Monthly mean meteorological parameters measured at the FEF.

Monthly means calculated between June to September during the 2012a and 2013a growing season in comparison with historical data of the climate normalb in the 30-year time period from 1981–2010 for Fairbanks, Alaska, USA, provided by the National Climatic Data Center. Hist. represents the mean monthly historical climatological data in the 30-year period. The second-four columns indicate mean air temperatures with standard deviation (Std dev) during two summer seasons compared to the 30-year average.a Meteorological station at the study sitebThe climate normal (a 30-year mean) at the Fairbanks International Airport (http://climate.gi.alaska.edu/Climate/Normals).C Here the growing period is calculated from 1 June to 20 SeptemberMonthly mean meteorological parameters measured at the FEF.