The effect of the meteorological parameters and rainfall size on rainfall interception of Cupressus arizonica and Pinus eldarica in the arid climate zone (case study: Biarjmand-e Shahroud)

The main goal was to measure interception loss (I) and to determine the contribution of the meteorological parameters as well as rainfall size in Pinus eldarica Medw. and Cupressus arizonica Green. in the arid climate zone of Iran. The selected trees were located inside a forest plantation in a dry area at Semnan province, where mean annual precipitation, and air temperature are 127 mm and 16˚C, respectively. The gross rainfall (GR) was measured by the mean of three hand-made collectors placed in an open area neighboring to the chosen trees. Eight throughfall (TF) collectors were positioned beneath the tree canopies to average into TF mean per species. Measurements were made on a rainfall event basis in a year, from March 2009 to March 2010. We investigated the correlations between intercepted rainfall (I:GR) with rainfall size (GR) and combination of the daily meteorological parameters of wind speed (WS), relative humidity (RH), evaporation (E) and air temperature (Ta). Averaged over all 26 events during a one-year measurement, approximately 44.6% of GR for P.eldarica and 32.6% for C. arizonica did not reach the soil surface beneath the afforestation and lost through evaporation process. The results showed that rainfall size was highly correlated with I:GR. However combinations of the meteorological parameters of Ta, RH and E improved the suggested models for estimation of I:GR. We concluded that the meteorological parameters could be usefully applied for estimation of interception of P. eldarica and C. arizonica planted in arid climate zone and in particular near meteorological stations like urban plantations