Advanced Search
Syntax
Search...
Volcani treasures
About
Terms of use
Manage
Community:
אסיף מאגר המחקר החקלאי
Powered by ClearMash Solutions Ltd -
On the variability of the Priestley-Taylor coefficient over water bodies
Year:
2016
Source of publication :
Water Resources Research
Authors :
Assouline, Shmuel
;
.
Cohen, Shabtai
;
.
Tanny, Josef
;
.
Volume :
52
Co-Authors:
Assouline, S., Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel
Li, D., Program of Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ, United States
Tyler, S., Department of Geological Sciences and Engineering, University of Nevada, Reno, Nevada, United States
Tanny, J., Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel
Cohen, S., Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel
Bou-Zeid, E., Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, United States
Parlange, M., Department of Civil Engineering, University of British Columbia, Vancouver, BC, Canada
Katul, G.G., Nicholas School of the Environment, Duke University, Durham, NC, United States
Facilitators :
From page:
150
To page:
163
(
Total pages:
14
)
Abstract:
Deviations in the Priestley-Taylor (PT) coefficient αPT from its accepted 1.26 value are analyzed over large lakes, reservoirs, and wetlands where stomatal or soil controls are minimal or absent. The data sets feature wide variations in water body sizes and climatic conditions. Neither surface temperature nor sensible heat flux variations alone, which proved successful in characterizing αPT variations over some crops, explain measured deviations in αPT over water. It is shown that the relative transport efficiency of turbulent heat and water vapor is key to explaining variations in αPT over water surfaces, thereby offering a new perspective over the concept of minimal advection or entrainment introduced by PT. Methods that allow the determination of αPT based on low-frequency sampling (i.e., 0.1 Hz) are then developed and tested, which are usable with standard meteorological sensors that filter some but not all turbulent fluctuations. Using approximations to the Gram determinant inequality, the relative transport efficiency is derived as a function of the correlation coefficient between temperature and water vapor concentration fluctuations (RTq). The proposed approach reasonably explains the measured deviations from the conventional αPT = 1.26 value even when RTq is determined from air temperature and water vapor concentration time series that are Gaussian-filtered and subsampled to a cutoff frequency of 0.1 Hz. Because over water bodies, RTq deviations from unity are often associated with advection and/or entrainment, linkages between αPT and RTq offer both a diagnostic approach to assess their significance and a prognostic approach to correct the 1.26 value when using routine meteorological measurements of temperature and humidity. © 2015. American Geophysical Union. All Rights Reserved.
Note:
Related Files :
correlation coefficient
Efficiency
Priestley-Taylor
Reservoirs (water)
Temperature and humidities
water surface
Water vapor concentration
Show More
Related Content
More details
DOI :
10.1002/2015WR017504
Article number:
Affiliations:
Database:
Scopus
Publication Type:
article
;
.
Language:
English
Editors' remarks:
ID:
28979
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:43
Scientific Publication
On the variability of the Priestley-Taylor coefficient over water bodies
52
Assouline, S., Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel
Li, D., Program of Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ, United States
Tyler, S., Department of Geological Sciences and Engineering, University of Nevada, Reno, Nevada, United States
Tanny, J., Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel
Cohen, S., Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel
Bou-Zeid, E., Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, United States
Parlange, M., Department of Civil Engineering, University of British Columbia, Vancouver, BC, Canada
Katul, G.G., Nicholas School of the Environment, Duke University, Durham, NC, United States
On the variability of the Priestley-Taylor coefficient over water bodies
Deviations in the Priestley-Taylor (PT) coefficient αPT from its accepted 1.26 value are analyzed over large lakes, reservoirs, and wetlands where stomatal or soil controls are minimal or absent. The data sets feature wide variations in water body sizes and climatic conditions. Neither surface temperature nor sensible heat flux variations alone, which proved successful in characterizing αPT variations over some crops, explain measured deviations in αPT over water. It is shown that the relative transport efficiency of turbulent heat and water vapor is key to explaining variations in αPT over water surfaces, thereby offering a new perspective over the concept of minimal advection or entrainment introduced by PT. Methods that allow the determination of αPT based on low-frequency sampling (i.e., 0.1 Hz) are then developed and tested, which are usable with standard meteorological sensors that filter some but not all turbulent fluctuations. Using approximations to the Gram determinant inequality, the relative transport efficiency is derived as a function of the correlation coefficient between temperature and water vapor concentration fluctuations (RTq). The proposed approach reasonably explains the measured deviations from the conventional αPT = 1.26 value even when RTq is determined from air temperature and water vapor concentration time series that are Gaussian-filtered and subsampled to a cutoff frequency of 0.1 Hz. Because over water bodies, RTq deviations from unity are often associated with advection and/or entrainment, linkages between αPT and RTq offer both a diagnostic approach to assess their significance and a prognostic approach to correct the 1.26 value when using routine meteorological measurements of temperature and humidity. © 2015. American Geophysical Union. All Rights Reserved.
Scientific Publication
נגישות
menu      
You may also be interested in