排序方式: 共有36条查询结果,搜索用时 31 毫秒
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使用区域气候模式(RegCM3)和大尺度汇流模型(LRM),研究中国地区土地利用/植被覆盖变化对黄河流域降雨径流过程的影响。RegCM3嵌套于欧洲数值预报中心(ECMWF)再分析资料ERA40,分别进行了中国区域在实际植被和理想植被分布情况下两个各15年(1987~2001年)时间长度的积分试验。随后,RegCM3 两个试验的输出径流结果分别用来驱动LRM。与观测资料的对比分析表明,在实际土地利用状况下,LRM能较好地模拟黄河河川径流的季节和年际变化。研究结果指出,当代土地利用引起了冬季黄河上游部分地区降水减少,中下游地区降水增加;引起夏季整个黄河流域降水的减少。总体来说,当代土地利用变化引起黄河流域年平均降水的减少。对于水文站河川径流量,除了冬春季略有增加外,其他月份河川径流均会减少,并且在9月减少最多。土地利用引起的植被退化造成黄河径流的大幅度减少,并且越向下游减少幅度越大,这可能是引起黄河下游断流的重要原因之一。 相似文献
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IPCC第一工作组(WGI)第四次评估报告(AR4)已于2007年2月2日公布(http://ipcc-wg1.ucar.edu/wg1/wg1-report.html)。我们对报告所引用的参考文献,主要针对论 相似文献
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The streamflow over the Yellow River basin is simulated using the PRECIS (Providing REgional Climates for Impacts Studies) regional climate model driven by 15-year (1979-1993) ECMWF reanalysis data as the initial and lateral boundary conditions and an off-line large-scale routing model (LRM). The LRM uses physical catchment and river channel information and allows streamflow to be predicted for large continental rivers with a 1°×1° spatial resolution. The results show that the PRECIS model can reproduce the general southeast to northwest gradient distribution of the precipitation over the Yellow River basin, The PRECIS- LRM model combination has the capability to simulate the seasonal and annual streamflow over the Yellow River basin. The simulated streamflow is generally coincident with the naturalized streamflow both in timing and in magnitude. 相似文献
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利用2006年内蒙古自治区共36个自动站和人工站平行观测资料,对观测得到的气象要素进行统计和评估。通过分析气温、气压、相对湿度、风等要素的对比差值及其标准差、对比差值的频次分布和空间分布等,探讨自动站与人工观测数据差异的可能原因。结果表明:内蒙古自动观测与人工观测各气象要素均存在一定的差异,对所有台站平均而言,其差异均在自动站差值允许范围之内。产生差异的原因:观测仪器结构与观测原理差异、观测时空差异和观测方式差异等。在将人工观测数据与自动观测数据连续使用时,需要根据当地情况进行适当订正,以确保资料的连续性。 相似文献
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基于Hadley气候预测与研究中心的区域气候模式系统PRECIS(Providing REgional Climates for Impacts Studies)单向嵌套该中心全球海-气耦合气候模式HadCM3高分辨率的大气部分HadAM3P, 检验PRECIS对我国气候基准时段(1961—1990年)极端温度事件的模拟能力, 分析IPCCSRES(Special Reporton Emission Scenarios)B2情景下未来2071—2100年相对于气候基准时段我国极端温度事件的变化响应。与观测资料的对比分析表明:PRECIS能够较好地模拟我国气候基准时段极端温度事件的局地分布特征。IPCC SRESB2情景下, 预估未来2071—2100年我国大部分地区高温日数出现频率均比气候基准时段高5倍以上; 霜冻日数将呈减少趋势, 我国南方地区的减少趋势大于北方地区; 暖期持续指数整体将呈增加趋势, 我国东北地区、西北地区中西部、华北地区和东南沿海地区增加显著; 冷期持续指数整体将呈减少趋势, 且东北地区、华北地区、西北地区及内蒙古、青藏高原大部地区的减少幅度将达到90%以上。 相似文献
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近百年中国气候经历了两次明显的年代际变暖,分别发生在20世纪40年代之前和70年代之后。由大气环流变化引起的冷、暖平流异常可为理解两次变暖提供参考。首先基于最新研制的近百年32站气温观测和集合经验模分解(Ensemble Empirical Mode Decomposition,EEMD)方法揭示两次变暖过程中国的冷、暖分布格局,进而利用全球格点气温和海平面气压资料计算了同期地转风导致的温度平流。结果表明,20世纪40年代中国华北北部至东北大部分地区和华南沿海局部地区偏冷而中东部至西南内陆大部分地区偏暖的年代际气候异常,站点冷、暖异常与大尺度温度平流的空间关联系数达0.85;而对于近20年中国气候变暖而言,这一关联系数仅0.49。研究结果从一个新颖的角度说明:早期变暖过程中气候系统内部过程如大气环流异常的作用较大,而近几十年气候变暖则更多地受迫于外强迫。 相似文献
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对新安江模型蒸散发计算的改进 总被引:4,自引:1,他引:4
基于DEM构建数字流域水文模型,在此基础上,利用新安江模型作径流计算。利用陆面模式SSIB中大气动力阻抗法计算蒸散发的方法改进新安江模型的蒸散发计算,从而改进新安江模型对流域出流量的模拟,得到更为合理的陆面水文模型。以安徽水阳江流域为研究区域,利用改进前后的新安江模型进行径流模拟。结果表明,对新安江模型蒸散发计算的改进提高了模型对径流量的模拟效果。 相似文献
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Comparison of two homogenized datasets of daily maximum/mean/minimum temperature in China during 1960–2013 下载免费PDF全文
Two homogenized datasets of daily maximum temperature (Tmax), mean temperature (Tm), and minimum temperature (Tmin) series in China have recently been developed. One is CHTM3.0, based on the Multiple Analysis of Series for Homogenization (MASH) method, and includes 753 stations for the period 1960–2013. The other is CHHTD1.0, based on the Relative Homogenization test (RHtest), and includes 2419 stations over the period 1951–2011. The daily Tmax/Tm/Tmin series at 751 stations, which are in both datasets, are chosen and compared against the raw dataset, with regard to the number of breakpoints, long-term climate trends, and their geographical patterns. The results indicate that some robust break points associated with relocations can be detected, the inhomogeneities are removed by both the MASH and RHtest method, and the data quality is improved in both homogenized datasets. However, the differences between CHTM3.0 and CHHTD1.0 are notable. By and large, in CHHTD1.0, the break points detected are fewer, but the adjustments for inhomogeneities and the resultant changes of linear trend estimates are larger. In contrast, CHTM3.0 provides more reasonable geographical patterns of long-term climate trends over the region. The reasons for the differences between the datasets include: (1) different algorithms for creating reference series for adjusting the candidate series—more neighboring stations used in MASH and hence larger-scale regional signals retained; (2) different algorithms for calculating the adjustments—larger adjustments in RHtest in general, partly due to the individual local reference information used; and (3) different rules for judging inhomogeneity—all detected break points are adjusted in CHTM3.0, based on MASH, while a number of break points detected via RHtest but without supporting metadata are overlooked in CHHTD1.0. The present results suggest that CHTM3.0 is more suitable for analyses of large-scale climate change in China, while CHHTD1.0 contains more original information regarding station temperature records. 相似文献
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