USGS - science for a changing world

Kansas Water Science Center

News Release

February 28, 2006

Charles Perry



Donita Turk


Variations in Sun’'s Output Linked to Midwestern Floods and Droughts


A USGS scientist has physically linked floods and droughts in the Upper Mississippi River Basin to variations in the Sun’'s total energy output. These variations of the Sun'’s output appear to affect Pacific Ocean temperatures and, as a result, the atmosphere above the Pacific Ocean and downwind over central parts of North America which is drained by the Mississippi River.


A research article titled “Midwestern streamflow, precipitation, and atmospheric vorticity influenced by Pacific sea-surface temperatures and total solar-irradiance variations”can be obtained online at and is published in the February, 2006, issue of the International Journal of Climatology. The author, U.S. Geological Survey Research Hydrologist, Charles Perry, provides evidence for the physical links between the Sun and flow volumes for major streams in Iowa and for the Mississippi River at St. Louis, Missouri.


Increased river flow volumes (floods) seem to occur approximately 3 years after an increase in the Sun’'s total irradiance. Decreased river flow volumes (droughts) follow 3 years after a decrease in solar output. This information could be used to improve estimates of the flow volume of the Mississippi River at least two years in advance.


This research demonstrates that the flow of the Mississippi River upstream of St. Louis, Missouri, is highly dependent upon the rainfall in Iowa which is produced by surface-level low pressure centers. The abundance of surface low pressure centers is dependent upon the level of jet stream vorticity (the degree of spinning of the atmosphere near the 30,000 foot level) especially in the North Pacific Ocean near 50 N 150 W. Jet-stream vorticity at this location is dependent upon the Sea Surface Temperatures (SSTs) immediately below. It is evident that these high latitude SSTs are related to SSTs that were measured 3 years previously in the western low-latitude tropical Pacific Ocean and those tropical SSTs are related to the variations of the Sun’'s total irradiance.


This research is part of a continuing study of the frequency of occurrence of floods and droughts in the Midwest and other parts of the United States by the U.S. Geological Survey’'s Water Science Center in Lawrence, Kansas. Additional information can be obtained online at:


The USGS serves the Nation by providing reliable scientific information to describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life.

Notes to Editors

1.                  Perry, C: Midwestern streamflow, precipitation, and atmospheric vorticity influenced by pacific sea-surface temperatures and total solar-irradiance variations, International Journal of Climatology.  206.  DOI: 10.1002/joc.1248 .  Volume 26, Issue 2; 2006


  1. The International Journal of Climatology aims to span the well established but rapidly growing field of climatology, through the publication of research papers, major reviews of progress and reviews of new books and reports in the area of climate science. The Journal's main role is to stimulate and report research in climatology, from the expansive fields of the atmospheric, biophysical, engineering and social sciences.  International Journal of Climatology can be accessed at: