The physical characteristics of the summer monsoon clouds were investigated. The results of a simple cloud model were compared with the aircraft cloud physical observations collected during the summer monsoon seasons ...The physical characteristics of the summer monsoon clouds were investigated. The results of a simple cloud model were compared with the aircraft cloud physical observations collected during the summer monsoon seasons of 1973, 1974, 1976 and 1981 in the Deccan Plateau region.The model predicted profiles of cloud liquid water content (LWC) are in agreement with the observed profiles. There is reasonable agreement between the model predicted cloud vertical thickness and observed rainfall.The observed cloud-drop spectra were found to be narrow and the concentration of drops with diameter > 20um is either low or absent on many occasions. In such clouds the rain-formation cannot take place under natural atmospheric conditions due to the absence of collision-coalescence process. A comparison of the model predicted and observed rainfall suggested that the precipitation efficiency in cumulus clouds of small vertical thickness could be as low as 20 per cent.The clouds forming in the Deccan Plateau region during the summer monsoon are, by and large, cumulus and strato-cumulus type. The vertical thickness of the cumulus clouds is in the range of 1.0-2.0 km. The LWC is found to be more in the region between 1.6-1.9 km A. S. L. , which corresponds to the level at almost 3 / 4 th of the total vertical thickness of the cloud and thereafter the LWC sharply decreased. Nearly 98 per cent of the tops of the low clouds in the region are below freezing level and the most frequent range of occurrence of these cloud-tops is in the range of 2.0-3.0 km A. S. L. The dominant physical mechanism of rain-formation in these summer monsoon clouds is the collision-coalescence process.展开更多
During the period from 9 to 11 November 2013,an explosive cyclone(EC)occurred over the Japan Sea-Okhotsk Sea.This EC initially formed around 18 UTC 9 November over the Japan Sea and developed over the Okhotsk Sea when...During the period from 9 to 11 November 2013,an explosive cyclone(EC)occurred over the Japan Sea-Okhotsk Sea.This EC initially formed around 18 UTC 9 November over the Japan Sea and developed over the Okhotsk Sea when moving northeastward.It had a minimum sea level pressure of 959.0 hPa,a significant deepening rate of central pressure of 2.9 Bergeron,and a maximum instantaneous wind speed of 42.7 m s−1.This paper aims to investigate the conditions that contributed to the rapid development of this low-pressure system through analyses of both observations and the Weather Research Forecasting(WRF)modeling results.The evolutionary processes of this EC were examined by using Final Analyses(FNL)data,Multi-Functional Transport Satellites-1R(MTSAT-1R)data,upper observation data and surface observation data.WRF-3.5 modeling results were also used to examine the development mechanism of this EC.It is shown that the interaction between upper-level and low-level potential vorticity seemed to be very essential to the rapid development of this EC.展开更多
The limited area 5-level primitive equation model,as the first operational precipitation forecast model in China,has been run at Beijing (National) Meteorological Center (BMC) for more than four years.The opera- tiona...The limited area 5-level primitive equation model,as the first operational precipitation forecast model in China,has been run at Beijing (National) Meteorological Center (BMC) for more than four years.The opera- tional results show that this model gives continuous services,and the forecast skill is satisfied for the forecast of some weather situations,such as extratropical cyclone,front and the precipitation associated with them. The forecast guides are widely used at the local weather services now.展开更多
Mayr <em>et al.</em><a href="#ref1"> [1]</a> proposed that the vertical velocities in the global scale meridional circulation can produce distinct latitude bands where Jovian vortices...Mayr <em>et al.</em><a href="#ref1"> [1]</a> proposed that the vertical velocities in the global scale meridional circulation can produce distinct latitude bands where Jovian vortices like the white and brown are observed, and we present here a brief review of the mechanism. The observed life times of the ovals are much longer than the estimated spin-down times, which indicates that the vortices must be sustained through the release of internal energy. Like Jupiter’s Great Red Spot (GRS), the white/brown ovals are treated like terrestrial hurricanes or cyclones, which are generated by convection. The planetary energy Jupiter emits is transferred by convection, and under this condition the upward motions in the meridional circulation, around the equator for example, release energy from below and decrease the convective instability to suppress the formation of cyclones. But the downward motions in the circulation, near 20<span style="white-space:nowrap;">°</span> latitude for example, carry energy down so that the convective instability is amplified to produce a dynamical environment that is favorable for the development of cyclones like the GRS and white/brown ovals. This picture is supported by an analysis of results from a numerical model of Jupiter’s alternating jets (Chan and Mayr <a href="#ref2" target="_blank">[2]</a>). Generated by alternating vertical winds in the meridional circulation, the vertical temperature variations reveal distinct latitude bands with enhanced convective instability, most prominent at high latitudes where long-lived circumpolar cyclones are observed from the Juno spacecraft.展开更多
