Land Cover Variability in Wet Bulb Globe Temperature Observations

Excessive heat is known to be a common cause of illness and fatalities, yet both forecasting and communicating heat risks to the public remains challenging. This is particularly true in forecast regions that cover large geographical areas that encompass urban, suburban, rural, and agricultural land covers. Each area has different physical and social characteristics, further complicating the need for clear, yet targeted messaging. Additionally, an underlying lack of data and general difficulty in quantifying heat health risk exists. The traditionally used heat index, which adjusts temperature based on relative humidity is known to be inapplicable in certain high temperature situations. While wet bulb globe temperature (WBGT) is more physiologically accurate, it is much more difficult to measure well, and several estimation methods for the wet bulb temperature component have been utilized. To address these issues, a study is being conducted in and around Columbia, SC with the primary goal of characterizing the variability of WBGT across different landcovers (urban, suburban, rural, grass, and forest) and evaluating the measurements against standard national weather service heat index-based advisories. Two summers of data will be presented, and the merits of each estimation technique as well as instrument limitations will be discussed.