ERA40 T106 Analysis Fields on Model Levels, created at NCAR

In this case, ERA-40 6-hourly upper air variables on 60 model levels were transformed from either spherical harmonics (surface geopotential, temperature, vertical velocity, vorticity, logarithm of surface pressure, divergence), or a reduced N80 Gaussian grid (specific humidity, ozone mass mixing ratio, cloud liquid water content, cloud ice water content, cloud cover), to a 320 by 160 regular Gaussian grid at T106 spectral truncation.

In addition, horizontal wind components were derived from spectral vorticity and divergence and also archived on a T106 Gaussian grid. All scalar fields were transformed using routines from the ECMWF EMOS library, whereas the horizontal winds were obtained using NCAR's SPHEREPACK library. The ERA-Interim data from ECMWF is an update to the ERA-40 project.