WUWT readers may recall that I wrote about this experiment being performed at Oak Ridge national Laboratory to test the issues related to station siting that I have long written about.
NOAA’s ‘Janus moment’ – while claiming ‘The American public can be confident in NOAA’s long-standing surface temperature record’, they fund an experiment to investigate the effects of station siting and heat sinks/sources on temperature data
This effort promises to be greatly useful to understanding climate quality temperature measurements and how they can be influenced by the station site environment.
From the USCRN Annual Report: http://www1.ncdc.noaa.gov/pub/data/uscrn/publications/annual_reports/FY11_USCRN_Annual_Report.pdf
Texas State Climatologist John Nielsen-Gammon writes about the the first results of this experiment presented at the recent AMS meeting in Austin, TX. The early results confirm what we have learned from the Surface Stations project. Nighttime temperatures are affected the most.
Two talks that caught my eye were on the land surface temperature record. They attacked the problem of land surface temperature accuracy in two completely different, but complementary ways.
One, by John Kochendorfer of NOAA at Oak Ridge, Tennessee, is a direct test of the importance of siting. They’ve installed four temperature sensors at varying distances across a field from the laboratory complex. The experiment has only been running since October, but already they’ve found out a couple of interesting things. First, the nighttime temperatures are indeed higher closer to the laboratory. Second, this is true whether the wind is blowing toward or away from the laboratory.
It’ll take a lot more data to sort out the various temperature effects. One way the buildings might affect the nighttime temperature even when the sensor is upwind of the buildings is infrared radiation: the heated buildings emit radiation that’s stronger than what would be emitted by the open sky or nearby hills.
Biases Associated with Air Temperature Measurements near Roadways and Buildings
Wednesday, 9 January 2013: 9:15 AM Room 15 (Austin Convention Center)
John Kochendorfer, NOAA, Oak Ridge, TN; and C. B. Baker, E. J. Dumas Jr., D. L. Senn, M. Heuer, M. E. Hall, and T. P. Meyers
Proximity to buildings and paved surfaces can affect the measured air temperature. When buildings and roadways are constructed near an existing meteorological site, this can affect the long-term temperature trend. Homogenization of the national temperature records is required to account for the effects of urbanization and changes in sensor technology. Homogenization is largely based on statistical techniques, however, and contributes to uncertainty in the measured U.S. surface-temperature record. To provide some physical basis for the ongoing controversy focused on the U.S. surface temperature record, an experiment is being performed to evaluate the effects of artificial heat sources such as buildings and parking lots on air temperature. Air temperature measurements within a grassy field, located at varying distances from artificial heat sources at the edge of the field, are being recorded using both the NOAA US Climate Reference Network methodology and the National Weather Service Maximum Minimum Temperature Sensor system. The effects of the roadways and buildings are quantified by comparing the air temperature measured close to the artificial heat sources to the air temperature measured well-within the grassy field, over 200 m downwind of the artificial heat sources.
Early results of what has been learned in the surface stations project can be seen here:
h/t to Dr. Roger Pielke Sr.