Barometric Pressure Sensor
Barometric Pressure Sensor

Barometric pressure is measured using a Vaisala model PTB-101 instrument, which was discontinued for manufacturing in 2005 and for support in 2010. The replacement is the PTB-110 instrument. Each of these instruments has a version which measures in the range of 600 hecto Pascals (hPa) to 1060 hPa [1 hPa = 1 millibar], which is the span selected by UVMRP as most applicable to the range of elevations (-18 meters to +3397 meters) at our sites.

Barometers have been installed at only some sites, which include, Alaska, Davis California, Pawnee Grasslands Colorado, Florida, Beltsville Maryland, Saskatchewan(closed 2012) and Big Bend Texas(closed 2012) chosen by NASA\Goddard for placement with the UVA instruments for use in their ground-truthing of satellite data. The other sites, Steamboat Springs, Hawaii, New Zealand, Ontario, Seguin and El Paso, Texas, and now Louisianna(opened 2013) were chosen because of the extensive amount of atmospheric science that is done using the data from these sites.

UVMRP does not maintain calibration of these instruments, as they are intended to provide only a relative indication of the weather conditions around the site.

All but one barometer is mounted inside the UV-MFRSR enclosure, and is connected to the UV-MFRSR datalogger, so its output is measured every 20 seconds and integrated into 3-minute averages, and its data is retrieved nightly in conjunction with the polling of the UV-MFRSR datalogger. The exception El Paso, Texas, which is inside the vis-MFRSR enclosure and is at the 15 second sampling rate.