Tempest Weather Stations in Meteorological Research - How do they Measure Up?

While hobbyist weather stations have been on the market for many years, a decrease in the size and cost of electrical components as well as the advent of the “internet of things” have increased the sophistication and usage applications of these systems. As these systems are much cheaper and easier to deploy than typical “research-grade” instrumentation, their applicability to certain research objectives could have large implications for organizations that receive little funding or even K-12 schools that wish to engage their students in meteorological research. In particular, this project focuses on the use of the Tempest Weather System by WeatherFlow to collect data that can be used in research projects requiring meteorological data. The “Tempest” is a low-cost all-in-one weather sensor that measures temperature, relative humidity, barometric pressure, wind speed, wind direction, and solar radiation. These systems also output a number of derived meteorological variables, including air density, dewpoint temperature, the heat index, and the wet bulb globe temperature. The weather sensors are powered by small solar panels and transmit data via radio to a hub that connects to a wireless network. The data are reported every minute and can be easily logged in CSV format through familiar cloud-based storage services, such as Dropbox or Google Drive. Given the ease of setup, the “app” based interface, and the hyper-local forecast based on an individual station’s data (all at a relatively low cost), these weather sensors have enjoyed wide popularity as a hobbyist device or for citizen / community-based science projects. This study explores the feasibility and use of these popular systems as affordable, meteorological, research tools through a field validation campaign as well as implementation in two field projects in Louisville, KY. The field validation campaign was conducted at the historic Bowman Airfield in Louisville. While this airfield now only supports private aircraft and a flight school, it still maintains an official National Weather Service Automated Surface Observation System (ASOS) station. In addition to providing an official source for data validation, this site also offered accessibility, security, and relatively few obstructions. Five Tempest sensors were deployed on tripods approximately 25 m apart and 500 m from the ASOS station, KLOU. In addition to the five Tempest sensors, a research-grade weather station was also deployed in closer proximity to the Tempest array. This research station measured the same variables as a Tempest system, but an aspirated temperature shield was included with the research station. The anemometer type also differed between the two systems, such that the research-grade system employed a cup-style anemometer and wind vane, while the Tempest system measures wind ultrasonically. The Tempest array was deployed on 15 October 2022, while the research-grade system was deployed on 20 October 2022. All sensors were removed on 7 November 2022 providing over 2 weeks of collocated validation data between the ASOS, the Tempest array, and the research-grade system. Multiple frontal passages, several rounds of precipitation, and a synoptically driven high wind event were all recorded during this period, as well as the first official freeze of the Fall 2022 season. Initial results indicate high precision among the Tempest array and reasonable agreement with the other platforms. In addition to the initial results of the Tempest performance in the validation experiment, this presentation will also offer two examples of the use of the Tempest system in urban meteorological research. These projects include an assessment of the urban heat island across Louisville, Kentucky, as well as the effects of heat mitigation efforts on human comfort in an urban environment. Initial project results as well as features that make the Tempest system ideally suited for these projects will be discussed.