Adjustment of leaf temperature measurements in LI-COR 6200 assimilation chamber using energy balance calculations

1990 ◽  
Vol 53 (1-2) ◽  
pp. 149-156 ◽  
Author(s):  
P. Rochette ◽  
E. Pattey ◽  
R.L. Desjardins ◽  
L.M. Dwyer
Keyword(s):  
Energy Balance ◽  
Leaf Temperature ◽  
Temperature Measurements ◽  
Assimilation Chamber

scholarly journals Parameter estimation for energy balance models with memory

2014 ◽  
Vol 470 (2169) ◽  
pp. 20140349 ◽  
Author(s):  
Lionel Roques ◽  
Mickaël D. Chekroun ◽  
Michel Cristofol ◽  
Samuel Soubeyrand ◽  
Michael Ghil
Keyword(s):  
Parameter Estimation ◽  
Energy Balance ◽  
Statistical Model ◽  
Ice Cores ◽  
Temperature Measurements ◽  
Age Dating ◽  
Observation Process ◽  
Wide Range ◽  
Energy Balance Models ◽  
With Memory

We study parameter estimation for one-dimensional energy balance models with memory (EBMMs) given localized and noisy temperature measurements. Our results apply to a wide range of nonlinear, parabolic partial differential equations with integral memory terms. First, we show that a space-dependent parameter can be determined uniquely everywhere in the PDE's domain of definition D , using only temperature information in a small subdomain E ⊂ D . This result is valid only when the data correspond to exact measurements of the temperature. We propose a method for estimating a model parameter of the EBMM using more realistic, error-contaminated temperature data derived, for example, from ice cores or marine-sediment cores. Our approach is based on a so-called mechanistic-statistical model that combines a deterministic EBMM with a statistical model of the observation process. Estimating a parameter in this setting is especially challenging, because the observation process induces a strong loss of information. Aside from the noise contained in past temperature measurements, an additional error is induced by the age-dating method, whose accuracy tends to decrease with a sample's remoteness in time. Using a Bayesian approach, we show that obtaining an accurate parameter estimate is still possible in certain cases.

Evaluation of SHAW Model in Simulating Energy Balance, Leaf Temperature, and Micrometeorological Variables within a Maize Canopy

2006 ◽  
Vol 98 (3) ◽  
pp. 722-729 ◽  
Author(s):  
Wei Xiao ◽  
Qiang Yu ◽  
Gerald N. Flerchinger ◽  
Youfei Zheng
Keyword(s):  
Energy Balance ◽  
Leaf Temperature

Automated leaf temperature monitoring of glasshouse tomato plants by using a leaf energy balance model

2012 ◽  
Vol 87 ◽  
pp. 19-31 ◽  
Author(s):  
Kristof Vermeulen ◽  
Jean-Marie Aerts ◽  
Jan Dekock ◽  
Peter Bleyaert ◽  
Daniël Berckmans ◽  
...  
Keyword(s):  
Energy Balance ◽  
Leaf Temperature ◽  
Temperature Monitoring ◽  
Energy Balance Model ◽  
Balance Model ◽  
Tomato Plants

scholarly journals Technical note: An experimental set-up to measure latent and sensible heat fluxes from (artificial) plant leaves

2017 ◽  
Vol 21 (7) ◽  
pp. 3377-3400 ◽  
Author(s):  
Stanislaus J. Schymanski ◽  
Daniel Breitenstein ◽  
Dani Or
Keyword(s):  
Energy Balance ◽  
Water Vapour ◽  
Energy Exchange ◽  
Hydrological Cycle ◽  
Leaf Temperature ◽  
Heat Fluxes ◽  
Coupled Processes ◽  
Balance Model ◽  
Sensible Heat ◽  
Set Up

Abstract. Leaf transpiration and energy exchange are coupled processes that operate at small scales yet exert a significant influence on the terrestrial hydrological cycle and climate. Surprisingly, experimental capabilities required to quantify the energy–transpiration coupling at the leaf scale are lacking, challenging our ability to test basic questions of importance for resolving large-scale processes. The present study describes an experimental set-up for the simultaneous observation of transpiration rates and all leaf energy balance components under controlled conditions, using an insulated closed loop miniature wind tunnel and artificial leaves with pre-defined and constant diffusive conductance for water vapour. A range of tests documents the above capabilities of the experimental set-up and points to potential improvements. The tests reveal a conceptual flaw in the assumption that leaf temperature can be characterized by a single value, suggesting that even for thin, planar leaves, a temperature gradient between the irradiated and shaded or transpiring and non-transpiring leaf side can lead to bias when using observed leaf temperatures and fluxes to deduce effective conductances to sensible heat or water vapour transfer. However, comparison of experimental results with an explicit leaf energy balance model revealed only minor effects on simulated leaf energy exchange rates by the neglect of cross-sectional leaf temperature gradients, lending experimental support to our current understanding of leaf gas and energy exchange processes.

