Distribution of convective energy at upper level in South Korea and the possibility of artificial showery rain caused by activated CAPE

Abstract

This paper reports a theoretical study on the possibility of inducing artificial showery rain using the convective available potential energy, which is naturally stored in the troposphere. We calculated the environmental parameters (frequency of climatic values, extreme value of stability index, etc.) in the upper troposphere using rawinsonde data from six main stations in Korea from 2001 to 2008 and examined the temporal spatial convective energy according to region. Our results showed that convective available potential energy, which can induce artificial rainfall, existed in the troposphere mainly in summer and were low in other seasons. Its value was found to be highest during late afternoon and in inland regions. We examined the vertical structure of the atmosphere using moisture convergence and vertical velocity (omega) and found that precipitation occurred under strong real latent instability conditions with high convective available potential energy (>3,000 J/kg) in summer and was characterized by moisture convergence at 1,000-400 hPa, moisture divergence at 400-300 hPa, and continuous ascending air current at 1,000-300 hPa (-ω), on average. However, precipitation still did not occur in more than half the cases with high convective available potential energy because, according to the analysis, convective rainfall is affected to a greater extent by the value of convective inhibition than by convective available potential energy. It was also verified that in spite of zero convective inhibition, if the updrafts at a lower level were not sufficient to generate high convective available potential energy at a level higher than the level of free convection, convective rainfall would not occur under real latent instability. Therefore, we suggest it might be possible during the summer to secure the water resources in regions without precipitation by inducing ascending air current artificially under unstable atmospheric conditions to induce showery rain.

Thermodynamic characteristics associated with localized torrential rainfall events in the southwest region of the Korean peninsula

“…Furthermore, a previous study (Lee and Byun, 2011) reported that values of CAPE in Gwangju are higher than those reported at the five other radiosonde observation sites on the Korean peninsula (Baengyeongdo, Gosan, Osan, Pohang, Sokcho) because it is located inland and at a low latitude compared to the other sites. The relationship between thermodynamic conditions (SRH) and precipitation characteristics (maximum rain areas and durations) are therefore discussed (see Fig.…”

Linkage between Projected Precipitation and Atmospheric Thermodynamic Changes

“…For example, Myoung and Nielsen-Gammon (2010b) indicated that monthly precipitation was mainly modulated by CIN through the feedbacks of soil moisture in Texas summertime. Lee and Byun (2011) also found that daily precipitation is strongly affected by CIN rather than CAPE in South Korea using rawinsonde data from 2001 to 2008. In a modeling study, Barthlott et al (2011) revealed the dependence of convective precipitation on soil moisture through CIN over complex terrain.…”

Characteristics of Rawinsonde Data-Based Storm-Relative Helicity Collected during the Early Summer Monsoon Period in the Southwest Korean Peninsula

“…This study used CAPE and SRH to better understand the thermodynamic characteristics during the early summer monsoon. CAPE has been characterized by multiple components (e.g., LFC, EL, q) in various studies (e.g., Lee and Byun 2011;Nomura and Takemi 2011;Jung et al 2015):…”

“…Several studies using diagnostic factors to indicate atmospheric conditions have been conducted to predict rainfall in the summer (Kerr and Darkow 1996;Thompson et al 2007;Eom et al 2008;Lee and Byun 2011;Nomura and Takemi 2011;Jung et al 2015). These studies can generally be divided into two categories of diagnostic variables.…”

“…However, several studies (Eom et al 2008;Lee and Byun 2011;Jung et al 2015) related to summer rainfall in Korea focused on the thermal instability. Although the seasonal variation of the thermal instability was related to the seasonal march of the Asian monsoon system (Eom et al 2008), the relationship in June was significant lower than July-August.…”