Processing QuikSCAT satellite wind data
Overview
Data is collected through from NOAA AOML and converted to a shapefile. Data is served to SECOORA via a WMS feed wrapped by a CGI wrapper for time handling.
Source
Server: http://cwcaribbean.aoml.noaa.gov/java2/java.html. Data is available here ~2 hours after overpass.
Contacts: Folks at AOML are aware of our collection routines. I have received technical assistance from NOAA contractor Joaquin Trinanes (joaquin.trinanes@noaa.gov) and have also discussed our access with Judy Gray at AOML.
Collection Scripts
This script essentially mimics interaction with the Java Applet GUI to send requests for data. Data are requested at two resolutions - full resolution (28km) and sub-sampled to every 5th observation. The data are received as CSV and converted to shapefiles with OGR. The script runs during several periods daily to match when the QuikSCAT bird has been over our region. The QS satellite has a 4 day/57 overpass repeat period, but generally collects data over the southeast US from 13-15 GMT (8-11 AM) and 2-4 GMT (10PM - Midnight). Each hourly script run is aggregated into an overpass set: an AM or PM shapefile. The script inserts a timestamp for each set into a database for lookup purposes later and then FTPs the shapefile-set to maury.marine.unc.edu.
Script: aoml_qs_2_shape.pl (link to SVN) runs on cromwell.marine.unc.edu.
Timing: the data collection script is cron'd to run at 9,10,11 and 22,23,0 localtime
SECOORA Access
Data is served to SECOORA via a WMS feed wrapped by two perl CGI wrappers for time handling. Both services hit the same mapfile on maury which renders the shapefiles identified by the wrapper and controls the scale-dependency between the two resolutions:
- Full resolution (28km): scales below 1:8000000
- Every 5th observation: scales above 1:8000000
http://maury.marine.unc.edu/cgi-bin/quikscat_wrap? accepts TIME and TIME_OFFSET_HOURS as arguments in addition to normal OGC WMS arguments. This wrapper then identifies which shapefile-set to map.
http://maury.marine.unc.edu/cgi-bin/quikscat_overpass? accepts OVERPASS (count from most recent as 1) in addition to normal OGC WMS arguments. This wrapper then identifies which shapefile-set to map.
Possible Improvements
Joaquin emailed me in the last few months and pointed to http://cwcaribbean.aoml.noaa.gov/wind/ which now has a higher resolution dataset (12.5km) if we want it.
