微物理过程参数化方案对辽宁一次暴雪的数值模拟差异分析   总被引：1，自引：0，他引：1  

滕方达  李得勤  蒋大凯  杨森  王寒  陆井龙  聂安祺 《气象学报》2020,78(4):608-622

利用WRFv3.9.1中尺度数值模式,采用Lin、WSM6、Thompson、WDM6四种微物理过程参数化方案对2007年3月4日辽宁特大暴雪过程进行了数值模拟研究。使用61个国家级气象站降水观测资料,评估了模式对此次降水过程的模拟能力,对比分析了不同微物理过程参数化方案模拟降雪过程中相态变化和水成物空间分布的差异。结果表明:4种微物理过程参数化方案均能模拟出与CloudSat卫星反演反射率分布相接近的结果,其中Thompson方案模拟的回波顶更高,向北伸展的范围也更大,其他3种方案回波顶高均在8 km附近。4种方案对降水落区的模拟略有差异,整体来看WSM6方案对本次降水的极值中心位置,以及不同降水量级的TS评分整体都优于其他3种参数化方案。降水相态模拟与观测的对比分析发现,WSM6、Lin和WDM6三种方案均能够模拟出雨雪分界线不断南压的过程且雨雪分界线位置准确,而Thompson方案对辽宁南部地区雨转雪时间模拟偏晚。从云微物理特征上看,4种方案均能模拟出大气低层存在的雨水粒子,其中WDM6方案模拟的雨水含量明显较其他3种方案更多,Thompson方案模拟出更多的雪粒子和最少的霰粒子,Lin方案霰粒子南北范围广、伸展高度高,WSM6和WDM6两种方案模拟出较少的霰粒子,这两种方案模拟的云冰高度也更低,正是各种水成物空间分布的差异决定了不同微物理过程参数化方案对降水量和降水相态模拟的差异。   相似文献   

沙尘天气过程起沙特征的观测试验和参数化研究进展   总被引：3，自引：0，他引：3  

张宏升  李晓岚 《气象学报》2014,72(5):987-1000

沙尘天气过程研究中,起沙过程是沙尘传输和沉降的基础,沙尘模式中的起沙参数化方案决定了能否准确模拟和预报沙尘天气。试验观测和数值模拟是研究起沙过程的重要途径。基于风蚀起沙的物理机制,总结了起沙机制和起沙特征的研究成果,介绍了风蚀起沙的主要影响因子,回顾了起沙关键参数（临界起沙摩擦速度（u*t ）或临界起沙风速（Ut ）、水平跃移沙尘通量（Q）和起沙通量（F））的试验观测及其沙尘模式应用中的参数化方案,并讨论了不同起沙参数化方案的应用与校验。同时,针对目前研究中存在的问题和今后可能的研究方向提出建议。  相似文献   

Rights-based management in the Western and Central Pacific Ocean tuna fishery: Economic and environmental change under the Vessel Day Scheme     

《Marine Policy》2013

Defining, strengthening and enforcing rights over fisheries resources is frequently identified as central to overcoming ‘the tragedy of the commons’ and associated environmental and economic challenges in fisheries systems. Though economic theory generally suggests that output control (e.g. quotas) creates the strongest incentives for efficiency and conservation, input controls (e.g. on effort) remain common. This paper explores the rationale for, and implications of, employing a transferable effort scheme in one of the largest and most valuable fisheries. In 2007, eight Pacific Island countries implemented the Vessel Day Scheme with the aims of strengthening their rights over tuna resources and control over economic and environmental trends. Four years since implementation, the scheme has significantly increased economic returns for the island states and generated improvements in data reporting. However, it has not generated a firm limit on fishing effort and its structure has made it difficult to directly target the biological concerns of individual species within the multi-species fishery. In the future, outcomes of the Vessel Day Scheme will continue to be tempered by the structural limitations of effort-based regulatory scheme, market conditions in the sector and the willingness of firms and island states to clarify, abide by and enforce the technical components of the scheme.  相似文献   

随机物理倾向扰动在风暴尺度集合预报中的影响研究   总被引：3，自引：0，他引：3  

闵锦忠  刘畅  王世璋  庄潇然  武天杰 《气象学报》2018,76(4):590-604

为深入探究随机物理倾向扰动（Stochastically Perturbed Parameterization Tendencies,SPPT）方案在风暴尺度集合预报中的影响,基于WRF模式利用FNL资料对SPPT方案中的3个参量分别进行敏感性试验,得到SPPT方案的最佳参数配置,并在此基础上分析SPPT方案模拟的降水分布特征。结果表明:SPPT方案敏感性试验中,去相关时间选择6 h时构造的集合成员可信度更高,逐时降水评分效果在积分中后期较高,对于暴雨及以上量级的评分技巧最优;造成降水主要天气系统的维持时间对该变量的选取有较大的影响。去相关空间尺度选择100 km的集合试验更为可靠,对降水预报技巧较高;同时该变量的选取与天气过程中的大尺度信息、中小尺度系统的活跃以及模式的空间分辨率有密切联系。通过对离散度和离群值分析认为扰动振幅选择0.525最为合理。SPPT方案集合成员在局部地区可以较大幅度地改变降水量,对降水落区的准确模拟存在一定的局限性。   相似文献   

