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利用1958—2011年NCEP/NCAR逐日再分析资料,根据Lorenz能量循环理论框架,分析了北半球大气能量循环的年变化特征,在此基础上给出了更具普适性的多年平均的大气能量循环框图.结果表明:北半球大气能量循环的年变化特征十分明显.大气能量及能量转换率均表现为冬季高、夏季低、春秋季过渡的演变特征;纬向平均有效位能、纬向平均动能和涡动动能中有少许能量在冬季时由南半球向北半球进行越赤道输送,夏季时则由北半球向南半球输送,而涡动有效位能的输送方向则与此相反;纬向平均有效位能的制造在秋季最大,涡动有效位能的制造在夏季最大;动能的耗散冬季最强,夏季最弱.就年平均而言,相较于能量转化过程,能量越赤道交换过程非常微弱.在经向上,纬向平均有效位能主要分布于高纬地区,纬向平均动能主要分布于中低纬地区,而涡动能量主要贮存在中纬和高纬地区;此外,能量转化过程一般在中纬度地区较活跃. 相似文献
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A new local kinetic energy (KE) budget for the Madden-Julian Oscillation (MJO) is constructed in a multi-scale framework. This energy budget framework allows us to analyze the local energy conversion processes of the MJO with the high-frequency disturbances and the low-frequency background state. The KE budget analysis is applied to a pronounced MJO event during the DYNAMO field campaign to investigate the KE transport path of the MJO. The work done by the pressure gradient force and the conversion of available potential energy at the MJO scale are the two dominant processes that affect the MJO KE tendency. The MJO winds transport MJO KE into the MJO convection region in the lower troposphere while it is transported away from the MJO convection region in the upper troposphere. The energy cascade process is relatively weak, but the interaction between high-frequency disturbances and the MJO plays an important role in maintaining the high-frequency disturbances within the MJO convection. The MJO KE mainly converts to interaction KE between MJO and high-frequency disturbances over the area where the MJO zonal wind is strong. This interaction KE over the MJO convection region is enhanced through its flux convergence and further transport KE to the high-frequency disturbances. This process is conducive to maintaining the MJO convection. This study highlights the importance of KE interaction between the MJO and the high-frequency disturbances in maintaining the MJO convection. 相似文献
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The local features of transient kinetic energy and available potential energy were investigated using ECMWF(European Centre for Medium-Range Weather Forecasts) Interim Reanalysis data for the stratospheric sudden warming(SSW) event of January 2009.The Western Europe high plays important roles in the propagation of the energy from North America to Eurasian.When the Western Europe high appeared and shifted eastward,energy conversions increased and energy propagated from North America to Eurasian as a form of interaction energy flow.The baroclinic conversion between transient-eddy kinetic energy(Ke) and transient-eddy available potential energy(Ae) and the horizontal advection of geopotential height were approximately one order of magnitude less than Ke and Ae generation terms.So,these terms were less important to this SSW event. 相似文献
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登陆台风莫拉克(2009)的涡度拟能收支分析 总被引：4，自引：0，他引：4
