Paper in Nature Climate Change Highlighted by NSF

A paper led by Prof. Auroop Ganguly about geographical patterns in observed rainfall extremes over India has been published in the February 2012 issue of the journal Nature Climate Change and highlighted as a significant news item on the website of the National Science Foundation. The paper helps resolve a long-standing debate and develops an important new insight on the important issues related to weather extremes. First, no uniform trend was found in the extremes of Indian rainfall over the last half-century, which contradicts some of the previously published literature but supports a few others. Second, a steady and significant increasing trend was discovered in the geographical variability of rainfall extremes, or in the extent to which the extreme values differ from each other in space. When taken together, the findings have relevance for the management of water resources and flood hazards in India as well as for policy decisions related to urbanization, changes in land use, and emissions negotiations. Sophisticated statistical methods specifically designed to analyze extreme value patterns and associated uncertainties in space and time were used to obtain the insights. The research was led by Prof. Ganguly and funded by the National Science Foundation, the Oak Ridge National Laboratory (ORNL), and the Department of Science and Technology of the Government of India. Other authors include Subimal Ghosh from the Indian Institute of Technology Bombay, Shih-Chieh Kao from ORNL, Debasish Das from Temple University.

Source: News @ Northeastern

Auroop Gan­guly, an asso­ciate pro­fessor of civil and envi­ron­mental engi­neering at North­eastern Uni­ver­sity, studies cli­mate change and extreme weather events — such as hur­ri­canes, rain­fall and heat waves — from an inter­dis­ci­pli­nary perspective.

Expanding his research beyond the sci­ence of cli­mate change and devel­oping data-​​driven cli­mate assess­ments, Gan­guly focuses on how climate-​​related extreme events affect water sus­tain­ability, how com­mu­ni­ties adapt to and mit­i­gate the effects of severe storms and floods and how gov­ern­ment offi­cials could use cli­mate and weather research to make sound policy decisions.

Knowing whether melting Arctic Sea ice is opening up new nav­i­gable path­ways for sea­faring ves­sels has the poten­tial to shape national secu­rity poli­cies, Gan­guly noted, dis­cussing prior work he led for the U.S. Depart­ment of Defense. As he put it, “All these issues are interrelated.”

Gan­guly, who joined Northeastern’s fac­ulty in the fall, recently led a new study that explored extreme rain­fall events during mon­soons in India.

The research team found that the fre­quency or inten­sity of extreme rain­fall events over the last 50 years has not increased on the average, but that there has been a steady and sig­nif­i­cant rise in the spa­tial vari­ability of Indian rain­fall extremes. Spa­tial vari­ability is a sta­tis­tical mea­sure of how much extreme rain­fall at one par­tic­ular geo­graphic loca­tion dif­fers from that of another.

Spa­tial vari­ability can dras­ti­cally com­pli­cate policy issues and water– and flood– hazard man­age­ment in the affected regions, he said.

We know there is global warming, but this won’t impact each and every­thing in a sim­ilar way,” Gan­guly said. “In some cases, regional processes will dom­i­nate. So in the con­text of Indian rain­fall, there are things like urban­iza­tion, defor­esta­tion and changes in land use that may be more rel­e­vant to explaining this trend. Are these con­tributing along with global warming? That’s what we’re inter­ested in.”

The find­ings were pub­lished online on Dec. 18 in the journal Nature Cli­mate Change. Gan­guly led an inter­dis­ci­pli­nary team of researchers from the Indian Insti­tute of Tech­nology Bombay, Temple Uni­ver­sity and the Oak Ridge National Lab­o­ra­tory (ORNL) in Ten­nessee, where Gan­guly worked before coming to North­eastern. ORNL and the Indian gov­ern­ment par­tially funded the research effort.

Our find­ings high­light the need for sys­tem­atic exam­i­na­tion of global versus regional dri­vers of trends in Indian rain­fall extremes, and this may help to inform flood hazard pre­pared­ness and water resource man­age­ment in the region,” the researchers wrote. The data-​​driven methods can be adapted to other regions of the world, both for obser­va­tions and for model simulations.

Gan­guly is a co-​​principal inves­ti­gator of a larger research team, led by the Uni­ver­sity of Min­nesota and funded by the National Sci­ence Foundation’s Expe­di­tions in Com­puting pro­gram, that has been devel­oping new data-​​driven methods for under­standing cli­mate change. The project’s focus on remotely sensed obser­va­tions and climate-​​model sim­u­la­tions is expected to fuel major inno­va­tions in com­pu­ta­tional and data-​​intensive sciences.

Data-​​driven methods for under­standing cli­mate change can help address large sci­ence gaps with major soci­etal rel­e­vance,” Gan­guly said.

Related Faculty: Auroop R. Ganguly

Related Departments:Civil & Environmental Engineering