Variability and trends in average and extreme summer near-surface equivalent temperature in the Eastern USA

Near surface air temperature is the metric most commonly used to assess change in climate, but recent studies have noted that air temperature alone provides an incomplete description of lower tropospheric heat content. Equivalent temperature, which combines terms representing the sensible heat and latent heat components of near surface air, is used here to investigate possible changes in near surface energy content of the eastern USA during the last 50 years. Specifically, we (1) use robust regression techniques to estimate trends in equivalent temperature computed from a network of more than 100 National Weather Service 1st order stations in the eastern USA, (2) conduct an analysis of trends in extreme equivalent temperature events, defined as multi-day events exceeding the long term 90th percentile equivalent temperature, and (3) investigate variations in equivalent temperature in the context of regional soil moisture anomalies and large-scale modes of climate variability.