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ESRL Physical Sciences Division Programs

20th Century Reanalysis

Using a state-of-the-art data assimilation system and surface pressure observations, the Twentieth Century Reanalysis Project is generating a six-hourly, four-dimensional global atmospheric dataset spanning 1871 to present to place current atmospheric circulation patterns into a historical perspective.

Hydrometeorology Testbed (HMT)

NOAA's Hydrometeorology Testbed (HMT) is a demonstration that focuses the use of advanced observational and modeling tools on quantitative precipitation estimation (QPE) and quantitative precipitation forecasting (QPF) for the purpose of improving hydrologic forecasts and warnings. The testbed approach will accelerate transitions from the research and development community to operations, as described in NOAA's Strategic Plan and recommended by the NOAA Hydrology Team's Science and Technology Infusion Plan (STIP) and the U.S. Weather Research Program (USWRP).

Interpreting Climate Conditions

Climate attribution is a scientific process for establishing the principal causes or physical explanation for observed climate conditions and phenomena. This includes attribution of the causes for observed climate variations that may not be unusual in a statistical sense but for which great public interest exists because they produce profound societal impacts.


Infrasonics is the study of sound below the range of human hearing. These low-frequency sounds are produced by a variety of geophysical processes including earthquakes, severe weather, volcanic activity, geomagnetic activity, ocean waves, avalanches, turbulence aloft, and meteors and by some man-made sources such as aircraft and explosions. Infrasonic and near-infrasonic sound may provide advanced warning and monitoring of these extreme events.

Field Programs

A chronologically ordered list of field programs until 2009.