GFDL - Geophysical Fluid Dynamics Laboratory

GFDL Events & Seminars

Upcoming GFDL events & seminars

Events and seminars

  • October 17, 2018: Testing Parameterizations of Convective Overshoot
    Lunchtime Seminar - Daniel Lecoanet (Princeton Center for Theoretical Science, Princeton University)
    There are many natural systems with convectively unstable fluid adjacent to stably stratified fluid: the Earth's atmosphere and ocean, as well as most stars, and perhaps even the Earth's liquid core. The convective motions penetrating into the stable region can enhance mixing, leading to changes in transport within the stable region. In this talk, I will present convective overshoot simulations, in which I quantitatively measure the extra mixing due to overshooting motions. I parameterize the extra mixing as a spatially-dependent turbulent diffusivity. Finally, I will test the parameterization and interpret the results.
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • October 23, 2018: On the nature of entrainment in dry convection
    Informal Seminar - Nadir Jeevanjee (Princeton University)
    Entrainment or mixing of environmental fluid is a key process in convection. It is thought to be fundamentally turbulent in nature, and is a lingering source of uncertainty in climate models. Here we study entrainment in the context of isolated, buoyant fluid parcels (known in the atmosphere as `thermals'), using direct numerical simulation. By varying the Reynolds number of our simulations we compare laminar and turbulent thermals, and find only small (~20%) differences in entrainment between them. This is consistent with some previous theoretical work suggesting that entrainment is driven by buoyancy, rather than turbulence. We build an analytical model for the motion of our thermals based on this notion, and test it against our simulations. We also perform mechanism-denial experiments in which we `turn off' our thermals' buoyancy midway into our simulations, and indeed find marked reductions in entrainment.
    Time: 10:30 am - 11:30 am
    Location: Smagorinsky Seminar Room
  • October 25, 2018: TBD
    Formal Seminar - Suzana Camargo (Lamont-Doherty Earth Observatory Columbia University)
    In this talk, I’ll discuss the characteristics of tropical cyclones in climate models, which are used in projections of TC activity under anthropogenic climate change. Some characteristics of TC climatology improve with model resolution, but not all do, and the improvement is not uniform across models. Using a large number of climate models, the relationship of standard TC diagnostics with the mean climate state is analyzed. Models with the same resolution can have a very different TC climatology, even if their large-scale environments are very similar. In order to understand these differences, two new diagnostics were developed that can give insight on how to improve models’ TC climatology, as well as the reliability of their projections. In the second part of this talk the ability of the current generation of models in forecasting tropical cyclones (TCs) – hurricanes, typhoons – weeks in advance will be discussed. There is predictability in this time scales due to the well-known modulation of TC activity by the Madden-Julian Oscillation (MJO), with a higher level of TC activity when the MJO is in its active phase in a region. As the models’ skill in forecasting the MJO has improved in the last few years, the possibility of forecasting TC formation weeks in advance can be examined. The questions we will discuss are: How well do models simulate the MJO-TC relationship? Do models have skill in forecasting the probability of TC formation weeks in advance? Is the model skill dependent on the amplitude of the MJO? Primary Host: Hiroyuki Murakami
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • October 29, 2018: Understanding and Modeling the Earth's Climate: A symposium in honor of Isaac Held
    Isaac Held Symposium
    This three-day symposium will foster scientific exchange at the interface of atmospheric and climate dynamics, celebrating Isaac Held's seminal contributions in advancing our understanding of the Earth's climate. A set of invited talks will provide the broad context for panel discussions and poster sessions that will address Isaac's core interests which include atmospheric general circulation, teleconnections, dynamical insights on climate change, geophysical turbulence, and tropical dynamics. Registration required. The symposium will be held in the Frick Chemistry Lab/Taylor Auditorium, Princeton, New Jersey. Program and additional information at splash.princeton.edu/heldfest
    Time: 8:00 am - 6:00 pm
    Location: Other (see event description)
  • October 30, 2018: Understanding and Modeling the Earth's Climate: A symposium in honor of Isaac Held
    Isaac Held Symposium
    This three-day symposium will foster scientific exchange at the interface of atmospheric and climate dynamics, celebrating Isaac Held's seminal contributions in advancing our understanding of the Earth's climate. A set of invited talks will provide the broad context for panel discussions and poster sessions that will address Isaac's core interests which include atmospheric general circulation, teleconnections, dynamical insights on climate change, geophysical turbulence, and tropical dynamics. Registration required. The symposium will be held in the Frick Chemistry Lab/Taylor Auditorium, Princeton, New Jersey. Program and additional information at splash.princeton.edu/heldfest
    Time: 8:00 am - 6:00 pm
    Location: Other (see event description)
  • October 31, 2018: Understanding and Modeling the Earth's Climate: A symposium in honor of Isaac Held
    Isaac Held Symposium
    This three-day symposium will foster scientific exchange at the interface of atmospheric and climate dynamics, celebrating Isaac Held's seminal contributions in advancing our understanding of the Earth's climate. A set of invited talks will provide the broad context for panel discussions and poster sessions that will address Isaac's core interests which include atmospheric general circulation, teleconnections, dynamical insights on climate change, geophysical turbulence, and tropical dynamics. Registration required. The symposium will be held in the Frick Chemistry Lab/Taylor Auditorium, Princeton, New Jersey. Program and additional information at splash.princeton.edu/heldfest
    Time: 8:00 am - 6:00 pm
    Location: Other (see event description)

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