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.

Propagation Characteristics of Mesoscale Convective Systems

Abstract: : Case studies were undertaken on mesoscale convective systems (MCS) an individual storm basis to examine factors influencing MCS propagation characteristics This was done by examining numerous specific storms during a portion of the warm seasons (June-September) of 1990 through 1992 Three cases were presented in detail to illustrate the types of propagation typically exhibited by mesoscale convective systems This research attempts to analyze why MCSs exhibit a particular type of propagation and if that propagation can be accurately predicted by forecasters on an operation basis Parameters such as moisture convergence, surface boundaries (fronts, dry lines, etc), Convective Available Potential Energy (CAPE), equivalent potential temperature, vertical wind shear, and others were used in the diagnosis of a particular region where a storm grew and propagated toward

Meteorological reconstruction of major floods in early instrumental period in Catalonia (NE Iberian Peninsula)

Abstract: Floods are among the most dangerous natural hazards in the Western Mediterranean area. Historically, these types of events have generated many affectations over several fields, such as agriculture or infrastructures, and even hundreds of fatalities. The historical archive data allow for a historical (Barriendos et al. 1993) and for a hydraulical and hydrological reconstruction (Balasch et al., 2010, 2011) of floods. However, there are few studies dealing with the meteorological reconstruction of historical floods. Within the early instrumental period (1780-1950), the 20 major floods (according to the affected area, peak and overflow magnitudes, high social damages) since 1870 affecting Catalonia (NE Iberian Peninsula) have been chosen with the aim of characterizing them under a meteorological point of view. By doing this, we improve the understanding of their atmospheric dynamics. For this purpose, the NOAA 3/6 Hourly 20thC V2 Reanalysis Data Composites database has been used to obtain the vertical profile of the air temperature from 1000 hPa to 200 hPa. This database allows us to evaluate several parameters related to convection, such as the Convective Available Potential Energy (CAPE), the Lift Index (LI), the K index (KI), the Vertical, Cross and Total Totals (VT, CT, TT respectively), and wind shear between surface and 1, 3 and 6 km levels, among many others. Moreover, the synoptic condition has been also reconstructed for each flood event. As a preliminary result, the estimated convective parameters as well as the prevailing synoptic conditions that favor convective precipitation have shown a good correspondence with the geographical and hydrological reconstruction. These results will be useful for the synoptic classification of the largest floods occurred in the past, in order to improve their forecasting in the future.

Future intensity–duration–frequency curves of Edmonton under climate warming and increased convective available potential energy

Abstract: A regional climate model called WRF (Weather Research and Forecasting) was set up in a two-way, three-domain nested framework to simulate future May to August precipitation of central Alberta, Canada. WRF is forced with climate outputs from four Global Climate Models (GCMs) for the baseline period 1980–2005, and for 2041–2100 based on the Representative Concentration Pathways (RCP) 4.5 and 8.5 climate scenarios of the Intergovernmental Panel on Climate Change (IPCC). A quantile–quantile bias correction method and a regional frequency analysis were applied to acquire future grid-based IDF curves for the city of Edmonton. Future trends of air temperature and convective available potential energy (CAPE) are investigated. Future IDF curves are expected to have higher intensities because of projected higher air temperature and atmospheric water vapor, and projected increase in CAPE by 2071–2100. Our results likely mean that under the impact of climate change, the future risk of flooding in Edmonton would increase.

Impact of vegetation changes on a mesoscale convective system

Abstract: The evolution of precipitating convective sys- tems in West Africa has been a research topic throughout the past three decades and is considered to be influenced by surface-atmosphere interactions. This study builds on the previous research by examining the sensitivity of a meso- scale convective system (MCS) to a change in the vege- tation cover by using a regional atmospheric model with a high horizontal resolution. Vegetation cover values in the region between 10 and 15N have increased by 10-30% over the last 20 years. The effect of both an increase and a decrease in vegetation cover by 10, 20 and 30% is inves- tigated. The MCS case selected occurred on 11 June 2006 and was observed during the African Monsoon Multidis- ciplinary Analysis field campaign in Dano, Burkina Faso. The model is able to reproduce the most important char- acteristics of the MCS and the atmospheric environment. For the investigated case, no clear precipitation response of the MCS to the applied vegetation scenarios is found. The vegetation changes do alter the surface fluxes in the days before the MCS arrives, which have a clear effect on the modelled convective available potential energy (CAPE) values. However, a link between CAPE, mesoscale circu- lation and rainfall amounts could not be demonstrated as a dynamical mechanism is found to counteract the CAPE signal. By using a kilometre-scale model, a change in the cold pool dynamics of the MCS could be detected which results from alterations in boundary layer moisture. The effect of vegetation changes on the MCS is thus not straightforward and a complex interaction between differ- ent processes should be taken into account.

Observed Climatology and Trend in Relative Humidity, CAPE, and CIN over India

Abstract: Water vapor is the most dominant greenhouse gas in the atmosphere and plays a critical role in Earth’s energy budget and hydrological cycle. This study aims to characterize the long-term seasonal variation of relative humidity (RH), convective available potential energy (CAPE), and convective inhibition (CIN) from surface and radiosonde observations from 1980–2020. The results show that during the monsoon season, very high RH values are depicted while low values are depicted during the pre-monsoon season. West Coast stations represent large RH values compared to other stations throughout the year. Irrespective of the season, the coastal regions show higher RH values during monsoon season. Regardless of season, the coastal regions have higher RH values during the monsoon season. During the pre-monsoon season, the coastal region has high RH values, whereas other regions have high RH values during the monsoon season. The rate of increase in RH in North-West India is 5.4%, followed by the West Coast, Central, and Southern parts of India. An increase in water vapor leads to raised temperature, which alters the instability conditions. In terms of seasonal variation, our findings show that CAPE follows a similar RH pattern. CAPE increases sharply in Central India and the West Coast region, while it declines in South India. Opposite features are observed in CIN with respect to CAPE variability over India. The results of the study provide additional evidence with respect to the role of RH as an influencing factor for an increase in CAPE over India.