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Chinese Agricultural Science Bulletin ›› 2023, Vol. 39 ›› Issue (5): 116-123.doi: 10.11924/j.issn.1000-6850.casb2022-0132

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Variation Characteristics of Sunshine Duration from 1961 to 2020 in Dingxi

SHANG Junlin1,2(), LEI Jun2(), YAO Yubi1, YAO Rui2, LU Guoyang3, LUAN Zhenbin2, CHANG Jinhui2   

  1. 1 Lanzhou Resources & Environment Voc-tech University, Key Laboratory of Climate Resources Develop and Disaster Prevention and Mitigation of Gansu Province, Lanzhou 730021
    2 Dingxi Meteorological Bureau, Dingxi, Gansu 743000
    3 Lanzhou Regional Climate Center, Lanzhou 730020
  • Received:2022-02-28 Revised:2022-04-29 Online:2023-02-15 Published:2023-02-06

Abstract:

To analyze the variation characteristics of sunshine duration in Dingxi City, the data of Dingxi Meteorological Observation Station from 1961 to 2020 was used, and the involved elements were: sunshine duration, precipitation, relative humidity, cloud amount and water vapor pressure. The interdecadal, interannual, seasonal and monthly variation characteristics of sunshine duration were analyzed by using the linear trend analysis, Mann-Kendall test and path analysis. In addition, the main meteorological factors affecting the variation of sunshine duration were discussed. The results showed that: the annual sunshine duration in Dingxi City had obvious interdecadal variation characteristics from 1961 to 2020, and the sunshine duration significantly decreased in the 1980s and 2000s (P<0.05) and its fluctuating trend also decreased with a linear tendency rate of -10.7 h/10 a (P<0.05). The maximum value of annual sunshine duration was 2790.2 h, which appeared in 1963, the minimum value of annual sunshine duration was 2159.7 h, which appeared in 1988, and the range was 810.5 h. The annual sunshine duration had abrupt change in 1967 and 1993. The sunshine duration showed obvious seasonal variation characteristics, which increased in spring with a linear tendency rate of 5.1 h/10 a, but decreased in summer, autumn and winter, and the decrease rate in summer was the largest (-8.9 h/10 a). There were differences in the variation trend of monthly sunshine duration, it decreased significantly in June (P<0.05), but not obvious (P>0.05) in other months. Sunshine duration had extremely obvious negative correlation with precipitation, relative humidity, cloud amount and water vapor pressure, and the main meteorological factors affecting sunshine hours were different in different seasons. The most obvious effect of meteorological factors on sunshine duration was found in autumn (R=0.862), and that in spring came the second. Relative humidity made the greatest contribution to the change of spring and annual sunshine duration variation, but it was the total cloud amount that mostly affected the sunshine duration change in summer, autumn and winter. This study can provide important reference for the efficient utilization of climate resources under the background of climate warming.

Key words: Dingxi, sunshine duration, climate tendency rate, Mann-Kendall test, path analysis