利用涡度拟能、散度平方项(简记为散度能量)和总变形平方项(简记为变形能量)来表征涡度、散度和变形的强度,并推导这3个物理量的倾向方程。这些方程中既包含代表这些物理量相互转化的符号相反项,也含有代表共同强迫的符号相同项,其中,涡度拟能局地变化主要由涡度拟能与变形能量的共同强迫项、涡度拟能与变形能量的转化项以及涡度拟能与散度能量的转化项组成。针对2009年第8号台风莫拉克,利用美国全球预报系统分析场资料计算这些方程中的强迫项,分析涡度拟能及其收支特征,以此来探讨影响台风莫拉克涡度拟能局地变化的主要物理因素。结果表明,在莫拉克发展和衰减阶段,涡度拟能与变形能量的共同强迫项(涡-形相同项)和涡度拟能与散度能量的转化项(涡-散转化项)是影响涡度拟能局地变化的重要强迫项。涡度拟能与变形能量转化项(涡-形转化项)的贡献相对来说弱一些。影响位涡拟能局地变化的重要物理因素是涡-形相同项和涡-形转化项中的平流输送项和散度耦合项,以及涡-散转化项中散度耦合项。变形能量一方面通过涡-形转化项向涡度拟能转化,直接促进涡度拟能增长;另一方面通过散-形转化项向散度能量转化,再通过涡-散转化项散度能量向涡度拟能转化,间接促进涡度拟能增长。 相似文献
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扰动位能理论及其应用——扰动位能的概念、表达及其时空结构 总被引：4，自引：1，他引：4
针对局地环流能量转换问题,该工作系列讨论扰动位能理论及其应用.此文是第一篇,提出了扰动位能的新概念,将其分解为大气扰动位能(简称扰动位能)和表面扰动位能两个部分,给出了扰动位能各阶矩项的数学表达形式,结合资料指出二阶以上的扰动位能高阶矩项相对于其一阶矩项和二阶矩项来说是小量,可忽略,并指出扰动位能二阶矩项的全球平均恰好等于传统的有效位能,但两者在物理意义上明显不同.结合NCEP/NCAR再分析资料,研究了扰动位能的时空结构以及与大气动能之间的联系.扰动位能一阶矩项在热带地区为正、高纬度地区为负; 二阶矩项在热带和高纬度地区出现极大值,在副热带及中纬度地区出现极小值,即在南北方向上呈现三峰二谷的特征; 在局地上,由于一阶矩项在数值上较二阶矩项绝对占优,因此,扰动位能的分布与其一阶矩项的情形相似.在垂直方向上,扰动位能主要集中在对流层下层,其数值随高度的增加而迅速减少,在50 hPa以上均可以忽略不计.扰动位能有明显的季节变化,其在高纬度地区在冬半球比夏半球大很多; 南、北半球平均的扰动位能一阶矩项季节变化的幅度约是相应二阶矩项的二十倍.随着季节变化扰动位能定常波的槽脊在北半球有显著的东西方向移动,而在南半球则只表现为振幅上的增减.分析表明,从区域或局地尺度上大气动能的季节变化与扰动位能一阶矩项的关系密切,二者呈显著反向变化关系,而与二阶矩项的关系不确定; 但在全球或半球尺度上,大气动能与扰动位能二阶矩项的比率随季节基本保持不变,约是20%.此外,对大气总动能时空结构的分析也得到了与前人不同的新结果.关于利用此文提出的概念和理论对局地环流能量收支的分析、表面扰动位能的作用以及它们在大气环流变化研究中的应用,将在以后的文章中给出. 相似文献
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Energy budgets were analyzed to study the development of an eastward propagating southwest vortex (SWV) associated with heavy rainfall over southern China(11-13 June 2008).The results show that kinetic energy(KE) generation and advection were the most important KE sources,while friction and sub-grid processes were the main KE sinks.There was downward conversion from divergent to rotational wind KE consistent with the downward stretching of SWVs.The Coriolis force was important for the formation and maintenance of the SWV.Convergence was also an important factor for maintenance,as was vertical motion during the mature stage of the SWV and the formation stage of a newly formed vortex(vortex B).The conversion from available potential energy(APE) to KE of divergent wind can lead to strong convection.Vertical motion influenced APE by dynamical and thermal processes which had opposite effects. The variation of APE was related to the heavy rainfall and convection;in this case,vertical motion with direct thermal circulation was the most important way in which APE was released,while latent heat release and vertical temperature advection were important for APE generation. 相似文献
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利用NCEP-DOE再分析数据分析了2008年1月26～28日中国南方罕见的低温雨雪冰冻天气的扰动能量的生成以及各种能量之间的转换。在急流中平均动能（Km）先转换成相互作用动能（Ki）然后再转化成扰动动能（Ke）。相互作用动能流是顺急流方向的。位势高度平流和有效位能与扰动动能的转化生成的扰动动能比平均动能转化的要小一个量级。中国中南部扰动有效位能（Ae）的产生主要由平均有效位能（Am）间接提供,其中相互作用有效位能（Ai）流起到了关键作用。生成的扰动有效位能在26日12：00（协调世界时）主要来源于两个地区：一个位于青藏高原,另一个位于中国东北部。随着两个主要源地的向东移动,转化也向东移动。相互作用有效位能流的方向同时存在逆急流方向和顺急流方向。 相似文献
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提出了用ｌｎσ等距分层和Ｔｓｃｈｅｂｙｓｃｈｅｆｆ多项式沿垂直方向展开气象要素的方案；并证明：在绝热无耗散且时间和水平方向要素连续的情况，可以在高精度条件下，保证质量和能量守恒，且具有正确的动、位能之间的转换关系。数值计算表明：两方案均有较高的计算精度；在积分静力方程时，位势高度计算误差显著小于ＥＣ７９方案。 相似文献
