Vertical Diffusion Parameterization For Kinetic Energy Equation
Abstract
The method of the vertical diffusion parameterization is considered and the estimates for winter and summer Northern Hemisphere are given. The local form of the ver- tical diffusion terms of momentum used in NCAR CCM3 is taken as basis. In this scheme the upward fluxes of momentum due to turbulent motions depends on the eddy-diffusivities that are the functions of gradient Richardson number. The last is calculated according to the GFDL SKYHI general circulation model. As input data for calculations the GDAAC data set is used. Both in winter and in summer the maximal magnitudes of the eddy-diffusivities are obtained at the 900 and 100 hPa levels. For first case these maximums are located at 30 N (3.1 and 4.1 m2/sec. respectively) and for second one - at 40 N (1.8 and 3.0 m2/sec. respectively). Between these maximums the narrow zone of the minimal values is located. It is connected with tropopause, in which the large Richardson number is obtained, and in the model that sort of values is compared to zero. Also in both seasons another maximum is located near equator in the boundary layer. For Northern Hemisphere the sink of zonal mean kinetic energy (KM) is 1.28 in winter and 0.30 W/m2 in summer; corresponding value of eddy kinetic energy (KE) is 0.63 and 0.54 W/m2 respectively. At that the main maximum of KM sink in winter (4.08 W/m2) is located at 28 N whereas the KE sink has a three almost even maximums (1.5 W/m2 approximately) at 0, 32 and 64 N. In summer the KM sink smoothly decreases poleward and the KE sink has main maximum (3.07 W/m2) at 10 N and secondary one at 40 N (0.82 W/m2). A comparison of this work results with received earlier by other scientists has shown the good coincidence.
- Publication:
-
EGS General Assembly Conference Abstracts
- Pub Date:
- 2002
- Bibcode:
- 2002EGSGA..27.3871K