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Updated 2 September, 2005
Floods and Drought
USGCRP Seminar, 8 May 1995
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What Causes Such Extremes? Can We Improve Forecasts of Their Occurrence?

SPEAKER: Dr. Edward Sarachik, University of Washington, Seattle WA

SPEAKER:Dr. Ants Leetma, National Meteorological Service, NOAA, Camp Springs MD

INTRODUCTION: Dr. J. Michael Hall, Director, Office of Global Programs, NOAA

TIME & LOCATION: Mon., May 8, 1995, 3:15pm - 4:45pm, Rayburn House Office Bldg., Room B369 - RECEPTION FOLLOWING


Drought in the Midwest in 1988 and in the Southeast in 1989. Floods in the Mississippi River Basin in 1992 and in California in 1994. Each year seems to bring with it droughts or floods that cause billions of dollars in economic losses and untold societal disruption to major parts of our nation. Around the world the situation is the same, even worse in some instances. We hear about the impact of drought and floods in the news and feel it in the cost of goods and services. What causes these extreme events and conditions? Can we predict the occurrence of such events as a means of being prepared, and reducing the impacts of extreme climate events? Can we be better prepared? What success to date has there been in predicting such events? What's the prognosis?


Analyses of the factors that lead to the changes in atmospheric circulation that cause wet and dry extremes over much of the United States point to unusual patterns of Pacific Ocean temperatures. Many of these unusual ocean temperature patterns relate to the El Nino-Southern Oscillation, or ENSO, cycle. As part of this cycle, the temperatures of the eastern tropical Pacific Ocean go through large swings in temperature as part of a global scale oscillation reaching across the Pacific to the East Indies and the Indian Ocean. The ENSO cycle also causes extremes in precipitation in Australia and across southern Asia.

As a result of a major international research program over the past ten years, to be described by Dr. Sarachik, scientists have improved the basis for predicting the changing phases of the ENSO cycle. Dr. Sarachik will describe a new research effort that seeks to now enhance forecast skill in the mid-latitudes and to increase the ability to predict wintertime extremes. While the research community is seeking to further improve its understanding of the ENSO cycle, Dr. Leetma will describe the National Meteorological Service's new program for issuing forecasts of unusual seasonal conditions out to a year in advance based on these advances.

To make these successes available internationally as well as within the U. S., particularly working with our neighbors around the Pacific Rim and in the tropical Americas where the cyclic conditions have their largest effects, NOAA is proposing a cooperative international effort that focuses intensely on improving prediction capabilities and on using experimental forecasts as early-warning information for climate sensitive societies and economic sectors. As Dr. Hall will describe, better information about future conditions, when appropriately integrated into planning and decision-making strategies, can reduce economic losses and thereby reduce outlays associated with ad hoc relief efforts, saving lives and tens to hundreds of millions of dollars. Furthermore, improved forecasts provide opportunities for adjusting strategies to create economically beneficial results by changing crops and adjusting planting schedules.

Biography of Dr. Ants Leetma

Dr. Leetma is currently the Chief of the Coupled Model Project, Office of the Director, National Meteorological Center of the National Weather Service. He has also served as Supervisory Oceanographer with the Climate Analysis Center of the National Weather Service, and with the NOAA Atlantic Oceanographic and Meteorological Laboratories. Dr. Leetma has degrees in Physics and Oceanography from the University of Chicago and Massachusetts Institute of Technology.

Biography of Dr. Edward S. Sarachik

Dr. Sarachik is a Professor in the Department of Atmospheric Sciences, University of Washington, Seattle WA. He has also taught physics, mathematics, and atmospheric physics at Stanford University, MIT, and Harvard University. He has served as a physicist with NASA, a mathematician with the Department of Transportation, and an atmospheric physicist with NOAA. Dr. Sarachik is the recipient of the Paul Klapper Physics prize from Queens College, the NOAA Outstanding Performance Award, and is a Fellow of the American Meteorological Society. He has degrees in Physics from Queens College, and from Brandeis University.

Biography of Dr. J. Michael Hall

Dr. Hall has been the Director of NOAA's Office of Global Programs for the past decade. Dr. Hall has also served with the National Academy of Sciences. His has degrees in Physics and Physical Oceanography from Rice University and the University of Washington.



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