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1990 Vol. 7, No. 1

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Thermodynamic Feedback between Clouds and the Ocean Surface Mixed Layer
P.C. Chu, Roland W. Garwood, Jr.
1990, 7(1): 1-10. doi: 10.1007/BF02919163
A cloud-ocean planetary boundary layer (OPBL) feedback mechanism is presented and tested in this paper. Water vapor, evaporated from the ocean surface or transported by the large-scale air flow, often forms convective clouds under a conditionally unstable lapse rate. The variable cloud cover and rainfall may have positive and negative feedback with the ocean mixed layer temperature and salinity structure. The coupling of the simplified Kuo’s (1965) cumulus cloud model to the Kraus-Turner’s (1967) ocean mixed layer model shows the existence of this feedback mechanism. The theory also predicts the generation of low frequency oscillation in the atmosphere and oceans.
On Eastern Asian Dust Storm
Zhao Bolin, Yu Xiaoding
1990, 7(1): 11-26. doi: 10.1007/BF02919164
In this paper, the characteristics of eastern Asian dust storm are examined with emphasis on the satellite measurements of aerosol optical thickness. The reflectivity of solar radiation from the earth’s atmosphere depends on the optical thickness. The satellite measurement of radiance of sunlight, scattered by the earth and its atmosphere, is used to derive the properties of aerosol on oceanic surfaces. This paper involves the following: (1) investigation of the measurement of dust storm over the oceanic surface by GMS satellite; (2) investigation of the measurement of dust storm over the land surface by ground-based instruments such as actinometer, lidar, etc.; (3) for comparison, de-riving an atmospheric aerosol size distribution over the oceanic surface of calm weather through measurements of NOAA satellite; and (4) the weather process and its mass load of eastern Asian dust storm.
A Regional Spectral Nested Multilevel Primitive Equation Model
Liao Dongxian
1990, 7(1): 27-35. doi: 10.1007/BF02919165
By means of vertical normal modes a regional nested multilevel primitive equation model can be reduced to sev-eral sets of shallow water equations characterized by various equivalent depths. Therefore, time integration of the model in spectral form can be performed in the manner similar to those used in the spectral nested shallow water equation model case.
Interaction between Anomalous Winter Monsoon in East Asia and El Nino Events
Li Chongyin
1990, 7(1): 36-46. doi: 10.1007/BF02919166
Based on a series of data analyses, the intimate relations between anomalous winter monsoon in East Asia and El Nino are studied in this paper.Anomalistic circulation in the Northern Hemisphere caused by El Nino event can lead to enhancing the Ferrel cell and the westerlies in the mid-latitudes as the Hadley cell and result in the location of the front zone in East Asia to the north. These are unfavourable for the cold wave breaking out southward in East Asia. Therefore, there are warmer weather and weaker winter monsoon in East Asia in El Nino winter.There are stronger and frequent cold waves in East Asia during the wintertime prior to the occurrence of El Nino event. They will induce stronger winter monsoon in East Asia. Thus, the weakened trade wind and enhanced cumulus convection in the equatorial middle-western Pacific area caused by the stronger winter monsoon will play an impor-tant role in the occurrence of El Nino event. Therefore, the anomalously strong winter monsoon in East Asia during wintertime might be an important mechanism to cause El Nino event.
Relationship between the Interannual Variations of Total Ozone in the Northern Hemisphere and the QBO of Basic Flow in the Tropical Stratosphere
Huang Ronghui, Wang Lianying
1990, 7(1): 47-56. doi: 10.1007/BF02919167
The harmonic analyses of monthly mean total ozone in the atmosphere over the Northern Hemisphere for 26 years (1960-1985) are made by using the Fourier expansion. The analysed results show that there is obviously a quasi-biennial oscillation (QBO) in the interannual variations of the amplitudes of total ozone. Generally, the amplitudes of wavenumber 1 and 2 during the westerly of the equatorial QBO are larger than those during the easter-ly. In the early winter, the amplitude of wavenumber 1 during the easterly phase is larger, and in the late winter, it is larger during the westerly phase. These are in good agreement with the observational distributions.
A Diagnostic Analysis of Winter Atmospheric Circulation during the 1982-1983 ENSO Event
Teng Xinglin, Fu Congbin
1990, 7(1): 57-66. doi: 10.1007/BF02919168
In this paper, the winter atmospheric circulation, the convection along the equator and their variations of 1982 und 1983 are investigated. It is suggested that there was a well organized three dimensional structure of anomalies of the atmospheric circulations during 1982 winter which may be related to the variations of the convection in the equa-torial region.
Dynamical Framework of IAP Nine-Level Atmospheric General Circulation Model
Zhang Xuehong
1990, 7(1): 67-77. doi: 10.1007/BF02919169
The dynamical framework of the nine-level version of the IAP AGCM is presented in this paper. The emphasis of the model’s description is put on the following two aspects:1) A model’s standard atmosphere, which is a satisfactory approximation to the observed troposphere and lower stratosphere standard atmosphere, is introduced into the equations of the model to permit a more accurate calcula-tion of the vertical transport terms, especially near the tropopause; (2) The vertical levels of the model are carefully se-lected to guarantee a smooth dependence of layer thickness upon pressure in order to reduce the truncation error in-volved in the unequal interval vertical finite-differencing. For testing the model, two kinds of linear baroclinic Rossby-Haurwitz waves, one of which has a dynamically stable vertical structure and the other has a relatively unstable one, are constructed to provide initial conditions for numerical experiments, The two waves have been inte-grated for more than 300 days and 100 days respectively by using the model and both of them are propagating west-ward with almost identical phase-speed during the time period of the integrations. No obvious change of the wave patterns is found at the levels in the model’s troposphere. The amplitudes of both two waves at the uppermost level, however, exhibit rather significant oscillation with time, of which the periods are exactly 20 days and 25 days respectively. The explanation of this interesting phenomena is still under investigation.
