This study investigates the effects of the assumption on the types of air-mass conservation prescribed in numerical models.First,predictions of the July 2021(“21.7”)Henan extreme rainfall event from the Integrated F...This study investigates the effects of the assumption on the types of air-mass conservation prescribed in numerical models.First,predictions of the July 2021(“21.7”)Henan extreme rainfall event from the Integrated Forecast System(IFS)at ECMWF were compared with those from the Yin-He Global Spectral Model(YHGSM),which is a global spectral model with total air-mass conservation(TMC)and dry air-mass conservation(DMC)options.Then,a sensitivity test between simulations from the YHGSM adopting TMC and DMC was conducted.The results show that both the IFS and YHGSM predicted relatively well the 24-h rainfall amount less than 100 mm day−1 on 20 and 21 July 2021 at lead times of 84,60,and 36 h.For heavy precipitation exceeding 100 mm day−1,however,both models obviously underestimated the daily rainfall amount on 20 July 2021,but the YHGSM produced more precise and stable precipitation forecasts on these two days than the IFS,especially the maximum 24-h precipitation amount,with better consistency at lead times of 84,60,and 36 h.These differences are further examined in the sensitivity test.Predictions from the YHGSM with DMC show rainfall distributions and daily rainfall amounts closer to the observations at longer lead times.It is inferred that considering sources or sinks of total water in dynamical cores with DMC may have positive feedback for the precise prediction of condensates.For extreme rainfall events,the high local loss of total water may have caused a loss of the atmospheric mass,leading to an additional decrease in surface pressure.Subsequently,the unbalanced pressure gradient force enhances the cyclonic rotation of surface wind and strengthens convergence in the lower troposphere,which in turn further strengthens the vertical velocity,circularly contributing to the enhanced precipitation if the water vapor condition is favorable.展开更多
In conversion of the integrated slant column amount of atmospheric ozone(O_3)measured by the ground-based spectrometer technique during twilight to the vertical quantity,the air-mass factor(AMF)is an important paramet...In conversion of the integrated slant column amount of atmospheric ozone(O_3)measured by the ground-based spectrometer technique during twilight to the vertical quantity,the air-mass factor(AMF)is an important parameter.In this work,calculations of AMF for ozone were performed for different atmospheres.It is shown that the O_3 AMF has seasonal variations with the minimum at the beginning of spring and the maximum in summer due to the seasonal change in the vertical distributions of O_3.A parameterization relation is obtained between O_3 AMF and optical thickness of stratospheric volcanic aerosols based on the Monte-Carlo radiative transfer simulations.展开更多
【目的】为了有效提升压缩空气储能(compressed air energy storage,CAES)系统的储能特性和系统效率,对各部件的性能及其耦合特性进行了建模分析。【方法】针对CAES系统,应用标准热阻方法考虑换热部件的传递特性,结合储气装置与做功部...【目的】为了有效提升压缩空气储能(compressed air energy storage,CAES)系统的储能特性和系统效率,对各部件的性能及其耦合特性进行了建模分析。【方法】针对CAES系统,应用标准热阻方法考虑换热部件的传递特性,结合储气装置与做功部件模型,构建传热、储气、做功耦合的完整热力学模型及能量、㶲分析模型,评价了压缩和膨胀过程中储(释)能质量流量比对系统性能的影响。揭示储气库最高储气压力与体积之间的关系对系统储能效率及储能密度的影响规律。【结果】随着储(释)能质量流量比的增加,压缩机的总能耗先降低后升高,膨胀机的输出功是先上升后降低,当储(释)能的质量比分别为1.2和1.3时,系统效率达到最高,为53.65%;另外,系统中首级压缩和膨胀机的㶲损最大,油-气换热器和压缩机的㶲损占系统总㶲损的69%。【结论】所建模型和研究结果对CAES运行策略具有一定的指导意义。展开更多
基金Supported by the National Natural Science Foundation of China(41875121,42205163,and 42275062).
文摘This study investigates the effects of the assumption on the types of air-mass conservation prescribed in numerical models.First,predictions of the July 2021(“21.7”)Henan extreme rainfall event from the Integrated Forecast System(IFS)at ECMWF were compared with those from the Yin-He Global Spectral Model(YHGSM),which is a global spectral model with total air-mass conservation(TMC)and dry air-mass conservation(DMC)options.Then,a sensitivity test between simulations from the YHGSM adopting TMC and DMC was conducted.The results show that both the IFS and YHGSM predicted relatively well the 24-h rainfall amount less than 100 mm day−1 on 20 and 21 July 2021 at lead times of 84,60,and 36 h.For heavy precipitation exceeding 100 mm day−1,however,both models obviously underestimated the daily rainfall amount on 20 July 2021,but the YHGSM produced more precise and stable precipitation forecasts on these two days than the IFS,especially the maximum 24-h precipitation amount,with better consistency at lead times of 84,60,and 36 h.These differences are further examined in the sensitivity test.Predictions from the YHGSM with DMC show rainfall distributions and daily rainfall amounts closer to the observations at longer lead times.It is inferred that considering sources or sinks of total water in dynamical cores with DMC may have positive feedback for the precise prediction of condensates.For extreme rainfall events,the high local loss of total water may have caused a loss of the atmospheric mass,leading to an additional decrease in surface pressure.Subsequently,the unbalanced pressure gradient force enhances the cyclonic rotation of surface wind and strengthens convergence in the lower troposphere,which in turn further strengthens the vertical velocity,circularly contributing to the enhanced precipitation if the water vapor condition is favorable.
文摘In conversion of the integrated slant column amount of atmospheric ozone(O_3)measured by the ground-based spectrometer technique during twilight to the vertical quantity,the air-mass factor(AMF)is an important parameter.In this work,calculations of AMF for ozone were performed for different atmospheres.It is shown that the O_3 AMF has seasonal variations with the minimum at the beginning of spring and the maximum in summer due to the seasonal change in the vertical distributions of O_3.A parameterization relation is obtained between O_3 AMF and optical thickness of stratospheric volcanic aerosols based on the Monte-Carlo radiative transfer simulations.
文摘【目的】为了有效提升压缩空气储能(compressed air energy storage,CAES)系统的储能特性和系统效率,对各部件的性能及其耦合特性进行了建模分析。【方法】针对CAES系统,应用标准热阻方法考虑换热部件的传递特性,结合储气装置与做功部件模型,构建传热、储气、做功耦合的完整热力学模型及能量、㶲分析模型,评价了压缩和膨胀过程中储(释)能质量流量比对系统性能的影响。揭示储气库最高储气压力与体积之间的关系对系统储能效率及储能密度的影响规律。【结果】随着储(释)能质量流量比的增加,压缩机的总能耗先降低后升高,膨胀机的输出功是先上升后降低,当储(释)能的质量比分别为1.2和1.3时,系统效率达到最高,为53.65%;另外,系统中首级压缩和膨胀机的㶲损最大,油-气换热器和压缩机的㶲损占系统总㶲损的69%。【结论】所建模型和研究结果对CAES运行策略具有一定的指导意义。
