Stevenson screen temperatures – an investigation

Aspirated and non‐aspirated automatic weather station Stevenson screen intercomparison

“…For specific cases with extended periods of low winds and high global radiation the non‐aspirated screen is as much as 2.1 °C warmer than the aspirated screen. This is in agreement with the findings of Burton (Burton, ) who observed maximum hourly temperature increases of 1.78 °C with the non‐aspirated screen.…”

“…The uncertainty of the measurement of air temperature is influenced by a number of environmental factors including global radiation, wind, cloud cover, surface albedo, precipitation, fog, dust and pollution (International Organization for Standardization, ; Van der Meulen and Brandsma, ; World Meteorological Organization, ; Lacombe et al, ; Harrison, ). The configuration of a temperature probe in a radiation shield with/without aspiration is of particular importance to block the exposure of the temperature probe to direct solar radiation while allowing adequate ventilation to limit the temperature difference between the probe temperature and the free air temperature (Sparks, ; Lin and Hubbard, ; Hubbard and Lin, ; Van der Meulen and Brandsma, ; Lacombe et al, ; Burton, ; Clark et al, ). Instrument siting is also important to limit the influence due to nearby obstacles and heat sources (Guttman and Baker, ; World Meteorological Organization, ).…”

“…Comparisons with non‐aspirated wooden and plastic Stevenson screens have demonstrated delayed response times, particularly for low wind speeds (Warne, ; Van der Meulen and Brandsma, ). Non‐aspirated Stevenson screens are also found to exhibit radiation errors up to and above 0.5 °C particularly during conditions with clear skies, high solar radiation and weak winds (Van der Meulen and Brandsma, ; Burton, ; Buisan et al, ). The differences between aspirated and non‐aspirated screen configurations can have significant effects on measured maximum and minimum temperatures as well (Quayle et al, ).…”

Impact of two different sized Stevenson screens on air temperature measurements

“…E-mail: sbuisans@aemet.es which have appeared in the scientific literature since the 19th century (e.g. Wild, 1879;Marriott, 1879;Gill, 1882;Whipple, 1883;Mawley, 1897;Hazen, 1885;Margary, 1924;Drummond, 1943;Chandler, 1964;Sparks, 1972;Laing, 1977;Andersson and Mattisson, 1991;Richards et al, 1992;Parker, 1994;Nicholls et al, 1996;Nordli et al, 1997;Böhm et al, 2001; Van der Meulen, 2003;Brunetti et al, 2006;Perry et al, 2007; Van der Brandsma and Van der Meulen, 2008;Azorín-Molina and Azorín-Molina, 2008;Martínez-Ibarra et al, 2010;Clark et al, 2014;Burton, 2014). In Spain, a pioneering project on intercomparison of thermometer screens corresponded to the Spanish-funded SCREEN project coordinated by the Centre of Climate Change (C3; http://www.c3.urv.cat/; last accessed 1 November 2014) which assessed the screen bias incorporated into the longest Spanish air temperature records by time-changing thermometric exposures; paired air temperature observations were taken using the old Montsouris stand and modern Stevenson screens (for details see Brunet et al, 2006).…”

A Global Climate Reference Network

“…Also, a change from Stevenson‐type screens to the small AWS screens will result in a different response to temperature, not necessarily for the better. Although Stevenson screens certainly have their errors (notably in high radiation and low wind‐speed conditions), the miniature AWS screens, containing platinum resistance thermometers (PRTs), are not free from such errors either (Burton, ); and there are many different designs of these small screens, each with different characteristics.…”