ESTIMATION OF EVAPORATION IN URBAN CONDITIONS

<p>Reliable method for estimating pan evaporation is essential for modelling precipitation, different water balance studies and water management, especially in conditions with prominent climatic changes, such are urban conditions. Four empirical equations (Stephens and Stewart, Griffiths, Kohler-Nordenson-Fox and Linacre 1994) are used for modelling pan evaporation in the urban area of Nis, Serbia. Also, all equations are modified using nonlinear regression technique, and compared with measured Class A pan evaporation data. The results of statistical tests (coefficient of determination – R<sup>2</sup>, root mean square error – RMSE and mean absolute error – MAE) showed that Griffiths equation (before modification) has the best match with pan evaporation data (R<sup>2</sup> = 0.698, RMSE = 1.224 and MAE = 0.956). Stephens and Stewart equation, from all modified equations, achieves the best matching with the measured pan evaporation data (R<sup>2</sup> = 0.866, RMSE = 0.787 and MAE = 0.588).</p>