NOAA OLR Monthly Means

SOURCE: Data Support Section Dataset ds718.5, and NOAA-CIRES Climate Diagnostics Center

DATA DESCRIPTION: OLR field from NOAA satellites.


FORMAT: netCDF (corrected* and after 1997 datasets), CCM1 History Tape (uncorrected datasets)


  • Corrected* Dataset: Global - 2.5 degree (144 x 73) (missing values near poles); Global - 2.5 degree (144 x 73) (extrapolated); Global - T63 (192 x 96)
  • Uncorrected Datasets: Global - T42 Gaussian (128 x 64) and 2.5 degree (144 x 72)

LEVELS: Single Level

TIMES: One mean per month

Current holdings:

  • Corrected* Datasets: January 1979 - December 1999 (252 time steps -- Mar-Dec 1999 filled with missing = 1.e+36)
  • Uncorrected Datasets: June 1974 - January 1994 (236 time steps per file; Data were not available from March through December 1978, and these months have been coded as missing = 1.e+36)
  • January 1999-February 2002 (38 times steps)


Description Name Units
Outgoing longwave radiation OLR W m-2

MSS Filelist :

  • /CTSAT/NOAA/2.5DG/ on 2.5 degree grid
  • /CTSAT/NOAA/2.5DG/ on 2.5 degree grid
  • /CTSAT/NOAA/T63/ on T63 grid
  • /CTSAT/NOAA/T63/ on T63 grid
  • /CTSAT/NOAA/T42/CCM1H/7494 on T42 grid
  • /CTSAT/NOAA/2.5DG/CCM1H/7494 on 2.5 degree grid

* Corrections: The OLR contains inhomogeneities associated with different satellites and their different equatorial crossing times and orbital drift, and we use a version for which some of these have been adjusted with results from Waliser and Zhou [1997]. We apply the correction to the region between +/- 30 degrees (through July 1996 only) and taper the correction to zero near +/- 30 degrees to smooth any discontinuities that might be introduced as follows: the region between +/- 27.5 degrees latitude is fully corrected; the correction at +/- 30 degrees is weighted 2/3 and also applied at +/- 32.5 degrees with 1/3 weight. There is no correction poleward of 32.5 degrees.

For more information about the corrections, please see:

  • Trenberth, K. E., D. P. Stepaniak and J. M. Caron, 2002: Interannual variations in the atmospheric heat budget. J. Geophys. Res., 107, D8, 10.1029/2000D000297. [pdf]

Comments on Data

Sample Grads .ddf file for reading the netCDF data files