National Centers for Environmental Prediction-Department of Energy (NCEP-DOE) Atmospheric Model Intercomparison Project (AMIP)-II Reanalysis (Reanalysis-2)

The NCEP-DOE Atmospheric Model Intercomparison Project (AMIP-II) reanalysis is a follow-on project to the "50-year" (1948-present) NCEP-NCAR Reanalysis Project. NCEP-DOE AMIP-II reanalysis covers the "20-year" satellite period of 1979 to the present and uses an updated forecast model, updated data assimilation system, improved diagnostic outputs, and fixes for the known processing problems of the NCEP-NCAR reanalysis. Only minor differences are found in the primary analysis variables such as free atmospheric geopotential height and winds in the Northern Hemisphere extratropics, while significant improvements upon NCEP-NCAR reanalysis are made in land surface parameters and land-ocean fluxes. This analysis can be used as a supplement to the NCEP-NCAR reanalysis especially where the original analysis has problems. The differences between the two analyses also provide a measure of uncertainty in current analyses. Atmospheric variables include temperature, humidity, wind speed, and geopotential height. Variables are available in several coordinate systems: pressure, Gaussian grid, spectral coefficients data, and as surface data. Temporal resolution is 6-hourly (4 time a day), and as daily and monthly averages.