• Corpus ID: 131691605

Variation of Sunlight Radiation Duration in the Yellow River Basin

@article{Fangfang2005VariationOS,
  title={Variation of Sunlight Radiation Duration in the Yellow River Basin},
  author={Zhao Fang-fang},
  journal={Resources Science},
  year={2005},
  url={https://api.semanticscholar.org/CorpusID:131691605}
}

• Zhao Fang-fang
• Published 2005
• Environmental Science
• Resources Science

The Mann-Kendall statistic test is a rank-based non-parametric method, which has been widely used to detect trends in hydro-meteorological time series such as streamflow, temperature, precipitation and sunlight radiation hours, etc. Sunlight radiation duration is one of the important climatic factors. The possible trend of annual and monthly sunlight radiation duration in the Yellow River basin was detected by using the Mann-Kendall test in this paper. The data used in this study were observed… 

The Mann-Kendall statistic test is a rank-based non-parametric method, which has been widely used to detect trends in hydro-meteorological time series such as streamflow, temperature, precipitation and sunlight radiation hours, etc. Sunlight radiation duration is one of the important climatic factors. The possible trend of annual and monthly sunlight radiation duration in the Yellow River basin was detected by using the Mann-Kendall test in this paper. The data used in this study were observed at 77 meteorological stations in the Yellow River basin. The Mann-Kendall test was applied to annual and monthly time series from 1958 to 2001. At the same time, a parametric test was also applied to make the trend analysis. The results shown that there is an obvious downward trend in the annual and monthly sunlight radiation durations in the subregion of Ⅰ,Ⅱ, and Ⅲ, but subregion of Ⅳ and Ⅴ did not exhibit significant long-term trend. The results from 53 stations shown a decreasing trend and only 24 stations exhibited an increasing trend. 34 stations rejected the null hypothesis, among which 28 stations shown significant decreasing trend, and only 6 stations shown significant increasing trend. In other words, most area of the middle- and downstream of the Yellow River basin exhibited downward trend of sunlight radiation duration, but the upstream did not show obvious long-term trend. This demonstrated that decreasing trend dominated the long-term trend of the sunlight radiation duration in the study area during the past fifty years. On the basis of above analysis, January, April, July, and October were selected as typical months to represent four seasons of the year, and the corresponding long-term trend for these representative months were further investigated. The results shown that in January, June, October and December there is a greater long-term trend and a greater contribution made by annual sunlight radiation duration. The temporal and spatial distribution of the long-term trend for the sunlight radiation duration in the study area shows that there is a difference for the trend of sunlight radiation duration over different area during different periods in the Yellow River basin from 1958 to 2001.