AOS Faculty Profile
Large-Scale Atmospheric Dynamics and Climate Modeling
The goal of my research is to gain a better understanding of such basic aspects of the atmospheric circulation as the pole-to-equator temperature gradient, the climatic distribution of surface easterlies and westerlies, and the location and strength of the jet stream. In this work I use a hierarchy of models ranging from comprehensive and realistic numerical circulation models to very idealized dynamical systems that capture some aspects of the relevant physics. I also try to apply the understanding of fundamental lunderstanding gained from this kind of work to the global warming problem.
Examples of topics on which I have focused include: how best to think of the atmosphere as a whole as a “heat engine” and how best to understand the relatively low efficiency with which the atmosphere generates kinetic energy; how changes in the water vapor distribution in the atmosphere as climate warms produce a positive feedback on this warming; factors that control how the poleward energy transport is partitioned between the atmosphere and the ocean; the way in which large-scale mountain ranges and land-sea heating contrasts create the stationary waves, or deviations from longitudinal symmetry, that we see in the planetary-scale tropospheric wind field, the response of tropical cyclone activity to warming, and the distinctions between transient and equilibrium responses to perturbations in the Earth's energy balance.
Most recently, I have also begun working on idealized models of the organization of turbulent moist convection in the tropics with the aim of improving our understanding of the temperature, relative humidity, and cloud profiles in the tropics.
Some Recent Publications:
Balaji, V, Rusty Benson, Bruce Wyman, and Isaac M Held, in press: Coarse-grained component concurrency in Earth System modeling. Geoscientific Model Development Discussion. DOI:10.5194/gmd-2016-114. May 2016.
Lutsko, Nicholas J., and Isaac M Held, in press: The Response of an Idealized Atmosphere to Orographic Forcing: Zonal vs Meridional Propagation. Journal of the Atmospheric Sciences. DOI:10.1175/JAS-D-16-0021.1. June 2016.
Merlis, Timothy M., W Zhou, Isaac M Held, and Ming Zhao, March 2016: Surface temperature dependence of tropical cyclone-permitting simulations in a spherical model with uniform thermal forcing. Geophysical Research Letters, 43(6), DOI:10.1002/2016GL067730.
Zhao, Ming, J-C Golaz, Isaac M Held, V Ramaswamy, Shian-Jiann Lin, Yi Ming, Paul Ginoux, Bruce Wyman, Leo J Donner, David J Paynter, and Huan Guo, January 2016: Uncertainty in model climate sensitivity traced to representations of cumulus precipitation microphysics. Journal of Climate, DOI:10.1175/JCLI-D-15-0191.1.
Ballinger, Andrew, Timothy M Merlis, Isaac M Held, and Ming Zhao, June 2015: The sensitivity of tropical cyclone activity to off-equatorial thermal forcing in aquaplanet simulations. Journal of the Atmospheric Sciences, 72(6), DOI:10.1175/JAS-D-14-0284.1.
Fueglistaler, Stephan, Claire Radley, and Isaac M Held, July 2015: The distribution of precipitation and the spread in tropical upper tropospheric temperature trends in CMIP5/AMIP simulations. Geophysical Research Letters, 42(14), DOI:10.1002/2015GL064966.
Hill, S A., Yi Ming, and Isaac M Held, March 2015: Mechanisms of forced tropical meridional energy flux change. Journal of Climate, 28(5), DOI:10.1175/JCLI-D-14-00165.1.
Jansen, Malte, Alistair Adcroft, Robert Hallberg, and Isaac M Held, August 2015: Parameterization of eddy fluxes based on a mesoscale energy budget. Ocean Modelling, 92, DOI:10.1016/j.ocemod.2015.05.007.
Jansen, Malte, Alistair Adcroft, Robert Hallberg, and Isaac M Held, October 2015: Energy budget-based backscatter in an eddy permitting primitive equation model. Ocean Modelling, 94, DOI:10.1016/j.ocemod.2015.07.015.
Lutsko, Nicholas J., Isaac M Held, and Pablo Zurita-Gotor, August 2015: Applying the Fluctuation-Dissipation Theorem to a Two-Layer Model of Quasi-Geostrophic Turbulence. Journal of the Atmospheric Sciences, 72(8), DOI:10.1175/JAS-D-14-0356.1.
Zurita-Gotor, Pablo, Isaac M Held, and Malte Jansen, September 2015: Kinetic energy-conserving hyperdiffusion can improve low-resolution atmospheric models. Journal of Advances in Modeling Earth Systems, 7(3), DOI:10.1002/2015MS000480.