Temperature Trends at the National Agricultural Research Center for Hokkaido Region in the 40 Years from 1966 to 2005

We examined 40-year temperature records maintained by the National Agricultural Research Center for Hokkaido Region (NARCH) in Sapporo, and compared them to temperature records from meteorological observatories of the Japan Meteorological Agency at Suttsu, Abashiri, and Nemuro, which are used to monitor global warming. The urbanization effect at NARCH was small. The rate of temperature increase (RTI) recorded at NARCH was less than 39% of the RTI recorded at the three JMA observatories over the 40 years covered by this study, which suggests that the RTI in rural agricultural areas unaffected by urbanization is less than the RTI estimated from temperature records from the JMA observatories.