ERA40 Model Resolution Gridded Upper Air Analysis on Model Levels from ECMWF

This dataset contains 9 variables on the original 60 model levels, as well as surface geopotential and log of surface pressure. Variables are archived at T159 spectral resolution in spherical harmonics or the reduced N80 gaussian grid with a resolution of approximately 125 kilometers. All variables are output four times per day for the entire period. The ERA-Interim data from ECMWF is an update to the ERA-40 project. The ERA-Interim data starts in 1989 and has a higher horizontal resolution (T255, N128 nominally 0.703125 degrees) than the ERA-40 data (T159, N80 nominally 1.125 degrees). ERA-Interim is based on a more current model than ERA-40 and uses 4DVAR (as opposed to 3DVAR in ERA-40). ECMWF will continue to run the ERA-Interim model in near real time through at least 2010, and possibly longer. This data is available in ds627.0 [https://rda.ucar.edu/datasets/ds627.0/].