There are many different ways to compute the dry/wet delay from the GPS satellite -- it is this delay that is used to determine the precipitable water in the column. To give you an idea of how things change, here's a scatterplot of data using the same software to compute delays -- Chuck Demets [UW-Madison] Yoaz Bar-Sever [JPL] provided me these datapoints of total delay (i.e., dry + wet). It looks pretty good to me. Click here (or on the plot at left) for a full-sized scatterplot.

The fit looks even better when you look at the two time series plots. Click here for a time series plot of the data that produced the scatterplot. Recall that these are time series of total delay.

Here is a scatterplot at a different station. Still very good agreement. Click here (or on the plot at left) for a full-sized scatterplot.

Here is the time series that corresponds to the scatterplot above. Click here or on the plot at left.

What do these plots show? They show that the GPS data I get from two different places track very closely. I'd like to think that comparisons of geostationary data with either Yoaz's data or Chuck's data will give essentially the same results

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