GRAPES_GFS中三维参考大气的研究:理论设计和理想试验

参考大气的选取对于半隐式半拉格朗日（Semi-Implicit Semi-Lagrangian,简称SISL）模式动力框架的计算精度至关重要。中国气象局数值预报中心自主研发的GRAPES_GFS（Global Regional Assimilation and PrEdiction System,Global Forecast System）采用基于等温大气构造的一维参考大气,该方法求解简单、易于实现,但无量纲气压和位势温度扰动量的数量级较大,降低空间计算精度的同时,由于非线性项较大,使得时间计算精度较低。借鉴近年来世界上各主要业务中心的数值模式框架搭建方法,拟在GRAPES_GFS的动力框架中引入不随时间变化且满足静力平衡的三维参考大气,使得积分过程中参考大气可以尽量地靠近模式大气,提高空间计算精度的同时,减小非线性项的数量级,进而提高时间积分的计算精度。本研究重新推导了引入三维参考大气之后模式动力学方程组的求解过程,通过若干个理想试验验证了理论方法以及代码实现的正确性,说明新的三维参考大气可以有效地提高模式动力框架的计算精度。      

An analysis of the air parcel trajectories of long- range transport at shanghai

CONCLUSION The analysis of air parcel trajectories affecting Shanghai indicates that the coming-direction of air parcel is different in various months. The transport track of trajectory (backward and forward) is closely related to the synoptic system, and also related to acid rain occurring in Shanghai region. Air pollution and acid rain in Shanghai region have relationship with both the influence of local pollutants and the influence of external pollutants from southwest and northeast.     

AN ANALYSIS ON THE STRUCTURE TYPES AND BENEFITS OF SLOPELAND AGROFORESTRY SYSTEMS-Taking the Three Gorge Reservoir Area As An Example

Chinahasalongltist0ryofaghcLIlturaldeveloPn1atn1edeveloPmatandLttilizahonofplanlsaremoreextensivethanthatofmotUAsinsandhills.Underthepressureofil11Promplivingstandardf0rl.2billionpeOPleatpresa1t,itistmdoubtedtoaCCeeratesl0PelanddeVeopmat.HOWdowerealizehig…     

Public housing and migration: a multi-level modelling approach

"This paper...[analyzes] the distance moved by one-year migrants using a multi-level modelling approach. Controlling for a range of socio-economic variables, derived from the 1991 British Census Sample of Anonymised Records (SAR), at both the individual and area level, the distance moved by household heads in public, privately rented and owner-occupied housing within Britain is assessed.... It is confirmed that migrants in public housing are less likely to migrate long distances than owner-occupiers and that the proportion of public housing in a SAR area, and the absolute reduction in public housing in a SAR area between 1981 and 1991, does not have a significant effect on the distance that in-migrants have moved."     

On hydraulic falls of two-layer flow

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Relationship between deep-sea fish distributions and oceanic conditions of the East China Sea

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Preface: Key technologies for enhancing the performance of FAST

The Five-hundred-meter Aperture Spherical radio Telescope(FAST)passed its national acceptance inspection on 2020 January 11.This special issue includes a total of 15 papers,which are selected to introduce the status of FAST’s performance and demonstrate the key technologies applied to FAST.The presented performance parameters can provide an important reference for scientists to propose observations with FAST.The key technologies presented in these papers include design and implementation in the measurement and control system,electromagnetic compatibility system,and receiver system.Finally,scientific achievements obtained by FAST during the commissioning phase are also reported.     

A Kinematical Calibration of the Galactocentric Distance

1 INTRODUCTION The distance to the Galactic center R0 is a fundamental constant for astronomy and astrophysics. Most determinations of astronomical quantities are directly connected with the Galactic distance scale, e.g., the rotational speed of our Galax…     

Rotation Periods of Nine ROSAT Selected Solar-Type Stars

We monitored 16 X-ray selected young solar-type stars for light variation and found appreciable periodic light variability with amplitudes of a few hundredths of a magni-tude in nine of the objects. Using the method of Phase Dispersion Minimization (PDM) and Fourier analysis (software PERIOD04), the rotation periods of these stars were determined from the photometric data. The rotation periods of all nine stars are shorter than about 3days. It is suggested that, as with the Pleiades cluster, small amplitude light variations are quite common among young solar-type stars with rotation periods around 3 days or less. This gives further evidence for the spin up of solar-type stars predicted by models of angular momentum evolution of pre-main sequence stars.