To get an idea of the measurement environment that exists today at stations used to gather climate data, I visited the Chico State University Fram on Hegan Lane, south of the city, to do a site survey in the format done by Dr. Roger Pielke of Colorado State University. This station is part of the US Historical Climate Network of weather stations that have been used as the source for surface temperature data in many climate models and studies.
There were some interesting discoveries.
Chico State University Farm, Hegan Lane, Chico,
CA 95926 (530) 898-6343
Survey By: Anthony Watts
USHCN Reported Coordinates of site: CHICO
(39.71°N, 121.82°W; 56 m)
Measured GPS Coordinates of site:
Lat/Lon 39.69194˚ N 121.82127˚ W
54.5592 m (179 feet)
Site description and known history:
California State University, Chico has been in operation since a land grant
made the college a reality in 1887. The CSUC
Farm has been in operation since 1963, and it is believed the current site
has been at the same location since then. The prior source and location for data in
the climate record for Chico is unknown as of this writing.
- There has been encroachment by Oleander bushes
onto the site in recent times, about 2 years ago, a prominent Oleander bush
that was blocking the pyranometer view was removed, see before (sketch) and
after photos below.
- The curator notes that there was a complaint
from a meteorologist from WeatherNews about a change in temperature data that
coincided with a repainting of the CRS’s a few years ago, but cannot recall
the date exactly.
Site surveyor notes:
- There are missing louvers on the north side of
the CRS containing the automated data logger and temp/dp sensor
- There is clear evidence that both shelters
have been repainted with latex paint, including brush marks and drip marks.
- There is an asphalt road that curves around
the site, from the southwest to the southeast
- The surface at the site is mixture of
gravel, soil, and debris. There is no grass.
- There is a water filled evapo-transpiration
pan within 10 feet of each CRS, its lineage seems to indicate it goes
back to the establishment of the site in 1963
- The fiberglass composite NEMA electronics
enclosure containing the data logger, radio modem, and solar battery charger are placed
inside the CRS within 6-8 inches of the temperature/dp sensor. The 12 volt gel
cel battery is also inside the CRS. These items may
introduce a heat bias from the operating electronics.
Images of the site:
(click for larger images)
(click for larger images)
Interior of west most CRS with data logger, temp/dp
Before (sketch) and after of vegetation
Various details of disrepair on both CRS’s
Interior of east most, manual mercury thermometer
Evidence of repainting, brush-marks, drips