## 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.

## 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.

## 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.

## 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)

## 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.

**Written by :** Pierre Queffeulou "Département D'Océanographie Spatiale"/IFREMER

**For more information :**Pierre.Queffeulou@ifremer.fr **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