The data in this directory is for a new version ("v0208") of the CAMS_OPI data. The following changes have been made to the original method: 1. To ensure consistency among this product and the CPC analyses over the US, Mexico and South America, this version does NOT use monthly reports from station in these areas. Instead, the analysis values from the CPC analyses are used. 2. The historical cams_opi data files have been modified by inserting the data from the CPC analyses over the US & Mexico back to 1979; this was not done over South America because historical data isn't available. 3. The climatology & gamma/beta computations have been recomputed so that the anomalies will be consistent with the data in these regions. The "CAMS_OPI" data are 2.5 degree lat/lon spatial means of monthly mean precipitation derived from station gauges and satellite estimates. Each data 'record' is a 144 x 72 array, oriented from SOUTH -> North and Eastward from 1.25E. The array orientation is: 0 2.5E 5.0E 2.5W 0 | | | | | ----------------------------------- South Pole | | | | | |(1,1) | (2,1)| .... |(144,1)|.............88.75S | | | | | ----------------------------------- 87.5S | | | | | |(1,2) | (2,2)| .... |(144,2)|.............86.25S | | | | | ----------------------------------- 85.0S . . . ----------------------------------- 87.5N | | | | | |(1,72)|(2,72)| .... |(144,72)|............88.75N | | | | | ----------------------------------- Nort Pole . . . . . . . . . 1.25E 3.75E 1.25W Note that the the coordinates for each grid correspond to the center of each box since the data values are spatial averages. A separate data file for each month exists. The data arrays are in a FORTRAN 77 "direct", binary records ("IEEE") and are grouped as follows: Record 1: Precipitation analysis based on raingauge data only (CAMS) 2: number of CAMS gauges 3: Precipitation analysis based on OPI estimates only 4: The blended analysis CAMS_OPI monthly total precip. analysis 5: For Internal Use only 6: CAMS_OPI monthly anomaly (1979-1995 base period) 7: " " " expressed as % of gamma distribution The units are "mm/day" for the means and anomalies. REFERENCE Janowiak, J. E. and P. Xie, 1999: CAMS_OPI: A Global Satellite-Rain Gauge Merged Product for Real-Time Precipitation Monitoring Applications. J. Climate, vol. 12, 3335-3342. John Janowiak (john.janowiak@noaa.gov) Climate Prediction Center/NCEP/NWS/NOAA