Atmospheric Structure for Convective Development in the Events of Cloud Clusters over the Korean Peninsula

Abstract

This study examines atmospheric structures causing convective development in the events of cloud cluster (CC) over the Korean peninsula using the analysis and forecast data of National Centers for Environmental Prediction (NCEP) climate forecast system reanalysis (CFSR) and observation data. Two CC types-CCs associated with meso-α-scale lows (CCMLs) and mesoscale troughs (CCMTs)-were investigated. The common atmospheric structure for convective development in CC events is comprised of i) a strong southwesterly band (SWB; a region with southwesterly wind speeds >12.5 m s −1) in the lower troposphere upstream of CCs with a mesoscale convergence zone in its exit area, ii) a layer of high-θ e air in the lower troposphere near the surface extending from the southwest to SWB exit, iii) elevated height of maximum θ e in the lower troposphere near and over the convergence zone, above which a convectively unstable layer exists. Generality of the above-described structure has been demonstrated via examination of composite fields. SWB plays a major role in producing the structure for convective development in CC events over the Korean peninsula mainly through i) advection of high-θ e air from the southwest, and ii) significant horizontal convergence in the exit area, which can facilitate convection initiation. The two types of CC show notable differences in atmospheric structure across the boundary between high-θ e air from the southwest and low-θ e air in the northeast and in the mode of high-θ e air transport to the region of convective development. The boundary is generally tilted northeastward with height for CCML cases, whereas it is nearly vertical for the majority of CCMT cases. This study indicates that, despite the abovementioned differences, convective developments in both CC types can be considered as elevated convection that occurs as air parcels in an elevated layer of convective instability are lifted by upward motion in the convergence zone. For both types of CC, differential θ e advection plays the key role for the occurrence of elevated layer of convective instability. And θ e front in CCML events indicates the presence of elevated convective instability above it and the possibility of elevated convection provided that a lifting mechanism is available.

Characterization of Atmospheric Mercury in the High-Altitude Background Station and Coastal Urban City in South Asia

“…Similarly, TGM concentrations were higher in the early in the morning and midnight times reported by Schmolke et al [36]. Such night-time maximums of TGM concentration [33,36,43,44] have been due to mercury releases in the night-time inversion layer from surface accumulations. The potential sources of TGM in the investigation ground are from coal-based power plants, vehicular discharge, and squander burning [11,12,43].…”

“…Such night-time maximums of TGM concentration [33,36,43,44] have been due to mercury releases in the night-time inversion layer from surface accumulations. The potential sources of TGM in the investigation ground are from coal-based power plants, vehicular discharge, and squander burning [11,12,43]. The short-term measurements of TGM in china report recommend that the TGM ranges from 2.5 to 3.5 ng/m 3 for east beach front territories of China, 1.94 to 3.22 ng m −3 for Indochina peninsular regions [29].…”

Influence of Aqueous‐Phase Chemistry on the Concentrations of PM2.5 and Hydrometers During the Development of Convective Clouds Over the Yellow Sea in July of 2017

“…Furthermore, the nocturnal enhancement of low-level jets over southeastern China contributed to increased moisture transport, a low-level ascent, and elevated convective instability (Chen et al, 2017;Zhang et al, 2022). Additionally, Lee et al (2021) examined how upward motion in a convergence zone over the Yellow Sea enhances convection in air parcels in an elevated layer of convective instability.…”

Synoptic Features of August Heavy Rainfall Episodes Accompanied By a Quasi-Stationary Front Over the Korean Peninsula and Its Relationship With the Western Pacific Subtropical High

“…Climatologically, different characteristics also exist between heavy rainfall episodes in August and in the Changma period. First, heavy rainfall caused by the Changma front tends to occur regularly every year, whereas the August heavy rainfall episodes caused by a quasi-stationary front do not occur regularly because synoptic systems such as typhoons can substantially influence them (e.g., Kim et al, 2006;Byun and Lee, 2012;Cheung et al, 2018;Lee et al, 2021). Suzuki, (1967) reported that the amount of August rainfall in Japan was composed mainly of rainfall caused by thunderstorms and typhoons.…”