Creating weather files for climate change and urbanization impacts analysis

Over the past 15 years, much scientific work has been published on the potential human impacts on climates. For the Third Assessment Report published by the United Nations International Program on Climate Change in 2001, a series of economic development scenarios were created and four major general circulation models (GCM) were used to estimate the anthropogenesis-forced climate change. These GCMs produce worldwide grids of predicted monthly temperature, cloud, and precipitation deviations from the period of 1961-1990. As this period is the same used for several major typical meteorological year data sets, these typical data sets can be used as a starting point for modifying weather  files to represent predicted climate change. Over the past 50 years, studies of urban heat island (UHI) or urbanization have provided detailed measurements of the diurnal and seasonal patterns and differences between urban and rural climatic conditions. While heat islands have been shown to be a function of both population and microclimatic and site conditions, they can be generalized into a predictable diurnal pattern. This paper presents the methodology used to create weather files which represent climate change scenarios in 2100 and heat island impacts today and present the typical climatic patterns resulting for 20 climate regions worldwide.