JISAO data

NOAA NCEP climate anomaly monitoring system - outgoing longwave radiation precipitation index (CAMS-OPI) Precipitation 1979-January 2009

NCEP maintains a WWW page for this data set. This data set was developed by John Janowiak and Pingping Xie, and is intended for real-time climate monitoring (Janowiak and Xie 1999). The authors "strongly suggest" that users employ either the CMAP or GPCP data sets for analyses that do not require real-time data or which would benefit from more strongly quality controlled data. I will update this file on occasions when I need more recent data.

example analysis | data | reference

The data set is produced from rain gauge data for land, and OPI estimates for land points without observations and over the oceans.

U.S. - Mexico 
June U.S. rainfall is characterized by precipitation < 5 cm over the west, 10-12.5 cm rainfall in the central states, and precipitation > 15 cm along the gulf coast states of Louisianna, Mississippi, and Florida. The onset of the North American monsoon in July is characterized by precipitation in excess of 10cm on the western flank of the Sierra Madre Occidental in Mexico, diminished rainfall in Texas and the central plains of the U.S., and slightly wetter conditions in the eastern U.S.

The data:
  • The data set is updated monthly and can be obtained from the NCEP ftp directory
  • In netCDF format:
    All errors in the netCDF files are due to Todd Mitchell.
    At JISAO the files can be found at /home/disk/muggy/data/merged_precip/cams-opi/
    monthly rain rate (mm/day)
    monthly rainfall amount (cm/mon)
    1979-99 climatological rainfall amounts
    Janowiak, J. E., and P. Xie, 1999: CAMS-OPI: A global satellite-rain gauge merged product for real-time precipitation monitoring applications. J. Climate, 12, 3335-3342.

    February 2009
    Todd Mitchell (
    mitchell@atmos.washington.edu )
    JISAO data