Water on an urban planet: Urbanization and the reach of urban water infrastructure     

《Global Environmental Change》2014

Urban growth is increasing the demand for freshwater resources, yet surprisingly the water sources of the world's large cities have never been globally assessed, hampering efforts to assess the distribution and causes of urban water stress. We conducted the first global survey of the large cities’ water sources, and show that previous global hydrologic models that ignored urban water infrastructure significantly overestimated urban water stress. Large cities obtain 78 ± 3% of their water from surface sources, some of which are far away: cumulatively, large cities moved 504 billion liters a day (184 km³ yr⁻¹) a distance of 27,000 ± 3800 km, and the upstream contributing area of urban water sources is 41% of the global land surface. Despite this infrastructure, one in four cities, containing $4.8 ± 0.7 trillion in economic activity, remain water stressed due to geographical and financial limitations. The strategic management of these cities’ water sources is therefore important for the future of the global economy.  相似文献   

Electricity generation and cooling water use: UK pathways to 2050     

《Global Environmental Change》2014

Thermoelectric generation contributes to 80% of global electricity production. Cooling of thermoelectric plants is often achieved by water abstractions from the natural environment. In England and Wales, the electricity sector is responsible for approximately half of all water abstractions and 40% of non-tidal surface water abstractions. We present a model that quantifies current water use of the UK electricity sector and use it to test six decarbonisation pathways to 2050. The pathways consist of a variety of generation technologies, with associated cooling methods, water use factors and cooling water sources. We find that up to 2030, water use across the six pathways is fairly consistent and all achieve significant reductions in both carbon and water intensity, based upon a transition to closed loop and hybrid cooling systems. From 2030 to 2050 our results diverge. Pathways with high levels of carbon capture and storage result in freshwater consumption that exceeds current levels (37–107%), and a consumptive intensity that is 30–69% higher. Risks to the aquatic environment will be intensified if generation with carbon capture and storage is clustered. Pathways of high nuclear capacity result in tidal and coastal abstraction that exceed current levels by 148–399%. Whilst reducing freshwater abstractions, the marine environment will be impacted if a shortage of coastal sites leads to clustering of nuclear reactors and concentration of heated water discharges. The pathway with the highest level of renewables has both lowest abstraction and consumption of water. Freshwater consumption can also be minimised through use of hybrid cooling, which despite marginally higher costs and emissions, would reduce dependence on scarce water resources thus increase security of supply.  相似文献   

“等熵思维”到“等熵位涡思维”回顾与讨论   总被引：3，自引：0，他引：3  

周小刚  王秀明  陶祖钰 《气象》2014,40(5):521-529

等熵位涡守恒与中纬度斜压扰动发展之间的诊断关系可用于对气旋发生发展的预报,并作为理解水汽图像的动力学场而在业务上使用。"等熵位涡思维"建立在等熵面分析的"等熵思维"基础上。本文首先依据基础的动力学理论,对等熵面上物理量场的动力学解释和业务应用作回顾和讨论,内容包括:等熵面随高度分布特征、等熵坐标中的垂直速度场、等熵面上水汽输送解释、等熵面上高空急流和锋区的特征等。其次,通过与等熵面物理量场分析和斜压二层模式准地转垂直运动方程的比较,着重回顾和讨论等熵位涡面上的物理量场和业务应用,内容包括:对流层顶定义及其温压湿分布特征、对流层顶等熵位涡面上急流和锋区的特征、对流层顶等熵位涡面上的垂直速度场、"等熵位涡思维"与气旋发展及位涡、水汽图像在改进数值预报模式中的作用等。  相似文献   

云中积冰过程微物理参量演变规律的数值模拟   总被引：2，自引：1，他引：1  

周悦  ;周月华  ;牛生杰  ;吕晶晶 《南京气象学院学报》2014,(4):441-448

利用耦合Thompson参数化物理方案的WRF（weather research and forecasting）中尺度数值模式,对发生在2008/2009年和2009/2010年冬季恩施雷达站处三次积冰过程的边界层特征和云雾微物理量进行了模拟,并与实测结果进行了对比分析.模拟结果较好地反映了恩施雷达站上空多逆温影响的温度层结特征;云水质量浓度和云雾滴中值体积直径的模拟值与观测值的平均绝对误差分别为10-2g·m-3和3.8μm;恩施雷达站上空存在一个质量浓度为0.3g ·m-3左右的高值中心,其逐渐下移接地,给积冰过程带来充足水汽,且此时通常也有降雨出现.  相似文献   

