熱帶對流的垂直結構與降雨強度

Abstract

Vertical structures associated with tropical convection are of vital importance to tropical climate and weather phenomena, especially the convective feedbacks to large-scale environment as manifested by them. In this thesis, we explore their relationship with precipitation intensity. We first propose a simple diagnostic framework to assess these profiles in ERA-Interim, in order to remedy previous studies’ deficiencies. By considering these profiles with multiple perspectives, we discuss the prominent characteristics of deep and shallow convection, as well as the corresponding variations in large-scale flows. We then shift our focus to their roles in the intensity changes of precipitation extremes. We find that under interannual tropical tropospheric warming, extreme rainfall strengthens due to enhanced moisture convergence and reduced gross moist stability. Analyzing the vertical structures of moist static energy and vertical motion, we argue that both a decrease of deep convective energy transport via enhanced low-level moisture and increase of shallow convection partitioning can account for these changes.