The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performa...The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients.展开更多
文摘The physical characteristics of the summer monsoon clouds were investigated. The results of a simple cloud model were compared with the aircraft cloud physical observations collected during the summer monsoon seasons of 1973, 1974, 1976 and 1981 in the Deccan Plateau region.The model predicted profiles of cloud liquid water content (LWC) are in agreement with the observed profiles. There is reasonable agreement between the model predicted cloud vertical thickness and observed rainfall.The observed cloud-drop spectra were found to be narrow and the concentration of drops with diameter > 20um is either low or absent on many occasions. In such clouds the rain-formation cannot take place under natural atmospheric conditions due to the absence of collision-coalescence process. A comparison of the model predicted and observed rainfall suggested that the precipitation efficiency in cumulus clouds of small vertical thickness could be as low as 20 per cent.The clouds forming in the Deccan Plateau region during the summer monsoon are, by and large, cumulus and strato-cumulus type. The vertical thickness of the cumulus clouds is in the range of 1.0-2.0 km. The LWC is found to be more in the region between 1.6-1.9 km A. S. L. , which corresponds to the level at almost 3 / 4 th of the total vertical thickness of the cloud and thereafter the LWC sharply decreased. Nearly 98 per cent of the tops of the low clouds in the region are below freezing level and the most frequent range of occurrence of these cloud-tops is in the range of 2.0-3.0 km A. S. L. The dominant physical mechanism of rain-formation in these summer monsoon clouds is the collision-coalescence process.
基金the National Natural Science Foundation of China(NSFC)for financial support(Nos.41775042 and 41275049)。
文摘During the period from 9 to 11 November 2013,an explosive cyclone(EC)occurred over the Japan Sea-Okhotsk Sea.This EC initially formed around 18 UTC 9 November over the Japan Sea and developed over the Okhotsk Sea when moving northeastward.It had a minimum sea level pressure of 959.0 hPa,a significant deepening rate of central pressure of 2.9 Bergeron,and a maximum instantaneous wind speed of 42.7 m s−1.This paper aims to investigate the conditions that contributed to the rapid development of this low-pressure system through analyses of both observations and the Weather Research Forecasting(WRF)modeling results.The evolutionary processes of this EC were examined by using Final Analyses(FNL)data,Multi-Functional Transport Satellites-1R(MTSAT-1R)data,upper observation data and surface observation data.WRF-3.5 modeling results were also used to examine the development mechanism of this EC.It is shown that the interaction between upper-level and low-level potential vorticity seemed to be very essential to the rapid development of this EC.
文摘The limited area 5-level primitive equation model,as the first operational precipitation forecast model in China,has been run at Beijing (National) Meteorological Center (BMC) for more than four years.The opera- tional results show that this model gives continuous services,and the forecast skill is satisfied for the forecast of some weather situations,such as extratropical cyclone,front and the precipitation associated with them. The forecast guides are widely used at the local weather services now.
文摘Mayr <em>et al.</em><a href="#ref1"> [1]</a> proposed that the vertical velocities in the global scale meridional circulation can produce distinct latitude bands where Jovian vortices like the white and brown are observed, and we present here a brief review of the mechanism. The observed life times of the ovals are much longer than the estimated spin-down times, which indicates that the vortices must be sustained through the release of internal energy. Like Jupiter’s Great Red Spot (GRS), the white/brown ovals are treated like terrestrial hurricanes or cyclones, which are generated by convection. The planetary energy Jupiter emits is transferred by convection, and under this condition the upward motions in the meridional circulation, around the equator for example, release energy from below and decrease the convective instability to suppress the formation of cyclones. But the downward motions in the circulation, near 20<span style="white-space:nowrap;">°</span> latitude for example, carry energy down so that the convective instability is amplified to produce a dynamical environment that is favorable for the development of cyclones like the GRS and white/brown ovals. This picture is supported by an analysis of results from a numerical model of Jupiter’s alternating jets (Chan and Mayr <a href="#ref2" target="_blank">[2]</a>). Generated by alternating vertical winds in the meridional circulation, the vertical temperature variations reveal distinct latitude bands with enhanced convective instability, most prominent at high latitudes where long-lived circumpolar cyclones are observed from the Juno spacecraft.
文摘The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients.
