Climate Data

CPC Unified Gauge-Based Analysis of Global Daily Precipitation

A gauge-based analysis of daily precipitation has been constructed over the global land areas. Gauge reports from over 30,000 stations are collected from multiple sources including GTS, COOP, and other national and international agencies. Quality control is performed through comparisons with historical records and independent information from measurements at nearby stations, concurrent radar / satellite observations, as well as numerical model forecasts. Quality controlled station reports are then interpolated to create analyzed fields of daily precipitation with consideration of orographic effects (Xie et al. 2007). The daily analysis is constructed on a 0.125 degree lat/lon grid over the entire global land areas, and released on a 0.5 degree lat/lon grid over the global domain for a period from 1979 to the present. [source Xie, 2010] This dataset has two components: (a) the "retrospective version" which uses 30K stations and spans 1979-2005 and (b) the "real-time version" which uses 17K stations and spans 2006-present. The real-time data will be reprocessed in the future to be consistent with the retrospective analysis.

Key Strengths:

  • High station density

Key Limitations:

  • Quality of the gauge-based analysis is poor over tropical Africa and Antarctica.
  • The analysis quality varies with the gauge network density.
  • Definition of the ending time for the daily accumulation differs from country to country. There might be discontinuity in the analyzed fields across the national boundaies

Years of Record

1979/01 to 2005/12
temporal metadataID:




Data Time Period Extended?

yes, data set is extended


Spatial Resolution


Ocean or Land

Land Only

Vertical Levels

Input Data

station gague data

Earth system components and main variables

Data Access: Please Cite data sources, following the data providers' instructions.

Key Figures

Click the thumbnails to view larger sizes



Climate Data Guide: CPC Unified Guage Based precipitation CPC-Unified daily guage based precipitation estimates for 11 August 2012. [Climate Data Guide; D. Shea]

Cite this page

National Center for Atmospheric Research Staff (Eds). Last modified 02 May 2014. "The Climate Data Guide: CPC Unified Gauge-Based Analysis of Global Daily Precipitation." Retrieved from

Acknowledgement of any material taken from this page is appreciated. On behalf of experts who have contributed data, advice, and/or figures, please cite their work as well.