Summary
Leaf wetness duration (LWD) is related to plant disease occurrence and is therefore a key parameter in agrometeorology. As LWD is seldom measured at standard weather stations, it must be estimated in order to ensure the effectiveness of warning systems and the scheduling of chemical disease control. Among the models used to estimate LWD, those that use physical principles of dew formation and dew and/or rain evaporation have shown good portability and sufficiently accurate results for operational use. However, the requirement of net radiation (Rn) is a disadvantage foroperational physical models, since this variable is usually not measured over crops or even at standard weather stations. With the objective of proposing a solution for this problem, this study has evaluated the ability of four models to estimate hourly Rn and their impact on LWD estimates using a Penman-Monteith approach. A field experiment was carried out in Elora, Ontario, Canada, with measurements of LWD, Rn and other meteorological variables over mowed turfgrass for a 58 day period during the growing season of 2003. Four models for estimating hourly Rn based on different combinations of incoming solar radiation (Rg), airtemperature (T), relative humidity (RH), cloud cover (CC) and cloud height (CH), were evaluated. Measured and estimated hourly Rn values were applied in a Penman-Monteith model to estimate LWD. Correlating measured and estimated Rn, we observed that all models performed well in terms of estimating hourly Rn. However, when cloud data were used the models overestimated positive Rn and underestimated negative Rn. When only Rg and T were used to estimate hourly Rn, the model underestimated positive Rn and no tendency was observed for negative Rn. The best performance was obtained with Model I, which presented, in general, the smallest mean absolute error (MAE) and the highest C-index. When measured LWD was compared to the Penman-Monteith LWD, calculated with measured and estimated Rn, few differences were observed. Both precision and accuracy were high, with the slopes of the relationships ranging from 0.96 to 1.02 and R2 from 0.85 to 0.92, resulting in C-indices between 0.87 and 0.93. The LWD mean absolute errors associated with Rn estimates were between 1.0 and 1.5 h, which is sufficient for use in plant disease management schemes.
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References
RG Allen LS Pereira D Raes M Smith (1998) Crop evapotranspiration – guidelines for computing crop water requirements FAO Roma 331
AP Camargo PC Sentelhas (1997) ArticleTitlePerformance evaluation of potencial evapotranspiration estimating methods in the State of São Paulo, Brazil Rev Bras Agrometeorol 5 89–97
GS Campbell JM Norman (1998) Introduction to environmental biophysics Springer New York 286
DM Gates (1980) Biophysical ecology Springer New York 611
TJ Gillespie A Barr (1984) ArticleTitleAdaptation of a dew estimation scheme to a new crop and site Agric Forest Meteorol 31 289–295 Occurrence Handle10.1016/0168-1923(84)90042-X
ML Gleason SE Taylor TM Loughin KJ Koehler (1994) ArticleTitleDevelopment and validation of an empirical model to estimate the duration of dew periods Plant Dis 78 1011–1016 Occurrence Handle10.1094/PD-78-1011
L Huber TJ Gillespie (1992) ArticleTitleModeling leaf wetness in relation to plant disease epidemiology Annu Rev Phytopathol 30 553–577 Occurrence Handle10.1146/annurev.py.30.090192.003005
MG Iziomon H Mayer A Matzarakis (2000) ArticleTitleEmpirical models for estimating net radiation flux: a case study for three mid-latitude sites with orographic variability Astrophys Space Sci 273 313–330 Occurrence Handle10.1023/A:1002787922933
OO Jegede (1997) ArticleTitleEstimating net radiation from air temperature for diffusion modeling applications in a tropical area Bound-Layer Meteor 85 161–173 Occurrence Handle10.1023/A:1000462626302
