Local Siting Impacts on a Mesoscale Network: A Review of NYS Mesonet Site Characteristics and WMO Siting Criteria

The New York State (NYS) Mesonet is comprised of 126 weather stations, spaced an average 19 miles apart, each reporting a suite of meteorological variables in real-time every 5 minutes. Stations were installed over a two year period beginning in August 2015. The WMO criteria for siting weather instrumentation was used as the primary guideline for placing each station. Every station had to be at least 100 m away from concrete surfaces, obstructions (trees, buildings) taller than 10 m AGL, and large bodies of water. In addition, FEMA regulations stated that no site could be placed within a 100 year flood zone; in a designated federal or state wetland; within view of a historically designated landmark or building; or on archaeologically sensitive land. Despite the above guidance, New York’s topography, forests, and political zoning limited site options in some areas of the state to less-than-ideal standards. To quantify the regional representativeness of each station, each site is compared against WMO siting standards and rated. In addition, long-term station averages are compared against neighboring averages to identify any unique features that may be tied to local obstructions or land features. These results highlight two major conclusions: (1) Weather observations are extremely sensitive to local siting anomalies, and (2) Even stations that satisfy WMO criteria may incur some localized ‘problems’.