Doppler radars help increase monsoon rainfall prediction accuracy

Oct 05, 2010

(PhysOrg.com) -- Doppler weather radar will significantly improve forecasting models used to track monsoon systems influencing the monsoon in and around India, according to a research collaboration including Purdue University, the National Center for Atmospheric Research and the Indian Institute of Technology Delhi.

Dev Niyogi, a Purdue associate professor of agronomy and earth and atmospheric sciences, said modeling of a depression track can have a margin of error of about 200 kilometers for landfall, which can be significant for storms that produce as much as 20-25 inches of rain as well as inland floods and fatalities.

"When you run a , how you represent the initial state of the atmosphere is critical. Even if information may seem highly localized, we find that it enhances the regional , which, in turn, can significantly improve the dynamic prediction of how the monsoon depression will move as the storm makes landfall," Niyogi said. "It certainly looks like a wise investment made in Doppler radars can help in monsoon forecasting, particularly the heavy rain from monsoon processes."

Niyogi, U.C. Mohanty, a professor in the Centre for Atmospheric Sciences at the Indian Institute of Technology, and Mohanty's doctoral student, Ashish Routray, collaborated with scientists at the National Center for Atmospheric Research and gathered information such as radial velocity and reflectivity from six Doppler weather radars that were in place during storms. Using the Weather Research and Forecasting Model, they found that incorporating the Doppler radar-based information decreased the error of the monsoon depression's landfall path from 200 kilometers to 75 kilometers.

Monsoons account for 80 percent of the rain India receives each year. Mohanty said more accurate predictions could better prepare people for heavy rains that account for a number of deaths in a .

"Once a monsoon depression passes through, it can cause catastrophic floods in the coastal areas of India," Mohanty said. "Doppler radar is a very useful tool to help assess these things."

The researchers modeled monsoon depressions and published their findings in the Quarterly Journal of the Royal Meteorological Society. Future studies will incorporate more simulations and more advanced models to test the ability of Doppler radar to track monsoon processes. Niyogi said the techniques and tools being developed also could help predict landfall of tropical storm systems that affect the Caribbean and the United States.

Explore further: Quakes destroy or damage 83 houses in Philippines

More information: Impact of Doppler Weather Radar Data on Numerical Forecast of Indian Monsoon Depressions, A. Routray, et al., Quarterly Journal of the Royal Meteorological Society 2010.

add to favorites email to friend print save as pdf

Related Stories

Arizona monsoons unpredictable

Jun 18, 2007

The Arizona monsoon season produces up to a third of the region's annual rainfall but it is tough for forecasters to predict.

Study projects weakened monsoon season in South Asia

Feb 27, 2009

(PhysOrg.com) -- The South Asian summer monsoon - critical to agriculture in Bangladesh, India, Nepal and Pakistan - could be weakened and delayed due to rising temperatures in the future, according to a recent ...

Recommended for you

Study links changing winds to warming in Pacific

6 hours ago

A new study released Monday found that warming temperatures in Pacific Ocean waters off the coast of North America over the past century closely followed natural changes in the wind, not increases in greenhouse ...

NASA image: Wildfires in Khabarovsk Krai, Russia

6 hours ago

Most of the fires captured in this image burn in Khabarovsk Krai, a territory occupying the coastline of the Sea of Okhotsk. Dozens of red hotspots, accompanied by plumes of smoke mark active fires. The smoke, ...

NASA sees Tropical Depression Polo winding down

9 hours ago

Infrared satellite imagery from NASA's Aqua satellite showed only a swirl of low-level clouds some deep clouds around Polo's weakening center on Sept. 22 as the storm weakened to a depression.

User comments : 0