Abstract
Atmospheric analysis data from the European Center for Medium-Range Weather Forecasts (ECMWF) have been acquired and are used to characterize the meteorological situation in Maroua, Cameroon ( 10.614 ∘ N, 14.361 ∘ E) at 12:00 UTC. These are then used to simulate downward global solar radiation (DGSR) with the moderate-resolution transmittance (MODTRAN) radiative transfer code (RTC). In comparison with meteorological data measured during the year 2014 in Maroua, ECMWF atmospheric quantities at ground level, in general, showed good correlation coefficients and slight differences. It is shown that ECMWF atmospheric profiles can thus be used to complete the scarce atmospheric data and to study the atmosphere state and dynamics, such as the African monsoon phenomenon detected in this region, which regulates the rainy season. In addition, they are more suitable to simulate clear-sky DGSR compared to MODTRAN standard atmospheric profiles. The causes and effects of the substantial bias and weak correlation coefficient observed with ECMWF wind data and the constant underestimation of simulated DGSR in comparison with ground-based measurements are investigated. The paper emphasizes the need for a better characterization of the Maroua atmosphere state and dynamics as well as the simulation of more accurate and reliable DGSR under any atmospheric conditions.
Highlights
The acquisition of atmospheric profiles and solar radiation data is a great challenge for developing countries such as Cameroon
In order to simulate radiances with European Center for Medium-Range Weather Forecasts (ECMWF) atmospheric profiles, we checked the consistency of the ECMWF data used as inputs to the measurements carried out at the site
To refine our comparisons and because the measurement sampling was modified in August, we present the previous statistics in Table 4 only for the moderate-resolution transmittance (MODTRAN) desert aerosol model under cloudless conditions and for the two periods (January–May and October–December) in the dry season
Summary
It has been exploited to retrieve global daily solar irradiation in Cameroon but was established to be appropriate in Maroua only for monthly variations [26] This method is under improvement to take into consideration surface albedo and vertical profiles and to provide direct and diffuse irradiation as well as their spectral distribution [27,28]. Maroua ground-level measurements should be consolidated and completed with data of upper atmospheric levels, in order to fully characterize the state of its atmosphere This task must be reproducible over time in order to continuously provide meteorological observations and analyses as required for environmental purposes. This study presents a method for permanent access to atmospheric parameters through the extraction of ECMWF vertical atmospheric profiles and their analysis It describes the simulation of solar radiation components with the MODTRAN RTC in the standard atmosphere. The impact of the insertion of ECMWF vertical profiles in simulations is evaluated by comparing simulated downward global solar radiation (DGSR), in clear-sky and various aerosol conditions, with in situ measurements
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call