1986 Vol. 3, No. 1
Display Method:
1986, 3(1): 1-9.
doi: 10.1007/BF02680041
Abstract:
An approximate expression of the sky radiance in almucantar is confirmed in this paper. Under the conditions with molecular optical depth<0.3, aerosol (or cloud) optical depth<0.6, solar zenith angle< 75° and scattering angle<30°, the errors of the sky radiance and the aerosol phase function computed from the expression are respectively less than 8 % and 10 %, but the phase functions computed from Box-Deepak formula and single-scattering formula can be 84 % and 260 % more than the exact value, respectively. Furthermore, by use of the expression we have inferred the volume scattering functions of 1°≤θ≤30° for retrieving aerosol size distribution with the conclusion that the distribution information in the range of 0.1
An approximate expression of the sky radiance in almucantar is confirmed in this paper. Under the conditions with molecular optical depth<0.3, aerosol (or cloud) optical depth<0.6, solar zenith angle< 75° and scattering angle<30°, the errors of the sky radiance and the aerosol phase function computed from the expression are respectively less than 8 % and 10 %, but the phase functions computed from Box-Deepak formula and single-scattering formula can be 84 % and 260 % more than the exact value, respectively. Furthermore, by use of the expression we have inferred the volume scattering functions of 1°≤θ≤30° for retrieving aerosol size distribution with the conclusion that the distribution information in the range of 0.1
1986, 3(1): 10-22.
doi: 10.1007/BF02680042
Abstract:
The atmospheric dynamic equations have been transformed from the z-coordinate system into a generalized vertical coordinate system by using a so-called DDD transformation method. Then the general-ized system is assumed being pressure, sigma or incorporated pressure-sigma coordinate system and corre-sponding equations are obtained with the second-order accuracy. It is pointed out that the usual equations are only of the first-order accuracy when their space-differential terms are approximated by central finite differences. Therefore the usual forms of the equations may result in quite large errors on steep slopes of mountains included in a model.
The atmospheric dynamic equations have been transformed from the z-coordinate system into a generalized vertical coordinate system by using a so-called DDD transformation method. Then the general-ized system is assumed being pressure, sigma or incorporated pressure-sigma coordinate system and corre-sponding equations are obtained with the second-order accuracy. It is pointed out that the usual equations are only of the first-order accuracy when their space-differential terms are approximated by central finite differences. Therefore the usual forms of the equations may result in quite large errors on steep slopes of mountains included in a model.
1986, 3(1): 23-38.
doi: 10.1007/BF02680043
Abstract:
Feasibility is investigated of multi-wavelength lidar exploration of size distribution patterns (SDP) and complex refractive indices (CRI) of aerosols in different layers of a stratified atmosphere, and an improved observational scheme is worked out for the optical parameters (extinction coefficients, angular scattering coef-ficients and their ratios) of the substance in layers homogeneous horizontally in optical depth obtained by a bi-static lidar system. Variations are examined of these parameters versus CRI (whose real part is 1.33- l.63 and imaginary 0.00-0.1) and working wavelengths (0.3472, 0.53, 0.6943 and 1.06 μm) in such SDP as Junge-3, 4 and 5. The Deirmendjian Haze M and L. A method is thereupon developed for retrieval of aerosols’ SDP and CRI from these parameters and tested by suitable numerical experiments.
Feasibility is investigated of multi-wavelength lidar exploration of size distribution patterns (SDP) and complex refractive indices (CRI) of aerosols in different layers of a stratified atmosphere, and an improved observational scheme is worked out for the optical parameters (extinction coefficients, angular scattering coef-ficients and their ratios) of the substance in layers homogeneous horizontally in optical depth obtained by a bi-static lidar system. Variations are examined of these parameters versus CRI (whose real part is 1.33- l.63 and imaginary 0.00-0.1) and working wavelengths (0.3472, 0.53, 0.6943 and 1.06 μm) in such SDP as Junge-3, 4 and 5. The Deirmendjian Haze M and L. A method is thereupon developed for retrieval of aerosols’ SDP and CRI from these parameters and tested by suitable numerical experiments.
1986, 3(1): 39-58.
doi: 10.1007/BF02682551
Abstract:
The problems on evolution of large-scale disturbances and their interaction with mean flow recently attract much effort of meteorologists due to their practical importance in weather and climate predictions. In this paper, some theoretical results obtained in current investigations of these problems will be reviewed. A barotropic atmosphere is taken in this paper, and the baroclinic atmosphere is left in our second paper.The following aspects are reviewed: First, the general properties of two-dimensional barotropic motion both in the nonlinear and linearized equations and both in the quasi-geostrophic and non-geostrophic models. Second, the evolution and the structure of Rossby wave packet superimposed on a zonal or non-zonal basic flow.In this part, only the above two problems are reviewed. The rernanent problems, i.e., the normal modes and continuous spectra of both quasi-geostrophic and non-geostrophic models, weakly nonlinear theory and the fully nonlinear theory will be discussed in part II (another paper).
