International Journal of Marine, Atmospheric and Earth Sciences
ISSN: 2327-3356 (online)Search Article(s) by:
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Current Issue: Vol. 5 No. 1or Keyword in Title:
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Table of Content for Vol. 5 No. 1, 2017

A Comparative Analysis of Empirical Models for the Estimation of Monthly Mean Daily Global Solar Radiation Using Different Climate Parameters in Sokoto, Nigeria
Sulaiman M. Y.  and Umar A. B.
      
 PP. 1 - 19
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ABSTRACT: Monthly average daily global solar radiation data are essential in the design and study of solar energy conversion devices. In this regard, different empirical models based on Angstrom-Prescott model were selected to estimate the monthly average daily global solar radiation (H), on a horizontal surface for Sokoto State using sunshine duration, relative humidity and temperature. The hourly solar radiation data measured at Sultan Abubakar III International Airport station during the period (2005–2015) was used to calculate the monthly mean values of H using selected models. The selected models were compared on the basis of the statistical error tests such as the mean bias error MBE, the mean percentage error MPE, the root mean square error RMSE, Nash–Sutcliffe equation NSE, correlation coefficient r coefficient of determination R2 and the t-test t. Based on the statistical results a new linear model H/H0 =0.192+0.281(ΔT/S0based on modified Angstrom model is recommended to estimate monthly average daily global solar radiation for Sokoto State areas and in elsewhere with similar climatic conditions where the radiation data is missing or unavailable. The present work will help to advance the state of knowledge of global solar radiation to the point where it has applications in the estimation of monthly average daily global solar radiation.


Simulating the Impacts of Global Warming on Water Budget Components in Nigeria
Olusegun K. Adetan, Olufemi T. Oluyede and Olaniran J. Matthew
      
 PP. 20 - 39
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ABSTRACT: This study assessed the temporal-spatial variations in the water budget components across Nigeria and examined the potential impacts of future global warming on available water for agricultural uses in the country. To achieve these objectives, daily data of precipitation, runoff, evapotranspiration and ground water (top soil and root-zone water) from RegCM3 simulations over the region for 1981-2000 (baseline) and 2031-2050 (future) periods were used. The climate model projections suggested significant increase in future temperature (1.6oC in the North, 1.4oC in the Mid-Belt and 1.2oC in the South zones) across the entire country. The annual projection in precipitation was predicted to decrease slightly (-0.5%) in the North zone but expected to increase by 2.26% and 1.50% in the Mid-belt and South zones respectively. Positive changes (+5 to +60%) in monthly precipitation were generally predicted in dry season and negative changes (-2 to -36%) in wet season across the zones. Significant future increase in temperature and reduced precipitation, particularly during the wet season, were found to have negatively impacted groundwater. The study concluded that future distortion in various water budget components could have negative impacts on crop production in the region.