THE MESOSCALE FORCING OF A MIDLATITUDE UPPER-TROPOSPHERIC JET STREAK BY A SIMULATED CONVECTIVE SYSTEM .2. KINETIC-ENERGY AND RESOLUTION ANALYSIS

A kinetic energy (KE) analysis of the forcing of a mesoscale upper-tro pospheric jet streak by organized diabatic processes within the simula ted convective system (SCS) that was discussed in Part I is presented in this study. The relative contributions of the ageostrophic componen ts of motion to the generation of KE of the convectively generated jet streak are compared, along with the KE generation by the rotational ( nondivergent) and irrotational (divergent) mass transport. The sensiti vity of the numerical simulations of SCS development to resolution is also briefly examined. Analysis within isentropic coordinates provides for an explicit determination of the influence of diabatic processes on the generation of KE. The upper-level production of specific KE is due predominantly to the inertial advective ageostrophic component (IA D), and as such represents the primary process through which the KE of the convectively generated jet streak is realized. A secondary contri bution by the inertial diabatic (IDI) term is observed. partitioning t he KE generation into its rotational and irrotational components revea ls that the latter, which is directly linked to the diabatic heating w ithin the SCS through isentropic continuity requirements, is the ultim ate source of KE generation as the global area integral of generation by the rotational component vanishes. Comparison with an identical dry simulation reveals that the net generation of KE must be attributed t o latent heating. Both the IAD and IDI ageostrophic components play im portant roles in this regard. Examination of results from simulations conducted at several resolutions supports the previous findings in tha t the effects of diabatic processes and ageostrophic motion on KE gene ration remain consistent. Resolution does impact the location and timi ng of SCS development, a result that has important implications in for ecasting the onset of convection that develops from evolution of the l arge-scale flow and moisture transport. Marked differences are observe d in the momentum field aloft subsequent to the life cycle of the SCS in the 1 degrees, 30-level base case (MP130) simulation discussed in P art I versus its 2 degrees counterparts in that the MP130 simulation w ith higher spatial resolution contains from 14% to 30% more total KE.