In addition to the existing gridded rainfall fields available at NCDC, one of the products to be provided by the SRDC is the assessment of the error characteristics of the available rainfields. Monthly totals for 2.5° by 2.5° latitude-longitude boxes have been computed using the Comprehensive Pacific Rainfall Data Base. This database consist of raingage data from over 200 standard meteorological sites throughout the Pacific combined with over 70 additional rainfall collection sites obtained through the Schools of the Pacific Rainfall Climatology Experiment (Postawko et al., 1995) many of which are on low-lying atolls and islands. In total, over 300 candidate stations were examined for this study, and 20 boxes were retained after initial data quality criteria were satisfied. The values on this web page are for 1987 through 1997, and correspond with the data sets produced by the GPCP.

Since one of the stated goals of the SRDC is to produce products with known error, an examination of the error characteristics of the data was undertaken. This includes the development of the standard error of the mean (Morrissey, et al., 1995) and the signal to noise ratio (Morrissey and Greene, 1998a). These estimates are provided in separate files and will allow for the user to determine if an individual value satisfies his/her error criteria. A similar analysis was performed for the WETNET PIP-3 intercomparison, and the reader is referred to Morrissey and Greene, 1998b for additional details.

References:

Morrissey, M.L., and J.S. Greene. 1998b. "Uncertainty Analysis of Satellite Rainfall Algorithms over the Tropical Pacific", Journal of Geophysical Research, 103 (D16): 19,569-19,576.

Morrissey, M.L., and J. S. Greene. 1998a. "Using the Oklahoma Mesonet to Develop and Test a Sampling Error Statistic for Meteorological Time Series".Journal of Geophysical Research,103 (D8) : 8979-8984.

Morrissey, M.L., J.A. Maliekal, J.S. Greene, and J. Wang, 1995. "The Uncertainty of Simple Spatial Averages using Rain Gauge Networks". Water Resources Research, 31: 2011-2017.

Two different satellite products are used in the comparisons:

1) The Precipitation Multi-Satellite (PMS) product is produced as part of the GPCP Version 1b Combined Precipitation Data Set by the Global Precipitation Climatology Project (GPCP) Merge Development Centre following Huffman et al. (1995). Infrared data from stationary and polar orbiting satellites, as well as microwave data, are used to produce the current 1b version of the PMS product (as reported by: Huffman, George J., GPCP Version 1B Combined Precipitation Data Set Documentation, March 8, 1999)

2) The Precipitation Satellite-Gauge (PSG) product is also produced as part of the GPCP Version 1b Combined Precipitation Data Set by the GPCP Merge Development Centre (Huffman et al. 1995). The PSG is merged from the PMS product and the GPCC rain gauge-based precipitation "Monitoring Product" (as reported by: Huffman, George J., GPCP Version 1B Combined Precipitation Data Set Documentation, March 8, 1999)

Rain gauge precipitation data are evaluated by the Global Precipitation Climatology Centre (GPCC) under the direction of Dr. Bruno Rudolf, located in the Deutscher Wetterdienst, Offenbach a.M., Germany (Rudolf 1993). Rain gauge reports are archived at GPCC from more than 47,000 stations around the globe, both from Global Telecommunications Network (GTS) reports, and from other world-wide or national data collections. The GPCC rain gauge-based precipitation "Monitoring Product" published thus far and used with the GPCP Combined Precipitation Data Set includes near-real time data from 6,000 - 7,000 GTS-stations. (As reported by Rudolf, Bruno., GPCC).

    Please send comments or questions concerning this web page to mdklatt@ou.edu.

Copyright © 2002, The Board of Regents of the University of Oklahoma
Last update: 16 August 2002