GOES versus GPS-Met Water Vapor Comparison
Welcome to the GOES versus GPS-Met water vapor (WV) comparison site. This site can be used to compare GOES water vapor retrievals against GPS-Met estimates and other estimates resulting from different processing schemes, designated as 'flavors'. View current favors here. In addtion to WV, the guess WV and both the WV and the guess WV from three layers can be compared.
Start by clicking on the calendars to choose the start and end dates. Then select a site. Sites shown in ALL CAPS represent aggregates of sites. The satellites in view of the chosen site will be automatically selected. Auto-selected satellites may be de-select if desired. A map depicting satellite visibility by site location is available here. Next select the processing flavor(s) of interest. Multiple adjacent flavors can be selected by holding down the ctrl key (shift key on a Macintosh) while clicking or draging across them. Non-adjacent multiple flavors can be selected by holding down the option (or shift on a Mac) key while clicking. Next select the data type(s) of interest. As with flavors, multiple data types can be selected. Finally, click the 'Update plot' button to view the graph.
One or more plot options can also be selected before requesting a plot. The Scatter plot option adds a GOES WV versus GPSWV scatter plot and fits an unweighted least-squares curve to the data, using the Statistics::LineFit module described here. The Differences plot option creates a (GPSWV - GOESWV) versus GPSPW time series plot. The Absolute Differences option creates an absolute_value(GPSWV - GOESWV) versus GPSPW time series plot. The Squared Differences option creates a (GPSWV - GOESWV)**2 versus GPSPW time series plot. If both scatter and difference plots are choosen, then the scatter plot will be a (GPSWV - GOESWV) versus GPSWV scatter plot. The Curve-fit history options adds a time series of the scatter plot curve fit parameters. Curve-fit history can not be selected unless the scatter plot or show differences has been selected. Finally, the Show text option returns the underlying data in addition to the plots.
The combination of a satellite, a processing flavor, and a data type is called a product in the context of this interface. In order to reduce confusion when comparing data products have been assigned a color and symbol for plotting purposes. The color/symbol table can be viewed here.
In addition to each physical site, within the list of 'sites' there are geographic regions and aggregate sites (those starting with 'GOES') that represent composite observations. The regions can be seen in the location map listed above. GOES11 represents all GOES11 only sites, GOES13 represents all GOES13 only sites, and GOES11and13_overlap represents the sites which are visible to BOTH GOES 11 and GOES13. When these aggregates sites are selected, then the 'Aggregate Bias & RMS' plot option can be selected. For the purpose of these statistics, data time-stamped for a given hour represents data observed during the period 30 minutes before to thirty minutes after. For example, data time-stamped for hour 8 represents satellite observations and GPSMet estimates for the period 7:30 to 8:30.