New York State Mesonet: Implementation of an Eddy Covariance Flux Subnetwork

The New York State Mesonet (NYS Mesonet) is an integral component of the New York State Early Warning Weather Detection System that was established by the Department of Homeland Security in January 2014 to improve weather monitoring and forecasting in the State of New York. The NYS Mesonet has implemented 126 advanced weather stations throughout the State of New York, seventeen (17) of which are complimented by closed-path eddy covariance (CPEC) flux systems for measuring fluxes of CO₂, water vapor, heat, and momentum. At the core of each CPEC flux system is an EC155 infrared gas analyzer and a CSAT3A sonic anemometer manufactured by Campbell Scientific Inc. (Logan UT, USA). Also included with each CPEC system is a Kipp & Zonen (Delft, NL) CNR4 net radiometer for monitoring radiation balance, and four Hukseflux (Delft, NL) HFP01 soil heat flux plates to measure heat flux near the soil surface. Software and hardware modifications have been made to the factory CPEC system components to enable integration with NYS Mesonet towers without significant modification to the existing infrastructure. Seventeen “flux sites” were chosen among the 126 standard NYS Mesonet sites based on scientific interest, uniqueness of land use, and objective suitability for measuring surface fluxes (i.e. flow distortion potential, fetch uniformity, and local terrain characteristics). Fifty percent of the flux sites represent agriculture including three (3) orchards, three (3) vineyards, and two (2) rotating crop fields. Other land-use types represented include urban (NYC), waterway, grassy field, wind farm, and mixed-use suburban. Nine (9) sites are co-located with the Mesonet’s Profiler sub-network and one is co-located with the Mesonet’s Snow sub-network. A schedule is being implemented for maintaining and calibrating the instruments using a combination of manual and automatic (remote) techniques to establish long-term confidence in data output. All calibrations of CO₂ will be grounded by NOAA standards and effort will be made to reduce temperature dependency of gas concentration measurements to better suit the system for monitoring CO₂ and water vapor. With continued development, the NYS Mesonet Flux Sub-network will open the door to a wide variety of research opportunities.