GFDL - Geophysical Fluid Dynamics Laboratory

GFDL Events & Seminars

Upcoming GFDL events & seminars

Events and seminars

  • May 2, 2017: GFDL Hurricane Science Symposium
    GFDL Hurricane Science Symposium
    GFDL Hurricane Science Symposium. For more information, see https://www.gfdl.noaa.gov/gfdl-hurricane-science-symposium/ New Meeting Tue, May 2, 2017 9:00 AM - 5:00 PM EDT Please join my meeting from your computer, tablet or smartphone. https://global.gotomeeting.com/join/884347445 You can also dial in using your phone. United States: +1 (872) 240-3212 Access Code: 884-347-445
    Time: 1:00 pm - 5:00 pm
    Location: Smagorinsky Seminar Room
  • May 3, 2017: Offline Tracer Modelling in MOM6
    Andrew Shao
    The inclusion of passive tracers into ocean general circulation models can represent a significant computational cost because they are often transported along at the same timestep as the thermodynamics (on the order of hours). Offline tracer methods reduce the computational requirements required to simulate tracers in two ways: 1) by saving diagnosed mass transports from a previous 'online' integration, only the tracer advection equation needs to be integrated and 2) longer tracer advective timesteps can be used (on the order of days or months) in most regions of the ocean. This seminar presents how we have implemented this idea into MOM6 and some initial evaluations of the differences in simulating ideal age and boundary impulse tracers between offline and online integrations of the half-degree version of OM4. Additionally, potential applications of this capability will be discussed including how external groups can take advantage of GFDL output, tracer sensitivity studies, and spinning up ocean biogeochemistry (with some early demonstrations using the BLING biogeochemical model).
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • May 4, 2017: A History of Bias in the Community Earth System Model (CESM): 20-years of Successes, Tough Choices and Persistent Problems
    Rich Neale (NCAR)
    This 'paleo-climate' talk will present a selection of results showing the evolution of skill metrics and diagnostics from simulations through six generations of the NCAR atmosphere model (CCM3 to CAM6) and five generations of the NCAR coupled model (CCSM2 to CESM2) spanning more than 20 years. During this time the complexity of the models have increased dramatically in almost every facet possible. These increases in complexity aim to target missing or poorly represented processes and interactions in models, but an improved simulation, where new representations are thought to play a substantial role, is frequently not guaranteed. Although advances from early model versions are undeniable, they are not monotonic in nature, and certain degradations often come at the expense of including these new processes, a result of the inevitable trade offs that come with model development. Precipitation is often a main target of model validation and the tropical double ITCZ crucial to model performance. The NCAR model has certainly had problems in the past, but in atmosphere-only simulations this was a minor problem prior to CAM4, became significant through CAM5 and was mostly remedied in CAM6. This recent degradation was the result of a trade off due to the improved variability, ENSO and regional precipitation characteristics with the inclusion of deep convection modifications in CAM4. Cloud radiative fields are important components of the global energy budget used to balance a fully coupled system. There is a stark contrast between short-wave cloud forcing, which has seen a 50% reduction in error, and long wave cloud forcing, which has seen virtually no improvement. This is somewhat surprising give that these fields are often addressed together as part of the model development process. Variability at timescales shorter than monthly have until relatively recently been a more secondary consideration. Since CAM3 tropical variability in particular has improved, but this has not been even when different models of variability are considered e.g., Kelvin Waves and the Madden Julian Oscillation (MJO). However, other improvements such as blocking statistics show more robust improvement over time. Finally we present a brief overview of the recent development process for CAM6, the need to continually consider the whole coupled system and its, at times, ad-hoc nature. -Evolution from CCSM2 and CCM2 -Mean climate -Coupled versus non-coupled -Non monotonic -Release variability -Paradigms for development (fully coupled) -A recent development exercise CAM6
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • May 10, 2017: The effect of buttressing on marine ice sheet dynamics
    Marianne Haseloff (GFDL/Princeton University)
    TBD
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • May 12, 2017: Southern Ocean response to recent changes in surface freshwater fluxes
    Alex Haumann (Swiss Federal Institute of Technology, Zurich)
    Earth's climate bears a close relation to the vertical exchange of water masses in the Southern Ocean. This connection originates from the transport of heat, carbon, and nutrients with the subduction and upwelling of water masses in this region. To date, the mechanisms that control long-term changes in this exchange between deep and surface waters are not firmly established. In this presentation, I will present observational and modeling studies to make the case that increased freshwater fluxes from sea ice are a major driver of observed changes in the Southern Ocean over recent decades by changing its surface density stratification in the upwelling region. An analysis of satellite and reanalysis data over the period 1982 to 2008 suggests that sea ice provides the dominant surface freshwater flux in the seasonally ice-covered region of the Southern Ocean compared to the available data of the atmospheric and land-ice freshwater fluxes. I will argue that the coastal formation, northward transport, and melting of sea ice is mainly responsible for observed meridional and vertical salinity gradient in the underlying ocean. This northward transport of freshwater through sea ice has increased by about 20% over the observational period, which explains the majority of the observed freshening of the open-ocean waters. Sensitivity studies with a regional ocean model suggest that this sea-ice induced freshening strongly increased the surface density stratification in the upwelling region