ERA40 T106 Analysis Fields on Pressure Surfaces, created at NCAR

DS127.1 represents a higher resolution version of ds124.1 [rda.ucar.edu/datasets/ds124.1/]. Both ds124.1 and 127.1 were implemented and computed by NCAR's Data Support Section, and form an essential part of efforts undertaken in late 2004, early 2005, to produce an archive of selected segments of ERA-40 on a standard transformation grid. In the case of ds127.1, ERA-40 6-hourly upper air variables on 23 pressure levels were transformed from either spherical harmonics (geopotential, temperature, vertical pressure velocity, vorticity, divergence, relative humidity), or a reduced N80 Gaussian grid (potential vorticity, specific humidity, ozone mass mixing ratio), 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.