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亚澳季风异常与ENSO准四年变化的联系分析 总被引:2,自引:0,他引:2
分析了赤道地区纬向风的年际变化特征,以及亚澳季风与ENSO在各个位相的联系。结果表明:赤道纬向风变化与中东太平洋海温变化在准四年周期上是强烈耦合的;在El Eino期间东亚冬季风弱,夏季风强,而南亚夏季风弱,反之,在La Nina期间东亚冬季风强,夏季风弱,而南亚夏季风强;东亚地区的异常北风有利于西太平洋西风异常爆发,使得东太平洋海温升高,但只有随后在中东太平洋出现持续性西风异常,El Nino才能发展,其中来自太平洋中部的异常北风(并不是来自东亚大陆地区)和南太平洋中部的异常南风的辐合对中东太平洋出现持续性西风异常起重要的作用,尤其是澳大利亚东北部的季风异常的影响更为显。 相似文献
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利用1955-2000年热带、副热带太平洋地区次表层温度距平资料,构造了温度距平极值深度分布曲面图,它很接近20°温度面的深度分布,因此有理由认为这一深度曲面很接近热带温跃层的深度面。在温度距平极值深度曲面上,分析了20世纪60年代后期以来所有El Nino/La Nina事件正/负海温距平信号的分布和传播“轨迹”,发现如果以暖池次表层作为起点,则一般来说,暖水或冷水先是沿赤道极值深度面向东、向上传播或运动,到达赤道东太平洋海盆边界附近后,在那里停留几个月,然后转北运动,在北纬10度左右再折向西运动到西太平洋转向南返回到暖池,即在赤道北侧形成闭合回路。温度距平运动一圈需时2-4年。如果暖(冷)水的温度距平都很强,就会在2-4年的时间上出现两次相邻的El Nino(La Nina)事件,但可能是由于大气或海洋环境条件不合适,温度距平的强度在运动过程中有时会减弱,就不能形成El Nino(La Nina)事件,但暖(冷)水运动的“轨迹”仍可辨认。由于暖、冷水绕环路的运动交替出现,El Nino(La Nina)爆发前,在赤道西太平洋出现正(负)距平信号的同时,在东太平洋北纬10度左右会有负(正)距平信号出现,并且当正(负)距平信号向东传播时,负(正)距平信号向西传播,在赤道上表现为2-4年间隔的El Nino(La Nina)交 相似文献
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Junghan Kim Young Cheol Kwon Tae-Hun Kim 《Asia-Pacific Journal of Atmospheric Sciences》2018,54(1):403-412
The design and implementation of a high-performance Input/Output (I/O) library for the Korean Integrated Model (KIM, KIM-IO) is described in this paper. The KIM is a next-generation global operational model for the Korea Meteorological Administration (KMA). The horizontal discretization of KIM consists of the spectral-element method on the cubed-sphere grid. The KIM-IO is developed to be a consistent and efficient approach for input and output of essential data in this particular grid structure in a multiprocessing environment. The KIM-IO provides three main features, comprising the sequential I/O, parallel I/O, and I/O decomposition methods, and adopts user-friendly interfaces similar to the Network Common Data Form (NetCDF). The efficiency of the KIM-IO is verified using experiments to analyze the performance of its three features. The scalability is also verified by implementing the KIMIO in the KIM at a resolution of approximately 12 km using the 4th supercomputer of KMA. The experimental results show that both regular parallel I/O and sequential I/O undergo performance degradation with an increasing number of processes. However, the I/O decomposition method in the KIM-IO overcomes this degradation, leading to improvement in scalability. The results also indicate that with using the new I/O decomposition method, the KIM attains good parallel scalability up to Ο (100,000) cores. 相似文献
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观测和分档方案的数值模拟都证明气溶胶的谱分布特征对云滴谱的演变有直接影响继而作用于降水的发展。目前广泛使用的总体双参数云滴谱方案因为表征云滴谱的预报量不足,在凝结过程中云滴谱呈不正常的拓宽现象。因此在参数化方案中,气溶胶谱对云滴谱的影响未有明确结论。中科学院大气物理研究所(IAP)云降水物理与强风暴重点实验室(LACS)新研发的三参数方案(IAP-LACS)通过增加的预报量克服了云滴谱的拓宽问题,提高了云滴谱模拟的准确性。为了研究在参数化方案中气溶胶谱分布特征对云滴谱的影响,本文采用新方案进行WRF(Weather Research and Forecasting mode)大涡理想性试验,验证了新方案中气溶胶对数正态谱函数中数浓度、几何半径和标准差3个参量对云滴谱演变的影响。针对3个参量的敏感性试验表明新的气溶胶活化方案和三参数云滴凝结增长方案能够描述气溶胶谱对云滴谱演变的影响规律:气溶胶数浓度对云滴谱影响最显著,数浓度越高活化生成的云滴数量越多,云滴半径越小,云滴谱趋向窄谱,气溶胶数浓度低时,云滴数量少、半径大。较大的几何半径使气溶胶谱向大粒径移动,导致大云滴生成,标准差对云滴谱的影响最不显著。 相似文献
