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“碧利斯”与“圣帕”引发湘东南特大暴雨雷达回波对比分析 被引量:12
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作者 黄小玉 胡文东 +2 位作者 孙弘 姚蓉 石喜民 《高原气象》 CSCD 北大核心 2009年第3期626-633,共8页
利用多普勒天气雷达、常规气象观测等资料,从雷达气象学和中小尺度天气学出发,对引发湘东南特大暴雨的两次强热带风暴"碧利斯"与超强台风"圣帕"进行了对比分析。结果表明:两次过程均为东风带系统影响,地形增幅作用... 利用多普勒天气雷达、常规气象观测等资料,从雷达气象学和中小尺度天气学出发,对引发湘东南特大暴雨的两次强热带风暴"碧利斯"与超强台风"圣帕"进行了对比分析。结果表明:两次过程均为东风带系统影响,地形增幅作用显著。螺旋带状、弥合回波阶段是造成强降水的主要时段。均有低质心暖性降水回波特征,降水效率高。"列车效应"是造成特大暴雨的关键,但形成方式不同:"碧利斯"主要由带状回波形成,而"圣帕"主要由回波在同一区域加强形成。"碧利斯"回波强度、回波顶高均大于"圣帕"过程,对流更旺盛,范围小而雨强大,与西风带冷式切变线暴雨回波相似。"圣帕"回波均匀,持续时间长,与西风带暖式切变线暴雨回波特征相似,回波移动缓慢,降水总量大。两次过程都有暖平流上叠加辐合风场的特征,形成了有利于强降水的环境背景。中γ尺度"大风核"造成有组织的次级环流,可能是"列车效应"形成和维持的主要原因。谱宽表明,受地面的摩擦作用,低层有强烈的湍流和乱流,有利于低压中心从低层减弱。中层为强而稳定的气流,有利于气旋强度的维持,形成长时间强降水。 展开更多
关键词 “碧利斯” “圣帕” 特大暴雨 雷达回波
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Temporal and Spatial Distribution of Evapotranspiration and Its Influencing Factors on Qinghai-Tibet Plateau from 1982 to 2014 被引量:14
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作者 CUI Mingyue WANG Junbang +2 位作者 WANG Shaoqiang YAN Hao LI Yingnian 《Journal of Resources and Ecology》 CSCD 2019年第2期213-224,共12页
Evapotranspiration is the key driving factor of the earth’s water cycle, and an important component of surface water and energy balances. Therefore, it also reflects the geothermal regulation function of ecohydrologi... Evapotranspiration is the key driving factor of the earth’s water cycle, and an important component of surface water and energy balances. Therefore, it also reflects the geothermal regulation function of ecohydrological process. The Qinghai-Tibet Plateau is the birthplace of important rivers such as the Yangtze River and the Yellow River. The regional water balance is of great significance to regional ecological security. In this study, ARTS, a dualsource remote sensing evapotranspiration model developed on a global scale, is used to evaluate the actual evapotranspiration(ET) in the Qinghai-Tibet Plateau from 1982 to 2014, using meteorological data interpolated from observations, as well as FPAR and LAI data obtained by satellite remote sensing. The characteristics of seasonal. interannual and dynamic changes of evapotranspiration were analyzed. The rates at which meteorological factors contribute to evapotranspiration are calculated by sensitivity analysis and multiple linear regression analysis,and the dominant factors affecting the change of evapotranspiration in the Qinghai-Tibet Plateau are discussed.The results show that:(1) The estimated values can explain more than 80% of the seasonal variation of the observed values(R^2 = 0.80, P < 0.001), which indicates that the model has a high accuracy.(2) The evapotranspiration in the whole year, spring, summer and autumn show significant increasing trends in the past 30 years, but have significant regional differences. Whether in the whole year or in summer, the southern Tibetan Valley shows a significant decreasing trend(more than 20 mm per 10 years), while the Ali, Lhasa Valley and Haibei areas show increasing trends(more than 10 mm per 10 years).(3) Sensitivity analysis and multiple linear regression analysis show that the main factor driving the interannual change trend is climate warming, followed by the non-significant increase of precipitation. However, vegetation change also has a considerable impact, and together with climate factors, it can explain 56% of the interannual variation of evapotranspiration(multiple linear regression equation R^2= 0.56, P < 0.001). The mean annual evapotranspiration of low-cover grassland was 26.9% of high-cover grassland and 21.1% of medium-cover grassland, respectively. Considering significant warming and insignificant wetting in the Qinghai-Tibet Plateau, the increase of surface evapotranspiration will threaten the regional ecological security at the cost of glacial melting water. Effectively protecting the ecological security and maintaining the sustainable development of regional society are difficult and huge challenges. 展开更多
关键词 EVAPOTRANSPIRATION Qinghai-Tibet Plateau climatic factors spatial and temporal distribution
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Spatio-temporal Variation of Vegetation Ecological Quality and Its Response to Climate Change in Rocky Desertification Areas in Southwest China during 2000–2020 被引量:1
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作者 XU Lingling QIAN Shuan +1 位作者 ZHAO Xiulan YAN Hao 《Journal of Resources and Ecology》 CSCD 2022年第1期27-33,共7页
Vegetation restoration is the primary task of ecological reconstruction and rocky desertification control in Karst areas. With vegetation net primary productivity and coverage as two key indicators, a vegetation ecolo... Vegetation restoration is the primary task of ecological reconstruction and rocky desertification control in Karst areas. With vegetation net primary productivity and coverage as two key indicators, a vegetation ecological quality evaluation model was built based on meteorological and remote sensing data. Spatiotemporal variation of vegetation ecological quality index and its response to climate change in rocky desertification areas in Southwest China during 2000-2020 were also analyzed by using the difference method and linear trend method. The results showed that:(1) Vegetation ecological quality in rocky desertification areas in Southwest China showed a fluctuating upward trend during 2000-2020. In 2020, the vegetation ecological quality index reached 69.7, which was 19.9% and 9.3% higher than the averaged values for 2000 and 2000-2019, respectively, ranking the fourth highest since 2000.(2) Vegetation ecological quality of the rocky desertification areas in Yunnan, Guangxi and Guizhou provinces have been improved by 89.2%, 99.2% and 98.5%, respectively, from 2000 to 2020, with their vegetation ecological quality index values increasing by 0.5-0.75 per year in southeast Yunnan, most areas in Guizhou and northwest Guangxi.(3) Precipitation was an important meteorological factor affecting the vegetation ecological quality in rocky desertification areas. The vegetation ecological quality index in the northwest and central Yunnan rocky desertification areas has been rising slowly, but with localized declines at a yearly rate of nearly 0.25 caused by climatic warming and drying. 展开更多
关键词 rocky desertification area vegetation ecological quality PRECIPITATION
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