ORBi: Troupin Charles - Generation of analysis and consistent error ﬁelds using the Data Interpolating Variational Analysis (Diva)

Reference : Generation of analysis and consistent error ﬁelds using the Data Interpolating Variation...


	Document type :	Scientific journals : Article
	Discipline(s) :	Physical, chemical, mathematical & earth Sciences : Earth sciences & physical geography
	To cite this reference:	http://hdl.handle.net/2268/125731

Title :	Generation of analysis and consistent error ﬁelds using the Data Interpolating Variational Analysis (Diva)
Language :	English
Alternative title :	[fr] Generation de champs d'analyse et d'erreur cohérents à l'aide de l'Interpolation de Données par Analyse Variationelle (Diva)
Author, co-author :	Troupin, Charles [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > GeoHydrodynamics and Environment Research (GHER) >]
	Barth, Alexander [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > GeoHydrodynamics and Environment Research (GHER) >]
	Sirjacobs, Damien [Université de Liège - ULg > Département des sciences de la vie > Phylogénomique des eucaryotes >]
	Ouberdous, Mohamed [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > GeoHydrodynamics and Environment Research (GHER) >]
	Brankart, Jean-Michel [> >]
	Brasseur, Pierre [> >]
	Rixen, Michel [> >]
	Alvera Azcarate, Aïda [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > GeoHydrodynamics and Environment Research (GHER) >]
	Belounis, Mahdia [> >]
	Capet, Arthur [Université de Liège - ULg > Département de Biologie, Ecologie et Evolution > Océanologie >]
	Lenartz, Fabian [> >]
	Toussaint, Marie-Eve [> >]
	Beckers, Jean-Marie [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > GeoHydrodynamics and Environment Research (GHER) >]
Publication date :	Aug-2012
Journal title :	Ocean Modelling
Publisher :	Elsevier Science
Volume :	52-53
Pages :	90-101
Audience :	International
ISSN :	1463-5003
City :	Oxford
Country :	United Kingdom
Keywords :	[en] Diva ; Climatology ; Seadatanet ; Interpolation ; Salinity ; Mediterranean Sea
Abstract :	[en] The Data Interpolating Variational Analysis (Diva) is a method designed to interpolate irregularly-spaced, noisy data onto any desired location, in most cases on regular grids. It is the combination of a particular methodology, based on the minimisation of a cost function, and a numerically efficient method, based on a finite-element solver. The cost function penalises the misfit between the observations and the reconstructed field, as well as the regularity or smoothness of the field. The intrinsic advantages of the method are its natural way to take into account topographic and dynamic constraints (coasts, advection, . . . ) and its capacity to handle large data sets, frequently encountered in oceanography. The method provides gridded fields in two dimensions, usually in horizontal layers. Three-dimension fields are obtained by stacking horizontal layers. In the present work, we summarize the background of the method and describe the possible methods to compute the error field associated to the analysis. In particular, we present new developments leading to a more consistent error estimation, by determining numerically the real covariance function in Diva, which is never formulated explicitly, contrarily to Optimal Interpolation. The real covariance function is obtained by two concurrent executions of Diva, the first providing the covariance for the second. With this improvement, the error field is now perfectly consistent with the inherent background covariance in all cases. A two-dimension application using salinity measurements in the Mediterranean Sea is presented. Applied on these measurements, Optimal Interpolation and Diva provided very similar gridded fields (correlation: 98.6%, RMS of the difference: 0.02). The method using the real covariance produces an error field similar to the one of OI, except in the coastal areas.
Research units :	Centre Interfacultaire de Recherches en Océanologie - MARE
Funders :	Union Européenne = European Union - UE = EU
Name of the research project :	Seadatanet2
Target :	Researchers ; Professionals ; Students
Permalink :	http://hdl.handle.net/2268/125731
DOI :	10.1016/j.ocemod.2012.05.002
Other URL :	http://www.sciencedirect.com/science/article/pii/S1463500312000790
Framework Programme / European Project :	FP7 ; 283607 - SEADATANET II - SeaDataNet II: Pan-European infrastructure for ocean and marine data management

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