The PBO H2O project was funded by the NSF GEO directorate, specifically the Atmospheric Sciences, Hydrology, Infrastructure, and EarthScope programs. We  computed water cycle products from GPS data (primarily the Plate Boundary Observatory) and made them available at our website until late 2017.  Now that the PBO H2O project is complete, users of the products can find information in the following locations:

Soil moisture products were archived at the International Soil Moisture Network

Snow products (snow depth and snow water equivalent) were archived at the NSIDC.

All PBOH2O products (soil moisture, snow, and vegetation) were archived at UNAVCO.  Our understanding is that the products have been separated by station name and are available via anonymous ftp:

Please email David Mencin ( at UNAVCO for more information.

You can also try this zip file link.

Here are flat copies of the documentation we provided for our PBO H2O products:

snow, SWE, soil moisture, vegetation.

Of course the links within the pages will not work, but you can find most of the papers at the publication section of this website.

More Information about Snow

Snow measurements are needed both to study climate and to predict drought, flooding, and water availability. In urban areas, weather spotter networks and citizen scientists measure snow depth. However, information about snow depth is more difficult to obtain in remote areas that are sparsely populated. Measuring snow is also difficult because it is highly variable in space and time.

Remote GPS station in Barrow, Alaska.

Remote GPS station in Barrow Alaska.

The U.S. national snow network (SNOTEL) has a large number of sensors in the western United States, but these sensors have fairly small sensing regions (a few square meters). Satellites – which in principle would be able to provide the large picture – do not currently provide accurate estimates of snow depth.

GPS Interferometric Reflectometry (GPS-IR) is a new method to measure snow depth. It has a footprint of ~1000 square meters. It was developed at the University of Colorado with our research partners at UCAR and NOAA. Our PBO H2O project routinely measured snow depth for 220 sites in North America.  Any geodetic quality GPS site can be used to measure snow depth if the site is surrounded by natural, planar surfaces.  Results are archived at the NSIDC and at CIRES.

Niwot Ridge