Distribution Characteristics of Sunshine Duration in Qinghai Province
Energy is the base of national economy. As China' s economy is growing rapidly, the problem of energy supply and security has emerged. Due to no environmental pollution, and clean and renewable characteristics, solar resources of sustainability and strategic energy will become increasingly important in the future. Qinghai Province is one of regions rich in solar radiation in China, and abounds in gifts of the nature, having a bright future through exploring and popularizing the solar energy resources. Sunshine duration seems to be the most promising indicator/variable to reflect the amount of radiation for a given region. Changes in sunshine duration would affect the growth of plant, animal, and anthropogenic activities. In this paper,annual sunshine duration time series and monthly sunshine duration in Qinghai Province were comprehensively examined using data from 51 meteorological stations during the period 1971-2007. Subsequently, the distribution characteristics of the sunshine duration in Qinghai Province were analyzed. Results show that: 1) the mean annual sunshine duration is 2351.5～3397.7h, with the maximum of 2951.1～3397.7h in the Qaidam basin and the minimum of 2351.5～2842.4h in Guoluo regions. As far as spatial distribution is concerned, the most of sunshine duration occurs in the west and the north of Qinghai Province, and the least takes place in the south and the east; 2)for annual variation, the mean annual sunshine duration is 2761.5h. The period 1971-1987 was found to be generally above the normal, whereas the 1988-2007 time period was essentially low. For seasonal variation, Yushu, Guoluo, Haibei, Hainan, and Qaidam regions showed more sunshine duration than other regions in spring, Qaidam, Haibei, and Haidong regions in summer, Qaidam and Haibei in autunm, and Qaidam, Haibei, and Hainan regions in winter,respectively. In general, the sunshine duration in Qinghai province significantly reduced. The monthly sunshine duration peaked in May, except for Guoluo regions (consisting of Maduo, Jiuzhi and Banma counties) showing the maximum in April; 3) for inter-annual variation, only the Geermu showed an increasing trend; others regions showed decreasing trends. In the 1980s and 1990s, the sunshine duration for Tongren and Gonghe increased by 83.7h and 60.8h, respectively.However, that of Xining, Delingha, Geermu, and Yushu decreased; 4) by the sliding t-test, an abrupt change in the sunshine duration series was detected in 1985 and 1997, with a marked variation appearing in the early 1980s and 1990s; and 5) the total cloudiness and low cloudiness show negative correlation with sunshine duration, but positively correlate with the daily temperature difference.
NETL
NSTL
万方数据
维普
