Performance of site-specific parameterizations of longwave radiation

In this work 10 algorithms for estimating downwelling longwave atmospheric radiation (<i>L</i><sub>↓</sub>) and 1 for upwelling longwave radiation (<i>L</i><sub><mo>↑</mo></sub>) are integrated into the JGrass-NewAge modelling system. The...

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Main Authors: G. Formetta, M. Bancheri, O. David, R. Rigon
Format: Article
Language:English
Published: Copernicus Publications 2016-11-01
Series:Hydrology and Earth System Sciences
Online Access:https://www.hydrol-earth-syst-sci.net/20/4641/2016/hess-20-4641-2016.pdf
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author G. Formetta
M. Bancheri
O. David
R. Rigon
author_facet G. Formetta
M. Bancheri
O. David
R. Rigon
author_sort G. Formetta
collection DOAJ
description In this work 10 algorithms for estimating downwelling longwave atmospheric radiation (<i>L</i><sub>↓</sub>) and 1 for upwelling longwave radiation (<i>L</i><sub><mo>↑</mo></sub>) are integrated into the JGrass-NewAge modelling system. The algorithms are tested against energy flux measurements available for 24 sites in North America to assess their reliability. These new JGrass-NewAge model components are used (i) to evaluate the performances of simplified models (SMs) of <i>L</i><sub>↓</sub>, as presented in literature formulations, and (ii) to determine by automatic calibration the site-specific parameter sets for <i>L</i><sub>↓</sub> in SMs. For locations where calibration is not possible because of a lack of measured data, we perform a multiple regression using on-site variables, i.e. mean annual air temperature, relative humidity, precipitation, and altitude. The regressions are verified through a leave-one-out cross validation, which also gathers information about the possible errors of estimation. Most of the SMs, when executed with parameters derived from the multiple regressions, give enhanced performances compared to the corresponding literature formulation. A sensitivity analysis is carried out for each SM to understand how small variations of a given parameter influence SM performance. Regarding the <i>L</i><sub>↓</sub> simulations, the Brunt (1932) and Idso (1981) SMs, in their literature formulations, provide the best performances in many of the sites. The site-specific parameter calibration improves SM performances compared to their literature formulations. Specifically, the root mean square error (RMSE) is almost halved and the Kling&ndash;Gupta efficiency is improved at all sites. Also in this case, Brunt (1932) and Idso (1981) SMs provided the best performances. <br><br> The <i>L</i><sub><mo>↑</mo></sub> SM is tested by using three different temperatures (surface soil temperature, air temperature at 2 m elevation, and soil temperature at 4 cm depth) and model performances are then assessed. Results show that the best performances are achieved using the surface soil temperature and the air temperature.
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spelling doaj.art-a00a6d54c02d47f79f9a72c022dca1992022-12-22T01:10:16ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382016-11-01204641465410.5194/hess-20-4641-2016Performance of site-specific parameterizations of longwave radiationG. Formetta0M. Bancheri1O. David2R. Rigon3Centre for Ecology & Hydrology, Crowmarsh Gifford, Wallingford, UKDipartimento di Ingegneria Civile Ambientale e Meccanica, Universita' degli Studi di Trento, Trent, ItalyDept. of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, USADipartimento di Ingegneria Civile Ambientale e Meccanica, Universita' degli Studi di Trento, Trent, ItalyIn this work 10 algorithms for estimating downwelling longwave atmospheric radiation (<i>L</i><sub>↓</sub>) and 1 for upwelling longwave radiation (<i>L</i><sub><mo>↑</mo></sub>) are integrated into the JGrass-NewAge modelling system. The algorithms are tested against energy flux measurements available for 24 sites in North America to assess their reliability. These new JGrass-NewAge model components are used (i) to evaluate the performances of simplified models (SMs) of <i>L</i><sub>↓</sub>, as presented in literature formulations, and (ii) to determine by automatic calibration the site-specific parameter sets for <i>L</i><sub>↓</sub> in SMs. For locations where calibration is not possible because of a lack of measured data, we perform a multiple regression using on-site variables, i.e. mean annual air temperature, relative humidity, precipitation, and altitude. The regressions are verified through a leave-one-out cross validation, which also gathers information about the possible errors of estimation. Most of the SMs, when executed with parameters derived from the multiple regressions, give enhanced performances compared to the corresponding literature formulation. A sensitivity analysis is carried out for each SM to understand how small variations of a given parameter influence SM performance. Regarding the <i>L</i><sub>↓</sub> simulations, the Brunt (1932) and Idso (1981) SMs, in their literature formulations, provide the best performances in many of the sites. The site-specific parameter calibration improves SM performances compared to their literature formulations. Specifically, the root mean square error (RMSE) is almost halved and the Kling&ndash;Gupta efficiency is improved at all sites. Also in this case, Brunt (1932) and Idso (1981) SMs provided the best performances. <br><br> The <i>L</i><sub><mo>↑</mo></sub> SM is tested by using three different temperatures (surface soil temperature, air temperature at 2 m elevation, and soil temperature at 4 cm depth) and model performances are then assessed. Results show that the best performances are achieved using the surface soil temperature and the air temperature.https://www.hydrol-earth-syst-sci.net/20/4641/2016/hess-20-4641-2016.pdf
spellingShingle G. Formetta
M. Bancheri
O. David
R. Rigon
Performance of site-specific parameterizations of longwave radiation
Hydrology and Earth System Sciences
title Performance of site-specific parameterizations of longwave radiation
title_full Performance of site-specific parameterizations of longwave radiation
title_fullStr Performance of site-specific parameterizations of longwave radiation
title_full_unstemmed Performance of site-specific parameterizations of longwave radiation
title_short Performance of site-specific parameterizations of longwave radiation
title_sort performance of site specific parameterizations of longwave radiation
url https://www.hydrol-earth-syst-sci.net/20/4641/2016/hess-20-4641-2016.pdf
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