N Kalthoff M Fiebig-Wittmaack C MeiBner M Kohler M Uriarte I Bischoff-GauB E Gonzales (2006) ArticleTitleThe energy balance, evapotranspiration and nocturnal dew deposition of an arid valley in the Andes J Arid Environ 65 420–443 Occurrence Handle10.1016/j.jaridenv.2005.08.013
WH Lou J Goudriaan (1999) ArticleTitleEffects of altering water temperature on leaf wetness in paddy rice crops Agric Forest Meteorol 97 33–42 Occurrence Handle10.1016/S0168-1923(99)00046-5
WH Lou J Goudriaan (2000) ArticleTitleDew formation on rice under varying durations of nocturnal radiative loss Agric Forest Meteorol 104 303–313 Occurrence Handle10.1016/S0168-1923(00)00168-4
AC Madeira KS Kim SE Taylor ML Gleason (2002) ArticleTitleA simple cloud-based energy balance model to estimate dew Agric Forest Meteorol 111 55–63 Occurrence Handle10.1016/S0168-1923(02)00004-7
JL Monteith MH Unsworth (1990) Principles of environmental physics Edward Arnold New York 291
MJ Pedro (1980) Relation of leaf surface wetness duration to meteorological parameters. PhD dissertation University of Guelph Guelph, ON, Canada
MJ Pedro TJ Gillespie (1982a) ArticleTitleEstimating dew duration. I. Utilizing micrometeorological data Agric Meteorol 25 283–296 Occurrence Handle10.1016/0002-1571(81)90081-9
MJ Pedro TJ Gillespie (1982b) ArticleTitleEstimating dew duration. II. Utilizing standard weather station data Agric Meteorol 25 297–310 Occurrence Handle10.1016/0002-1571(81)90082-0
AB Pereira PC Sentelhas NA Villa Nova (1998) ArticleTitleEstimate of the radiant energy budget as a function of climatic elements Rev Bras Agrometeorol 6 201–206
AR Pereira PC Sentelhas MV Folegatti NA Villa Nova SR Maggiotto FA Carvalho (2002) ArticleTitleSubstantiation of daily FAO-56 reference evapotranspiration with data from automatic and conventional weather stations Rev Bras Agrometeorol 10 251–257
PS Rao TJ Gillespie AW Schaafsma (1998) ArticleTitleEstimating wetness duration on maize ears from meteorological observations Can J Soil Sci 78 149–154
NJ Rosenberg BL Blad SB Verma (1983) Microclimate – the biological environment John Wiley & Sons New York 495
PC Sentelhas TJ Gillespie JEBA Monteiro T Rowlandson (2004a) ArticleTitleEstimating leaf wetness duration on a cotton crop from meteorological data Rev Bras Agrometeorol 12 235–245
PC Sentelhas TJ Gillespie ML Gleason JEBA Monteiro ST Helland (2004b) ArticleTitleOperational exposure of leaf wetness sensors Agric Forest Meteorol 126 59–72 Occurrence Handle10.1016/j.agrformet.2004.05.009
PC Sentelhas TJ Gillespie ML Gleason JEBA Monteiro JRM Pezzopane MJ Pedro SuffixJr (2006) ArticleTitleEvaluation of a Penman-Monteith approach to provide “reference” and crop canopy leaf wetness duration estimates Agric Forest Meteorol 141 105–117 Occurrence Handle10.1016/j.agrformet.2006.09.010
CJ Willmott SG Ackleson RE Davis JJ Feddema KM Klink DR Legates J O’donnel CM Rowe (1985) ArticleTitleStatistics for the evaluation and comparison of models J Geophys Res 90 8995–9005 Occurrence Handle10.1029/JC090iC05p08995
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Authors’ addresses: Paulo C. Sentelhas, Agrometeorology Group, Department of Exact Sciences, ESALQ, University of São Paulo, P.O. Box 9, 13418-900, Piracicaba, SP, Brazil; Terry J. Gillespie, Agrometeorology Group, Department of Land Resource Science, Ontario Agricultural College, University of Guelph, NIG-2W1, Guelph, ON, Canada.
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Sentelhas, P., Gillespie, T. Estimating hourly net radiation for leaf wetness duration using the Penman-Monteith equation. Theor Appl Climatol 91, 205–215 (2008). https://doi.org/10.1007/s00704-006-0290-0
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DOI: https://doi.org/10.1007/s00704-006-0290-0