Solar Radiation, Air Temperature, Relative Humidity, and Dew Point Study: Damak, Jhapa, Nepal

Monitoring and prediction of the climatic phenomenon are of keen interest in recent years because it has great influence in the lives of people and their environments. This paper is aimed at reporting the variation of daily and monthly solar radiation, air temperature, relative humidity (RH), and dew point over the year of 2013 based on the data obtained from the weather station situated in Damak, Nepal. The result shows that on a clear day, the variation of solar radiation and RH follows the Gaussian function in which the first one has an upward trend and the second one has a downward trend. However, the change in air temperature satisfies the sine function. The dew point temperature shows somewhat complex behavior. Monthly variation of solar radiation, air temperature, and dew point shows a similar pattern, lower at winter and higher in summer. Maximum solar radiation (331 Wm-2) was observed in May and minimum (170 Wm-2) in December. Air temperature and dew point had the highest value from June to September nearly at 29°C and 25°C, respectively. The lowest value of the relative humidity (55.4%) in April indicates the driest month of the year. Dew point was also calculated from the actual readings of air temperature and relative humidity using the online calculator, and the calculated value showed the exact linear relationship with the observed value. The diurnal and nocturnal temperature of each month showed that temperature difference was relatively lower (less than 10°C) at summer rather than in winter.

[1]  Aaas News,et al.  Book Reviews , 1893, Buffalo Medical and Surgical Journal.

[2]  Binod K. Bhattarai,et al.  Estimation of Global Solar Radiation using Pyranometer and NILU-UV Irradiance Meter at Pokhara Valley in Nepal , 2014 .

[3]  Modified Relative Humidity Based on the Johnson's SB Distribution Function , 2013 .

[4]  K. Ukhurebor,et al.  The Influence of Air Temperature on the Dew Point Temperature in Benin City, Nigeria , 2017 .

[5]  Yi Lin,et al.  Monitoring and Modeling of Spatiotemporal Urban Expansion and Land-Use/Land-Cover Change Using Integrated Markov Chain Cellular Automata Model , 2017, ISPRS Int. J. Geo Inf..

[6]  J. C. Martínez-García,et al.  Correlation between global solar irradiation and air temperature in Asturias, Spain , 2009 .

[7]  Wilfried Elmenreich,et al.  A Model for Hourly Solar Radiation Data Generation from Daily Solar Radiation Data Using a Generalized Regression Artificial Neural Network , 2015 .

[8]  S. Regmi,et al.  Solar Energy Potential in Kathmandu Valley, Nepal , 2016 .

[9]  B. Bhattarai,et al.  Solar Energy Potential in Nepal and Global Context , 2014 .

[10]  R. Pongrácz,et al.  Analysis of the air temperature and relative humidity measurements in Budapest-Ferencváros , 2016 .

[11]  Solar radiation and air temperature: A study of Santiago de Chile and Salamanca , 1993 .

[12]  Binod K. Bhattarai,et al.  Estimation of Global Solar Radiation Using Clearness Index and Cloud Transmittance Factor at Trans-Himalayan Region in Nepal , 2012 .

[13]  F. Chabane,et al.  Forecast of relationship between a relative humidity and a dew point temperature , 2018 .

[14]  Shekhar Gurung,et al.  Estimation of Global Solar Radiation for Four Selected Sites in Nepal Using Sunshine Hours, Temperature and Relative Humidity , 2013 .

[15]  M. Lawrence.  The relationship between relative humidity and the dewpoint temperature in moist air - A simple conversion and applications , 2005 .

[16]  J. Almorox.  Estimating global solar radiation from common meteorological data in Aranjuez, Spain , 2011 .

[17]  J. Oosthuizen,et al.  Recent Trends In Temperature And Relative Humidity in Bawku East, Northern Ghana , 2014 .

[18]  K. Górnicki,et al.  Evaluation of models for the dew point temperature determination , 2017 .

[19]  Ibidun O. Adelekan,et al.  Air temperature, relative humidity, climate regionalization and thermal comfort of Nigeria , 2014 .

[20]  V. Russak.  Changes in solar radiation and their influence on temperature trend in Estonia (1955–2007) , 2009 .

[21]  Berit Kjeldstad,et al.  Solar Radiation Potential at Four Sites of Nepal , 2012 .

[22]  S. M. El shazly,et al.  Estimation of hourly and daily global solar radiation at clear days using an approach based on modified version of gaussian distribution , 1996 .

[23]  Relationship between relative humidity and the dew point temperature in Benin City, Nigeria , 2017 .

[24]  B. Geerts.  Empirical estimation of the monthly-mean daily temperature range , 2003 .

[25]  N. Shanks,et al.  Environmental factors and heatstroke. , 2001, Occupational medicine.

[26]  M. Rebetez.  Changes in daily and nightly day-to-day temperature variability during the twentieth century for two stations in Switzerland , 2001 .

[27]  D. Fitzgerald,et al.  What is the air temperature? , 1985 .

[28]  Nejib Hamrouni,et al.  Solar radiation and ambient temperature effects on the performances of a PV pumping system , 2008, Journal of Renewable Energies.

[29]  S. Adhikari.  Seasonal and spatial variation of solar radiation in Nepal Himalayas , 2016 .