Convective available potential energy

About: Convective available potential energy is a research topic. Over the lifetime, 936 publications have been published within this topic receiving 43773 citations. The topic is also known as: CAPE.

Analysis of the convective available potential energy by precipitation over Iraq using ECMWF data for the period of 1989–2018

Abstract: The rain is the most common type of precipitation in our atmosphere and when liquid droplet falls to the earth surface. The source of precipitation is water vapor, which is always present in the atmosphere in varying amounts; there are three major types of rain can be distinguished depending on the different factors that cause the airlifting and formation of clouds and rain falling as well as meteorology factors (Niwas, Singh, Singh, Khichar & Singh, 2006): Convectional rainfall: this type of rainfall occurs due to the ground surface heating. When the land warms up, it heats the air above it. This causes the air to expand and – rise. As the air rises it cools and condenses. If this process continues then rain will fall. Convectional rainfall occurs for a very short duration but occurs in the form of heavy showers. This type of rain is often accompanied by lightning and thunder. It is called ascending/rising rain because it is the result of a rising process of the atmosphere, which is exposed to thermal heating and clouds resulting from this type cumulus and cumulonimbus (Saxena & Gupta, 2017). Cyclonic/Frontal rainfall: this type of rainfall occurs when a warm and moist air mass (warm front) meets a cold and dry air mass (cold front). When both masses come together, warmer air is forced to rise over cold air. The moist warm air condenses as it cool, which causes cloud and rain. When there are condensation nuclei and when the atmosphere arrives at saturation – Scientifi c Review – Engineering and Environmental Sciences (2020), 29 (2), 196–211 Sci. Rev. Eng. Env. Sci. (2020), 29 (2) Przegląd Naukowy – Inżynieria i Kształtowanie Środowiska (2020), 29 (2), 196–211 Prz. Nauk. Inż. Kszt. Środ. (2020), 29 (2) http://iks.pn.sggw.pl DOI 10.22630/PNIKS.2020.29.2.17

Time‐dependent response of the tropical atmosphere to a fixed sea surface temperature anomaly

Abstract: [1] The time-dependent response of the tropical atmosphere to a fixed, localized sea surface temperature (SST) anomaly is explored using a highly simplified nonlinear shallow water numerical model. The work builds on that by Webster [1972] and Gill [1980]. The present model has three layers and is formulated on an equatorial beta plane in an atmosphere initially in radiative-convective equilibrium. Observations suggest that the tropical atmosphere is only marginally unstable to moist convection. Accordingly, the convective parameterization in the model assumes that clouds consume the convective available potential energy at approximately the same rate as large-scale processes generate it. The convective parameterization allows for both shallow nonprecipitating and deep precipitating clouds. The convection scheme allows the shallow convection to condition the atmosphere for further deep convection, which is an important factor controlling deep convection in the tropics. The model calculations show that shallow convection moistens the middle troposphere, providing favorable conditions for the development of deep convection. In contrast, radiative cooling and drying of the middle troposphere act to suppress deep convection. In the model, these competing processes modulate the deep convection over the localized SST anomaly with a period of about 30 days. The convective heating also excites large-scale, equatorially trapped normal modes. The response ranges from a steady state flow similar to that by Gill to a periodic generation of Rossby-Kelvin wave couplets and finally to a transition to chaotic behavior depending on the strength of the forcing.

Mechanism of strong rainstorm and structure of mesoscale system

Abstract: Based on the synoptic analysis of the strong rainstorm of Hunan on June 23,2004, the nonhydrostatic version of mesoscale numerical model MM5-V3.6 was used to simulate this case.The results indicate that high resolution model MM5 can preferably simulate the occurrence and development of the low mesovortex with shear line,and that there are many disturbances in front of the low vortex and the strong mesoscale convective system inspired with the development of the low vortex.Over the rainstorm area,the vertical double-circulation causes the mesoscale convective system to become much more systematic.The development of the rainstorm and MCS were investigated with moist potential vorticity principle and slantwise vorticity development theory.The establishment of convective instability and conditional symmetry instability,and the centralized release of convective available potential energy(CAPE) are important conditions of the occurrence and development in this rainstorm.

Case Study of Bow Echo,Severe Convective Storm and Merger Process I:Taking Single Doppler Radar Data as a Case

Abstract: Using CINRAD/SA radar data in Jinan,combined with satellite,automatic weather station and other conventional data,the research about occurrenceanddevelopmentof a bow echo and severe convective stormwas studied in this paper.Bow echo and severe convective storms merged to form new bow echo,and it then developed by the process into comma echo.Firstly,Convective process tookplace under the background of horizontaltrough turning to vertical trough.The atmospheric environment existed large convective available potential energy(CAPE)and moderate-intensity low vertical wind shear.FY-2C satellite infrared images clearly showedthat the development andenhancement of bow echowere influenced by outflow boundary of neighbor cloud.At the same time,thetemperature,pressureand humidity observed from automatic weather station had strong changes within 20 min,obviously.Secondly,the result obtained from Doppler radar data indicated that it was a typical bow echo process,because the system evolved through a typical evolution of the bow echo at every stage,such as tall convective echoes,bow and spear-shaped stage,comma echo.Thirdly,the severe convective storm was in the warm area in front of bow echo about 75 km and moved slowly,with some characteristics of common storms.At last,during the stage about bow echo and severe convective storm merging,the bow echo was already in late comma-cloud system.With time going on,the supercell gradually closed to the neck of bow echo.After experienced short decrease,it strengthened rapidly and filled the weakened part of the bow echo.Supercell developed into bow echo withstrong rear inflow in the bow echo,and soon evolved into a comma cloud.The disastrous wind was produced at the rotating head of comma cloud.