About - Emigrant Pass Observatory

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About EPO

Location map of northwestern Utah showing boreholes (triangles) and meteorological stations (circles)
The Emigrant Pass Observatory (EPO) is located at the southern end of the Grouse Creek Mountains of northwestern Utah (figure - right). It was established near the end of 1993 next to a 160 m deep borehole GC-1 as part of a climate change observatory that would allow concurrent monitoring of both meteorological conditions (such as air temperature, solar radiation, snow and rainfall) and subsurface temperatures (Putnam and Chapman, 1996). The station ran continually through 2004, with minor operational setbacks due to battery, data storage, and instrument failures (Bartlett et al., 2006). A major upgrade of the station near the end of 2004 allowed telemetry of daily observations at EPO (Bartlett et al., 2006), and near 100 percent data recovery.

The borehole and weather station are located on a granitic outcrop in the midst of a sparsely vegetated area of pinyon pine and juniper (figures - bottom). The topography is generally flat with a gentle slope to the northeast. These factors aid in making this desert environment an ideal location for such an observatory.

The instruments at EPO consists of a solar powered Campbell Scientific CR-10 data logger that controls a collection of meteorological instruments and several shallow thermistor strings designed to measure temperature in the granite outcrop and nearby soil as well as air temperature, solar radiation, precipitation, snow depth, wind speed, and wind direction (Figure 2). The data logger interrogates the sensors every 60 seconds and stores 30-minute averages.

Publications from our group that specifically report and analyze data from EPO are Putnam and Chapman (1996) and Bartlett et al. (2006). For further information about utilizing ground and air temperatures measured at EPO and GC-1, see Davis et al. (2010).

Image of the meteorological station (EPO). Note the borehole GC-1 to the left of the station.

Cartoon map view of EPO with locations of ground temperature probes and surrounding vegetation. The image to the left is taken from the bottom-right and is looking towards the upper-left (northwest).