Droughts represent one of the most dangerous natural disasters in the world, due to their ability to progressively spread over large areas up to continental scale, as well as their adverse environmental, human and soc...Droughts represent one of the most dangerous natural disasters in the world, due to their ability to progressively spread over large areas up to continental scale, as well as their adverse environmental, human and socio-economic effects. Unfortunately, these effects are increasingly accentuated under the influence of climate change. One of the main challenges today is to mitigate the damage associated with droughts by developing tools capable of predicting the occurrence of such events in advance. Many solutions have been implemented for this purpose. But with the great progress in artificial intelligence, many scientists propose the use of Machine Learning to provide more optimal solutions to the problem related to droughts. In the present study, a bibliometric analysis was conducted to assess the current level of research on forecasting and monitoring of droughts in the world in general, particularly in West Africa through different methods based on the artificial intelligence. A search for articles on the topic was performed in the Web of Science (WoS) database, which is a global, publisher-independent citation database. The search identified a total of 3284 documents and the collected data was analyzed using a bibliometric tool called Bibliometrix. The main results are presented and discussed, followed by some potential avenues for research.展开更多
Energy exchange between land and atmosphere are important in climatic processes. In this paper, the seasonal dynamics and diurnal variations of surface radiation components of agricultural crops are investigated. One ...Energy exchange between land and atmosphere are important in climatic processes. In this paper, the seasonal dynamics and diurnal variations of surface radiation components of agricultural crops are investigated. One year data are used to emphasize the separate contribution of each radiation balance component. From the energy budget equation and FAO empirical model, we compare the clear sky solar radiation and the incoming short wave radiation in order to highlight aerosols and water vapor role in the studied area. The analysis show two important results: 1) The relevance of the short wave radiation in the net radiation budget especially in the wet season and 2) The variations of the long wave radiation were small. Analyses provide an understanding of net radiation seasonal variations in the northern part of Benin.展开更多
The use of solar energy is today widely recognized for the green transition but also for addressing societal challenges associated with the rise in global surface temperature. The design of a photovoltaic solar panel ...The use of solar energy is today widely recognized for the green transition but also for addressing societal challenges associated with the rise in global surface temperature. The design of a photovoltaic solar panel field may require an understanding of how solar radiation oscillates with other variables or factors since multiple interactions occur during its transfer within the atmosphere. In this study, three years of the incoming shortwave radiation (SWin) and air temperature (Tair) data acquired within the “Institut de Mathématiques et de Sciences Physiques” were analyzed using the continuous wavelet transform to extract the inherent variability of these signals. The underlying characteristics meaning the timescale of these variabilities as well as the lead-lag relationship between SWin and Tair were also examined. With the wavelet power spectrum, the highest variability was evidenced at the 2 - 8 band period for the SWin, coinciding almost with that of Tair. This suggests that these two signals are well interconnected at this temporal scale. The results obtained with the phase (∅xy) difference analysis, reveal that SWin leads Tair by ~ 23.5˚ on average when (0 ∅xy∅xyi.e., periods ≤ 32 days), Tair increases with an increasing SWin since the lags between these two signals range between 0.09 - 2.30 days. However, when looking at their interdependence at a larger temporal scale (> 32 days), Tair lags SWin. An increase in SWin might not directly imply an increase in Tair. Overall, these findings give insight into complex relationships across scales between the incoming shortwave radiation and air temperature in a tropical humid region of Bénin.展开更多
In 2022, an eddy covariance site was established in a young oil palm plantation in southeast Dangbo, Bénin, to study the exchange of CO2, energy, and water vapor. This study aims to present the first one-year ana...In 2022, an eddy covariance site was established in a young oil palm plantation in southeast Dangbo, Bénin, to study the exchange of CO2, energy, and water vapor. This study aims to present the first one-year analysis of seasonal dynamics in energy balance components and net ecosystem exchange above this type of ecosystem in Africa. The first results show that on average during the 2023 year, 55% of net radiation is consumed into actual evapotranspiration, demonstrating the significant amount of latent heat flux in the energy balance, as expected at this tropical humid site. The sensible heat flux was substantial, ranging between 60 and 200 W·m−2, while net radiation varied between 440 and 650 W·m−2. Carbon uptake and net release of CO2 into the atmosphere were permanent at the site. However, the CO2 uptake increases more when rainy events become regular. On average, the mean nighttime CO2 flux was ~8 µmol·m−2·s−1, while during the daytime it was ~−20 µmol·m−2·s−1.展开更多
