Atmospheric pollution evaluation in brasov romania based on turbidity factor analysis

Abstract

Turbidity factor (TR) varies from one geographic area to another according to the specific in-field conditions: site altitude, atmospheric pollution, water vapor and gasses in the air etc. Therefore the turbidity factor is a synthetic parameter that offers information on how much solar radiation is lost when passing through cloudless atmosphere and moreover it can be used to evaluate the atmospheric pollution on a given site. To obtain a realistic and accurate TR estimation for Brasov, Romania, the beam solar radiation values, registered by the Delta-T meteorological station, were modeled according to three stages of refinement, based on a method proposed by the German meteorological services (the considered meteorological database contains registrations for 2006 2009 interval). For the first and second stages, were considered only the days with the highest and densest beam solar radiation values, registered on each month; accordingly, the daily mean solar radiation values and the correspondent TR were calculated. Because the first stage results were inconsistent to the real situation, on the second stage were considered only the beam radiation registrations corresponding to a solar elevation above 20 ; still the results were inconsistent with reality. On the third stage, the single instantaneous maximum beam solar radiation value is considered, for each month, based on 2006 2009 database, and only for these twelve values is calculated the corresponding monthly TR; the consequently results are consistent to the in-field values. Moreover, based on the third stage s results, the optimum annual constant TR=3 is identified for Brasov, Romania.