FN Archimer Export Format
PT J
TI Exploitation of error correlation in a large analysis validation: GlobCurrent case study
BT 
AF DANIELSON, Richard E.
   JOHANNESSEN, Johnny A.
   QUARTLY, Graham D.
   RIO, Marie-Helene
   CHAPRON, Bertrand
   COLLARD, Fabrice
   DONLON, Craig
AS 1:1;2:1;3:2;4:3;5:4;6:5;7:6;
FF 1:;2:;3:;4:;5:PDG-ODE-LOPS-SIAM;6:;7:;
C1 Nansen Environm & Remote Sensing Ctr, Bergen, Norway.
   Plymouth Marine Lab, Plymouth, Devon, England.
   Collecte Localisat Satellites, Ramonville St Agne, France.
   IFREMER, Plouzane, France.
   OceanDataLab, Locmaria Plouzane, France.
   European Space Agcy, Noordwijk, Netherlands.
C2 NERSC, NORWAY
   PML, UK
   CLS, FRANCE
   IFREMER, FRANCE
   OCEANDATALAB, FRANCE
   ESA, NETHERLANDS
SI BREST
SE PDG-ODE-LOPS-SIAM
UM LOPS
IN WOS Ifremer jusqu'en 2018
   copubli-france
   copubli-europe
IF 8.218
TC 8
UR https://archimer.ifremer.fr/doc/00465/57713/84528.pdf
LA English
DT Article
DE ;Measurement model;Ocean current;Collocation;Validation
AB An assessment of variance in ocean current signal and noise shared by in situ observations (drifters) and a large gridded analysis (GlobCurrent) is sought as a function of day of the year for 1993-2015 and across a broad spectrum of current speed. Regardless of the division of collocations, it is difficult to claim that any synoptic assessment can be based on independent observations. Instead, a measurement model that departs from ordinary linear regression by accommodating error correlation is proposed. The interpretation of independence is explored by applying Fuller's (1987) concept of equation and measurement error to a division of error into shared (correlated) and unshared (uncorrelated) components, respectively. The resulting division of variance in the new model favours noise. Ocean current shared (equation) error is of comparable magnitude to unshared (measurement) error and the latter is, for GlobCurrent and drifters respectively, comparable to ordinary and reverse linear regression. Although signal variance appears to be small, its utility as a measure of agreement between two variates is highlighted. Sparse collocations that sample a dense (high resolution) grid permit a first order autoregressive form of measurement model to be considered, including parameterizations of analysis-in situ error cross-correlation and analysis temporal error autocorrelation. The former (cross-correlation) is an equation error term that accommodates error shared by both GlobCurrent and drifters. The latter (autocorrelation) facilitates an identification and retrieval of all model parameters. Solutions are sought using a prescribed calibration between GlobCurrent and drifters (by variance matching). Because the true current variance of GlobCurrent and drifters is small, signal to noise ratio is near zero at best. This is particularly evident for moderate current speed and for the meridional current component 
PY 2018
PD NOV
SO Remote Sensing Of Environment
SN 0034-4257
PU Elsevier Science Inc
VL 217
UT 000447570900035
BP 476
EP 490
DI 10.1016/j.rse.2018.07.016
ID 57713
ER

EF