The Vertical Profile of Entrainment Rate Simulated by a Cloud-Resolving Model and Application to a Cumulus Parameterization
スポンサーリンク
概要
- 論文の詳細を見る
To investigate the vertical profiles of fractional entrainment rate as to cumulus convection, numerical simulations of a tropical cyclone rainband are conducted, using a high-resolution three-dimensional cloud-resolving model (CRM), with the 200-m horizontal resolution. On the basis of the results of CRM simulations, vertically variable entrainment rate is applied to the Arakawa-Schubert (AS) cumulus parameterization. Fractional entrainment rate, derived from the calculation based on the vertical gradient of cloud mass flux, clearly shows larger near cloud base and top. Between the heights of cloud base and top, entrainment rate is smaller, and even negative in many cases, suggesting laterally detrained air from a cumulus into the environment. From the analyses where entrainment rate is divided into three terms, it is found that the contributions of updraft is relatively large near the cloud base and top, compared to that in between. The cloud amount contribution depends on whether cloudy areas expand or shrink accompanying cloud growth or decay, respectively. On the basis of the result of the CRM simulations, vertically variable entrainment rate is applied to the AS scheme. For investigating the effect of the modifications of the scheme, simulations of typhoon Saomai (2000) are conducted. The simulations show significant improvements : underestimates of moisture in the mid- to upper troposphere are reduced. The result is predominantly attributed to cloud mass flux, greatly influenced by lateral detrainment. The peak height of the mass flux corresponds to that in the moisture tendency.
- 2005-10-25
著者
-
Murata Akihiko
Typhoon Res. Dep. Meteorological Res. Inst.
-
UENO Mitsuru
Typhoon Research Department, Meteorological Research Institute
-
Ueno Mitsuru
Typhoon Res. Dep. Meteorological Res. Inst.
関連論文
- A Mechanism for Heavy Precipitation over the Kii Peninsula Accompanying Typhoon Meari (2004)
- The Vertical Profile of Entrainment Rate Simulated by a Cloud-Resolving Model and Application to a Cumulus Parameterization
- Effects of Ambient Vertical Wind Shear on the Inner-Core Asymmetries and Vertical Tilt of a Simulated Tropical Cyclone
- Observational Analysis and Numerical Evaluation of the Effects of Vertical Wind Shear on the Rainfall Asymmetry in the Typhoon Inner-Core Region
- Steering Weight Concept and its Application to Tropical Cyclones Simulated in a Vertical Shear Experiment
- Some Aspects of Azimuthal Wavenumber-One Structure of Typhoons Represented in the JMA Operational Mesoscale Analyses