WindSat Research Topics and Issues
The latest WindSat dataset (version 1.9.0) spans almost three years, but with several large gaps:
- year 2003: days 32 - 365, total missing 041 days: 1- 31 = 31, 196-200 = 5, 340-344 = 5
- year 2004: days 01 - 366, total missing 019 days: 27- 28 = 2, 60- 64 = 5, 195-199 = 5, 288-294 = 7
- year 2005: days 01 - 334, total missing 182 days: 27- 32 = 6, 44-167 = 124, 271-277 = 7, 301-311 = 11, 335-365 = 31
WindSat data are available from http://podaac.jpl.nasa.gov/windsat/calval , but are currectly restricted to members
of the Cal/Val Science Team. For access please contact Peter Gaiser at Naval Research Laboratory, peter.gaiser@nrl.navy.mil.
For the following figures, click on images for enlarged versions of plots.
1. Rain-flagging in WindSat swaths
Rain-flagging in WindSat (ERD and SDR rain flags) is contrasted with rain-flagging in QSCAT-R2 (March 2006 "beta" Release).
WindSat rain-flagging:
- EDR rain-flagging: Observations where the retrieved integrated cloud liquid water is greater than 0.2 mm are flagged for rain.
This rain-flagging less conservative than SDR rain-flagging and is the preferred rain-flagging method.
- SDR rain-flagging: Rain is considered to be present by the condition
37V - 0.979 x 37H < 55.0, or 1.175 x 18V - 30.0 > 37V, or 18H > 170.0, or 37H > 210 (V&H are vertical and horizontal polarizations).
Fig. 1.1 WindSat rain-flagging: (a) EDR rainflags about 8% of all data in 7 revs, and (b) SDR rainflags about 18%.
Fig. 1.2 QSCAT (R2, "beta" Release) rain-flagging for same 12hr period as in WindSat (fig. 1.1): ca. 1% of data are rain-flagged.
Examples of rain-flagging in a swath in the central Pacific, on 9/25/2003, are shown below, for WindSat and QSCAT.
Fig. 1.3 Rain-flagging in central Pacific, on 9/25/2003, (a) WSAT SDR-rainflag, (b) WSAT EDR-rainflag,
and (c) QSCAT rainflag.
The typical percentage of rain-flagged wind vectors binned by wind speed are plotted below as a histogram.
Fig. 1.4 Percent rain-flagging binned by wind speed, for WSAT EDR and QSCAT-R2 rainflagging.
2. Windstress Curl
Windstress curl global averages for 2003 are shown below. Rain-flagged wind vector cells are excluded: using WindSat EDR-flagging
and QSCAT-R2 rain-flagging. For the WindSat average, also all RFI-flagged data are excluded (RFI = Radio Frequency Interference).
The WindSat data record does not start until 2/1/2003, so the 2003 average consists of the 11-months Feb-Dec average.
Fig. 2.1 Windstress curl, 11-month average Feb-Dec 2003: (a) WindSat (EDR rain-flagged data excldued),
(b) QSCAT-R2 (rain-flagged data excluded), and (c) QSCAT-WindSat difference.
Fig. 2.2 Zonal average of windstress curl. For comparison, the 2003 Jan-Dec 12-months QSCAT-R2 average
is shown as well (in blue, in upper panel).
last modified on May 24, 2006
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