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A three-dimensional variational ocean data assimilation system:Scheme and preliminary results

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Science china Earth Sciences 2006年第11期49卷 1212-1222页

作者： ZHU Jiang1,2, ZHOU Guangqing1, YAN Changxiang1, FU Weiwei1 & YOU Xiaobao1,3 1. International Center for Climate and Environment Sciences, institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, china 2. Jiangsu Key Laboratory of Meteorological Disaster, nanjing University of Information Science and Technology, nanjing 2..044, china 3. Beijing institute of Applied meteorology, Beijing 100029, china International Center for Climate and Environment Sciences Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Jiangsu Key Laboratory of Meteorological Disaster Nanjing University of Information Science and Technology Nanjing China Beijing institute of Applied meteorology Beijing China

A new 3DVAR-based Ocean Variational Analysis System (OVALS) is developed. OVALS is capable of assimilating in situ sea water temperature and salinity observations and satellite altimetry data. As a component of OVALS, a new variational scheme is proposed to assimilate the sea surface height data. This scheme considers both the vertical correlation of background errors and the nonlinear temperature-salinity relationship which is derived from the generalization of the linear balance constraints to the nonlinear in the 3DVAR. By this scheme, the model temperature and salinity fields are directly adjusted from the altimetry data. Additionally, OVALS can assimilate the temperature and salinity profiles from the ARGO floats which have been implemented in recent years and some temperature and salinity data such as from expendable bathythermograph, moored ocean buoys, etc. A 21-year assimilation experiment is carried out by using OVALS and the Tropical Pacific circulation model. The results show that the assimilation system may effectively improve the estimations of temperature and salinity by assimilating all kinds of observations. Moreover, the root mean square errors of temperature and salinity in the upper depth less than 420 m reach 0.63℃ and 0.34 psu.

关键词： data assimilation, 3DVAR, sea surface height, ARGO floats.

THEORETICAL ANALYSES AND NUMERICAL EXPERIMENTS FOR TWO-DIMENSIONAL WIND RETRIEVALS FROM SINGLE-DOPPLER DATA

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Journal of Hydrodynamics 2010年第2期22卷 185-195页

作者： HUANG Si-xun CAO Xiao-qun DU Hua-dong ZHONG Ji-qin institute of meteorology PLA University of Science and Technology Nanjing 211101 China National University of Defense Technolog Changsha 410073 China institute of Urban meteorology China Meteorological Administration Beijing 100089 China

Based on variational adjoint methods,theoretical analyses and numerical experiments are performed for retrievals of two-dimensional winds and related parameters from single-Doppler radar data in polar *** the method,the reflectivity conservation equation is used as the governing equation and the mass continuity equation as a weak *** the same time,the stable functional of regularization and background field are also introduced in the cost *** on the ideal experiments with artificial data,real two-dimensional wind fields are retrieved with low-altitude data from the nanjing Doppler Radar Station,and the results are encouraging and promising.

关键词： single-Doppler retrievals adjoint methods regularization methods two-dimensional wind

Numerical Modelings of the Climatic Effects of the Land-Sea Distribution and Topography

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Advances in Atmospheric Sciences 1996年第3期13卷 383-398页

作者：钱永甫王谦谦nanjing institute of meteorology nanjing 2..044 Department of Atmospheric Sciences Nanjing UniversityNanjing 210093

The effects of the land-sea contrast and the topography on the climatic properties are simulated rn this paper by use of a p- a incorporated coordinate system mode! in a zonal *** this paper we firstly discuss the statistical features of the model and find that the capability of the model is stable,with the same land-sea distribution and topography seven monthly mean climate states are close to one another,their variance is even less than the initial ***,we focally discuss the effects of the land-sea contrast and the topography on the modeled climate *** is pointed out that the land-sea contrast and the topography influence the atmosphere mainly through the heating ef-fect and the former has larger influences on the simulated large scale climate fields than the latter.

