Deep convection systems (DCSs) can rapidly lift water vapor and other pollutants from the lower troposphere to the upper troposphere and lower stratosphere. The main detrainment height determines the level to which th...Deep convection systems (DCSs) can rapidly lift water vapor and other pollutants from the lower troposphere to the upper troposphere and lower stratosphere. The main detrainment height determines the level to which the air parcel is lifted. We analyzed the main detrainment height over the Tibetan Plateau and its southern slope based on the CloudSat Cloud Profiling Radar 2B_GEOPROF dataset and the Aura Microwave Limb Sounder Level 2 cloud ice product onboard the Atrain constellation of Earth-observing satellites. It was found that the DCSs over the Tibetan Plateau and its southern slope have a higher main detrainment height (about 10-16 km) than other regions in the same latitude. The mean main detrainment heights are 12.9 and 13.3 km over the Tibetan Plateau and its southern slope, respectively. The cloud ice water path decreases by 16.8% after excluding the influences of DCSs, and the height with the maximum increase in cloud ice water content is located at 178 hPa (about 13 km). The main detrainment height and outflow horizontal range are higher and larger over the central and eastern Tibetan Plateau, the west of the southern slope, and the southeastern edge of the Tibetan Plateau than that over the northwestern Tibetan Plateau. The main detrainment height and outflow horizontal range are lower and broader at nighttime than during daytime.展开更多
The chute aerators separate the flow from the chute bottom,and the air can enter into the flow through the lower surface.In this study,the air concentration and the pressure along the chute bottom are investigated sys...The chute aerators separate the flow from the chute bottom,and the air can enter into the flow through the lower surface.In this study,the air concentration and the pressure along the chute bottom are investigated systematically by a series of model tests with the upper aeration effect being eliminated.The chute downstream the aerator is partitioned into four zones:the cavity zone,the impact zone,the equilibrium zone,and the far zone.It is found that a large amount of air entrained in the cavity zone is only partially entrained into the flow finally.Furthermore,the lower air discharge is decreased sharply in the impact zone,and the detrainment disappearsonthe section of x= Lm.In the equilibrium zone,the lower air discharge is kept unchanged.With the in crease of the flow Froude number and withthe other parameters kept unchanged,it is found that the dimensionless value of K has a significant increase.Meanwhile,a formula to calculate K is proposed,with results in good agreement with the model and prototype data.展开更多
基金supported by the National Key Research and Development Program on Monitoring, Early Warning and Prevention of Major Natural Disasters (Grant No. 2018YFC1506006)the National Natural Science Foundation of China (Project Nos. 41875108 and 41475037)
文摘Deep convection systems (DCSs) can rapidly lift water vapor and other pollutants from the lower troposphere to the upper troposphere and lower stratosphere. The main detrainment height determines the level to which the air parcel is lifted. We analyzed the main detrainment height over the Tibetan Plateau and its southern slope based on the CloudSat Cloud Profiling Radar 2B_GEOPROF dataset and the Aura Microwave Limb Sounder Level 2 cloud ice product onboard the Atrain constellation of Earth-observing satellites. It was found that the DCSs over the Tibetan Plateau and its southern slope have a higher main detrainment height (about 10-16 km) than other regions in the same latitude. The mean main detrainment heights are 12.9 and 13.3 km over the Tibetan Plateau and its southern slope, respectively. The cloud ice water path decreases by 16.8% after excluding the influences of DCSs, and the height with the maximum increase in cloud ice water content is located at 178 hPa (about 13 km). The main detrainment height and outflow horizontal range are higher and larger over the central and eastern Tibetan Plateau, the west of the southern slope, and the southeastern edge of the Tibetan Plateau than that over the northwestern Tibetan Plateau. The main detrainment height and outflow horizontal range are lower and broader at nighttime than during daytime.
基金the National Key Research and Development Program (Grant No.2016YFC0401707)the National Natural Science Foundation of China (Grant Nos.51709293,51479129).
文摘The chute aerators separate the flow from the chute bottom,and the air can enter into the flow through the lower surface.In this study,the air concentration and the pressure along the chute bottom are investigated systematically by a series of model tests with the upper aeration effect being eliminated.The chute downstream the aerator is partitioned into four zones:the cavity zone,the impact zone,the equilibrium zone,and the far zone.It is found that a large amount of air entrained in the cavity zone is only partially entrained into the flow finally.Furthermore,the lower air discharge is decreased sharply in the impact zone,and the detrainment disappearsonthe section of x= Lm.In the equilibrium zone,the lower air discharge is kept unchanged.With the in crease of the flow Froude number and withthe other parameters kept unchanged,it is found that the dimensionless value of K has a significant increase.Meanwhile,a formula to calculate K is proposed,with results in good agreement with the model and prototype data.
