Speaker: Kirsten Findell from GFDL
Title: "Land-Atmosphere Interactions, Anthropogenic Land Cover Change, and Future Aridity from local to continental scales"
Abstract: Land surface processes modulate the severity of heat waves, droughts, and other extreme events. However, models show contrasting effects of land surface changes on mean and extreme temperatures. I will first discuss core principles of land-atmosphere interactions from a one-dimensional column perspective to explain how vegetation and soil moisture control the partitioning of available radiant energy into sensible and latent heat fluxes, and how this can influence local temperature, humidity, and subsequent precipitation. We then use an earth system model to investigate the regional impacts of land use/land cover change on combined extremes of temperature and humidity, namely aridity and moist enthalpy, quantities central to human physiological experience of near-surface climate. I will show that the model’s near-surface temperature response to deforestation is consistent with recent observations, and that in many parts of the mid-latitudes, including the United States and Europe, forest clearing over the past few centuries has likely doubled to quadrupled the frequency of extremely hot, dry summers. Finally, I will discuss the role of land-atmosphere feedbacks on future projections of aridity on continental scales.