Theoretical Analysis and Experimental Verification of a Remotely Measurable Plant Transpiration Transfer Coefficient

Japan Agricultural Research Quarterly
ISSN 00213551
NII recode ID (NCID) AA0068709X
Full text
37-03-01.pdf403.05 KB

The objectives of this study are to propose a remotely measurable plant transpiration transfer coefficient (hat) and to verify its characteristics under various environmental conditions. The hat is defined as (Tc - Ta) / (Tp - Ta), where Tc, Tp, and Ta are the temperatures of the canopy, a non-transpiring canopy, and air, respectively. Theoretically, hat ≦ 1, and determines transpiration from its minimum value (zero) to its maximum value (potential transpiration rate). Five experiments were conducted between 1994 and 1999 to verify the characteristics of hat, using 3 plant species (sorghum, tomato and melon). Theoretical validation showed that the proposed model agreed well with conventional models. Experimental results showed that the hat value was approximately equal to the value of the ratio of sensible heat fluxes (H/Hp), and the slope of the regression line between them was close to 1, the intercept was close to 0, and the regression coefficient was r2 = 0.70. In addition, hat was not only an indicator of the water status in the plant root zone, but also an indicator of atmospheric variables. Under waterstressed conditions, hat was affected mainly by the water status in the plant root zone. Therefore, hat can be used as an indicator of plant water stress. The main advantages are that hat can be easily measured and applied under various conditions. Due to its simplicity, hat is a suitable coefficient for analyzing the process of transpiration and for determining the transpiration rate.

Date of issued
Creator QIU Guo Yu SASE Sadanori SHI Peijun DING Guodong
Subject

remote sensing

sensible heat flux

surface temperature

Publisher Japan International Research Center for Agricultural Sciences
Available Online
NII resource type vocabulary Journal Article
Volume 37
Issue 3
spage 141
epage 149
DOI 10.6090/jarq.37.141
Rights Japan International Research Center for Agricultural Sciences
Language eng

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