Modeling atmospheric longwave radiation at the surface during overcast skies: The role of cloud base height
dc.contributor.author
dc.date.accessioned
2019-04-24T07:10:29Z
dc.date.available
2019-04-24T07:10:29Z
dc.date.issued
2015-01-16
dc.identifier.issn
0148-0227
dc.identifier.uri
dc.description.abstract
The behavior of the atmospheric downward longwave radiation at the surface under overcast conditions is studied. For optically thick clouds, longwave radiation depends greatly on the cloud base height (CBH), besides temperature and water vapor profiles. The CBH determines the cloud emission temperature and the air layers contributing to the longwave radiation that reaches the surface. Overcast situations observed at Girona (NE Iberian Peninsula) were studied by using a radiative transfer model. The data set includes different seasons, and a large range of CBH (0–5000 m). The atmosphere profiles were taken from the European Center for Medium-Range Weather Forecast analysis. The CBH was determined from ceilometer measurements and also estimated by using a suitable method applied to the vertical profile of relative humidity. The agreement between calculations and pyrgeometer measurements is remarkably good (1.6 ± 6.2 W m−2) if the observed CBH is used; poorer results are obtained with the estimated CBH (4.3 ± 7.0 W m−2). These results are better than those obtained from a simple parameterization based upon ground-level data (1.1 ± 11.6 W m−2), which can be corrected by adding a term that takes into account the CBH (−0.1 ± 7.3 W m−2). At this site, the cloud radiative effect (CRE) at the surface lies in the range 50–80 W m−2, has a clear seasonal behavior (higher CRE in winter), and depends upon the CBH. For the cold and the warm seasons, CRE decreases with CBH at a rate of −5 and −4 W m−2/km, respectively. Results obtained for other climates (subarctic and tropical) are also presented
dc.description.sponsorship
This study has been partly financed by the Spanish Ministry of Science and Innovation (currently Ministry of Economy and Competitiveness) projects NUCLIEREX (CGL 2007-62664/CLI) and NUCLIERSOL (CGL 2010-18546)
dc.format.mimetype
application/pdf
dc.language.iso
eng
dc.publisher
American Geophysical Union (AGU)
dc.relation
info:eu-repo/grantAgreement/MEC//CGL2007-62664/ES/NUBES Y CAMBIO CLIMATICO: VARIABILIDAD Y TENDENCIAS DE LA NUBOSIDAD E INSOLACION EN LA PENINSULA IBERICA, Y MEDIDA Y MODELIZACION DE LOS EFECTOS RADIATIVOS DE LAS NUBES EN SUPERFICIE/
info:eu-repo/grantAgreement/MICINN//CGL2010-18546/ES/LAS NUBES Y SUS EFECTOS SOBRE LA RADIACION: DEL ESTUDIO DE SITUACIONES A ESCALA LOCAL AL ANALISIS CLIMATOLOGICO DE ALCANCE GLOBAL. INTERACCIONES CON EL AEROSOL ATMOSFERICO/
dc.relation.isformatof
Reproducció digital del document publicat a: https://doi.org/10.1002/2014JD022310
dc.relation.ispartof
© Journal of Geophysical Research, 2015, vol. 120, núm. 1, p. 199-214
dc.relation.ispartofseries
Articles publicats (D-F)
dc.rights
Tots els drets reservats
dc.subject
dc.title
Modeling atmospheric longwave radiation at the surface during overcast skies: The role of cloud base height
dc.type
info:eu-repo/semantics/article
dc.rights.accessRights
info:eu-repo/semantics/openAccess
dc.type.version
info:eu-repo/semantics/publishedVersion
dc.identifier.doi
dc.identifier.idgrec
022952
dc.contributor.funder
dc.type.peerreviewed
peer-reviewed
dc.relation.ProjectAcronym
dc.identifier.eissn
2156-2202