The calibration of thermocouples for leaf temperature measurements in gas exchange cuvettes

Oecologia ◽  
1986 ◽  
Vol 68 (4) ◽  
pp. 611-614 ◽  
Author(s):  
Alexander Ziegler-Jöns ◽  
Dietmar Knoppik ◽  
Helmut Selinger
Keyword(s):  
Gas Exchange ◽  
Leaf Temperature ◽  
Temperature Measurements

scholarly journals Technical note: An experimental setup to measure latent and sensible heat fluxes from (artificial) plant leaves

2017 ◽  
Author(s):  
Stanislaus J. Schymanski ◽  
Daniel Breitenstein ◽  
Dani Or
Keyword(s):  
Energy Balance ◽  
Water Vapour ◽  
Energy Exchange ◽  
Hydrological Cycle ◽  
Leaf Temperature ◽  
Coupled Processes ◽  
Balance Model ◽  
Minor Effect ◽  
Experimental Setup ◽  
Sensible Heat

Abstract. Leaf transpiration and energy exchange are coupled processes that operate at small scales yet exert a significant influence on terrestrial hydrological cycle and climate. Surprisingly, experimental capabilities required for quantifying the energy-transpiration coupling at the leaf scale are lacking, challenging our ability to test basic questions of importance for resolving large scale processes. The present study describes an experimental setup for the simultaneous observation of transpiration rates and all leaf energy balance components under controlled conditions, using an insulated closed-loop miniature wind tunnel and artificial leaves with pre-defined and constant diffusive conductance for water vapour. A range of tests documents the above capabilities of the experimental setup and points to potential improvements. The tests reveal a conceptual flaw in the assumption that leaf temperature can be characterised by a single value, suggesting that even for thin, planar leaves, a temperature gradient between the irradiated and shaded or transpiring and non-transpiring leaf side can lead to bias when using observed leaf temperatures and fluxes to deduce effective conductances to sensible heat or water vapour transfer. However, comparison of experimental results with an explicit leaf energy balance model revealed only minor effect on simulated leaf energy exchange rates by the neglect of cross-sectional leaf temperature gradients, lending experimental support to our current understanding of leaf gas and energy exchange processes.

scholarly journals Studying the large-scale effect of leaf thermoregulation using an Earth system model

2020 ◽  
Author(s):  
Marvin Heidkamp ◽  
Felix Ament ◽  
Philipp de Vrese ◽  
Andreas Chlond
Keyword(s):  
Energy Balance ◽  
Air Temperature ◽  
Negative Correlation ◽  
Ambient Air ◽  
Leaf Temperature ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Ambient Air Temperature ◽  
Temperature Excess

Abstract. Plants have the ability to regulate heat and water losses. This process also known as leaf thermoregulation helps to maintain the leaf temperature within an optimal range. In a number of laboratory and field experiments, the leaf temperature has been found to deviate substantially from the ambient temperature. In the present study, we address the question of whether the negative correlation between the leaf temperature excess and the ambient air temperature, which is characteristic of leaf thermoregulation, constitutes a robust feature at larger scales, across a broad range of atmospheric conditions and canopy characteristics. To this end, we developed a new dual-source canopy layer energy balance scheme (CEBa) and implemented it into JSBACH, the land component of the Max Planck Institute for Meteorology's Earth system model (MPI-ESM). The approach calculates the temperature and humidity in the ambient canopy air space, the temperature of the ground surface, and the temperature of the leaf as well as the energy and moisture fluxes between the different compartments. Here leaf thermoregulation is investigated using different modeling approaches, namely a zero-dimensional instantaneous solution of the energy balance as well as offline FLUXNET site experiments and coupled global simulations. With the help of the simulations at the site-level, we can show that the model is capable of reproducing the effect of leaf thermoregulation even though the simulated signal at the canopy scale is less pronounced than indicated by measurements at the leaf scale. However, on a global scale and over longer-timescales, this negative correlation is only simulated in idealized setups that neglect limitations on the plant available water, and even then, the signal is less pronounced than indicated by the short-term observations of individual leaves. When accounting for moisture limitations, we predominantly find positive correlations between leaf temperature excess and the ambient air temperature.

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