沙尘辐射效应对天气和沙尘输送影响的数值模拟

本研究利用WRF-Chem（Weather Research and Forecasting model with online coupled Chemistry）模式对未来中国北方沙尘起沙过程变化进行了模拟预测。为了提高预测结果的准确度,研究综合考虑了气溶胶、温室气体和植被覆盖率等因素对天气、气候和起沙过程的影响。预测结果显示,2016～2029年西北部沙尘源地起沙量高于北部沙尘源地,地形和气候的差异是导致两地起沙过程及其季节变化差异的主要原因。两个沙尘源地四季起沙通量呈总体减少而部分季节增加的趋势,西北部沙尘源地起沙通量在春季总体呈上升趋势,在夏、秋和冬季呈下降趋势;北部沙尘源地起沙通量在春、夏和冬季呈下降趋势,在秋季呈微弱上升趋势。两个沙尘源地各季起沙通量的变化趋势由近地面风速主导,植被覆盖率、降水和地面温度等因素对起沙通量的年际波动有着重要影响。     

基于非充分掺混模式的流域来水组成模型

针对如何减小数值求解对流输运方程耗散误差的问题,引进断面计算浓度的概念来计算河段平均浓度,提出了非充分掺混模式的有限控制体积法离散对流输运方程的新算法,据此构建了模拟流域内的水源组成以及不同水源在流域内的时空变化情况的流域来水组成模型。通过数值试验与具体实例验证,结果表明所提出的非充分掺混模式的新算法可有效地提高流域来水模型的计算精度。     

Implications of Japan’s long term climate mitigation target and the relevance of uncertain nuclear policy

Achieving long-term climate mitigation goals in Japan faces several challenges, starting with the uncertain nuclear power policy after the 2011 earthquake, the uncertain availability and progress of energy technologies, as well as energy security concerns in light of a high dependency on fuel imports. The combined weight of these challenges needs to be clarified in terms of the energy system and macroeconomic impacts. We applied a general equilibrium energy economic model to assess these impacts on an 80% emission reduction target by 2050 considering several alternative scenarios for nuclear power deployment, technology availability, end use energy efficiency, and the price of fossil fuels. We found that achieving the mitigation target was feasible for all scenarios, with considerable reductions in total energy consumption (39%–50%), higher shares of low-carbon sources (43%–72% compared to 15%), and larger shares of electricity in the final energy supply (51%–58% compared to 42%). The economic impacts of limiting nuclear power by 2050 (3.5% GDP loss) were small compared to the lack of carbon capture and storage (CCS) (6.4% GDP loss). Mitigation scenarios led to an improvement in energy security indicators (trade dependency and diversity of primary energy sources) even in the absence of nuclear power. Moreover, preliminary analysis indicates that expanding the range of renewable energy resources can lower the macroeconomic impacts of the long term target considerably, and thus further in depth analysis is needed on this aspect.

Key policy insights

• For Japan, an emissions reduction target of 80% by 2050 is feasible without nuclear power or CCS.

• The macroeconomic impact of such a 2050 target was largest without CCS, and smallest without nuclear power.

• Energy security indicators improved in mitigation scenarios compared to the baseline.

     

渭河流域1980-2000年LUCC时空变化特征及其驱动力分析

自然资源综合调查作为中国地质调查局2021年的新拓展业务,旨在服务国土空间规划、用途管制及生态保护修复。

本文基于流域2000年、2010年和2020年土地利用/覆被变化监测数据,利用ArcGIS软件对流域的土地利用类型和生态空间用地时空变化特征进行分析。

结果表明：（1）2000—2010年流域耕地转换为草地、林地以及建设用地的面积分别为804.4 km²、350.3 km²、327.6 km²,而草地、林地以及建设用地转换为耕地的面积分别为94.3 km²、10.4 km²、1.2 km²;（2）2010—2020年流域耕地转换为草地、林地以及建设用地的面积分别为16646.8 km²、3024.5 km²、2547.9 km²,而草地、林地以及建设用地转换为耕地的面积分别为16867.7 km²、3103.6km²、2528.82 km²;（3）2000—2020年流域生态空间用地面积转换达48165 km²,其中生态用地→半生态用地面积为20172 km²,半生态用地→生态用地面积为20897 km²,弱生态用地→半生态用地面积为2519 km²,半生态用地→弱生态用地面积为2754 km²,反映流域生态空间用地转换趋于平衡和生态系统服务质量稳中趋增。

