Analyzing and Categorizing Misoscale Topographical Impacts on Climatological Wind Roses from the New York State Mesonet

The standard practice for landsite weather observation stations is to follow the World Meteorological Organization (WMO) land site criteria and guidelines. A variable that is not taken into consideration when determining a sites WMO Wind Class is the topography surrounding the site. New York State is unique in that, it has a large variety of topographical regions across the state which can result in non-negligible impacts on wind measurements not previously accounted for in more flat terrain. The New York State (NYS) Mesonet has 126 standard sites across New York and is the first statewide network to take 10m wind measurements from both a sonic anemometer and a propeller wind monitor. While the NYS Mesonet is designed to help capture weather phenomenon for an area of at least 10km on a horizontal scale, this analysis focuses on the misoscale (40m - 4km). Focusing on a smaller area allows the identification of the sites which are representative of a greater geographical radius versus those sites whose measurements are dominated by topographical features less than 4km from the site. The number of directions impacted and relative frequency to the other directions were compared with both, the surrounding topography and other climatological wind roses from surrounding sites in the region. Primarily utilizing Google Earth and a topographical overlay from the U.S. Geological Survey, each site was reviewed for the apparent topographical impacts and classified broadly into low, moderate and high impact sites. To further investigate the impacts of valleys on the historical wind roses, two additional wind roses were generated and reviewed; one representing daytime winds (15:00z-20:00z) and one representing night (05:00z-10:00z). Overall, this analysis assists in identifying topographical impacts on the historical wind measurements for each site and may provide additional guidance upon future site selections depending on their intended uses.