eprintid: 10116897 rev_number: 14 eprint_status: archive userid: 608 dir: disk0/10/11/68/97 datestamp: 2020-12-11 12:19:58 lastmod: 2021-10-09 22:54:13 status_changed: 2020-12-11 12:19:58 type: article metadata_visibility: show creators_name: Binks, O creators_name: Finnigan, J creators_name: Coughlin, I creators_name: Disney, M creators_name: Calders, K creators_name: Burt, A creators_name: Vicari, MB creators_name: da Costa, AL creators_name: Mencuccini, M creators_name: Meir, P title: Canopy wetness in the Eastern Amazon ispublished: inpress divisions: UCL divisions: B03 divisions: C03 divisions: F26 keywords: leaf wetness, foliar water uptake, Amazon, forest micrometeorology, dew note: Copyright © 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). abstract: Canopy wetness is a common condition that influences photosynthesis, the leaching or uptake of solutes, the water status and energy balance of canopies, and the interpretation of eddy covariance and remote sensing data. While often treated as a binary variable, ‘wet’ or ‘dry’, forest canopies are often partially wet, requiring the use of a continuous description of wetness. Minor precipitation events such as dew, that wet a fraction of the canopy, have been found to contribute to dry season foliar water uptake in the Eastern Amazon, and are fundamentally important to the canopy energy balance. However, few studies have reported the spatial and temporal distribution of canopy wetness, or the relative contribution of dew to leaf wetness, for forest ecosystems. In this study, we use two canopy profiles of leaf wetness sensors, coupled with meteorological data, to address fundamental questions about spatial and temporal variation of leaf wetness in an Eastern Amazonian rainforest. We also investigate how well meteorological tower data can predict canopy wetness using two models, one empirical and one that is physically-based. The results show that the canopy is 100% dry only for 34% of the time, otherwise being between 5% and 100% wet. Dew accounts for 20% or 43% of total annual leaf wetness, and 36% or 50% of canopy wetness in dry season, excluding or including dew events that co-occur with rain, respectively. Wetness duration was higher at the top than bottom of the canopy, mainly because of rain events, whilst dew formation was strongly dependent on the local canopy structure and varied horizontally through the canopy. The best empirical model accounted for 55% of the variance in canopy wetness, while the physical model accounted for 48% of the variance. We discuss future modelling improvements of the physical model to increase its predictive capacity. date: 2020-11-24 date_type: published official_url: https://doi.org/10.1016/j.agrformet.2020.108250 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1833898 doi: 10.1016/j.agrformet.2020.108250 lyricists_name: Burt, Andrew lyricists_name: Disney, Mathias lyricists_id: ABURT75 lyricists_id: MIDIS56 actors_name: Flynn, Bernadette actors_id: BFFLY94 actors_role: owner full_text_status: public publication: Agricultural and Forest Meteorology article_number: 108250 citation: Binks, O; Finnigan, J; Coughlin, I; Disney, M; Calders, K; Burt, A; Vicari, MB; ... Meir, P; + view all <#> Binks, O; Finnigan, J; Coughlin, I; Disney, M; Calders, K; Burt, A; Vicari, MB; da Costa, AL; Mencuccini, M; Meir, P; - view fewer <#> (2020) Canopy wetness in the Eastern Amazon. Agricultural and Forest Meteorology , Article 108250. 10.1016/j.agrformet.2020.108250 <https://doi.org/10.1016/j.agrformet.2020.108250>. (In press). Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10116897/1/1-s2.0-S016819232030352X-main.pdf