Mean seasonal and spatial variability in gauge‐corrected, global precipitation

TLDR

A global climatology of mean monthly precipitation has been developed using traditional land‑based gauge measurements and shipboard estimates. The authors compiled and cleaned 24,635 terrestrial and 2,223 oceanic station records from ten sources, corrected gauge biases, and interpolated the observations onto a 0.5° latitude–longitude grid using a spherical method. The resulting bias‑corrected maps display the annual mean and intra‑annual variance of precipitation, and a harmonic decomposition of the intra‑annual variance is provided.

Abstract

Abstract Using traditional land‐based gauge measurements and shipboard estimates, a global climatology of mean monthly precipitation has been developed. Data were obtained from ten existing sources, screened for coding errors, and redundant station records were removed. The edited data base contains 24,635 spatially independent terrestrial station records and 2223 oceanic grid‐point records. A procedure for correcting gauge‐induced biases is presented and used to remove systematic errors caused by wind, wetting on the interior walls of the gauge, and evaporation from the gauge. These ‘corrected’ monthly precipitation observations were then interpolated to a 0·5° of latitude by 0·5° of longitude grid using a spherically based interpolation procedure. Bias‐corrected spatial distributions of the annual mean and intraannual variance are presented along with a harmonic decomposition of the intra‐annual variance.