Biophysical homoeostasis of leaf temperature: A neglected process for vegetation and land‐surface modelling

Autor: Ning Dong, Sandy P. Harrison, Iain Colin Prentice, Yun Zhang, Q. H. Song
Přispěvatelé: AXA Research Fund
Rok vydání: 2017
Předmět:
0106 biological sciences
Canopy
ENVIRONMENT SIMULATOR JULES
Stomatal conductance
010504 meteorology & atmospheric sciences
boundary-layer conductance
THERMOREGULATION
STOMATAL CONDUCTANCE
Energy balance
Environmental Sciences & Ecology
crossover temperature
land-surface model
01 natural sciences
transpiration
ENERGY
Diurnal cycle
Evapotranspiration
CONVERGENCE
PLANTS
Ecosystem
Ecology
Evolution
Behavior and Systematics
0105 earth and related environmental sciences
Transpiration
Global and Planetary Change
Science & Technology
0602 Ecology
Ecology
Vegetation
leaf temperature
15. Life on land
energy balance
EVAPORATION
Geography
Physical
0501 Ecological Applications
SIZE
Physical Geography
CONVECTIVE BOUNDARY-LAYER
13. Climate action
Physical Sciences
Environmental science
Life Sciences & Biomedicine
010606 plant biology & botany
Zdroj: Global Ecology and Biogeography. 26:998-1007
ISSN: 1466-8238
1466-822X
DOI: 10.1111/geb.12614
Popis: Aim\ud \ud Leaf and air temperatures are seldom equal, but many vegetation models assume that they are. Land-surface models calculate canopy temperatures, but how well they do so is unknown. We encourage consideration of the leaf- and canopy-to-air temperature difference (ΔΤ) as a benchmark for land-surface modelling and an important feature of plant and ecosystem function.\ud Location\ud \ud Tropical SW China.\ud Time period\ud \ud 2013.\ud Major Taxa studies\ud \ud Tropical trees.\ud Methods\ud \ud We illustrate diurnal cycles of leaf- and canopy-to-air temperature difference (ΔΤ) with field measurements in a tropical dry woodland and with continuous monitoring data in a tropical seasonal forest. The Priestley–Taylor (PT) and Penman–Monteith (PM) approaches to evapotranspiration are used to provide insights into the interpretation and prediction of ΔT. Field measurements are also compared with land-surface model results obtained with the Joint U.K. Land Environment Simulator (JULES) set up for the conditions of the site.\ud Results\ud \ud The ΔT followed a consistent diurnal cycle, with negative values at night (attributable to negative net radiation) becoming positive in the morning, reaching a plateau and becoming negative again when air temperature exceeded a ‘crossover’ in the 24–29 °C range. Daily time courses of ΔT could be approximated by either the PT or the PM model, but JULES tended to underestimate the magnitude of negative ΔT.\ud Main conclusions\ud \ud Leaves with adequate water supply are partly buffered against air-temperature variations, through a passive biophysical mechanism. This is likely to be important for optimal leaf function, and land-surface and vegetation models should aim to reproduce it.
Databáze: OpenAIRE
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