부산대학교 도서관

Evaporation from wet-canopy ( $$E_\mathrm{C}$$ ) and stem ( $$E_\mathrm{S}$$ ) surfaces during rainfall represents a significant portion of municipal-to-global scale hydrologic cycles. For urban ecosystems, $$E_\mathrm{C}$$ and $$E_\mathrm{S}$$ dynamics play valuable roles in stormwater management. Despite this, canopy-interception loss studies typically ignore crown-scale variability in $$E_\mathrm{C}$$ and assume (with few indirect data) that $$E_\mathrm{S}$$ is generally $${<}2\%$$ of total wet-canopy evaporation. We test these common assumptions for the first time with a spatially-distributed network of in-canopy meteorological monitoring and 45 surface temperature sensors in an urban Pinus elliottii tree row to estimate $$E_\mathrm{C}$$ and $$E_\mathrm{S}$$ under the assumption that crown surfaces behave as 'wet bulbs'. From December 2015 through July 2016, 33 saturated crown periods (195 h of 5-min observations) were isolated from storms for determination of 5-min evaporation rates ranging from negligible to 0.67 $$\hbox {mm h}^{-1}$$ . Mean $$E_\mathrm{S}$$ (0.10 $$\hbox {mm h}^{-1}$$ ) was significantly lower ( $$p < 0.01$$ ) than mean $$E_\mathrm{C}$$ (0.16 $$\hbox {mm h}^{-1}$$ ). But, $$E_\mathrm{S}$$ values often equalled $$E_\mathrm{C}$$ and, when scaled to trunk area using terrestrial lidar, accounted for 8-13% (inter-quartile range) of total wet-crown evaporation ( $$E_\mathrm{S}+E_\mathrm{C}$$ scaled to surface area). $$E_\mathrm{S}$$ contributions to total wet-crown evaporation maximized at 33%, showing a general underestimate (by 2-17 times) of this quantity in the literature. Moreover, results suggest wet-crown evaporation from urban tree rows can be adequately estimated by simply assuming saturated tree surfaces behave as wet bulbs, avoiding problematic assumptions associated with other physically-based methods. [ABSTRACT FROM AUTHOR]