An Analysis of Station Spacing for Use in the Allocation of Resources for Surface Mesonets

The amount and usability of both public and private weather data has increased significantly over the last few decades with the advent of new technologies and the expansion of Public Private Partnerships between governments and industry. The National Mesonet Program (NMP) has allowed the National Weather Service (NWS) to leverage thousands of non-federal weather stations for use in performing its mission of saving lives and protecting property. Each of the NMP's nearly forty partner networks has been designed and installed to satisfy its own unique requirements. This talk will explore a few such partners and assess and analyze their station spacing and density compared to specific design requirements from published recommendations.

The 2009 From the Ground Up report detailed nominal station spacing broken down by weather phenomena. From tornadoes to nor’easters to air quality, a suggested density was determined that would ensure the relevant characteristics of that particular phenomenon would be captured. Knowing that mesonets themselves are usually not built with a specific phenomenon in mind (except for a few agricultural or air quality networks), and acknowledging that varying geography and terrain bring their own requirements, it is hard to decide on a single universal spacing that can be applied to the NMP as a whole. This analysis looks at specific NMP partner networks to examine how station spacing has evolved in real-world applications. Two such networks, the Oklahoma Mesonet and the New York State Mesonet, could be utilized as examples for how other networks should operate, as well as helping Congress understand the needs (both in political and monetary support) that are needed to ensure all state mesonets can adhere to a certain density standard; allowing for a denser network, more observations for the NWS, and better forecasts for all.

Initial steps to analyze network density were undertaken with the Oklahoma Mesonet using a great-circle distance analysis to determine average station spacing. This particular analysis only compared the Oklahoma Mesonet stations with each other. Future work will include expanding to other partner networks and using all available NMP assets in each mesonet’s state (e.g., ASOS, AWOS, commercial stations) to see how station spacing and density are affected as well as discovering how the stations themselves are aggregated, i.e. near large cities, agricultural areas of interest, coastlines, etc.) This process can also be extended to vertical assets (SODARs, radiometers, etc).

The goals of this initial exercise are to address, and hopefully answer, the following questions: How well are these networks (and the NMP as a whole) following the general guidelines set out in the From the Ground Up report? Are these guidelines applicable for today or should they be updated from lessons learned? Is there an ideal universal station spacing? If so, what should it be? Should it be determined based on geographical area, type and quality of station, or some other specification? These questions will be explored as well as what, if any, future considerations should be examined to help make the National Mesonet Program even stronger and more robust than it is today.

The information to be presented here will not only aid in helping determine the most ideal station spacing, thereby increasing the usability of each mesonet network, but will, in the end, ensure that the NWS is leveraging all available surface observations for use in both real-time situational awareness forecasting and short-term high-resolution modeling. The outcomes from this project will hopefully lead to important discussions regarding political support and funding both at the county, state, and national level. Conversations such as these are needed to ensure continued innovation, evolution, and growth of the Weather, Water, and Climate Enterprise.