Discussion of Meridional Propagation Mechanism of Quasi-40-Day Oscillation
He Jinhai
1990, 7(1): 78-86. doi: 10.1007/BF02919170
Based on researches made by the author in recent years, discussion is made of the quasi-40-day oscillation (QDO) nature and its characteristic propagation, with emphasis on the Southern Hemisphere mid-latitude quasi-periodic cold air forcing on the tropical atmosphere quasi-40-day oscillation along with its effect upon the Northern Hemisphere summer monsoon. It is proposed that the interaction between, or lateral coupling of, meridional circulation systems may serve as the mechanism of the oscillation propagation in a meridional direction.
Some Characteristics of Cumulus Convection over the Tibetan Plateau
Duan Tingyang, Elmar R. Reiter
1990, 7(1): 87-97. doi: 10.1007/BF02919171
The diagnostic model of the cumulus convection proposed by Yanai et al. (1973) was applied to the atmosphere over the Tibetan Plateau, and used to estimate the vertical mass flux, entrainment and detrainment, excess temperature and moisture, liquid water content, and condensation and precipitation rates of highland cloud clusters. The re-sults illustrated that in clouds over the Tibetan Plateau, the water vapor condensation rate, liquid water content, and efficiency of the rain generation process are less than those in the tropics (represented by the Marshall Islands region). Therefore, the condensational latent heat released over the Tibetan Plateau, overall, is much smaller than that in the tropics. The water vapor and liquid water detrainment from shallow nonprecipitating cumulus clouds, and their entrainment into deep cumulus clouds, serve as a growing mechanism for the deep precipitating cumulus towers over the Tibetan Plateau. It should be noted that there is a stronger detrainment of liquid water from cumulus clouds and a stronger re-evaporation rate in environment. The process of the condensation-detrainment-re-evaporation-entrainment is repeatedly in progress. It would play an important role in maintaining of cumulus convection on the condition that the supply of moisture is not plentiful over the Tibetan Plateau.The analyses also showed that the cloud mass flux Mc over the Tibetan Plateau is less, and the large-scale av-erage upward motion is much less than those over the Marshall Islands. Stronger compensating downward motion in the cloud environment over the Tibetan Plateau, responsible for the area’s strong environmental heating rate was re-vealed, and would link to the stability of the South Asian High in summer.
Simulation of the Influence of Ion-Produced NOX and HOX Radicals on the Antarctic Ozone Depletion with a One-Dimensional Model
Wang Guiqin
1990, 7(1): 98-103. doi: 10.1007/BF02919172
A one-dimensional time-dependent photochemical model is used to simulate the influence of ion-produced NOx, and HOx radicals on the Antarctic ozone depletion in polar night and polar spring at a latitude of 73 degrees south.Vertical transport and nitrogen-oxygen (NOx), hydrogen-oxygen (HOx) production by ionic reactions have been introduced into the model.NOx and HOx produced by precipitating ions are transported into the lower stratosphere by vertical motion and have some effects in the development of the Antarctic ozone depletion.From winter through spring the calculated ozone column decreases to 269.4 DU. However, this value is significantly higher than the total ozone observed at several Antarctic ozone stations.
The Investigation of Microwave Precipitation Measurement at 37GHz
Liu Jinli, Xiao Jianming, Zhang Ling
1990, 7(1): 104-110. doi: 10.1007/BF02919173
In this paper we use a 10-layer radiation transfer model to systematically investigate the relation between brightness temperature and the rainfall rates at 37 GHz, including various viewing of microwave (MW) remote sens-ing and different surface condition, with main focus on the influence of the structure of ice-phase layer. The results show that the quantitative rainfall measurement can not be reliably obtained over the land from spaceborne radiometer at this wavelength and the structures of ice layer are very important in determining the “observed” bright-ness temperature for the spaceborne MW remote sensing.
A Limited Area Model for Monsoon Prediction
S.S. Singh, S. S Vaidya, E. N. Rajagopal
1990, 7(1): 111-126. doi: 10.1007/BF02919174
A six level regional primitive equation model has been formulated and tested for monsoon prediction. The model uses dynamic normal mode initialization scheme for obtaining initial balance. The physical processes included are: the large scale condensation, the Kuo type of cumulus convection, the surface friction, the sensible heat supply and evap-oration over the sea. The actual smooth orography is included. The model has been integrated for 48 hrs using input of 7 July and 8 August 1979 when the domain of integration was dominated by an intense monsoon depression. In order to investigate the model simulation of formative stage of the depression, the model was also integrated using input of 4 July 1979.Furthermore, the envelope orography has been constructed and included in the model for investigating its effects on the monsoon prediction. Results of the model forecast are presented and discussed.