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黄河源区地表湿润指数及与气象因素的敏感性分析 总被引：4，自引：2，他引：2
应用Penman-Monteith模型计算了黄河源区地表潜在蒸散,分析了区域1961-2009年49 a来地表湿润指数的变化特征和趋势,并进行影响地表湿润指数的气象因素敏感性分析.结果表明:49 a来黄河源区年地表湿润指数呈减小趋势,其中20世纪60年代相对湿冷,70年代半湿冷,80年代为弱暖湿型,90年代暖干化明显.但进入21世纪初,特别是2003年以来,黄河源区降水增多,湿润指数上升,表现为暖湿型的气候特征.不同季节湿润指数变化略有不同,比较而言,49 a来地表湿润指数在冬春季呈增加趋势,夏秋季呈减小.湿润指数对降水量、日照时数和相对湿度的响应最为敏感. 相似文献
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《山地科学学报》2020,17(6):1387-1397
Alpine meadows, comprising the main ecosystem of the Three-River Source Region, play an important role in the economic development of western pastoral areas. To determine whether the grazing level was too intense or the nutrient-carrying capacity of the meadows was overloaded, and to offer solutions in Maqin County, Qinghai Province, China,the meadows carrying capacity was determined by combining grass-yield and nutrients data for different seasons across different meadows. The results showed that the levels of crude protein(CP), ether extract(EE), ash, soluble sugars(SS), gas production, and energy value of forage in the summer–autumn grazing meadows were higher than those of the winter–spring meadows. Neutral detergent fiber(NDF) and acid detergent fiber(ADF) of forage in the summer–autumn grazing meadows were lower than those of the winter–spring meadows. We found that no pastures were overloaded with metabolizable energy(ME) for the whole year but digestible crude protein(DCP) was overloaded in winter–spring. And there were differences in the amount carrying capacity(forage yield) of seasonal grazing meadows for the different herds, the overload types were annual overloading(herd A), overloaded in summer–autumn(herd B), overloaded in winter–spring(herd C), and not overloaded(herd D). Compared with the previous grazing mode, theoretical carrying capacity, DCP carrying capacity, and ME carrying capacity of herd A increased by 20, 19, and 27 sheep units, respectively,after optimization; herd B: 36, 31, and 45 sheep units,respectively; herd C: 28, 23, and 44 sheep units,respectively; and herd D: 43, 40, and 61 sheep units,respectively. In the Three-River Source Region and similar alpine pastoral areas, the grassland-livestock structure should be optimized to improve grassland vegetation status and increase the theoretical carrying capacity. 相似文献
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