Increased frequency of extreme precipitation events in the North Atlantic during the PETM: Observations and theory ...

• Main Author: Rush, William
• Format: Dataset
• Language: English
• Published: Dryad 2021
• Subjects: PETM; runoff; climate model; CAM5; Mid Atlantic; Pyrenees; North Atlantic
• Online Access: https://dx.doi.org/10.7291/d1fq18; https://datadryad.org/stash/dataset/doi:10.7291/D1FQ18

Climate model simulations of the PETM (Paleocene-Eocene Thermal Maximum) warming have mainly focused on replicating the global thermal response through greenhouse forcing, i.e. CO2, at levels compatible with observations. Comparatively less effort has gone into assessing the skill of models to replicate the response of the hydrologic cycle to the warming, particularly on regional scales. Here we have assembled proxy records of regional precipitation, focusing on the Mid-Atlantic Coasts of North America (New Jersey) and Europe (Spain) to test the response of the hydrologic system to greenhouse gas forcing of the magnitude estimated for the PETM (i.e., 2x). Given evidence that the PETM initiated during a maximum in eccentricity, this includes the response under neutral and extreme orbital configurations. Modeled results show excellent agreement with observations in Northern Spain, with a significant increase in both mean annual and extreme precipitation resulting from increased CO2 levels under a neutral ... : A series of experiments simulating the PETM warming have been conducted (Kiehl et al., in prep; Shields et al., in prep) utilizing the high resolution (0.25°) CAM5, Version 5.3, with fixed sea surface temperatures and finite volume dynamical (FV) core, with 30 levels in the vertical for the atmosphere component (Neale et al., 2010; Park et al., 2014). The land component is the Community Land Model, Version 4 (CLM4) (Lawrence et al., 2011), also at 0.25° resolution, with the river transport model (RTM) at 1° resolution. Organic aerosol emissions were produced by running MEGAN (Model of Emissions of Gases and Aerosols) approximated from PETM biomes using DeepMIP protocols (Guenther et al., 2012; Lunt et al., 2017). The boundary conditions and sea surface temperatures from this model were obtained from a fully coupled LP and PETM FV 2° CESM1.2.2 (Community Earth System Model, Version 1.2) with output taken at a monthly temporal resolution over 1800 years. Output was obtained from CAM5 at 6 hourly, daily, and ...