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991.
992.
Based on a high-resolution regional climate model (RegCM3) simulation over East Asia, future climate changes over the Miyun Reservoir in the 21st century under the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario are analyzed. The model simulation extends from 1951 to 2100 at a grid spacing of 25 km and is one-way nested within a global model of MIROC3.2_ hires (the Model for Interdisciplinary Research on Climate). The focus of the analysis is on the Watershed of Miyun Reservoir, the main water supply for Beijing in northern China. The results show that RegCM3 reproduces the observed temperature well but it overestimates precipitation over the region. Significant warming in the 21st century is simulated in the annual mean, December-January-February (DJF) and June-July-August (JJA), although with differences concerning the spatial distribution and magnitude. Changes in precipitation for the annual mean, DJF, and JJA also show differences. A prevailing increase of precipitation in DJF and a decrease of it in JJA is projected over the region, while little change in the annual mean is projected. Changes of the difference between precipitation and evapotranspiration to measure the potential water availability are also presented in the paper. 相似文献
993.
Using the monthly NCEP-NCAR reanalysis dataset, the monthly temperature and precipitation
at surface stations of China, and the MM5 model, we examine impacts of vegetation cover changes in
western China on the interdecadal variability of the summer climate over northwestern China during
the past 30 years. It is found that the summer atmospheric circulation, surface air temperature,
and rainfall in the 1990s were different from those in the 1970s over northwestern China, with
generally more rainfall and higher temperatures in the 1990s. Associated with these changes, an
anomalous wave train appears in the lower troposphere at the midlatitudes of East Asia and the
low-pressure system to the north of the Tibetan Plateau is weaker. Meanwhile, the South Asian
high in the upper troposphere is also located more eastward. Numerical experiments show that
change of vegetation cover in western China generally forces anomalous circulations and
temperatures and rainfall over these regions. This consistency between the observations and
simulations implies that the interdecadal variability of the summer climate over northwestern
China between the 1990s and 1970s may result from a change of vegetation cover over western
China. 相似文献
994.
Seasonal Prediction of the Global Precipitation Annual Modes with the Grid-Point Atmospheric Model of IAP LASG 下载免费PDF全文
A right annual cycle is of critical importance for a model to improve its seasonal prediction skill. This work assesses the performance of the Grid-point Atmospheric Model of IAP LASG (GAMIL) in retrospective prediction of the global precipitation annual modes for the 1980 2004 period. The annual modes are gauged by a three-parameter metrics: the long-term annual mean and two major modes of annual cycle (AC), namely, a solstitial mode and an equinoctial asymmetric mode. The results demonstrate that the GAMIL one-month lead prediction is basically able to capture the major patterns of the long-term annual mean as well as the first AC mode (the solstitial monsoon mode). The GAMIL has deficiencies in reproducing the second AC mode (the equinoctial asymmetric mode). The magnitude of the GAMIL prediction tends to be greater than the observed precipitation, especially in the sea areas including the Arabian Sea, the Bay of Bengal (BOB), and the western North Pacific (WNP). These biases may be due to underestimation of the convective activity predicted in the tropics, especially over the western Pacific warm pool (WPWP) and its neighboring areas. It is suggested that a more accurate parameterization of convection in the tropics, especially in the Maritime Continent, the WPWP and its neighboring areas, may be critical for reproducing the more realistic annual modes, since the enhancement of convective activity over the WPWP and its vicinity can induce suppressed convection over the WNP, the BOB, and the South Indian Ocean where the GAMIL produces falsely vigorous convections. More efforts are needed to improve the simulation not only in monsoon seasons but also in transitional seasons when the second AC mode takes place. Selection of the one-tier or coupled atmosphere-ocean system may also reduce the systematic error of the GAMIL prediction. These results offer some references for improvement of the GAMIL seasonal prediction skill. 相似文献
995.
