Long-Term Variation of Sunshine Duration and Their Inter-Action with Meteorogical Parameters over Chad, Central Africa

Abstract

This study aims to evaluate the long-term variations of sunshine duration and to estimate its interaction with meteorogical parameters from 1950 to 2010 in Chad, Central Africa. The results show that Chad is the one of world's sunniest countries. Each year, Chad receives more than 3030.91 ± 176.33 hours of sunning corresponding to 8.9 hours daily. Likewise, a strong north-south gradient is noted over Chad. For instance, the daily insolation is 10 ± 0.41 hours in the north, 8.85 ± 1.1 hours in the center and 7.75 ± 1.8 hours in the south. Furthermore, there is a marked seasonality of sunshine duration with maximums in dry season and minimums during the rainy season. The lowest values of sunshine duration are found in August. On the contrary, maximums are recorded from November to February with values greater than 9.5 hours per day. Moreover, the annual anomalies study allowed determining three great periods in terms of sunshine variability in Chad. Firstly, the period between 1950 to 1970 (named humid period) is characterized by the lowest values of sunshine duration in Chad. Secondly, from 1970 and 1990, the region suffered an unprecedented drought which resulted in an increase of sunstroke duration in Chad. And finally, the period from 1990 to 2010 called the return period is characterized by a rapid year-to-year fluctuations of insolation duration. Unlike to surface temperature, we have also shown that there is a direct relation between the duration of insolation and the meteorological parameters such as precipitations and relative humidity.

Estimation of Solar Radiation and Feasibility Analysis of a Concentrating Solar Power Plant in Birao, Central African Republic

“…They have the advantage of estimating solar radiation on different planes and even adapt to the modes of tracking the sun for moving collectors [23]. In addition, there are estimation techniques from satellite images where the results are very close to those of measurements made in situ [24], then the prediction from artificial intelligence [25][26][27], and others [28][29][30][31]. Depending on the contexts of the study conducted, the choice of the solar radiation estimation model is very judicious.…”

Development and Assessment of Feed Forward Back Propagation Neural Network Models to Predict Sunshine Duration

“…In Saudi Arabia, a study calculated the SD utilizing the two algorithms of neural network and the input variables were the maximum length of the possible day, the number of months, longitude, latitude, height and extraterrestrial solar radiation in a specific location [16]. In Central Africa, the research assessed the long-term differences in sunshine duration and estimated its interplay with meteorological variables from 1950 to 2010 [17]. A new method has been proposed to estimate sunshine duration utilizing hourly cloud data from the satellite of geostationary metrological in China [18].…”

Modeling and Simulation of Hourly Irradiance for Solar Applications in Chad: Case of the City of Abeche

“…Thus, the need for energy is becoming more and more important. Chad is one of the Sahelian countries that, thanks to its geographical position, has a very high renewable energy potential, particularly wind and solar energy, which unfortunately are not used to cover the population's energy needs [1][2][3][4][5][6]. The city of Abeche covers an area of 3,000 hectares and is located in the Sahelian climatic zone in eastern Chad (Figure 1), with geographical coordinates of 13°85 North and 20°85 East and an altitude of 545 meters.…”