关键词： Climate modelings Land-sea contrast and topography

Covarying modes of the Pacific SST and northern hemispheric midlatitude atmospheric circulation anomalies during winter

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Progress in Natural Science:Materials International 2008年第10期18卷 1261-1270页

作者： Yimin Zhu~(a,b,*) Xiuqun Yang~a Qian Xie~b Yongqiang Yu~c ~a Department of A tmospheric Science,nanjing University,nanjing 210093,china ~b institute of meteorology,PLA University of Science and Technology,nanjing 211101,china ~c LASG,institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,china Department of Atmospheric Science Nanjing University Nanjing 210093 China institute of meteorology PLA University of Science and Technology Nanjing 211101 China LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The interannual-to-interdecadal relationship between the Pacific sea surface temperature (SST) and the northern hemispheric midlati- tude’s atmosphere represented by the circumpolar vortex was documented with the global oceanic and atmospheric reanalysis data of recent 50 *** covarying modes of the Pacific SST and northern circumpolar vortex anomalies during winter were examined using the sin- gular value decomposition and wavelet analysis *** is the interannual,ENSO-related mode and the other is the interdecadal, North Pacific SST-related mode with a period of around 20 *** two modes exhibit distinct spatial *** the interannual mode,the SST anomaly is characterized by a typical ENSO pattern with the principal signature in the tropical eastern Pacific and secondary one in the central North Pacific,while the atmospheric anomaly is regional,characterized by a Pacific-North American *** the inter- decadal mode,large SST anomaly is located in the central North Pacific,while the atmospheric anomaly is zonally global,associated with the midlatitute’s standing long-wave *** the central North Pacific is colder,the long-wave is stronger,and vice *** investigations suggest that the interdecadal mode could involve an interaction between "two oceans and an atmosphere".

关键词： Sea surface temperature Atmospheric circulation ENSO Decadal variability

ENVIRONMENTAL AND TOPOGRAPHIC INFLUENCES ON ATMOSPHERIC INTERNAL SHIP WAVES

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Journal of Hydrodynamics 2008年第4期20卷 440-447页

作者： ZANG Zeng-liang PAN Xiao-bin ZHANG Ming Department of Martial meteorology Institute of Meteorology PLA University of Science and TechnologyNanjing 211101 China State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

A theoretical model was used to investigate the influences of environmental and topographic parameters on the atmospheric three-layer internal ship waves. The results show that both the wavelength and the wedge angle decrease with an increase in the Scorer parameter, and the rate of changes in the wavelength and wedge angle are also alike. The results also show that the wedge angle decreases with an increase in the width of mountain, but the wavelength varies little with it. It is suggested that the wedge angle is determined by the ratio of the wavelength to the scale of the mountain. Besides, numerical sensitivity experiments were performed to test the former numerical experiments. The simulated results are consistent with the analytical results.

关键词： Scorer parameter topographic parameter atmospheric internal ship waves numerical simulation

Computational properties of a new horizontal staggered grid

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Science china Earth Sciences 2005年第9期48卷 1559-1568页

作者： LIU YudiState Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, china institute of meteorology, PLA University of Science and Technology, nanjing 211101, china State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Ph Chinese Academy of Sciences Beijing China institute of meteorology PLA University of Science and Technology Nanjing China

This paper presents a new horizontal staggered grid (LE grid), which defines h at a gridpoint, and both u and v at the same mid-gridpoint along the x and y directions. A general method is used to deduce the dispersion relationships of describing inertia gravity waves on LE grid and Arakawa A―E grids, which are then compared with the analytical solution (AS) in re- solved or under-resolved cases, using two-order central difference or four-order compact differ- ence scheme from the frequency and group velocity. Results show that in both resolved and under-resolved cases, no matter whether two-order central difference or four-order compact dif- ference scheme is used, the frequency and group velocity discrete errors on LE grid in describing inertia gravity waves are smaller than those of Arakawa A―E grids. At the same time, it is only on LE or Arakawa grid C that the employment of a compact difference scheme of higher difference precision can improve their accuracy in describing inertia gravity waves. However, as for the other four grids (Arakawa A,B,D and E), when the difference precision increases, the accuracy of simulating inertia gravity waves decreases.

关键词： horizontal staggered grid, inertia gravity wave, LE grid, Arakawa A-E grid, compact difference scheme, central difference.

