苏勇,沈学顺. 2009. 相变修正方案在GRAPES模式标量平流中的应用[J]. 气象学报, 67(6):1089-1100, doi:10.11676/qxxb2009.105
相变修正方案在GRAPES模式标量平流中的应用
Application of amendment to phase change scheme in scalar advection of GRAPES model
投稿时间:2009-06-15  修订日期:2009-11-20
DOI:10.11676/qxxb2009.105
中文关键词:  GRAPES模式,非线性半拉格朗日,相变,分段有理函数方法
英文关键词:GRAPES model, NLSL, phase-change, PRM
基金项目:国家自然科学基金面上项目(40675063),国家重点基础研究发展计划 项目(2004CB418306),国际科技合作项目(2008DFA22180)和国家科技支撑计划项目(20 06BAC02B02)。
作者单位
苏勇 中国气象科学研究院数值预报研究中心北京100081 
沈学顺 中国气象科学研究院数值预报研究中心北京100081 
摘要点击次数: 2393
全文下载次数: 1849
中文摘要:
      如何更好地模拟水物质的空间分布和小尺度变化,对于数值天气预报效果的改进,特别是 对于更好地模拟降水过程,具有重要的意义。计算机的飞速发展使数值模式的分辨率不 断提高,云的显式计算成为可能,这样就要求水物质在平流的过程中必须要做到高精度、 守恒、保形。水物质场是正定标量的场,具有空间和时间变化幅度大、存在强梯度甚至不 连续的特点,水物质场的合理模拟一直是数值预报中的一个难题。GRAPES模式中的标量平 流方案 采用PRM分段有理函数方法,比较好地解决了该半拉格朗日模式中水物质平流的高精度、 守 恒、保形问题,但是当有凝结潜热发生时,由于半拉格朗日平流方案求解上游点时的插值, 在云边缘区域会造成虚假的云水,进而导致不合理的相变过程。为了解决以上问题,本研究 在GRAPES模式中PRM平流方案的基础上,加入了非线性半拉格朗日相变 潜热的修正方案,旨在改进GRAPES模式对水物质平流问题的模拟,提高降水的预报效果。 该研究通过理想试验,验证了非线性半拉格朗日相变修正方案可以有效地限制云边缘由于半拉格朗日平流方案插值产生的虚假相变;然后将该方案加入GRAPES模式的PRM 水物质平流方案中,通过实际个例模拟验证了加入非线性半拉格朗日方案以后,模式可以更好地模拟水物质的平流过程,且对云中热力场及水物质分布地模拟更加合理,同时预报出的雨带中心区与实况更加符合。
英文摘要:
      To better simulate the spatial characteristics and small-scale variations of wa ter substances in numerical models is of crucial importance for improving the nu merical weather prediction models, especially for precipitation forecast. With t he rapid development of work station, the resolution of numerical model is incr easingly sophisticated, it is possible to calculate the cloud explicitly, so it bring forward a higher request for the computation of water substance advection, it must be high order accuracy, conservation, and shape preserving. The water substance field is positive definite scalar field, with the characteristics of l arge variations in space and time, strong gradients and not even continuous, the simulation of water substance is always a problem in numerical prediction. The piece wise rational method is adopted as the scalar advection scheme in the GRAPES model, and this advection scheme is of high order accuracy, conservati on, and shape preserving in solving the water substance advection. However, unph ysical phase change may occured over the computational areas of cloud boundary w hen coupling the advection scheme with precipitation processes. Such unreasonabl e features result from the semi Lagrangian interpolation of cloud water around the cloud boundary and the consequent nonlinear interaction with physical proces ses. To mitigate this problem, a physical limitation method NLSL scheme in PRM s calar advection scheme in the GRAPES model was introduced, and tries to improve the simulation of cloud substances and precipitation forecast.Through one and tw o dimensional idealized experiments, the feasibility and effect of the physical limitation method in scalar advection scheme are verified. Furthermore, by imple menting this scheme into PRM advection scheme of high resolution GRAPES meso s cale model, both case study and continuous forecast experiment show that the simulated distribution of cloud water and thermal structures aro und the cloud boundary and within the cloud is improved to a certain extent. And , the forecast location of heavy rainfall and rain band exhibit more consistency with the observation.
HTML   查看全文   查看/发表评论  下载PDF阅读器
分享按钮