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

Al-Taai Osama T., Abbood Zainab M.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

2020

Vol. 29, No. 2

196--211

The Convective Available Potential Energy (CAPE) represents the amount of energy for a sample of air. The sample departs vertically within the atmosphere and through these values the potential energy to predict the extreme weather conditions such as storms, hurricanes, lightning and thunder. Data are taken by CAPE, convective precipitation (Cp) and total precipitation (Tp) from satellites recorded by the European Centre for Medium-Range Weather Forecasts (ECMWF). The choice of 30 years (1989–2018) over Iraq station between two latitudes (29.5°–37.22° N) and two longitudes (48.45°–38.45° E). Otherwise, we have studied total yearly mean of CAPE, Cp and Tp over Iraq, the total monthly mean of CAPE, Cp and Tp for the selected station, as well as the relationship between of CAPE, Cp and Tp for the selected station. The results showed that the highest total yearly mean of CAPE, Cp and Tp over Iraq was included northern stations and lowest was included central and southern stations. The highest total monthly mean of CAPE, Cp and Tp for Zakho station. The relationship between the CAPE and Cp is positive and the relationship between CAPE and Tp is positive too at five stations but Mosul station represents very high correlation while Zakho station represents the low correlation.

Sensitivities of the Tiedtke and Kain-Fritsch Convection Schemes for RegCM4.5 over West Africa

Adeniyi Mojisola Oluwayemisi

Meteorology Hydrology and Water Management. Research and Operational Applications

2019

Vol. 7, Iss. 2

27--37

Realistic simulation of weather and climate parameters over West Africa is daunting, so the performance of the Tiedtke and Kain-Fritsch convection schemes within version 4.5 of the Regional Climate Model (RegCM4.5) of the International Centre for Theoretical Physics, Trieste is evaluated over West Africa for improved simulation. The two schemes are compared to two traditional mixture schemes (Grell on land and Emanuel on Ocean), outperforming the mixture schemes with reduced magnitude and spatial coverage of dry bias. Both schemes simulate precipitation over West Africa with a low dry bias, however, the Kain-Fritsch convection scheme simulates more realistic precipitation in the West African convective environment. This is associated with the inclusion of a variable cloud radius and the convective available potential energy closure for the Kain-Fritsch in contrast to a fixed cloud radius and moisture convergence of the of the Tiedtke scheme. The simulated outgoing longwave radiation and omega lend support to the spatial variations and amount of simulated precipitation in the different areas by the schemes. The spatial variation of simulated temperature over the target region shows lower bias than precipitation by all the convection schemes. Soil moisture is more accurately simulated (correlation coefficient ~1) in the savannah (8-10°N) and Sahel (22-28°N) environments by all the convection schemes. Tiedtke performs the most accurate simulations of the pattern and profile of zonal wind which controls climate circulation, with slightly weaker simulations of the Africa easterly jet with core magnitude less than 10 m·s-1. The accuracy of the KF and Tiedtke in RegCM4.5 in simulating the climate of West Africa is documented for the first time for application in future studies over the region.