Verifying Experimental Wet Bulb Globe Temperature Hindcasts Across the United States. (1st April 2022)

• Record Type: Journal Article
• Authors: Ahn, Yoonjung; Uejio, Christopher K.; Rennie, Jared; Schmit, Lisa
• Is Part Of: GeoHealth. Volume 6:Number 4(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-01
• Subjects: climate change adaptation -- heat exposure -- weather forecast -- occupational exposure; Environmental health -- Periodicals; Electronic journals; Periodicals; 616.98
• DOI: 10.1029/2021GH000527
• Languages: English
• ISSNs: 2471-1403

Abstract

Abstract: Hot and humid heat exposures challenge the health of outdoor workers engaged in occupations such as construction, agriculture, first response, manufacturing, military, or resource extraction. Therefore, government institutes developed guidelines to prevent heat‐related illnesses and death during high heat exposures. The guidelines use Wet Bulb Globe Temperature (WBGT), which integrates temperature, humidity, solar radiation, and wind speed. However, occupational heat exposure guidelines cannot be readily applied to outdoor work places due to limited WBGT validation studies. In recent years, institutions have started providing experimental WBGT forecasts. These experimental products are continually being refined and have been minimally validated with ground‐based observations. This study evaluated a modified WBGT hindcast using the historical National Digital Forecast Database and the European Centre for Medium‐Range Weather Forecasts Reanalysis v5. We verified the hindcasts with hourly WBGT estimated from ground‐based weather observations. After controlling for geographic attributes and temporal trends, the average difference between the hindcast and in situ data varied from −0.64°C to 1.46°C for different Köppen‐Geiger climate regions, and the average differences are reliable for decision making. However, the results showed statistically significant variances according to geographical features such as aspect, coastal proximity, land use, topographic position index, and Köppen‐Geiger climate categories. The largest absolute difference was observed in the arid desert climates (1.46: 95% CI: 1.45, 1.47), including some parts of Nevada, Arizona, Colorado, and New Mexico. This research investigates geographic factors associated with systematic WBGT differences and points toward ways future forecasts may be statistically adjusted to improve accuracy. Plain Language Summary: Guidelines for the duration and intensity of work that can be safely performed depend on a complex heat exposure metric. This metric considers air temperature, humidity, wind speed, and solar radiation. However, the most common U.S. heat exposure metric only considers temperature and humidity. Thus, the safe outdoor work guidelines have not been widely applied since the complex heat exposure metric was not widely available nor rigorously evaluated. The US National Oceanic and Atmospheric Administration National Weather Service (NOAA NWS) started issuing experimental WBGT in Fall of 2019. This study validated the complex heat exposure information with weather prediction models and ground‐based weather stations. We found fairly reliable correspondence between estimated and local values. However, we found that the differences varied according to geographical features, time, and the climatic zone. Key Points: The estimated Wet Bulb Globe Temperature seems to be reliable for most parts of the U.S. The differences varied according to geographical features, temporal variables, and the Köppen‐Geiger climatic zones The estimated average differences varied from −0.64°C to 1.46°C according to the Köppen‐Geiger climate categories