Topography-adjusted solar radiation indices and their importance in hydrology [Indices de rayonnement solaire ajustés à la topographie et leur importance en l'hydrologie]

Mamassis, N; Efstratiadis, A; Apostolidou, I-G

dc.contributor.author	Mamassis, N	en
dc.contributor.author	Efstratiadis, A	en
dc.contributor.author	Apostolidou, I-G	en
dc.date.accessioned	2014-03-01T02:14:51Z
dc.date.available	2014-03-01T02:14:51Z
dc.date.issued	2012	en
dc.identifier.issn	02626667	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/30149
dc.relation.uri	http://www.scopus.com/inward/record.url?eid=2-s2.0-84861581593&partnerID=40&md5=1f5adb7ef0ee2b1d0cb5a6f99c234ce8	en
dc.subject	Angström formula	en
dc.subject	Aspect	en
dc.subject	Direct and diffuse radiation	en
dc.subject	Geographical information systems	en
dc.subject	Shadow	en
dc.subject	Slope	en
dc.subject.other	Aspect	en
dc.subject.other	Diffuse radiation	en
dc.subject.other	Geographical Information System	en
dc.subject.other	Shadow	en
dc.subject.other	Slope	en
dc.subject.other	Atmospheric radiation	en
dc.subject.other	Estimation	en
dc.subject.other	Geographic information systems	en
dc.subject.other	Meteorology	en
dc.subject.other	Solar radiation	en
dc.subject.other	Sun	en
dc.subject.other	Radiation effects	en
dc.subject.other	aspect	en
dc.subject.other	GIS	en
dc.subject.other	hydrometeorology	en
dc.subject.other	slope	en
dc.subject.other	solar radiation	en
dc.subject.other	spatiotemporal analysis	en
dc.subject.other	topography	en
dc.subject.other	Greece	en
dc.title	Topography-adjusted solar radiation indices and their importance in hydrology [Indices de rayonnement solaire ajustés à la topographie et leur importance en l'hydrologie]	en
heal.type	journalArticle	en
heal.publicationDate	2012	en
heal.abstract	Solar radiation, direct and diffuse, is affected by surface characteristics, such as slope, aspect, altitude and shading. The paper examines the effects of topography on radiation, at multiple spatiotemporal scales, using suitable geometric methods for the direct and diffuse components. Two indices are introduced for comparing the direct radiation received by areas at the same and different latitudes. To investigate the profile of direct radiation across the whole of Greece, these are evaluated from an hourly to annual basis, via GIS techniques. Moreover, different approaches are examined for estimating the actual global radiation at operational spatial scales (subbasin and terrain), according to the available meteorological data. The study indicates that the errors of typical hydrometeorological modelling formulas, which ignore the topographic effects and the seasonal allocation of direct and diffuse radiation, depend on the spatial scale and are non-uniformly distributed in time. In all cases, the estimations are improved by applying the proposed adjustment approaches. In particular, the adjustment of the measured global radiation ensures up to 10% increase of efficiency, while the modified Angström formula achieves slight (i.e. 2-4%) increase of efficiency and notable reduction of bias. © 2012 IAHS Press.	en
heal.journalName	Hydrological Sciences Journal	en
dc.identifier.volume	57	en
dc.identifier.issue	4	en
dc.identifier.spage	756	en
dc.identifier.epage	775	en