Browsing by Author "Nymphas E. F."

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Assessing Wildfire Occurrence in West Africa with Atmospheric Co₂ Removal
(2025-06) Uzoma E.K.; Otunla T. A.; Nymphas E. F.; Ogunsola O. E.; Adeniyi M. O.
The increase in wildfire occurrence is one of the consequences of the recent global temperature rise. Understanding wildfire occurrence in West Africa under atmospheric carbon dioxide removal is significant because of its implications on climate systems, ecosystems, agriculture, and socioeconomic development. This study projected the impacts of atmospheric carbon dioxide removal on fire occurrence in West Africa by analyzing the CNRM ESM1 C1 model output for the Carbon Dioxide Removal Model Inter-comparison Project (CDRMIP). Four climatological periods–1990–2019 (reference period), 2040 – 2069, 2070–2099 and 2100-2129 were analyzed using four fire indices. The periods 2040–2069, 2070–2099, and 2100–2129 have 42%, 45.9%, and 49.4% of “No Fire” category among other categories, respectively, with the Lebanese Index. With Mark 4 Grassland Fire Danger Index, a low category of fire risk is also predominant at 95.6%, 96.4%, and 66.1% for 2040–2069, 2070–2099, and 2100–2129, respectively. None of the indices projected a case of high, very high, or extreme risk in any period. “Low risk” category is predominant with all indices, particularly in Cote D’Ivoire, Ghana, Burkina Faso, Togo, Benin, and Nigeria. The low-risk category for fire occurrence during carbon dioxide removal in West Africa suggests a favorable outcome for the region’s ecosystems, agriculture, and communities. The study highlights the potential benefits of CDR beyond carbon removal, such as enhanced resilience, sustained productivity, and reduced vulnerability to climate-induced hazards like wildfires.
Characteristics of total solar radiation in an urban tropical environment
(2012) Adeniyi M. O.,; Nymphas E. F.; Oladiran, E. O.
The maximum total solar radiation in Ibadan (7.38° N, 3.93° E), Nigeria occurred around 13 and 14h local time (LT) and it varied from an average value of 584.3±10.9 Wm-2 in the wet season (April to October) to 642.5±10.8 Wm-2 in the dry season (November to March) throughout the period of 1997 to 2001. Maximum total solar radiation had two peaks, one in March/April/May with value 750.3±41 Wm-2 and the other in October/November with value 633.1±63.5 Wm-2. The minimum was in July/August with the value 404.8±54 Wm-2. Diurnal total solar radiation had a similar variation with mean day total solar radiation; the latter had its maxima and minimum values to be 564.7±19, 488±36 and 308.4±40 respectively. The annual trend of solar radiation was positive throughout the period considered, which revealed global brightening. The values of total solar radiation observed in Ibadan compared well with those obtained at Ife (7.55° N, 4.56° E) a nearby tropical station. A time lag of about 3 h between the peak of the diurnal temperature and solar radiation was observed. During the month of July or August as the case may be, there was little or no time lag between the time of maximum total solar radiation and maximum diurnal temperature. Significant intra-annual solar radiation cycles (at 0.05 significant level) of 360 to 370 days (1 per year); 180 to 200 days (2 per year), 90 to 121 days (3 per year), 45 to 70days (5 per year); 20 to 35 days (10 per year), 4 to 16 days (20 per year) were obtained for all the years (1997 to 2001).