The 20th Century Reanalysis Project

The goal of this project is to use a newly developed Kalman filter-based technique to produce a global tropospheric circulation dataset at four-times daily resolution back to 1892. The only dataset available for the early 20th century consists of error-ridden hand-drawn analyses of the mean sea level pressure field over the Northern Hemisphere. Modern data assimilation systems have the potential to improve upon these maps, but prior to 1948, few digitized upper-air sounding observations are available for such a reanalysis. The timely production of the proposed global tropospheric circulation dataset will provide an important validation check on the climate models being used to make 21st century climate projections in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) released in 2007.