Simulating Dropsondes to Assess Moist Static Energy Variability in Tropical Cyclones

Abstract

Organized convective systems like tropical cyclones (TCs) (Emanuel, 2003) produce much of the extreme weather in the tropics, and influence large-scale patterns of circulation, moisture, and radiation (Khairoutdinov & Emanuel, 2010;Silvers & Robinson, 2021;Wing et al., 2020). Idealized modeling studies have improved our understanding of convective organization, including the spontaneous self-aggregation that arises due to interactions between clouds, water vapor, radiation, and circulations (e.g., Held et al. (1993); Bretherton et al. (2005); Wing et al. (2017); Carstens and Wing ( 2022)). Similar feedbacks are also relevant in the development of TCs (Ruppert et al., 2020;Wing et al., 2016;Wu et al., 2021). Radiation feedbacks have long been thought to contribute to the diurnal cycles of tropical convection (Gray & Jacobson Jr., 1977), and more recently, TC precipitation, structure, and intensity (e.g., Dunion et al. ( 2014)).To quantify feedbacks on convective organization, Wing and Emanuel (2014) developed a budget equation for the spatial variance of column-integrated moist static energy (MSE). MSE consists of contributions by temperature (c p T), gravitational potential energy (gz), and water vapor (L v q v ):Under weak temperature gradients, MSE variance is a proxy for moisture variability associated with organized convection. Chen et al. ( 2019) suggested that TC rapid intensification is preceded by an increase in inner-core column-integrated MSE, and therefore, increased MSE spatial variance. A strong relationship between MSE variance and TC intensity was also found in both climate models and idealized simulations (Wing, 2022;Wing et al., 2019). Dropsondes from aircraft reconnaissance sample profiles of all inputs to MSE with fine vertical resolution. Prior analysis of dropsonde data has produced valuable information on TC structure,

Examining the Predictability of Tropical Cyclogenesis over the East Sea of Vietnam through the Ensemble-Based Data Assimilation System

“…These variables are indicative of convective processes and enhanced moisture in the atmospheric column. The average moist static energy (MSE) over the entire column in TC's core region is an important feature reflecting the oscillation of moisture related to organized convective activities [57], and enhanced MSE signifies intensified TC intensity [58]. Thus, it can be observed that enhanced convective processes during 3 days before TC formation can play a crucial role in determining the TC genesis, as forecasted by the WRF-LETKF ensemble assimilation system.…”