Change wind speed averaging time

Alter the gust factor to return a wind speed corresponding to a 10-minute
mean wind speed. Per requirements for TC hazard model intercomparison
project.

wind/__init__.py

@@ -7,8 +7,8 @@
 primary vortex of the simulated TC, and bounday layer models that
 define the asymmetry induced by surface friction and forward motion of
 the TC over the earth's surface. The final output from the module is a
-netCDF file containing the maximum surface gust wind speed (a 3-second
-gust, at 10 metres above ground level), along with the components
+netCDF file containing the maximum surface gust wind speed (a 10-minute 
+mean wind speed, at 10 metres above ground level), along with the components
 (eastward and westward) that generated the wind gust and the minimum
 mean sea level pressure over the lifetime of the event. If multiple
 TCs are contained in a track file, then the output file contains the
@@ -494,6 +494,7 @@ def calculateExtremesFromTrack(self, track, callback=None):
                                   margin=self.margin,
                                   resolution=self.resolution,
                                   gridLimit=self.gridLimit,
+                                  gustFactor=0.9009,
                                   domain=self.domain)
 
         return track, wt.regionalExtremes(self.gridLimit, callback)