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Category Text Publication
Reference Category Journals
DOI 10.1007/s10546-017-0277-7
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Title (Primary) Edge-to-stem variability in wet canopy evaporation from an urban tree row
Author Van Stan II, J.T.; Norman, Z.; Meghoo, A.; Friesen, J.; Hildebrandt, A.; Côté, J.-F.; Underwood, S.J.; Maldonado, G.
Source Titel Boundary-Layer Meteorology
Year 2017
Department CATHYD
Volume 165
Issue 2
Page From 295
Page To 310
Language englisch
Keywords Pinus elliottii; Rainfall interception; Tree surface temperature; Urban forest; Wet-canopy evaporation; Wet-bulb temperature
UFZ wide themes RU2;
Abstract

Evaporation from wet-canopy (EC) and stem (ES) surfaces during rainfall represents a significant portion of municipal-to-global scale hydrologic cycles. For urban ecosystems, EC and ES dynamics play valuable roles in stormwater management. Despite this, canopy-interception loss studies typically ignore crown-scale variability in EC and assume (with few indirect data) that ES 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 EC and ES 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 mm h−1. Mean ES (0.10 mm h−1) was significantly lower (p<0.01) than mean EC (0.16 mm h−1). But, ES values often equalled EC and, when scaled to trunk area using terrestrial lidar, accounted for 8–13% (inter-quartile range) of total wet-crown evaporation (ES+EC scaled to surface area). ES 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.

Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=19038
Van Stan II, J.T., Norman, Z., Meghoo, A., Friesen, J., Hildebrandt, A., Côté, J.-F., Underwood, S.J., Maldonado, G. (2017):
Edge-to-stem variability in wet canopy evaporation from an urban tree row
Bound.-Layer Meteor. 165 (2), 295 - 310 10.1007/s10546-017-0277-7