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GFDL Events & Seminars

Poster Expos

Upcoming GFDL events & seminars

Events and seminars
  • July 8, 2015: The impact of the North Atlantic Oscillation on climate through its influence on the Atlantic Meridional Overturning Circulation (AMOC)
    Tom Delworth (NOAA/GFDL)
    TBA
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • July 9, 2015: Idealized Cloud-Resolving Modeling for Tropical Climate Studies
    Usama Anber (Department of Earth and Environmental Sciences/Columbia University. )
    Many studies have utilized cloud-resolving models (CRMs) to study the characteristics of tropical moist convection in the state of radiative-convective equilibrium (RCE). However, RCE cannot be used to represent the tropical atmosphere locally because it lacks large-scale mean circulation. For this matter, I will use a limited domain model in idealized configuration that explicitly resolves convection and parameterizes the large scale vertical motion. This method allows a two-way interaction between the large scale dynamics and cumulus convection when the model domain is too small to resolve the large scale circulation, allowing the model itself to determine the occurrence and intensity of deep convection. This is as opposed to more traditional methods, in which otherwise similar numerical experiments are performed with specified large-scale vertical motion, strongly constraining the bulk properties of convection a priori. It is also computationally inexpensive and can be used to explore the effect of a wide range of parameters. In this talk I will introduce two methods used to represent the large-scale motion in CRMs. Then, utilizing a theory for tropical mean precipitation based on conserved variables of the dry and moist static energy, I will examine some parameters controlling mean precipitation: surface fluxes vs. radiative heating, vertical wind shear, and interactive radiation. Finally, I will use the model in its idealized settings to test its predictive power to simulate the seasonal and diurnal cycle in the Amazon basin.
    Time: 11:00 am - 12:00 pm
    Location: Smagorinsky Seminar Room
  • July 10, 2015: Different Response of Extreme Precipitation to Warming over Mountains, Plains, and Oceans
    Xiaoming Shi (Department of Atmospheric Sciences/University of Washington)
    Climate simulations predict an intensification of extreme precipitation in almost all areas of the world under global warming. The rate of this intensification depends on the change in temperature and vertical velocity in extreme events, because temperature determines the amount of moisture available to condense for a given adiabatic ascent, and vertical velocity determines the timescale of that condensation. Over mountains, the response of vertical motion to warming was recently found controlled by gravity wave dynamics. Here we show that, in idealized climate simulations where orography can be modestly resolved, precipitation extremes over mid-latitude at areas and idealized mountains respond to climate change differently, due to distinct dynamical forcings to their vertical motion. In both cases, the increase in the intensity of precipitation extremes caused by temperature rise is around 6% per K of surface warming, yet the ascent in the extreme events over oceans and plains is enhanced due to stronger diabatic forcing from moist processes, whereas the ascent in orographic extremes mostly weakens. This makes the precipitation extremes over plains and oceans increase about 3%/K faster than orographic extremes, suggesting that the population in mid-latitude at regions might be more susceptible to the impacts of global warming.
    Time: 11:00 am - 12:00 pm
    Location: Smagorinsky Seminar Room
  • July 14, 2015: Archimedes Revisited: Rethinking Buoyancy for a Better Understanding of Convective Dynamics
    Nadir Jeevanjee ( University of California, Berkeley)
    The Archimedean buoyancy is the standard measure of buoyant acceleration, but fails to account for the well-known (but often ignored) back-reaction of the environment on accelerating parcels. For wide, squat parcels near the surface, such as the "cold pools" of air produced by low-level rain evaporation, this back-reaction can offset over 90% of the original Archimedean buoyancy. In this talk we present exact analytical expressions for the net buoyant acceleration which encapsulate this dependence on aspect ratio and surface proximity, and use them to understand the nature of convective triggering at cold pool gust fronts. These formulae may also be useful in parameterizations of the vertical velocity equation for clouds, as well as for mapping out the transition from hydrostatic to non-hydrostatic regimes in large-scale numerical models.
    Time: 10:30 am - 11:30 am
    Location: 309 Seminar Room
  • July 15, 2015: Climate trends analysis updates: Heat stress and the global warming hiatus
    Thomas Knutson (NOAA/GFDL)
    TBD
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • July 27, 2015: Antarctic Bottom Water influence on the last glacial and deglaciation
    Laurie Menviel (University of New South Wales, Sydney, Australia)
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • July 29, 2015: TBD
    Dr. Paul Spence (UNSW, Sydney, Australia)
    TBD
    Time: 12:00 pm - 2:00 pm
    Location: Smagorinsky Seminar Room
  • September 2, 2015: Analytical solution of PBL
    Ben-Jei Tsuang (NOAA)
    TBD
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • September 9, 2015: Roles of Climate Variability on Western US Ozone Pollution: Decadal Changes, Extremes, and Implications for Seasonal Prediction
    Meiyun Lin (NOAA/GFDL)
    TBD
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • September 30, 2015: TBD
    Vaishali Naik (NOAA/GFDL)
    TBD
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • October 8, 2015: TBA
    Amy Clement (RSMAS - Miami)
    TBA
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • November 18, 2015: TBD
    Lorenzo Polvani (Columbia University)
    TBD
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room

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