“…1 ). The catchment covers an area of nearly 5133 km 2 with a mean elevation of 2164 m above sea level (elevation varies from 955 to 3295 m) [ 1 , 2 ]. The catchment is extensively cultivated and agricultural activities occur even on many of the steep and stony valley sides [3] .…”
Section: Experimental Design Materials and Methodsmentioning
confidence: 99%
“… Fig. 10 Seasonal average daily solar irradiation (kWh/m 2 ) distribution (a) autumn, (b) winter, (c) spring, (d) summer [2] . …”
Section: Experimental Design Materials and Methodsmentioning
“…1 ). The catchment covers an area of nearly 5133 km 2 with a mean elevation of 2164 m above sea level (elevation varies from 955 to 3295 m) [ 1 , 2 ]. The catchment is extensively cultivated and agricultural activities occur even on many of the steep and stony valley sides [3] .…”
Section: Experimental Design Materials and Methodsmentioning
confidence: 99%
“… Fig. 10 Seasonal average daily solar irradiation (kWh/m 2 ) distribution (a) autumn, (b) winter, (c) spring, (d) summer [2] . …”
Section: Experimental Design Materials and Methodsmentioning
“…It would be of interest to extend the validation of the ALARO model simulation to other variables than rainfall. The diurnal cycle of surface air temperature was contrasted with solar irradiance measurements over northern Ethiopia by Bayray et al (2021Bayray et al ( , 2022). These measurements could also be used to further validate highresolution climate models and provide information on biases in, for example, cloudiness.…”
Section: Mechanisms Of Convective Rainfallmentioning
Topoclimate, orographically enhanced rain on windward slopes and leeward rain shadows, control rainfall variability in tropical mountains. Such variability may cause a substantial societal impact in populated highlands such as in Ethiopia. This study aims at understanding the rainfall diurnal cycle and the orographic driving factors over the Ethiopian highlands using the ALARO‐0 regional climate model at convection‐permitting resolution, over a period of 21 years. While the evaluation against satellite‐based observations shows a too early onset of the model diurnal cycle and a too low nocturnal rainfall, several conclusions can be drawn from the model simulations presented here. Elevation is the most important determining factor for modelled rainfall with increased average rainfall and rainfall per rainfall event towards higher elevations. Ethiopia's simulated summer rain exhibits a pronounced diurnal cycle with the highest rainfall occurring during the early afternoon hours and the minimum values occurring in the late night. Average rainfall and rainfall per rainfall event are substantially larger on the windward sides than on the leeward sides of the mountains, except during the peak hours. The diurnal cycles of temperature and humidity start earlier in the morning and recede later than the cycles of wind speed and rainfall. Moreover, rainfall peaks occur earlier in the day at higher elevations, and at night in valleys and in Afar Triangle. Rain intensities around noon on the leeward side are slightly higher than those on the windward side of the highest mountains (>3000 m). This could be due to delayed onset of cloudiness and larger morning insolation on the leeward side of the mountain, but this needs further study. The prevalence of windward over leeward rainfall, the stark contrast in wind‐speed diurnal cycle between windward and leeward slopes, and the early peak hour of surface air and dew point temperature all point towards temperature‐induced rather than wind‐induced convection. These differences are likely to determine hydrology and vegetation distribution, and farmers economy at large. Hence, the need for a way out from the ‘one‐size‐fits‐all’ agro‐ecosystem management approach towards a site‐specific policy that takes into account climatic differences.
“…Solar radiation data from Mekelle city were used to represent health center sites in the Tigray region that are located a short distance from the city. Previous reports assessed the solar energy of four sites, of which, one was located at Mekelle University campus [13,14]. Recently collected solar radiation measurement data were also employed [15].…”
Section: Solar Radiation Datamentioning
confidence: 99%
“…The first consisted of the data that provides the typical hourly variation in global solar radiation for each month in a year. These hourly radiation model data represent an average value for a month based on measurement data for the years 2011 to 2015 [13,14]; hence, instantaneous variations are smoothed over an hour. The second dataset measured global solar radiation at ten-minute intervals for one year in 2019 [15], to analyze the effect of short-term variations.…”
PV-Battery systems are commonly sized based on the lowest solar radiation of the site of implementation. This implies that during days of high solar radiation excess energy is available. This study investigated the potential of excess energy for thermal storage from PV systems for a case of a rural health center. The system components of a typical PV installation in a rural health center in Tigray, Ethiopia, were considered. The electricity load profile of the health center and solar radiation data available from Mekelle city were used as inputs to a TRNSYS model. Analysis of excess energy in the system at hourly and ten-minute time intervals was conducted. The analysis results indicate that during the months from September to May excess energy was available that could be thermally stored and utilized. During these months, the excess peak power ranged from 737 to 841 W and daily average excess energy ranged from 2070 to 2959 Wh. In contrast, in the months from June to August, no excess energy was available due to low solar radiation.
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