This paper gives a definition of earth system model and shows three development phases of it, including physical climate system model, earth climate system model, and earth system model, based on an inves- tigation of climate system models in the world. It provides an expatiation on the strategic significance of future development of earth system model, an introduction of some representative scientific research plans on development of earth system model home and abroad, and a review of its status and trends based on the models of the fourth assessment report (AR4) ofthe Intergovernmental Panel on Climate Change (IPCC). Some suggestions on future development of earth system model in China are given, which are expected to be helpful to advance the development. 相似文献
996.
利用澳门的气温观测资料, 分析了澳门1901-2007年地面气温变化的基本特征。结果表明:近107 a的升温率为0.066℃/10a, 明显低于全球平均升温率。季节平均气温的年代际变化有明显的季节差异,最大的增暖发生在春季和冬季,夏季的增暖最小;冬、夏季的变化分别有明显的时间尺度约为60 a和30 a的振动。年平均最高气温的升温率仅为最低气温的一半左右。最高气温的年代际变化呈缓慢的气候波动现象,20世纪80年代中期以后的升幅与历史上的增暖大致相当;最低气温近20多年来的增暖趋势可能是其长期(变暖)趋势的延续。年平均日较差整体来说是趋于减少的,但近30 a却趋于增加。 相似文献
997.
对黑龙江省小兴安岭五营丰林国家自然保护区建立的红松 (Pinus koraiensis) 树轮宽度年表与五营气象站的气候要素响应分析表明,树轮年表与生长季上一年10月份的平均温度显著相关,由此重建了1796-2004年五营10月份平均温度。此外,4月下旬的温度变化对五营红松树木的径向生长也具有一定的影响。1796-2004年,五营共经历了4个偏冷和4个偏暖期。周期分析表明,重建序列以3.33 a的周期最为显著,对重建序列30 a尺度的突变检验结果表明,1871年和1900年前后,五营地区10月份平均温度出现了显著的均值突变,1851年前后出现了明显的方差突变。 相似文献
998.
温度变化是全球变化研究中非常重要的基础性问题,在中国近百年温度变化方面,十几年来已取得了明显进展,这首先表现在建立了若干条全国平均气温序列,而几条主要序列间的相关系数在0.73~0.97之间。同时,这些进展也表现在基础资料质量提高、空间覆盖面扩大、序列均一性改善以及结果可靠性提高等方面。对多序列进行综合分析得到的新结果显示,1906-2005年中国的年平均气温上升了(0.78±0.27)℃,2007年是我国近百年来最暖的一年;代表性分析显示,现有的几条中国温度序列中除覆盖完整的序列外,其他序列在1920或1930年代以前可能主要反映中国东部变化情况,但在此之后则能较好地代表全国大部分地区的气候变化特征。 相似文献
999.
利用NCEP再分析资料,对2008年8~9月内蒙主着陆场区强对流天气频发和降水异常偏多现象,研究其形成的气候背景和大尺度环流特征.结果表明:前期赤道西太平洋海表温度异常偏低、欧亚和青藏高原积雪异常偏深是其前期气候背景.极涡中心8月位于东半球和9月位于西半球,是场区前期降水偏多和后期气温偏高的原因之一.欧亚经向环流的偏强,有利于南北方冷暖空气的交汇.副热带高压偏强偏西及活跃的印缅槽为场区提供了充沛的水汽和强对流天气必要的扰动能量.中低层偏南风和偏北风在淮河以北地区汇合与维持,是场区降水异常和强对流偏多的主要原因. 相似文献
1000.
A nested-model system is constructed by embedding the regional climate model RegCM3 into a
general circulation model for monthly-scale regional climate forecast over East China. The systematic
errors are formulated for the region on the basis of 10-yr (1991-2000) results of the nested-model system,
and of the datasets of the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) and
the temperature analysis of the National Meteorological Center (NMC), U.S.A., which are then used for
correcting the original forecast by the system for the period 2001-2005. After the assessment of the original
and corrected forecasts for monthly precipitation and surface air temperature, it is found that the corrected
forecast is apparently better than the original, suggesting that the approach can be applied for improving
monthly-scale regional climate dynamical forecast. 相似文献