The oceanographic, or flow vector, convention for wind direction is adopted for QuikSCAT. Under this convention, a wind direction of 0 degrees implies flow toward the north."(QuikSCAT User's Manual, section 1.2.3)

You need to download version 4, available here.

The main reason for having fewer measurements over the bands around 90 and 270 degrees longitude is the fact that only the latest measurements are kept, in case there are overlapping measurements within a day.

Since a day starts at 00:00:00 UTC and the ascending pass crosses the equator each day at approximately 6:00 am local solar time, it means that a L3 file will start always over an area located around 90 degrees longitude. Since the number of orbits within a day is not a whole number (~14 1/2), the last portion of an ascending swath within a day (also located around 90 east) partially overlaps the first one, so that only the measurements close to the end of a day are kept, while those from the very beginning of a day are discarded.

A similar process happens around 270 degrees longitude, for the descending pass.

To minimize the chance of damage during the Leonid meteor shower, the solar panels on the QuikSCAT spacecraft are rotated to present the minimum cross-sectional area to the direction of the meteor flow. Also, the instrument high voltage is turned off to prevent possible shorting caused by plasma clouds generated by meteor impacts.

http://podaac.jpl.nasa.gov/quikscat/qscat_prob.html lists all data gaps longer than 4 seconds. If the gap spans an entire rev, no L2B file will exist for that rev. Furthermore, if the gap spans an entire day, no L3 file will exist for that day.

Due to storage limitations and high user demand for the newly processed data, we no longer store the originally processed Level 2B and Level 3 data in our archives. The post-processing algorithms for the Level 2B and Level 3 QuikSCAT data was officially changed in June of 2006. To maintain continuity, all data that was processed prior to this date was re-processed using the new QSCAT-1/F13 model function relationship.

The accuracy of wind vector magnitudes in excess of 16 m/s has increased based upon the tuning from the SSM/I F13 measurements. This results in a systematic overall increase in the wind vector magnitudes, when compared to the original QSCAT-1 algorithm, but this only applies to wind speeds in excess of 16 m/s.

Another improvement is in the multidimensional histogram (MUDH) rain flagging algorithm. The SeaWinds on ADEOS II mission provided tandem measurements from the SeaWinds scatterometer and the AMSR microwave radiometer, which was used to provide an “impact-based” MUDH rain flagging algorithm (IMUDH). This results in less “over-flagging” in rain-free regions, which was more problematic with the previous MUDH algorithm, especially in high wind speed regimes.

A final bi-product is the availability of a higher resolution (12.5 km) level 2B product.

Yes, but this validation study only applies to the QSCAT-1 processing algorithm. Please click here to download the IEEE published paper by Tang et al. (2004).