A new method for deduction of the sensible heat flux is validated with three sets of published SODAR （sound detection and ranging） data. Although the related expressions have previously been confirmed by the author ...A new method for deduction of the sensible heat flux is validated with three sets of published SODAR （sound detection and ranging） data. Although the related expressions have previously been confirmed by the author with surface layer data, they have not yet been validated with observations from the boundary layer before this work. In the study, selected SODAR data are used to test the method for the convective boundary layer. The sensible heat flux （SHF） retrieved from SODAR data is found to decrease linearly with height in the mixed layer. The surface sensible heat fluxes derived from the deduced sensible heat flux profiles under convective conditions agree well with those measured by the eddy correlation method. The characteristics of SHF profiles deduced from SODAR data in different places reflect the background meteorology and terrain. The upper part of the SHF profile （SHFP） for a complicated terrain is found to have a different slope from the lower part. It is suggested that the former reflects the advective characteristic of turbulence in upwind topography. A similarity relationship for the estimation of SHFP in a well mixed layer with surface SHF and zero-heat-flux layer height is presented.展开更多
During the second course of USA - PRC joint air sea interaction experiment in 1986, the temperature structure parameters CT2 were measured by sodar over the Western Pacific Ocean. Based on similarity theory, a method ...During the second course of USA - PRC joint air sea interaction experiment in 1986, the temperature structure parameters CT2 were measured by sodar over the Western Pacific Ocean. Based on similarity theory, a method is discussed to calculate the sensible heat flux over the ocean in unstable stratification. Becausehumidity is great over the ocean, so we have to consider the influence of water vapor structure parameter Ce2and the correlation coefficient betweene and T on the calculation of sensible heat flux using CT2 profiles measured by sodar. A new formula is suggested in terms of parameterization. The sensible heat flux calculated by sodar measurements is compared with that by bulk transfer method, and the results agree well.展开更多
I.INTRODUCTION The temperature stratification is an important factor which strongly influences the transportation and diffusion processes of pollutants in atmospheric boundary lay-
A Doppler sodar system controlled by microcomputer is described in this paper. The sodar was used to detect the vertical distribution of wind and temperature stratification in the atmospheric boundary layer. The detec...A Doppler sodar system controlled by microcomputer is described in this paper. The sodar was used to detect the vertical distribution of wind and temperature stratification in the atmospheric boundary layer. The detecting results show that at night the vertical distribution of wind is very complicated, which can appear as a structure of two or three layers. In nocturnal atmospheric boundary layer sometimes there exists very thin layer in multi-layer inversion and it can be retained for a long time.展开更多
In this paper, the autoregressive (AR) and FFT methods are used to estimate the power spectra of deterministic narrow-band signal with theoretic autocorrelation functions and signal samples, stochastic narrow-band sig...In this paper, the autoregressive (AR) and FFT methods are used to estimate the power spectra of deterministic narrow-band signal with theoretic autocorrelation functions and signal samples, stochastic narrow-band signal with samples, and sodar signal. Some satisfying results are obtained. That is in the case of sodar signal, for two closer spectral peaks, the resolution of the AR method is lower than the FFT's; for two spectral peaks which are a little far apart from each other and single spectral peak, the precision of the AR method is better than the FFT's. The power spectrum curves of the AR method are smooth and low sidelobes at any case. We consider that a good spectral estimation method for sodar signal is the combination of the AR and the FFT methods.展开更多
According to the characteristics of sodar echo,a classified method for temperature stratification is given. By using sodar data observed in Yanshan Mountain area in Beijing,the statistical characteristics for the heig...According to the characteristics of sodar echo,a classified method for temperature stratification is given. By using sodar data observed in Yanshan Mountain area in Beijing,the statistical characteristics for the height of inversion layer,thermal plume,and the depth of mixed layer are compared.Finally,the appearance frequency for stable,unstable and neutral stratification is analyzed.展开更多
文摘A new method for deduction of the sensible heat flux is validated with three sets of published SODAR （sound detection and ranging） data. Although the related expressions have previously been confirmed by the author with surface layer data, they have not yet been validated with observations from the boundary layer before this work. In the study, selected SODAR data are used to test the method for the convective boundary layer. The sensible heat flux （SHF） retrieved from SODAR data is found to decrease linearly with height in the mixed layer. The surface sensible heat fluxes derived from the deduced sensible heat flux profiles under convective conditions agree well with those measured by the eddy correlation method. The characteristics of SHF profiles deduced from SODAR data in different places reflect the background meteorology and terrain. The upper part of the SHF profile （SHFP） for a complicated terrain is found to have a different slope from the lower part. It is suggested that the former reflects the advective characteristic of turbulence in upwind topography. A similarity relationship for the estimation of SHFP in a well mixed layer with surface SHF and zero-heat-flux layer height is presented.
文摘During the second course of USA - PRC joint air sea interaction experiment in 1986, the temperature structure parameters CT2 were measured by sodar over the Western Pacific Ocean. Based on similarity theory, a method is discussed to calculate the sensible heat flux over the ocean in unstable stratification. Becausehumidity is great over the ocean, so we have to consider the influence of water vapor structure parameter Ce2and the correlation coefficient betweene and T on the calculation of sensible heat flux using CT2 profiles measured by sodar. A new formula is suggested in terms of parameterization. The sensible heat flux calculated by sodar measurements is compared with that by bulk transfer method, and the results agree well.
文摘I.INTRODUCTION The temperature stratification is an important factor which strongly influences the transportation and diffusion processes of pollutants in atmospheric boundary lay-
文摘A Doppler sodar system controlled by microcomputer is described in this paper. The sodar was used to detect the vertical distribution of wind and temperature stratification in the atmospheric boundary layer. The detecting results show that at night the vertical distribution of wind is very complicated, which can appear as a structure of two or three layers. In nocturnal atmospheric boundary layer sometimes there exists very thin layer in multi-layer inversion and it can be retained for a long time.
文摘In this paper, the autoregressive (AR) and FFT methods are used to estimate the power spectra of deterministic narrow-band signal with theoretic autocorrelation functions and signal samples, stochastic narrow-band signal with samples, and sodar signal. Some satisfying results are obtained. That is in the case of sodar signal, for two closer spectral peaks, the resolution of the AR method is lower than the FFT's; for two spectral peaks which are a little far apart from each other and single spectral peak, the precision of the AR method is better than the FFT's. The power spectrum curves of the AR method are smooth and low sidelobes at any case. We consider that a good spectral estimation method for sodar signal is the combination of the AR and the FFT methods.
文摘According to the characteristics of sodar echo,a classified method for temperature stratification is given. By using sodar data observed in Yanshan Mountain area in Beijing,the statistical characteristics for the height of inversion layer,thermal plume,and the depth of mixed layer are compared.Finally,the appearance frequency for stable,unstable and neutral stratification is analyzed.
