NCEP–DOE AMIP-II Reanalysis (R-2)

TLDR

The NCEP–DOE AMIP‑II reanalysis is a follow‑on to the 50‑year NCEP–NCAR reanalysis, extending coverage to the 1979‑present satellite era. It aims to supplement the NCEP–NCAR reanalysis where the original analysis has problems. It uses an updated forecast model, data‑assimilation system, improved diagnostics, and fixes known processing issues. Compared to NCEP–NCAR, AMIP‑II shows only minor differences in free‑air geopotential height and winds in the Northern Hemisphere extratropics, but significant improvements in land‑surface parameters and land‑ocean fluxes, providing a measure of uncertainty between the two analyses.

Abstract

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 re-analysis 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.