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Evaluation of Atmometers within Urban Home Lawn Microclimates
Author(s) -
Peterson K. W.,
Bremer D. J.,
Fry J. D.
Publication year - 2015
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2015.02.0073
Subject(s) - microclimate , lawn , evapotranspiration , wind speed , vapour pressure deficit , environmental science , relative humidity , atmospheric sciences , humidity , weather station , hydrology (agriculture) , meteorology , geography , ecology , biology , botany , physics , photosynthesis , geotechnical engineering , transpiration , engineering
An atmometer is an inexpensive tool used to measure evapotranspiration (ET) in situ. The effects of microclimates associated with urban lawns on the performance of atmometers are not well documented. Our objective was to compare ET estimates between atmometers and the FAO‐56 Penman–Monteith equation (PM ET , FAO56‐PM), including within urban lawns. The study was conducted in six lawns in 2010 and one in 2011 in Manhattan, KS, and four lawns in Wichita, KS, in 2011. A weather station and atmometer were positioned in an open sward of turfgrass near each city during each measurement period in Manhattan and Wichita. A commercially available Bellani plate atmometer, using a green canvas cover for grass reference ET (AT ET ), was placed next to a portable weather station in two contrasting microclimates within each lawn. Weather stations recorded temperature, net radiation, relative humidity, and wind speed data used to calculate PM ET . Open sward AT ET (4.73 mm d –1 ) averaged 14% less than PM ET (5.48 mm d –1 ). Within microclimates, AT ET (3.94mm d –1 ) averaged 22% greater than PM ET (3.23 mm d –1 ). The differences in ET estimates between measurement techniques varied with wind speed, net radiation, and vapor pressure deficit. The best relationships between AT ET and PM ET , at the open sward and within microclimates, occurred when wind speed was >1 m s –1 , vapor pressure deficit was >2 kPa, and net radiation was >5 MJ m –2 d –1 . Overall, atmometers can provide reliable estimates of PM ET and could benefit practitioners with irrigation management within microclimates.