and reduced the strength and depth of deep wintertime mixing. As a consequence, the surface ocean in these simulations cools with a spatial pattern and magnitude that is consistent with the satellite observed surface cooling over this period. Additionally, both the surface cooling and reduced vertical exchange considerably strengthen the net uptake of CO2 in the model, providing a potential explanation why the Southern Ocean carbon sink strengthened over recent decades despite an increase in westerly winds. In conclusion, the insights gained from the presented studies point towards much higher sensitivity of the upwelling in the Southern Ocean to changes in the sea-ice freshwater fluxes than previously thought and suggested by global climate models. Therefore, surface freshwater fluxes in the Southern Ocean could play a fundamental role in modifying the surface heat and CO2 exchange with the atmosphere during past and future changes in the global climate system.
    Time: 2:00 pm - 3:30 pm
    Location: Smagorinsky Seminar Room
  • May 16, 2017: TBD
    Daniel Gilford (MIT)
    TBD
    Time: 11:00 am - 12:00 pm
    Location: Smagorinsky Seminar Room
  • May 17, 2017: Precipitation Budget of the MJO
    Angel Adames
    TBD
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • May 18, 2017: TBD
    Rob DeConto (University of Massachusetts)
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • May 22, 2017: Anna Trugman - Final Public Oral
    Anna Trugman - Final Public Oral
    Anna Trugman - Final Public Oral
    Time: 10:00 am - 12:00 pm
    Location: Smagorinsky Seminar Room
  • May 25, 2017: TBD
    Ning Lin (Princeton University)
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • May 31, 2017: Predicting and characterizing atmospheric states from local dynamical properties of the underlying attractor
    Davide Faranda (Laboratorie des Sciences du Climate (LSCE) of the University of Paris-Saclay)
    Mid-latitude flows are characterized by a chaotic dynamics and recurring patterns hinting to the existence of an atmospheric attractor. In 1963 Lorenz described this object as: “the collection of all states that the system can assume or approach again and again, as opposed to those that it will ultimately avoid" and analyzed a low dimensional system describing a convective dynamics whose attractor has the shape of a butterfly. Since then, many studies try to find equivalent of the Lorenz butterfly in the complex atmospheric dynamics. Most of the studies where focused to determine the average dimension D of the attractor i.e. the number of degrees of freedom sufficient to describe the atmospheric circulation. However, obtaining reliable estimates of D has proved challenging. Moreover, D does not provide information on transient atmospheric motions, such as those leading to weather extremes. Using recent developments in dynamical systems theory, we show that such motions can be classified through instantaneous rather than average properties of the attractor. The instantaneous properties are uniquely determined by instantaneous dimension and stability. Their extreme values correspond to specific atmospheric patterns, and match extreme weather occurrences. We further show the existence of a significant correlation between the time series of instantaneous stability and dimension and the mean spread of sea-level pressure fields in an operational ensemble weather forecast at lead times of over two weeks. Instantaneous properties of the attractor therefore provide an efficient way of evaluating and informing operational weather forecasts
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • June 1, 2017: TBD
    Nicholas Lutsko - FPO (Princeton University)
    TBD
    Time: 10:00 am - 12:00 pm
    Location: Smagorinsky Seminar Room
  • June 1, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • June 8, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • June 9, 2017: Hold for Speaker for Griffies
    Hold for Speaker for Griffies
    Hold for Speaker for Griffies
    Time: 10:30 am - 11:30 am
    Location: Smagorinsky Seminar Room
  • June 14, 2017: TBD
    Bing Pu (Princeton University)
    TBD
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • June 15, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • June 21, 2017: Circulation and mixing in deep arctic ocean
    Hayley Dosser
    Circulation and mixing in deep arctic ocean
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • June 22, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • June 29, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • July 5, 2017: TBD
    Kun Gao (GFDL/Princeton University)
    TBD
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • July 6, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • July 13, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • July 20, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • July 27, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • August 3, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • August 10, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • August 17, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • August 24, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • August 28, 2017: Held Symposium
    Held Symposium
    Held Symposium
    Time: 8:00 am - 6:00 pm
    Location: Smagorinsky Seminar Room
  • August 29, 2017: Held Symposium
    Held Symposium
    Held Symposium
    Time: 8:00 am - 6:00 pm
    Location: Smagorinsky Seminar Room
  • August 30, 2017: Held Symposium
    Held Symposium
    Held Symposium
    Time: 8:00 am - 6:00 pm
    Location: Smagorinsky Seminar Room
  • August 31, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • September 7, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • September 13, 2017: TBD
    Lorenzo Polvani (Columbia University)
    TBD
    Time: 12:00 pm - 1:00 pm
    Location: Smagorinsky Seminar Room
  • September 14, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • September 21, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • September 28, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • October 5, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • October 12, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • October 19, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room
  • October 26, 2017: TBD
    Formal Seminar
    TBD
    Time: 2:00 pm - 3:00 pm
    Location: Smagorinsky Seminar Room

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