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.

The Characteristics and Predictability of Convective System Based on GOES-9 Observations during the Summer of 2004 over East Asia

Abstract: Convective systems propagate eastward with a persistent pattern in the longitude-time space. The characteristic structure and fluctuation of convective system is helpful in determining its predictability. In this study, convective index (CI) was defined as a difference between GOES-9 window and water vapor channel brightness temperatures following Mosher (2001). Then the temporal-spatial scales and variational characteristics of the summer convective systems in the East Asia were analyzed. It is found that the average moving speed of the convective system is about 14 m/s which is much faster than the low pressure system in the summer. Their average duration is about 12 hours and the average length of the cloud streak is about 750km. These characteristics are consistent with results from other studies. Although the convective systems are forced by the synoptic system and are mostly developed in the eastern edge of the Tibetan Plateau, they have a persistent pattern, i.e., appearance of the maximum intensity of convective systems, as they approach the Korean Peninsula. The consistency of the convective systems, i.e., the eastward propagation, suggests that there exists an intrinsic predictability.

Vertical Distribution of Aerosols during Deep-Convective Event in the Himalaya Using WRF-Chem Model at Convection Permitting Scale

Abstract: The Himalayan region is facing frequent cloud bursts and flood events during the summer monsoon season. The Kedarnath flooding of 2013 was one of the most devastating recent events, which claimed thousands of human lives, heavy infrastructure, and economic losses. Previous research reported that the combination of fast-moving monsoon, pre-existing westerlies, and orographic uplifting were the major reasons for the observed cloud burst over Kedarnath. Our study illustrates the vertical distribution of aerosols during this event and its possible role using the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) simulations. Model performance evaluation shows that simulations can capture the spatial and temporal patterns of observed precipitation during this event. Model simulation at 25 km and 4 km horizontal grid resolution, without any changes in physical parameterization, shows a very minimal difference in precipitation. Simulation at convection-permitting scale shows detailed information related to parcel motion compared to coarser resolution. This indicates that the parameterization at different resolutions needs to be further examined for a better outcome. The modeled result shows changes of up to 20–50% in the rainfall over the area near Kedarnath due to the presence of aerosols. Simulation at both resolutions shows the significant vertical transport of natural (increases by 50%+) and anthropogenic aerosols (increases by 200%+) during the convective event, which leads to significant changes in cloud properties, rain concentration, and ice concentration in the presence of these aerosols. Simulations can detect changes in important instability indices such as convective available potential energy (CAPE), convective inhibition energy (CIN), vorticity, etc., near Kedarnath due to aerosol–radiation feedback.

Studies of Two Important Stability Indices of Earth’s Atmosphere Determined by using the COSMIC GPS Radio Occultation Technique

Abstract: Objectives: To study the seasonal variations of two important atmosphere stability indices, i.e. Convective Available Potential Energy (CAPE) and Convective Inhibition (CIN) for the selected years, i.e. from 2007 to 2012 using the COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) Radio occultation (RO) technique. Methods/Analysis: We used the COSMIC RO technique as we consider that it provides more accurate, all-weather, round the-clock and global coverage of the lower atmosphere and ionosphere constituents with unprecedented resolutions. Further, we used the lower atmosphere database provided by the COSMIC RO technique in order to study the above two parameters (CAPE & CIN). Findings: It was found that, for the very first time, the consistency of wavy nature in CAPE seasonal trends which are confined to northern and southern hemispheres alternatively. The wavelike nature in CAPE trends seems to be following Inter- Tropical Convergence Zone (ITCZ) movement and, in such case, the CAPE trends may be useful to ascertain the ITCZ movements during different seasons of a year and the CAPE magnitude shows higher values over land than oceanic regions, which confirms the consistency of their calculations. In this regard, the trends of both CAPE and CIN have shown a close bimodal distribution. Applications/Improvement: As a result, we find better correlations of both CAPE and CIN computed through the atmospheric data measured with the COSMIC RO and collocated Radiosonde technique when the profile data are reaching to the near-surface of the Earth.

Analysis of gravity wave characteristics of a strong squall line process in april 2006 in shandong province

Abstract: A squall line that occurred on 28 April 2006 in Shandong province is investigated by using multiple observations of satellite,radar and data measured at mesoscale automatic weather stations.The PSU/NCAR mesoscale nonhydrostatic model MM5 is used to simulate and analyze the process.The result of the analysis shows that large amount of Convective Available Potential Energy(CAPE) is accumulated from an atmospheric thermal stratification that is warmer at lower levels than at higher ones because of the superimposition of a cold upper-level trough over warm lower-level air.A mesoscale convergence line,which is formed by downslope wind from the Taihang Mts.Converging with southwest warm humid wind in front of a surface trough,induces the release of the CAPE and initiates convection and organizes the convective cells into a squall line.The wavelet analysis method is used to transform the simulation results into continuous wave structures.The analysis of the transformed result shows that the lee waves generated from the Taihang Mts.are one of the initiation mechanisms of this process,during which there are obvious mesosclae gravity wave structures with the main wavelengths about 50~100 km,the group velocity about 14~28 m/s,but with a slightly faster phase velocity with the 50 km wave than with the 100 km wave.

Study of Ardmore, Oklahoma, storm clouds. I. Convective storm cloud initiation and development based on the remote sensing gravity-wave-induced convection

Abstract: Convective instability can be induced by unstable vertical temperature profiles and can be supported by the release of latent heat of water vapour provided by a large quantity of moisture in the air. It can also be released by the presence of gravity waves. Large amplitude gravity waves have been linked to the onset of convective storm systems. In this study, the vertical velocity of convection initiated by gravity waves was investigated. The study of Ardmore, Oklahoma, storms showed that weak convection was initiated by gravity waves having wave periods of 35 min and the convection was enhanced by gravity waves having wave periods of 20 min. Evidence for cloud formation, due to the condensation of water vapour through convection initiated by the gravity waves, was obtained from rapid-scan satellite imagery and radar summaries. In this particular case, the convective motion, initiated and supported by the gravity-wave-induced activity (excluding contributions made by other mechanisms), reached it...