NEWS RELEASE: July 1, 2007

Contact: Tommy Jensen: (808) 956-5468 tjensen@hawaii.edu

Gisela Speidel 808-956-9252 gspeidel@hawaii.edu

UH Climate Researcher, Editor of American Meteorological Special Issue
Indian Ocean Climate

Honolulu - The American Meteorological Society’s Journal of Climate is releasing a special issue, Indian Ocean Climate, on July 1, 2007. The editor is Tommy Jensen, a researcher at the International Pacific Research Center (IPRC), the UH climate research center, which hosted the conference leading up to the special issue.

The Indian Ocean is so far from Hawaii that readers here may wonder why what happens there is important to them. In fact, there are close climate connections. In 1978 Klaus Wyrtki, the famous UH emeritus oceanography professor, published his seminal article “Teleconnections in the Equatorial Pacific Ocean” in Science. In that article, he provided a key element to the then mysterious El Nino climate phenomenon. His discovery was actually based on his previous studies of the Indian-Ocean circulation. There, he found that westerly winds on the equator create narrow currents along the equator (equatorial jets) that pile up warm water along the Sumatra coast in only a few months time. Similarly, during El Nino westerly winds are more common, and warm water piles up in the usually cold eastern tropical Pacific. Wyrtki once said, “Studying the Indian-Ocean jets gave me the explanation for El Nino!”

For years, scientists thought that the Indian Ocean was climatically a “slave” to El Nino and La Nina in the Pacific. Then in 1999, scientists described for the first time a temperature pattern in the Indian Ocean they called the “Indian Ocean Dipole.” It is a phenomenon similar to the La Nina conditions in the Pacific Ocean: warmer water than usual is seen in the western and colder water in the eastern regions of the Indian Ocean. This dipole, together with unusual sea surface temperature occurring in the Southwest Indian Ocean during the winter and following spring, need to be taken into account in climate predictions. For example, Indian Ocean temperature patterns affect not only rainfall in countries bordering its coasts, but in regions as far away as Hawaii and North America through an atmospheric wave pattern thought to have its origins in anomalous Indian Ocean sea surface temperatures.

These discoveries produced a flurry of new research on the Indian Ocean, much of which is captured in this special issue. The issue includes 24 papers written by foremost atmospheric scientists and oceanographers with expertise in the Indian Ocean region. The papers discuss, among other issues, how best to monitor the Indian Ocean, how Indian and Pacific Ocean conditions impact each other, and how the Indian Ocean affects the Asian monsoon and, through teleconnections, far away midlatitude climate.