongest storms were found to occur east of the Andes Mountains in Argentina, where warm, humid air often collides with cooler, drier air, similar to storms that form east of the Rockies in the United States. Surprisingly, some semi-arid regions have powerful storms, including the southern fringes of the Sahara, northern Australia, and parts of the Indian subcontinent. In contrast, rainy areas such as western Amazonia and Southeast Asia experience frequent storms, but relatively few are severe. Northern Pakistan, Bangladesh, and parts of Central Africa also experience intense thunderstorms.
"TRMM has given us the ability to extend local knowledge about storms to a near-global reach," said lead author Edward Zipser, University of Utah, Salt Lake City. "In addition to containing the only precipitation radar in space, TRMM's other instruments provide a powerful overlap of data that is extremely useful for studying storms."
The researchers examined global thunderstorm data supplied by TRMM from 1998-2004. To determine an individual storm's intensity, they specifically examined the height of radar echoes, radiation temperature, and lightning flash rate, each measured by separate TRMM instruments.
The study also confirmed previous findings. For example, the locations of the heaviest rainfall on Earth -- usually in tropical oceans and along certain mountain slopes -- rarely coincide with the regions of most intense storms. They also found that the strongest storms tend to occur over land, rather than over oceans. The intense storms that do develop over oceans usually occur in areas near land that favor storm motion from land to ocean. Examples include tropical oceans west of Central America and West Africa, and subtropical oceans east of the southeastern United States, South America, Australia and Africa. Many regions of the world also have a seasonal preference for strong storms, including spring and summer for the south-central United States, June-August in the Sahel, and March-May over the Ganges Plain and Bangladesh.
Studying storms with satellite data began in the 1960s when researchers discovered that colder cloud top temperatures were linked to more intense storms. But later, scientists found that many storms of average intensity also reach very high altitudes, where colder temperatures are found. For a more accurate, quantitative description of a storm, radar, microwave, and lightning data are also needed to study a thunderstorm's inner structure.
"Prior to TRMM, we could only study individual storms that were captured by a ground-based radar or lightning network," said co-author Daniel Cecil, University of Alabama-Huntsville, Huntsville, Ala. "Those instruments are not available in many places and trying to find an interesting storm that was simultaneously observed by a satellite required remarkable luck, but TRMM has been supplying a variety of measurements from individual storms around the world for nearly nine years now."
The instruments on TRMM provide data and precision that other satellites cannot. Its precipitation radar is unique because it measures the properties of a storm with high vertical resolution, helping scientists to identify the stronger rising air currents, or updrafts, in a thunderstorm. TRMM also has a lightning sensor, which identifies both cloud-to-ground and in-cloud lightning, and its microwave imager gives detailed information on the ice content within a storm, also related to the speed of updrafts.
While each TRMM instrument measures different aspects of a storm, the researchers found that the data from each usually matched quite well, agreeing on the location and distribution of the strongest storms.
"The results from this study help to quantify the differences in the type and intensity of thunderstorms that occur in different climate regimes around the world," said Cecil. "The effects on the atmosphere of an intense, monstrous thunderstorm over Argentina or Oklahoma contrasts greatly with the effects from a more ordinary storm over the Amazon basin."
In the future, and as the dataset from TRMM continues to increase, these observations will be used to test whether computer models used for climate prediction and weather forecasting are accurately capturing the details of thunderstorms. If not, scientists will have the details necessary to build better, more realistic models that will aid meteorologists in providing more accurate forecasts.
The Tropical Rainfall Measuring Mission (TRMM) is a joint mission between NASA and the Japan Aerospace Exploration Agency (JAXA) and is designed to monitor and study tropical rainfall.
Rob Gutro | EurekAlert!
New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center
Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research