Precipitation Database in the Third Pole region
Accurate evaluation of precipitation is essential for understanding hydrometeorological processes and water resources at both regional and global scales. To improve the accuracy of gauge-measured precipitation in the Third Pole region, Prof. Yinsheng Zhang’s group employ the bias adjustment procedure recommanded by the WMO; this addresses all biases, including wind-induced undercatch, wetting and evaporation losses, and trace precipitaiton at 241 meteorological stations in various countries, which consequently involves a variety of gauge types and also updated the preciptation data to cover the past 60 years.
The mainly results are as follows：
■ Wind-induced error is the greatest error in the gauge measurement. The other biases such as wetting and evaporation losses, and trace amounts, are also significant across the Third Pole region.
■ The mean annual bias ranges from a minimum of 4mm to a maximum of 409mm, with an average of 90mm across the Third Pole region. The corresponding mean CF ranges from 6-94%, with an average of 27%, which is higher than the global value of 11%.
■ Temporally, the correction factor (CF) is greater in cold season and smaller in warm season, but the total biases in the warm season are greater than those in the cold periods. Spatially, the CF trends range from 1.06 in the southwest to 1.94 in the center.
■ As for gauges, the U.S.8’’ gauge has the highest proportional wind loss. The Tretyakov gauge shows the lowest proportional wind loss, but highest percentages of evaporation loss and trace precipitation. The CSPG has the highest proportional wetting loss.
■ The bias shows variable spatial and temporal patterns in different climate zones across the Third Pole region.
■ The time scale (60 years) in the current study is the longest available in the Third Pole region, which is a substantive contribution to climate and hydrological research and applications over such a large area.
Please cited from: Ma, Y., Zhang, Y., Yang, D. and Farhan, S. B. (2014), Precipitation bias variability versus various gauges under different climatic conditions over the Third Pole Environment (TPE) region. Int. J.Climatol. doi: 10.1002/joc.4045.
2. Systematic errors criterion with various gauges across the Third Pole region [Table]
3. Annual mean observed and adjusted precipitation, and correction factor among 241 stations across the Third Pole region [Figure]
4. Annual, warm/cold seasonal summary of precipitation adjustments and related climatic features across the Third Pole region [Table]
Remarks:All the data are used for non-commercial purposes.
If any problems, please contact with Yingzhao Ma
Institute of Tibetan Plateau Research, Chinese Academy of Sciences