陆面过程模式的研究进展简介   总被引：1，自引：0，他引：1  

汪薇  张瑛 《气象与减灾研究》2010,33(3):1-6

陆面过程是影响大气环流和气候变化的基本物理、生化过程之一。根据陆面过程研究的发展进程,介绍了三代陆面过程模式的不同特点和发展历程,指出在未来陆面方案中,引入光合作用和碳循环,可以更加真实地反映土壤、地表、大气、生物圈相互作用。陆面过程模式发展应该着眼于综合并且动态考虑植被类型变化、光合作用、碳循环和水循环的真实水文生化模型建立,将有效增强对气候变化的研究,提高天气预报模式的准确率。  相似文献   

Application of a Large-Eddy Simulation Database to Optimisation of First-Order Closures for Neutral and Stably Stratified Boundary Layers     

Igor N. Esau  Øyvind Byrkjedal 《Boundary-Layer Meteorology》2007,125(2):207-225

Large-eddy simulation (LES) is a well-established numerical technique, resolving the most energetic turbulent fluctuations in the planetary boundary layer. By averaging these fluctuations, high-quality profiles of mean quantities and turbulence statistics can be obtained in experiments with well-defined initial and boundary conditions. Hence, LES data can be beneficial for assessment and optimisation of turbulence closure schemes. A database of 80 LES runs (DATABASE64) for neutral and stably stratified planetary boundary layers (PBLs) is applied in this study to optimize first-order turbulence closure (FOC). Approximations for the mixing length scale and stability correction functions have been made to minimise a relative root-mean-square error over the entire database. New stability functions have correct asymptotes describing regimes of strong and weak mixing found in theoretical approaches, atmospheric observations and LES. The correct asymptotes exclude the need for a critical Richardson number in the FOC formulation. Further, we analysed the FOC quality as functions of the integral PBL stability and the vertical model resolution. We show that the FOC is never perfect because the turbulence in the upper half of the PBL is not generated by the local vertical gradients. Accordingly, the parameterised and LES-based fluxes decorrelate in the upper PBL. With this imperfection in mind, we show that there is no systematic quality deterioration of the FOC in the strongly stable PBL provided that the vertical model resolution is better than 10 levels within the PBL. In agreement with previous studies, we found that the quality improves slowly with the vertical resolution refinement, though it is generally wise not to overstretch the mesh in the lowest 500 m of the atmosphere where the observed, simulated and theoretically predicted stably stratified PBL is mostly located. The submission to a special issue of the “Boundary-Layer Meteorology” devoted to the NATO advanced research workshop “Atmospheric Boundary Layers: Modelling and Applications for Environmental Security”.  相似文献   

青藏高原边界层高度特征对大气环流动力学效应的数值试验   总被引：7，自引：2，他引：7       下载免费PDF全文

卓嘎  徐祥德等 《应用气象学报》2002,13(2):163-169

利用NCAR的全球气候模式 (CCM3) 及第二次青藏高原边界层观测试验的研究结果, 对青藏高原上大气边界层高度的作用进行了研究, 分析了夏季青藏高原地区与长江流域上空的环流状况。研究表明:青藏高原的边界层高度特征对高原东南部地区以及长江流域出现强烈的垂直上升运动及其低层辐合、高层辐散存在着显著的动力效应, 深厚的高原边界层特征将使长江流域夏季区域性的云量及降水明显增加, 河套地区与黄河流域的夏季云量及降水有所减少。  相似文献   

陆面气象要素非均匀分布对模式计算的影响及其参数化初步探讨   总被引：3，自引：1，他引：3       下载免费PDF全文

张正秋周秀骥  李维亮 《应用气象学报》2002,13(6):641-649

为改进陆面过程的参数化，初步探讨了模式中陆面气象要素次网格尺度不均匀性分布对模拟计算结果的影响。应用平均化方法初步探讨陆面过程的参数化，并分析了气象要素次网格尺度不均匀性分布对计算结果的影响特征。结果表明，次网格尺度不均匀性分布对模式的计算结果会产生一定的偏差，可用平均化方法对陆面过程次网格尺度不均匀性分布进行初步参数化。  相似文献   

平均环流参数化预报的初步试验     

陈英仪  佟建平 《大气科学》1992,16(4):444-451

本文提出一个对包括下垫面温度在内的未知总强迫项进行参数化作平均环流的预报方法.该参数化方案是假设未知作用力距平与流函数距平成正比,其比例系数是空间位置的函数,得到一个平均环流距平的预报方程.该方程表明,预报结果的好坏不仅取决于初始状态和动力学的考虑,还取决于环流的历史演变情况. 根据历史资料反求其比例系数,所作的平均环流距平的历史拟合结果令人满意.独立样本的预报结果比不上历史拟合的结果.试验结果还表明,如果加长历史资料的时间序列,把310天的历史资料增加到620天,则独立样本的预报结果有较大的改善,不仅有很多旬平均和月平均的个例非常成功,而且预报的半均准确率已超过一般惯性预报的水平.  相似文献   

A Data-Adaptive Filter of the Tahiti-Darwin Southern Oscillation Index and the Associate Scheme of Filling Data Gaps     

Zhang Banglin 《大气科学进展》1994,11(4):447-458

The Tahiti-Darwin Southern Oscillation index provided by Climate Analysis Center of USA has been used in numerous studies. But, it has some deficiency. It contains noise mainly due to high month-to-month variability. In order to reduce the level of noise in the SO index, this paper introduces a fully data-adaptive filter based on singular spectrum analysis. Another interesting aspect of the filter is that it can be used to fill data gaps of the SO index by an iterative process. Eventually, a noiseless long-period data series without any gaps is obtained.  相似文献