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QuickSCAT vs. Altimeters

 The preliminary results presented in this topic were produced using the QuikSCAT colocated data, processed at CERSAT, with TOPEX/GDR products and with ERS-2/OPR products.

The Quikscat colocated data

 

Nb of weeks (week numbers)

Start date - Stop date

Start orbit - Stop orbit

Nb of data

with TOPEX

14 (29-42)

99/7/19 - 99/10/15

430 - 1815

89022 ( 6360 per week)

with ERS-2

24 (29-52)

99/7/19 - 00/01/02

430 - 2811

20299 (850 per week)

Geographical distribution of (30 min, 12.5 km) colocated data.

QuikSCAT - TOPEX in red and QuikSCAT - ERS-2 in green.

 qscat vs topex ers1

 Scatterplots and histograms comparing QuikSCAT Wind Vector Cell wind speed with TOPEX altimeter wind speed, within 12.5 km and 30 min.

TOPEX 1 second along track measurements on the left side of the
figure, and TOPEX 13 second averages (equivalent to about 70 km
averages) on the right side of the figure. Number of data, mean value
and standard deviation of QuikSCAT minus TOPEX wind speed differences
are given in the figure.

qscat vs topex ers3

 

qscat vs topex ers4

 Scatterplots and histograms comparing QuikSCAT Wind Vector Cell wind speed with ERS-2 altimeter wind speed, within 12.5 km and 30 min.

ERS-2 1 second along track measurements on the left side of the
figure, and ERS-2 13 second averages (equivalent to about 70 km
averages) on the right side of the figure. Number of data, mean value
and standard deviation of QuikSCAT minus ERS-2 wind speed differences
are given in the figure.

qscat vs topex ers5

 

qscat vs topex ers6

Results as a function of altimeter wind speed classes(left graphs) or of QuikSCAT wind speed classes (right graphs), 1 m/swide, for TOPEX in green and for ERS-2 in red.

From top to bottom, for each wind speed class: number of data, mean value of QuikSCAT wind speed (m/s), mean value of QuikSCAT minus altimeter wind speed (m/s) and standard deviation of QuikSCAT minus altimeter wind speed (m/s)

qscat vs topex ers7

Impact of significant wave height (SWH) on the difference between QuikSCAT and altimeter wind speed measurements.

Topex in red and ERS-2 in green. The black line is the results
obtained with NSCAT (for incidence angles between 45 and 55 degrees)
and ERS-2.

qscat vs topex ers9

 

Written by : Pierre Queffeulou "Département D'Océanographie Spatiale"/IFREMER
For more information :This email address is being protected from spambots. You need JavaScript enabled to view it.

Copyright © Ifremer 2000. The ERS data is courtesy of the European Space Agency. The QuikSCAT data is courtesy of the Jet Propulsion Laboratory, NASA. The TOPEX data is courtesy of CLS/Argos