以上成果对于促进渭河流域自然资源综合区划和国土空间“三区三线”优化具有重要意义。

     

北半球冬季纬向平均环流的结构及对我国气候的影响

As revealed by the empirical orthogonal function analysis (EOF), the dominant modes of northern hemispheric zonally-mean wind (u) in winter show two centers of opposite sign, one center located near 30?-35癗 and another near 55癗. The prominent modes of geopotential heights also show two centers, one is at 40癗 and another at 65癗. These two modes connected tightly. So, the zonal index can be defined as the difference in geopotential height between 40癗 and 65癗. This kind of zonal index correlate with westerly of 55癗 at 0.96. The anomalous variation of the westerly can impact the winter surface temperature and precipitation of China significantly. During the high-index years, most of China become warmer, and the precipitation in the mid-eastern China will increase. Correlation between the zonal index and the 160-station mean temperature and precipitation is 0.63 and 0.38 respectively.The Siberia High and Eastern Asia Trough that show the powerful control of winter climate of China, usually become weak during the high zonal index years.     

云南老王寨金矿煌斑岩地球化学研究中的某些问题──与宋新宇等同志商榷

本文对“云南老王寨金矿煌斑岩地球化学研究”一文中的部分结论及其解释，提出一些不同意见与原文作者宋新宇等先生商榷     

“经济大国能源与气候论坛”进展及前景展望

\"经济大国能源与气候论坛\"在推动全球主要国家就应对气候变化主要议题达成一致方面取得了进展,已初步显示出其作为联合国气候谈判晴雨表的特征。该论坛的实质是主要发达国家为转移减排责任和压力,降低减排成本,绑架主要发展中国家在全球应对气候变化领域实施的集体强权政治。论坛的核心目标在于推动全球量化减排,目的是借全球量化减排,营造低碳和气候友好技术的广大市场,使得具有技术优势的这些经济大国拥有新的主导全球经济的力量。我国应坚持\"共同但有区别的责任\"原则,联合与会发展中国家强调气候变化的历史责任,反对为全球温室气体排放设限等不公平提议,团结广大发展中国家,同时抓住论坛力推低碳经济和低碳技术发展的机遇,使我国站在全球新一轮技术革命的前沿。     

On the recent warming of the southeastern Bering Sea shelf

During the last decade, the southeastern Bering Sea shelf has undergone a warming of 3 °C that is closely associated with a marked decrease of sea ice over the area. This shift in the physical environment of the shelf can be attributed to a combination of mechanisms, including the presence over the eastern Bering Sea shelf of a relatively mild air mass during the winter, especially from 2000 to 2005; a shorter ice season caused by a later fall transition and/or an earlier spring transition; increased flow through Unimak Pass during winter, which introduces warm Gulf of Alaska water onto the southeastern shelf; and the feedback mechanism whereby warmer ocean temperatures during the summer delay the southward advection of sea ice during winter. While the relative importance of these four mechanisms is difficult to quantify, it is evident that for sea ice to form, cold arctic winds must cool the water column. Sea ice is then formed in the polynyas during periods of cold north winds, and this ice is advected southward over the eastern shelf. The other three mechanisms can modify ice formation and melt, and hence its extent. In combination, these four mechanisms have served to temporally and spatially limit ice during the 5-year period (2001–2005). Warming of the eastern Bering Sea shelf could have profound influences on the ecosystem of the Bering Sea—from modification of the timing of the spring phytoplankton bloom to the northward advance of subarctic species and the northward retreat of arctic species.     

近50年气候变化对滦河上游径流的影响

为了解近50年滦河上游气温和降水气候的变化特征、趋势及其对该流域径流量的影响,利用1956-2009年滦河上游的实测气温、降水量和径流深资料,分析了该流域气温、降水和径流深的年均和季度变化的时间序列,并建立了该流域气候变化对径流影响的复相关回归模型。结果表明,年径流深随着年降水量的减少而减少,随着年平均气温的升高而减少;春、夏和秋季的径流深随着同期降水量和气温的变化趋势与年际变化趋势基本一致,但冬季径流深则相反,而且其变化幅度非常小。