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采用NCEP1°×1°客观再分析资料和常规观测资料,对2008年1月25—29日发生在长江中下游地区的强雨雪过程进行诊断分析,结果表明,低空急流与强雨雪有着密切关系,强雨雪的发生需具备一定的温度条件以及水汽场与动力场的耦合机制。对强雨雪过程的湿Q矢量诊断分析表明,700hPa湿Q矢量辐合区以及850hPa锋生函数正值区与强雨雪区对应较好,对雨雪天气的发生有着很好的指示意义。湿位涡特征分析表明,此次强雨雪过程发生在层结稳定的大气中且垂直涡度发展较强。 相似文献
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Evaluation of the computational performance of the finite-volume atmospheric model of the IAP/LASG(FAMIL) on a high-performance computer
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《大气和海洋科学快报》2017,(4)
高性能计算指标对于气候模式的发展,尤其是高分辨率气候模式的发展至关重要。本文系统性的评估了IAP/LASG新一代有限体积大气环流模式FAMIL在Tianhe-2超算平台上的计算性能。通过标准的AMIP试验,本文重点评估FAMIL在每个节点的高性能指标、每天所积分的模式年(SYPD)、计算成本加速比、可扩展性五方面的性能。结果表明:1)FAMIL在CPU使用率、CPU节点间信息传输等待时间、代码向量化、Gflops平均值、Gflops峰值五个方面表现出优异性能。2)综合考虑SYPD和计算成本加速比,对于C96(100km)和C384(25km)水平分辨率的FAMIL积分,最优进程使用数(MNPs)分别为384和1536。3)FAMIL具有良好的可扩展性,并且随着Tianhe-2网络传输速度的提升及MIC加速的使用,FAMIL的计算新能可以进一步得到提升。 相似文献
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The present paper selects the northern winter of December 1995–February 1996 for a case study on the impact of sea surface temperature (SST) anomalies on the atmospheric circulation over the North Atlantic and Western Europe. In the Atlantic, the selected winter was characterized by positive SST anomalies over the northern subtropics and east of Newfoundland, and negative anomalies along the US coast. A weak La Niña event developed in the Pacific. The North Atlantic Oscillation (NAO) index was low, precipitation over the Iberian Peninsula and northern Africa was anomalously high, and precipitation over northern Europe was anomalously low. The method of study consists of assessing the sensitivity of ensemble simulations by the UCLA atmospheric general circulation model (UCLA AGCM) to SST anomalies from the observation, which are prescribed either in the World Oceans, the Atlantic Ocean only, or the subtropical North Atlantic only. The results obtained are compared with a control run that uses global, time-varying climatological SST. The ensemble simulations with global and Atlantic-only SST anomalies both produce results that resemble the observations over the North Atlantic and Western Europe. It is suggested that the anomalous behavior of the atmosphere in the selected winter over those regions, therefore, was primarily determined by conditions within the Atlantic basin. The simulated fields in the tropical North Atlantic show anomalous upward motion and lower (upper) level convergence (divergence) in the atmosphere overlying the positive SST anomalies. Consistently, the subtropical jet intensifies and its core moves equatorward, and precipitation increases over northern Africa and southern Europe. The results also suggest that the SST anomalies in the tropical North Atlantic only do not suffice to produce the atmospheric anomalies observed in the basin during the selected winter. The extratropical SST anomalies would provide a key contribution through increased transient eddy activity, which causes an extension of the subtropical jet eastward from the coast of North America. 相似文献
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