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利用WRF模式和NCEP再分析资料,对一次梅雨暴雨个例进行了数值模拟,基于高分辨率的模拟结果计算了水平动能谱、涡旋动能谱及辐散动能谱,诊断了动能收支谱方程。结果表明:在暴雨发展阶段,各个高度上都有中尺度动能增长,其显著增加始于中尺度低端,这导致了在中尺度波段出现谱转折特征,但在不同高度转折尺度不同;对流层高层涡旋动能大于辐散动能,平流层低层反之;不同降水阶段、不同高度和不同尺度上动能的来源不同,对流层高层,中尺度动能倾向由非线性项和气压项贡献;平流层低层,气压项的作用更为明显。 相似文献
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气候变暖与西安市冬季供暖的能源消耗分析 总被引：3，自引：0，他引：3
摘 要：综合分析了西安市负积温、供暖初日、供暖终日、供暖期天数以及西安集中供暖面积和供暖热消耗量的多年变化。结果表明：在全球变暖的背景下,西安市亦存在冬季越来越暖,采暖期越来越短的趋势;随着经济的发展,集中供暖总面积和总供暖热消耗量不断增加,而单位供暖面积的热消耗量的总趋势随年代有所减少,但逐年耗热量与冬季气温的相关性并不好,说明实际供暖部门并没有根据气候变化调整能源投入。因此,建议冬季供暖的初、终日期及供暖强度应随着天气冷暖变化而随时调整,实现合理节能。 相似文献
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利用能量天气学原理,统计了3种天气类型的暴雨过程中潜热能场的水平分布特征。对1999年8月11日出现在山东省的大范围暴雨天气过程(99.8),分别就潜热能场水平分布特征、潜热能场垂直分布特征、能量锋生特征进行了分析。结果表明,潜热能场对暴雨预报有较好的指示作用,仅仅是能量高值区并不一定能产生大降水,当较强的能量锋区(或冷空气)与高能轴交汇、能量锋生函数负值区域移入当地,低层辐合条件较好时,预示强降水将要发生。"99.8"大暴雨主要发生在能量锋区与高能轴线交汇的地方,进而沿高能轴右侧向锋区密度较大地区移动,高能轴顶端的右前方、冷槽的后部也是强降水易发生的地区。 相似文献
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对一次登陆台风及其外围暴雨和环境的动能平衡以及天气尺度动能与中尺度扰动动能的转换进行了诊断分析，指出摩擦消耗和动能的水平输出是台风的主要能汇。台风消亡期间，外围暴雨区动能增大，动能制造项Ｇｋ是暴雨区的主要能源。Ｇｋ的增大可能与天气尺度动能转换成中尺度扰动引起暴雨的发展相联系。 相似文献
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The accumulated negative temperature,the first heating date,the last heating date,heating duration,collective heating area and energy consumption for winter heating in Xi'an during 1986-2002 were comprehensively analyzed.The results show that under the global warming,winter in Xi'an became warmer and heating duration shone,With the development of economy,the area and energy consumption for collective heating increased continually.In the meantime,the energy consumption per unit area for winter heating decreased year by year,but it did not match the winter temperature well because the energy was not proportionally consumed according to the change of temperature.In order to conserve energy effectively,heating in winter should be timely adjusted according to actual temperature change. 相似文献
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The accumulated negative temperature, the first heating date, the last heating date, heating duration, collective heating area and energy consumption for winter heating in Xi'an during 1986-2002 were comprehensively analyzed. The results show that under the global warming, winter in Xi'an became warmer and heating duration shorter. With the development of economy, the area and energy consumption for collective heating increased continually. In the meantime, the energy consumption per unit area for winter heating decreased year by year, but it did not match the winter temperature well because the energy was not proportionally consumed according to the change of temperature. In order to conserve energy effectively, heating in winter should be timely adjusted according to actual temperature change. 相似文献
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粤东地区太阳能资源及其利用气候分析 总被引：2，自引：0，他引：2
利用1971～2000年广东省汕头站日射观测资料,计算了粤东地区太阳总辐射,从太阳总辐射、气温、天空状况等方面分析了粤东地区太阳能资源的时空分布及其特点.指出粤东地区具有太阳总辐射量大、气候环境温度高,天空状况良好等自然气候条件,太阳能资源丰富,热状况优越,太阳能利用具有极大的发展空间. 相似文献
