FN Archimer Export Format
PT J
TI Evaluation of GlobCurrent surface ocean current products: A case study in Australia
BT 
AF CANCET, Mathilde
   GRIFFIN, David
   CAHILL, Madeleine
   CHAPRON, Bertrand
   JOHANNESSEN, Johnny
   DONLON, Craig
AS 1:1;2:2;3:2;4:3;5:4;6:5;
FF 1:;2:;3:;4:PDG-ODE-LOPS-SIAM;5:;6:;
C1 NOVELTIS, 153 Rue Lac, F-31670 Labege, France.
   CSIRO, Canberra, ACT, Australia.
   IFREMER, Issy Les Moulineaux, France.
   NERSC, Bergen, Norway.
   ESA ESTEC, Noordwijk, Netherlands.
C2 NOVELTIS, FRANCE
   CSIRO, AUSTRALIA
   IFREMER, FRANCE
   NERSC, NORWAY
   ESA, NETHERLANDS
SI BREST
SE PDG-ODE-LOPS-SIAM
UM LOPS
IN WOS Ifremer UMR
   copubli-france
   copubli-europe
   copubli-int-hors-europe
IF 9.085
TC 16
UR https://archimer.ifremer.fr/doc/00464/57607/60173.pdf
LA English
DT Article
DE ;Surface ocean currents;GlobCurrent assessment;East Australian Current;Tidal currents;In situ measurements
AB Australia's marginal seas include a wide range of ocean current regimes ranging from tide-dominated in the North-West where the continental shelf is wide, to boundary current- and eddy-dominated in the South-East, where the shelf is narrow. Here, we take the opportunity to test the GlobCurrent surface ocean current products against in-situ observations in these two contrasting regimes. Observations by Acoustic Doppler Current Profiler (ADCP) instruments of Australia's Integrated Marine Observing System (IMOS) and drifting buoys of the Global Drifting Programme (GDP) are used. The monthly-timescale variability of the GlobCurrent alongshore current component is in moderately good agreement with the observations on the continental shelf in the South-East but neither the shorter period variability nor the long-term mean are representative of the ADCP observations. While the observed tidal currents are negligibly small, the wind-driven signals are not. But these are evidently too transient to be adequately sampled by altimetry. The inclusion of an Ekman component does not represent these signals because the interaction of the Ekman transport with the coastal boundary condition is not included. Similarly, the error of the time-mean velocity, which is the dominant error, is because that product is not designed to represent the highly anisotropic nature of the sea level gradients over the continental shelf nor the constraints on the flow field that are imposed by the topography. We thus conclude that the GlobCurrent product needs improvements before it can be described as very suitable for applications on this, and probably other, narrow continental shelf. Off the continental shelf, in contrast, the GlobCurrent products compare quite well with the trajectories of drifting buoys, confirming that the products are quite suitable for blue-water applications. In contrast to the South-East, the tides are very strong in the North-West region of Australia. The sub-tidal variability is weak, in both relative and absolute senses. Consequently, the removal of the tidal signal from the sea level observations needs to be very complete for the residual error to be smaller than the true sub-tidal signal. Transient wind forced signals are also occasionally large so this step of the de-aliasing also needs to be very accurate. Unfortunately, it appears that more work is required before accurate estimates of sub-tidal variability are available from GlobCurrent: the magnitude of the GlobCurrent estimates of sub-tidal current variability far exceed the magnitude of, and are uncorrelated with, the detided ADCP data. 
PY 2019
PD JAN
SO Remote Sensing Of Environment
SN 0034-4257
PU Elsevier Science Inc
VL 220
UT 000451936700007
BP 71
EP 93
DI 10.1016/j.rse.2018.10.029
ID 57607
ER

EF