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    费学海, 张一平, 宋清海, 李培广, 刘运通, 金艳强, 李敬,
    林友兴, 张树斌. 元江干热河谷太阳辐射各分量及反照率变化特征[J]. 北京林业大学学报, 2016, 38(3): 1-10. DOI: 10.13332/j.1000-1522.20150360
    引用本文: 费学海, 张一平, 宋清海, 李培广, 刘运通, 金艳强, 李敬,
    林友兴, 张树斌. 元江干热河谷太阳辐射各分量及反照率变化特征[J]. 北京林业大学学报, 2016, 38(3): 1-10. DOI: 10.13332/j.1000-1522.20150360
    FEI Xue-hai, ZHANG Yi-ping, SONG Qing-hai, LI Pei-guang, LIU Yun-tong, JIN Yan-qiang, LI Jing, LIN You-xing, ZHANG Shu-bin. Characteristics of solar radiation distribution and albedo in Yuanjiang dry-hot valley, Southwest China[J]. Journal of Beijing Forestry University, 2016, 38(3): 1-10. DOI: 10.13332/j.1000-1522.20150360
    Citation: FEI Xue-hai, ZHANG Yi-ping, SONG Qing-hai, LI Pei-guang, LIU Yun-tong, JIN Yan-qiang, LI Jing, LIN You-xing, ZHANG Shu-bin. Characteristics of solar radiation distribution and albedo in Yuanjiang dry-hot valley, Southwest China[J]. Journal of Beijing Forestry University, 2016, 38(3): 1-10. DOI: 10.13332/j.1000-1522.20150360

    元江干热河谷太阳辐射各分量及反照率变化特征

    Characteristics of solar radiation distribution and albedo in Yuanjiang dry-hot valley, Southwest China

    • 摘要: 为了探讨干热河谷太阳辐射的特征,本文利用元江干热河谷稀树灌草丛通量塔上连续2年(2013年5月至2015年4月)辐射数据,对元江干热河谷稀树灌草丛植被林冠上太阳辐射(总辐射(Q)、反射辐射(Qα)、有效辐射(I)、净辐射(Rn))的日变化、季节和年变化特征进行分析,探讨了反照率(α)和I变化特征及其原因。结果表明: 该区域Q、Qα、I、Rn的年均辐射值分别为6 210.2、807.9、1 822.9、3 578.7 MJ/(m2·a)。雨季各辐射总量占年总量比例分别为52.9%、56.3%、39.1%、59.2%,除雨季I占全年的比例小于干季外,其他3个辐射分量占全年的比例均是干季雨季。α由于受雨季叶面积指数(LAI)增大和林冠郁闭度增加的影响,其季节变化特征表现为干季雨季,这是生态系统为缓解该区域尖锐的水热矛盾而长期进化的结果。Qα、I和Rn年分配率分别为13.0%、29.8%、56.9%,其中Qα和Rn分配率的季节变化均表现为干季雨季,而I的分配率特征与Qα和Rn的相反。干季I分配率的增加降低了地面和林冠温度,减少了生态系统水分流失,削弱了研究区域干季时水分的胁迫效应,避免了森林植被因水力结构破坏而引发的碳饥饿所导致的死亡,有利于元江干热河谷稀树灌草丛植被在干季生存和维持该生态系统平衡。由于元江干热河谷Q和Rn都较大且该地区降雨少,故人类活动及气候变化更容易影响该地区的生态系统平衡。

       

      Abstract: Based on the continuous observation data of solar radiation (SR) through two years(from May 2013 to April 2015)in a dry-hot valley in southwest China's Yuanjiang, daily, seasonal and annual variations of SR components above the canopy of open shrubland were addressed. Meantime, values of SR components, e.g., total global radiation (Q), reflective radiation (Qα), effective radiation (I) and net radiation (Rn) related to global radiation and variations of albedo (α) as well as its driving factor were investigated. The results showed that yearly average of Q, Qα, I and Rn were 6 210.2, 807.9, 1 822.9, 3 578.7 MJ/(m2·yr), respectively, and the ratios of Q, Qα, I, Rn in rainy season to yearly average value were 52.9%, 56.3%, 39.1%, 59.2% separately. Except for the seasonal variations of I appearing higher value in rainy season than that in dry season, Q, Qα and Rn in rainy season were higher than those in dry season. Albedo (α) in dry season was lower than that in rainy season because of the increasing leaf area index (LAI) and canopy closure extent in rainy season, and this is also the result of long-term evolution ecological strategy of local ecosystem to reduce evaportranspiration (ET) and increase net primary production. The annual distribution ratios of Qα, I and Rn were 13.0%, 29.8% and 56.9% separately. The seasonal variations in the distribution ratios of Qα and Rn were both higher in rainy season than those in dry season; however, the distribution ratios of I showed an opposite seasonal variations pattern. The increasing distribution ratios of I in dry season decreased land surface and canopy temperatures, reduced ET of ecosystem, weakened drought stress of ecosystem in dry season and avoided vegetation death due to the damage of hydraulic architecture inducing carbohydrate starvation, which is beneficial to vegetation survival in dry season and maintain the ecosystem balance in Yuanjiang dry-hot valley. As Q and Rn of Yuanjiang hot-dry valley vegetation were higher and considering the precipitation in this region was just about 700 mm, thus human activities and climate change are more likely to affect this ecosystem balance.

       

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