一次冷锋云系的宏微观物理特征分析     

孟宪罗  汤达章  郭金平  裴宇杰  赵娜  秦彦硕  段宇辉  赵利品 《南京气象学院学报》2014,6(6):539-548

利用常规气象资料、自动站资料、卫星云图、CINRAD-SA多普勒天气雷达资料以及NCEP再分析资料,结合飞行探测数据,对影响2011年4月17日河北抚宁县森林大火的一次冷锋云系进行分析.结果表明:1)宏观分析,过程降水的水汽仅来自冷锋自身所携带的微弱水汽,水汽辐合值较小,不利降水;2)微观分析,冷锋层状云系在水平和垂直方向上存在较薄的过冷水云区,小粒子数浓度大于20 cm^-3的云区占一定比例.飞机催化作业后,雷达回波强度增强,CAS(云气溶胶粒子探头)探测的小粒子数浓度、云含水量及粒子平均直径均有明显变化,说明该次冷锋云系有一定的增雨潜力.  相似文献   

华北区域冰雹天气分型及云系特征   总被引：2，自引：0，他引：2       下载免费PDF全文

蓝渝  郑永光  毛冬艳  林隐静  朱文剑  方翀 《应用气象学报》2014,25(5):538-549

基于地面加密观测资料、FY-2E静止气象卫星观测资料和NCEP分析资料,选取2010—2012年华北区域内27次冰雹过程,按大气环流背景、主要影响系统和云系的云型特征等将其分为冷涡云系尾部型、低涡槽前型和偏北气流控制型3种类型。分析结果表明:3种天气型下冰雹对流云系特征存在差异,但90%以上的冰雹过程发生在对流云团的快速发展阶段中,降雹集中出现于准圆形或椭圆形对流云团边缘或带状对流云系的传播前沿区域,对应于云顶亮温梯度的大值区。在掌握背景环境的前提下,综合分析红外图像中对流系统的发展演变、水汽图像暗带和暗区变化等信息,对冰雹的监测和预警有一定的参考价值。定量统计分析表明,大的亮温梯度值 (不低于8 ℃/0.05°) 是辅助判断冰雹能否发生的重要参量,而当冰雹云同时具备低云顶亮温和大亮温梯度的情况下,更有利于大于10 mm大冰雹的发生。  相似文献   

2013年南疆2场罕见暴雨落区和强度的对比分析     

张俊兰  魏荣庆  杨柳 《沙漠与绿洲气象(新疆气象)》2014,8(5):1-9

2013年5月26～28日和6月15～18日南疆连续出现了2场罕见的暴雨过程,利用常规地面和高空探测资料、NCEP/NCAR每日4时次 1°×1°再分析资料和欧洲ECWMF 0.25°×0.25°细网格数值预报产品,对比分析了这2场暴雨的落区和强度差异的成因。2场暴雨均在有利的环流背景下产生,较强暴雨的高空环流经向度更大、中亚低槽与北支槽打通并南伸更南,低层700hPa以下水汽输送较中高层更为重要,日常预报更应注重低层的水汽输入。对比暴雨强度,低层水汽输送越强(更多水汽路径、更多边界的水汽输入、更强水汽通量和水汽输入量)、低层水汽输送时间越长、低层切变线持续时间长且伸展至中高层,暴雨强度均可能更强。中尺度切变线和涌线在暴雨落区预报中具有一定的指示意义。  相似文献   

新疆塔额盆地各气象要素对水面蒸发影响的敏感性分析     

魏光辉 《沙漠与绿洲气象(新疆气象)》2014,8(5):44-47

水面蒸发敏感因素的判断,对于干旱区水资源的规划与利用具有重要指导意义。文章以新疆塔额盆地内的塔城市气象站1981—2010年资料为例,采用敏感系数法对研究区多年月均水面蒸发影响因素进行敏感性分析,并与关联分析法分析的结果对比。结果表明：在塔额盆地内,温度与水汽压二因素对水面蒸发影响最为敏感;基于敏感系数法的敏感因素研究结果与关联分析的结果基本一致,尤其在主要影响因子的判定上。  相似文献   

����GRACE����ʱ����������ⳤ�����ƺ�����ˮ�����仯     

尼胜楠  陈剑利  李进  陈超  梁青 《大地测量与地球动力学》2014,34(4):49-55

????GRACE??????????????????????????????????????仯??????????????о??伾????????仯??????????????????仯?????????ж??????????????????????????????仯???????????????δ?????????仯???????о???????????GRACE????????????????????????????仯??????????????cm????Ч???仯??  相似文献   

���ö�̬PPP�������ZTD��Ƶ�仯     

李黎  龙四春  沈军  李浩军  张立亚 《大地测量与地球动力学》2014,34(2):74-78

??????PPP????????IGS?ο????????????ж??PPP???????????????PPP??ZTD?????????????PPP??ZTD??IGS??????ZTD?ο???????????????PPP???????????????????????30 s????????t???????????????<6 mm????  相似文献