Comparison of Two Homogenized Datasets of Daily Maximum/Mean/Minimum Temperature in China during 1960-2013

• Published in: Acta meteorologica Sinica 2016-02, Vol.30 (1), p.53-66
• Main Author: 李珍 曹丽娟 朱亚妮 严中伟
• Format: Article
• Language: English
• Subjects: Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Earth and Environmental Science; Earth Sciences; Geophysics and Environmental Physics; Meteorology; 不均匀性; 中国; 同质化; 平均温度; 最低温度; 最高温度; 气候趋势; 突变点检测
• ISSN: 2095-6037; 0894-0525; 2198-0934; 2191-4788
• DOI: 10.1007/s13351-016-5054-x

Two homogenized datasets of daily maximum temperature （Tmax）, mean temperature （Tm）, and min- imum temperature （Tmin） series in China have recently been developed. One is CHTM3.0, based on the Multiple Analysis of Series for Homogenization （MASH） method, and includes 753 stations for the period 1960-2013. The other is CHHTD1.0, based on the Relative Homogenization test （RHtest）, and includes 2419 stations over the period 1951-2011. The daily Tmax/Tm/Tmin series at 751 stations, which are in both datasets, are chosen and compared against the raw dataset, with regard to the number of breakpoints, long-term climate trends, and their geographical patterns. The results indicate that some robust break points associated with relocations can be detected, the inhomogeneities are removed by both the MASH and RHtest method, and the data quality is improved in both homogenized datasets. However, the differences between CHTM3.0 and CHHTD1.0 are notable. By and large, in CHHTD1.0, the break points detected are fewer, but the adjustments for inhomogeneities and the resultant changes of linear trend estimates are larger. In contrast, CHTM3.0 provides more reasonable geographical patterns of long-term climate trends over the region. The reasons for the differences between the datasets include： （1） different algorithms for creating reference series for adjusting the candidate series--more neighboring stations used in MASH and hence larger-scale regional signals retained; （2） different algorithms for cMculating the adjustments--larger adjustments in RHtest in general, partly due to the individual local reference information used; and （3） different rules for judging inhomogeneity--all detected break points are adjusted in CHTM3.0, based on MASH, while a number of break points detected via RHtest but without supporting metadata are overlooked in CHHTD1.0. The present results suggest that CHTM3.0 is more suitable for analyses of large-scale climate change in China, while CHHTD1.0 contains more original information regarding station temperature records.