Sand-dust storms in china: temporal-spatial distribution and tracks of source lands

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Journal of Geographical Sciences 2001年第3期11卷 253-260页

作者： QIU Xin-fa1, ZENG Yan2, MIAO Qi-long2 (1. Urban & Resource Department, nanjing University, nanjing 210009, china 2. Department of Environmental Science, nanjing institute of meteorology, nanjing 2..044, china) Urban Resource Department Nanjing University Department of Environmental Science Nanjing Institute of Meteorology

Sand-dust storm is a special natural disaster that frequently occurs in deserts and their surrounding areas. With the data published onSurface Meteorological Monthly Bulletin andSurface Chart during 1971–1996, the temporal-spatial distribution and annual variation of sand-dust storms are analyzed on the basis of the case study of atmospheric processes. Furthermore, the tracks and source areas of sand-dust storms are determined with the aid of GIS. The results show that except some parts of Qinghai Province and Inner Mongolia as well as Beijing, sand-dust storms decrease apparently in time and space in recent decades in china. Sand-dust storms occur most frequently in spring, especially in April. According to their source areas, sand-dust storms are classified into two types, i.e., the inner-source and outer-source sand-dust storms. Most of the outer-source sand-dust storms move along the north and west tracks. The north-track outer-source sand-dust storms always intrude into china across the Sino-Mongolian border from Hami, a city in the eastern part ofXinjiang, to Xilin Gol, a league in Inner Mongolia, while the west-track ones intrude into china from both southern and northern Xinjiang. The source lands of inner-source sand-dust storms concentrate in the Taklimakan Desert and its surrounding areas in southern Xinjiang, southern part of the Junggar Basin in north of Xinjiang, the Hexi Corridor in western Gansu Province, the dry deserts of Inner Mongolia and the Qaidam Basin in Qinghai.

关键词： sand-dust storm temporal-spatial distribution tracks source lands

Urban effects and summer thunderstorms in a tropical cyclone affected situation over Guangzhou city

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Science china Earth Sciences 2007年第12期50卷 1867-1876页

作者： MENG WeiGuang1,3,YAN JingHua1 & HU HaiBo2 1 institute of Tropical and Marine meteorology,Chinese Meteorological Administration(CMA),Guangzhou 510080,china 2 institute of Urban meteorology,CMA,Beijing 100089,china 3 State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,china institute of Tropical and Marine meteorology Chinese Meteorological Administration (CMA) Guangzhou China State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing China institute of Urban meteorology CMA Beijing China

With data mainly from Guangzhou mesonet Automatic Weather Stations(AWS),Guangzhou Doppler Radar and satellite TBB data,characteristics and evolution of the urban heat island(UHI) over Guang-zhou City were analyzed in a tropical cyclone affected situation for early August *** particular,two thunderstorms occurring during this period respectively at the night of 4 August and in the afternoon of 7 August were investigated to study the relationships between the development of thunderstorms and the *** showed that two thunderstorms were associated with the UHI *** induced local air convergence and initiated the thunderstorm *** cases showed a general agreement in time and space for the locations of maximum UHI,convergence,convection,and *** was found to be more favorable to developing in time periods and locations with stronger intensity of *** also showed that,due to the urban effects,both thunderstorms got strengthened when moving over Guangzhou City,with maximum radar echoes observed right over the urban area and precipitation located within the *** these features reveal that two thunderstorms were urban-induced storms.

关键词： summer thunderstorms, urban heat islands (UHI), urban effects, tropical cyclone

NEW WAVE-DEPENDENT FORMULAE FOR SEA SPRAY FLUX AT AIR-SEA INTERFACE

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Journal of Hydrodynamics 2009年第4期21卷 573-581页

作者： SHI Jian ZHAO Dong-liang LI Xun-qiang ZHONG Zhong Key Laboratory of Coastal Disaster and Defense Ministry of Education Hohai University Nanjing 210098 China institute of meteorology PLA University of Science and Technology Nanjing 211101 China College of Physical and Environment Oceanography Ocean University of China Qingdao 266100 China

A bubble-derived Sea Spray Generation Function （SSGF） was deduced, which was integrated into the new wave-dependent SSGF. The effect of sea spray feedback was parameterized by the feedback coefficients A and B. The relationship of A（B） and the wind-sea Reynolds number was derived, which shows that the feedback effect of sea spray is decreasing with the wave developing. New sea spray flux formulae, including the new SSGF and new feedback coefficients, were proposed, which can reveal clearly the influence of wave state on sea spray fluxes. Spray fluxes in the Humidity Exchange Over the Sea （HEXOS） experiment were simulated again, and results show that spray momentum flux is small in this experiment, but spray heat flux is large. Comparisons of the sea spray fluxes calculated by two kinds of formulae in different wave states show that previous wave-independent spray flux formulae are the special cases of the presented new wave dependent formulae for sea spray flnx.

关键词： sea sray flux HEXOS wave state Sea Spray Generation Function (SSGF)