A gridded daily observation dataset over China region and comparison with the other datasets

A new gridded daily dataset with the resolution of 0.25 degrees latitude by 0.25 degrees longitude, CN05.1, is constructed for the purpose of high resolution climate model validation over China region. The dataset is based on the interpolation from over 2400 observing stations in China, includes 4 variables: daily mean, minimum and maximum temperature, daily precipitation. The anomaly approach is applied in this interpolation. The climatology is first interpolated by thin-plate smoothing splines and then a gridded daily anomaly derived from angular distance weighting method is added to climatology to obtain the final dataset. Intercomparison of the dataset with other three daily datasets, CN05 for temperature, and EA05 and APHRO for precipitation is conducted. The analysis period is from 1961 to 2005. For multi-annual mean temperature variables, results show small differences over eastern China with dense observation stations, but larger differences (warmer) over western China with less stations between CN05.1 and CN05. The temperature extremes are measured by TX3D (mean of the 3 greatest maximum temperatures in a year) and TN3D (mean of the 3 lowest minimum temperatures). CN05. 1 in general shows a warmer TX3D over China, while a lower TN3D in the east and greater TN3D in the west are found compared to CN05. A greater value of annual mean precipitation compared to EA05 and APHRO, especially to the latter, is found in CN05.1. For precipitation extreme of R3D (mean of the 3 largest precipitations in a year), CN05.1 presents lover value of it in western China compared to EA05.