The problems on evolution of large-scale disturbances and their interaction with mean flow recently attract much effort of meteorologists due to their practical importance in weather and climate predictions. In this paper, some theoretical results obtained in current investigations of these problems will be reviewed. A barotropic atmosphere is taken in this paper, and the baroclinic atmosphere is left in our second paper.The following aspects are reviewed: First, the general properties of two-dimensional barotropic motion both in the nonlinear and linearized equations and both in the quasi-geostrophic and non-geostrophic models. Second, the evolution and the structure of Rossby wave packet superimposed on a zonal or non-zonal basic flow.In this part, only the above two problems are reviewed. The rernanent problems, i.e., the normal modes and continuous spectra of both quasi-geostrophic and non-geostrophic models, weakly nonlinear theory and the fully nonlinear theory will be discussed in part II (another paper).
1986, 3(1): 59-71.
doi: 10.1007/BF02680045
Abstract:
In this paper, a second-order model is proposed for the study of the evolution of the nocturnal boundary layer (NBL). The model is tested against the Wangara data on atmospheric boundary layer. The computer results show ihat the model can simulate some important characters observed in the NBL, and that a kind of sudden change may occur in the developing process of NBL.
In this paper, a second-order model is proposed for the study of the evolution of the nocturnal boundary layer (NBL). The model is tested against the Wangara data on atmospheric boundary layer. The computer results show ihat the model can simulate some important characters observed in the NBL, and that a kind of sudden change may occur in the developing process of NBL.
1986, 3(1): 72-85.
doi: 10.1007/BF02680046
Abstract:
Four numerical experiments of simulation have been conducted in this paper by the use of a five-layer primitive equation numerical model with incorporated pressure-sigma vertical coordinate system. The initial fields are taken from the July zonal mean data of many years, while the heat sources and sinks are ideally specified according to the mean heating field over the East Asia calculated from the real data of July, 1979. On the basis of simulated results of temperature and geopotential height patterns we emphatically discuss the effects of the topography and the heating of the Qinghai-Xizang Plateau. From the analyses in this paper, it appears that the heating over the Bengal region makes a larger contribution to the middle and the south branches of the monsoon cell and is also the main cause for the existence of the southerly channel to the east of the Plateau, for the break of the subtropical anticyclone belt below the 500 hPa level and for the formation of the summer Asian anticyclone at the 300 hPa level, while the heating over the Plateau makes a larger contribution to the Plateau monsoon cell and to the anticyclone at the 100 hPa.
Four numerical experiments of simulation have been conducted in this paper by the use of a five-layer primitive equation numerical model with incorporated pressure-sigma vertical coordinate system. The initial fields are taken from the July zonal mean data of many years, while the heat sources and sinks are ideally specified according to the mean heating field over the East Asia calculated from the real data of July, 1979. On the basis of simulated results of temperature and geopotential height patterns we emphatically discuss the effects of the topography and the heating of the Qinghai-Xizang Plateau. From the analyses in this paper, it appears that the heating over the Bengal region makes a larger contribution to the middle and the south branches of the monsoon cell and is also the main cause for the existence of the southerly channel to the east of the Plateau, for the break of the subtropical anticyclone belt below the 500 hPa level and for the formation of the summer Asian anticyclone at the 300 hPa level, while the heating over the Plateau makes a larger contribution to the Plateau monsoon cell and to the anticyclone at the 100 hPa.
1986, 3(1): 86-93.
doi: 10.1007/BF02680047
Abstract:
The principle and technique of real-time remote sensing of the layered atmospheric precipitable by using a ground-based radiometer of 1.35 cm wavelength with a microcomputer as a controlling and data process-ing unit are presented. The stability and calibration of the instrument are outlined. Observations during the summer of 1984 show that the RMS deviation of the layered precipitable between the radiometer meas-urement and the radiosonde ranges from 0.20 to 0.25 g/cm2 with a correlation coefficient of above 90 %.
The principle and technique of real-time remote sensing of the layered atmospheric precipitable by using a ground-based radiometer of 1.35 cm wavelength with a microcomputer as a controlling and data process-ing unit are presented. The stability and calibration of the instrument are outlined. Observations during the summer of 1984 show that the RMS deviation of the layered precipitable between the radiometer meas-urement and the radiosonde ranges from 0.20 to 0.25 g/cm2 with a correlation coefficient of above 90 %.
