Efforts are underway in many locations to create more detailed spatial and temporal data sets from different specialized observing systems for a variety of applications. In Iowa such a high resolution data set is being developed. An important process in creating the data set is to compare observations among Automated Weather Observing System (AWOS), Automated Surface Observing System (ASOS) and the Roadway Weather Information System (RWIS) of the Iowa Department of Transportation (Iowa DOT). Such comparisons are attempting to assess the meteorological similarity of the systems and the ability for data gathered from them to be used interchangeably. Initial comparisons will be used to support a COMET-funded project to forecast frost along Iowa roadways. In the longer term the combined data will be central to an Iowa state wide effort to gather environmental data into a single database called the Iowa Environmental Mesonet (IEM).

Initial qualitative impressions indicate that the RWIS temperatures and dew points are lower overall for all stations across the state. Wind data is indeterminate since station locations vary in exposure. Quantitative assessment is under way to compare temperatures, dew points, and winds at 19 locations where an RWIS and AWOS/ASOS site are within 15 km of each other. Data from these stations will be compared to note any diurnal differences as well as possible seasonal differences. Assessment of station locations for comparability of the data will be conducted. Some spatial comparisons are underway over the whole network to determine an underlying system bias within the instruments or a spatial bias within the state.

If the data are found to be compatible the density of surface observations in Iowa will increase to roughly 40 km because of the large number of RWIS sites (50) and AWOS/ASOS sites (49) in the state.