文摘Droughts represent one of the most dangerous natural disasters in the world, due to their ability to progressively spread over large areas up to continental scale, as well as their adverse environmental, human and socio-economic effects. Unfortunately, these effects are increasingly accentuated under the influence of climate change. One of the main challenges today is to mitigate the damage associated with droughts by developing tools capable of predicting the occurrence of such events in advance. Many solutions have been implemented for this purpose. But with the great progress in artificial intelligence, many scientists propose the use of Machine Learning to provide more optimal solutions to the problem related to droughts. In the present study, a bibliometric analysis was conducted to assess the current level of research on forecasting and monitoring of droughts in the world in general, particularly in West Africa through different methods based on the artificial intelligence. A search for articles on the topic was performed in the Web of Science (WoS) database, which is a global, publisher-independent citation database. The search identified a total of 3284 documents and the collected data was analyzed using a bibliometric tool called Bibliometrix. The main results are presented and discussed, followed by some potential avenues for research.
文摘Energy exchange between land and atmosphere are important in climatic processes. In this paper, the seasonal dynamics and diurnal variations of surface radiation components of agricultural crops are investigated. One year data are used to emphasize the separate contribution of each radiation balance component. From the energy budget equation and FAO empirical model, we compare the clear sky solar radiation and the incoming short wave radiation in order to highlight aerosols and water vapor role in the studied area. The analysis show two important results: 1) The relevance of the short wave radiation in the net radiation budget especially in the wet season and 2) The variations of the long wave radiation were small. Analyses provide an understanding of net radiation seasonal variations in the northern part of Benin.
文摘The use of solar energy is today widely recognized for the green transition but also for addressing societal challenges associated with the rise in global surface temperature. The design of a photovoltaic solar panel field may require an understanding of how solar radiation oscillates with other variables or factors since multiple interactions occur during its transfer within the atmosphere. In this study, three years of the incoming shortwave radiation (SWin) and air temperature (Tair) data acquired within the “Institut de Mathématiques et de Sciences Physiques” were analyzed using the continuous wavelet transform to extract the inherent variability of these signals. The underlying characteristics meaning the timescale of these variabilities as well as the lead-lag relationship between SWin and Tair were also examined. With the wavelet power spectrum, the highest variability was evidenced at the 2 - 8 band period for the SWin, coinciding almost with that of Tair. This suggests that these two signals are well interconnected at this temporal scale. The results obtained with the phase (∅xy) difference analysis, reveal that SWin leads Tair by ~ 23.5˚ on average when (0 ∅xy∅xyi.e., periods ≤ 32 days), Tair increases with an increasing SWin since the lags between these two signals range between 0.09 - 2.30 days. However, when looking at their interdependence at a larger temporal scale (> 32 days), Tair lags SWin. An increase in SWin might not directly imply an increase in Tair. Overall, these findings give insight into complex relationships across scales between the incoming shortwave radiation and air temperature in a tropical humid region of Bénin.
文摘In 2022, an eddy covariance site was established in a young oil palm plantation in southeast Dangbo, Bénin, to study the exchange of CO2, energy, and water vapor. This study aims to present the first one-year analysis of seasonal dynamics in energy balance components and net ecosystem exchange above this type of ecosystem in Africa. The first results show that on average during the 2023 year, 55% of net radiation is consumed into actual evapotranspiration, demonstrating the significant amount of latent heat flux in the energy balance, as expected at this tropical humid site. The sensible heat flux was substantial, ranging between 60 and 200 W·m−2, while net radiation varied between 440 and 650 W·m−2. Carbon uptake and net release of CO2 into the atmosphere were permanent at the site. However, the CO2 uptake increases more when rainy events become regular. On average, the mean nighttime CO2 flux was ~8 µmol·m−2·s−1, while during the daytime it was ~−20 µmol·m−2·s−1.