1986, 3(1): 94-104.
doi: 10.1007/BF02680048
Abstract:
The present work is devoted to multi-dimensional sequence similarity method with a view to predicting a typhoon analogous in both rainfall and track to the historical event. The result can be used in operational forecasts.
The present work is devoted to multi-dimensional sequence similarity method with a view to predicting a typhoon analogous in both rainfall and track to the historical event. The result can be used in operational forecasts.
1986, 3(1): 105-114.
doi: 10.1007/BF02680049
Abstract:
By using a two-level quasi-geostrophic spectral model, the numerical experiments on blocking process affected by thermal forcing are conducted. The dynamic mechanisms of blocking, including the resonance between wave and forcing, the control effects of thermal forcing on the position and intensity of the highs and the instabilities of two kinds of equilibrium states are studied by controlled experiments.
By using a two-level quasi-geostrophic spectral model, the numerical experiments on blocking process affected by thermal forcing are conducted. The dynamic mechanisms of blocking, including the resonance between wave and forcing, the control effects of thermal forcing on the position and intensity of the highs and the instabilities of two kinds of equilibrium states are studied by controlled experiments.
1986, 3(1): 115-124.
doi: 10.1007/BF02680050
Abstract:
Many studies show that, within a certain distance (ca. 700-800 n mi), two typhoons forming a binary typhoon (BT) system would rotate as a whole and attract each other, which is known as “Fuji-whara Effect” (FE). This paper indicates that only 30.3% of BTs has experienced remarkable cyclonic rotation with a 12-hr angle ≥+10° when two components are less than 20° lat apart, and that the probability is much higher with the eastern, component in the NE than in the SE quadrant for the western one, implying the steering effect of the environmental flow field (EFF) on them.47 observations from 13 BTs are separately used for calculating the angular velocity due to FE and EFF and the results are compared. The conclusion can be stated as follows: FE is dominant with the centers of two elements below 7° lat apart; the EFF steering current plays a major role when they are in the range of 7-15° and for a distance above 15° the principle of FE holds no longer.
Many studies show that, within a certain distance (ca. 700-800 n mi), two typhoons forming a binary typhoon (BT) system would rotate as a whole and attract each other, which is known as “Fuji-whara Effect” (FE). This paper indicates that only 30.3% of BTs has experienced remarkable cyclonic rotation with a 12-hr angle ≥+10° when two components are less than 20° lat apart, and that the probability is much higher with the eastern, component in the NE than in the SE quadrant for the western one, implying the steering effect of the environmental flow field (EFF) on them.47 observations from 13 BTs are separately used for calculating the angular velocity due to FE and EFF and the results are compared. The conclusion can be stated as follows: FE is dominant with the centers of two elements below 7° lat apart; the EFF steering current plays a major role when they are in the range of 7-15° and for a distance above 15° the principle of FE holds no longer.
1986, 3(1): 125-133.
doi: 10.1007/BF02680051
Abstract:
The method of quadratic discrimination through orthogonal transformation is introduced to optimize quadratic discriminant function, which has been proved more effective than the method of stepwise multiple discrimination. It is noteworthy that, in the case of a large number of predictors, it is better to make a preliminary choice by using stepwise multiple discrimination or stepwise regression so that the calculation can be made more stable and the effectiveness of discrimination can be improved.
The method of quadratic discrimination through orthogonal transformation is introduced to optimize quadratic discriminant function, which has been proved more effective than the method of stepwise multiple discrimination. It is noteworthy that, in the case of a large number of predictors, it is better to make a preliminary choice by using stepwise multiple discrimination or stepwise regression so that the calculation can be made more stable and the effectiveness of discrimination can be improved.
1986, 3(1): 134-138.
doi: 10.1007/BF02680052
Abstract:
In this paper a nonlinear method of time series analysis-threshold autoregressive (TAR) model in discrete time is used. The TAR procedure consists of four parts: model building, statistical identification, parameter estimation and forecasting.The object of this study is to estimate monthly total precipitation of Shanghai and Beijing by using open loop TAR model. We can see that the trend of forecasting is in agreement with observations.
In this paper a nonlinear method of time series analysis-threshold autoregressive (TAR) model in discrete time is used. The TAR procedure consists of four parts: model building, statistical identification, parameter estimation and forecasting.The object of this study is to estimate monthly total precipitation of Shanghai and Beijing by using open loop TAR model. We can see that the trend of forecasting is in agreement with observations.