Effects of grid spacing on high-frequency precipitation variance in coupled high-resolution global ocean-atmosphere models.
Charles X Light, Brian K Arbic, Paige E Martin, Laurent Brodeau, J Thomas Farrar, Stephen M Griffies, Ben P Kirtman, Lucas C Laurindo, Dimitris Menemenlis, Andrea Molod, Arin D Nelson, Ebenezer Nyadjro, Amanda K O'Rourke, Jay F Shriver, Leo Siqueira, R Justin Small, Ehud Strobach
Author Information
Charles X Light: Electrical Engineering and Computer Science Department, University of Michigan, Ann Arbor, MI USA. ORCID
Brian K Arbic: Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI USA.
Paige E Martin: Department of Physics, University of Michigan, Ann Arbor, MI USA.
Laurent Brodeau: Institut des Géosciences de L'Environnement, CNRS-UGA, Grenoble, France.
J Thomas Farrar: Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA USA.
Stephen M Griffies: Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration, + Princeton University Atmospheric and Oceanic Science Program, Princeton, NJ USA.
Ben P Kirtman: Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL USA.
Lucas C Laurindo: National Center for Atmospheric Research, Boulder, CO USA.
Dimitris Menemenlis: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA.
Andrea Molod: NASA Goddard Space Flight Center, Greenbelt, MD USA.
Arin D Nelson: Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI USA.
Ebenezer Nyadjro: Northern Gulf Institute, Mississippi State University, Stennis Space Center, Hancock County, MS USA.
Amanda K O'Rourke: Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI USA.
Jay F Shriver: Oceanographic Division, Naval Research Laboratory, Stennis Space Center, Hancock County, MS USA.
Leo Siqueira: Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL USA.
R Justin Small: National Center for Atmospheric Research, Boulder, CO USA.
Ehud Strobach: CMNS-Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD USA.
High-frequency precipitation variance is calculated in 12 different free-running (non-data-assimilative) coupled high resolution atmosphere-ocean model simulations, an assimilative coupled atmosphere-ocean weather forecast model, and an assimilative reanalysis. The results are compared with results from satellite estimates of precipitation and rain gauge observations. An analysis of irregular sub-daily fluctuations, which was applied by Covey et al. (Geophys Res Lett 45:12514-12522, 2018. 10.1029/2018GL078926) to satellite products and low-resolution climate models, is applied here to rain gauges and higher-resolution models. In contrast to lower-resolution climate simulations, which Covey et al. (2018) found to be lacking with respect to variance in irregular sub-daily fluctuations, the highest-resolution simulations examined here display an irregular sub-daily fluctuation variance that lies closer to that found in satellite products. Most of the simulations used here cannot be analyzed via the Covey et al. (2018) technique, because they do not output precipitation at sub-daily intervals. Thus the remainder of the paper focuses on frequency power spectral density of precipitation and on cumulative distribution functions over time scales (2-100 days) that are still relatively "high-frequency" in the context of climate modeling. Refined atmospheric or oceanic model grid spacing is generally found to increase high-frequency precipitation variance in simulations, approaching the values derived from observations. Mesoscale-eddy-rich ocean simulations significantly increase precipitation variance only when the atmosphere grid spacing is sufficiently fine (< 0.5°). Despite the improvements noted above, all of the simulations examined here suffer from the "drizzle effect", in which precipitation is not temporally intermittent to the extent found in observations.