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Hydropower is the dominant renewable energy source to date, providing over two-thirds of all renewable electricity globally. For countries with significant hydropower potential, the technology is expected to play a major role in the energy transition needed to meet nationally determined contributions (NDCs) for greenhouse gas (GHG) emission reductions as laid out in the Paris Agreement. For the Republic of Ecuador, large hydropower is currently considered as the main means for attaining energy security, reducing electricity prices and mitigating GHG emissions in the long-term. However, uncertainty around the impacts of climate change, investment cost overruns and restrictions to untapped resources may challenge the future deployment of hydropower and consequently impact decarbonization efforts for Ecuador’s power sector. To address these questions, a partial equilibrium energy system optimization model for Ecuador (TIMES-EC) is used to simulate alternative electricity capacity expansion scenarios up to 2050. Results show that the share of total electricity supplied by hydropower in Ecuador might vary significantly between 53% to 81% by 2050. Restricting large hydropower due to social-environmental constraints can cause a fourfold increase in cumulative emissions compared to NDC implied levels, while a 25% reduction of hydropower availability due to climate change would cause cumulative emissions to double. In comparison, a more diversified power system (although more expensive) which limits the share of large hydropower and natural gas in favour of other renewables could achieve the expected NDC emission levels. These insights underscore the critical importance of undertaking detailed whole energy system analyses to assess the long-term challenges for hydropower deployment and the trade-offs among power system configuration, system costs and expected GHG emissions in hydropower-dependent countries, states and territories.
Key policy insights
Ecuador’s hydropower-based NDC is highly vulnerable to the occurrence of a dry climate scenario and restrictions to deployment of large hydropower in the Amazon region.
Given Ecuador’s seasonal runoff pattern, fossil-fuel or renewable thermoelectric backup will always be required, whatever the amount of hydropower installed.
Ecuador’s NDC target for the power sector is achievable without the deployment of large hydropower infrastructure, through a more diversified portfolio with non-hydro renewables.
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用ECMWF的ERA-40海浪再分析资料,应用波浪能流密度计算方法,对西北太平洋海域的风浪能、涌浪能、混合浪能展开研究。结果表明:(1)波浪能流密度呈现出显著季节性差异。混合浪能流密度表现为冬高夏低;春、夏、秋季的涌浪能流密度明显大于风浪能流密度,冬季相反;(2)混合浪能流密度的大值区主要分布于阿留申群岛附近海域,高值中心可达60 kW/m以上;近海的大值区主要分布于琉球群岛—巴士海峡—传统的南海大风区一带,年平均值在4 kW/m以上,南海北部可达12 kW/m以上;(3)黄渤海的涌浪和混合浪能流密度峰值出现在8—9月,波谷出现在6月。风浪能流密度峰值出现在11月—次年3月,波谷出现在6—8月,均呈现双峰型月变化特征。东海、南海北部、南海中南部海域能流密度的月变化特征相似,都为双峰型,12月—次年4月的能流密度整体较高,波峰出现在12月,波谷出现在5—7月;(4)2 kW/m以上混合浪能流密度出现的频率较高,近海低于大洋;(5)0.5 m以上有效波高出现的频率都非常高,中国近海稍低于大洋;(6)涌浪能流密度的稳定性明显好于风浪能流密度;大洋的能流密度稳定性明显强于近岸。1月份能流密度的稳定性最好,4月和7月次之,10月的稳定性最差。 相似文献