The Suburban Energy Balance in Shunyi, Beijing City

Abstract The suburban energy partitioning was examined by using the data collected in Beijing city during the period from November 2007 to October 2009. The results show that two years had similar annual average values but different seasonal trend of net radiation. Monthly average net radiation was higher in May and June but significantly smaller in September and October of 2009 than those same periods of 2008. The annual variations of the turbulent fluxes over the two years were similar with that of net radiation. The fraction of net radiation used to latent heat was approximately 50-60% in summer and 120-150% in winter. Sensible heat flux accounted for 30-40% of net radiation in summer, while the partitioning of net radiation converted away as sensible heat was great in winter, with the values of 140-160%. Seasonal difference in Bowen ratios reflected that daytime available energy dominated by latent heat in summer but sensible heat in winter. The average daily daytime Bowen ratio varied from 0.6 to 0.9 during the periods of June to September, owing to vegetation growth effects. While in other times, Bowen ratios were always above 1, with value reaching 5.62 in February 2008. These fraction values about sensible heat were lower but about latent heat were higher than the values reported for some suburban areas in North America. Keywords Energy balance, Net radiation, Latent heat flux, Sensible heat flux, Bowen ratio, Beijing