GFDL Events

Upcoming GFDL events & seminars

• October 17, 2012: More frequent future monsoon failure due to inherent instability
  Jacob Schewe (Potsdam Institute for Climate Impact Research, Germany)
  Indian monsoon rainfall is vital for a large share of the world's population. Both reliably projecting India's future precipitation and unraveling abrupt cessations of monsoon rainfall found in paleorecords require improved understanding of its stability properties. We show that in a comprehensive climate model, monsoon failure is possible but very rare under pre-industrial conditions, while under future warming it becomes much more frequent. We identify the fundamental intraseasonal feedbacks that are responsible for monsoon failure in the climate model, relate these to observational data, and build a statistically predictive model for such failure. Thereby we provide a simple dynamical explanation for future changes in the frequency distribution of seasonal mean all-Indian rainfall. Forced only by global mean temperature and the strength of the Pacific Walker circulation in spring, the simple model reproduces the future trend as well as the multi-decadal variability in seasonal monsoon rainfall, as found in the climate model. The approach offers a novel perspective on large-scale monsoon variability as the result of internal instabilities modulated by pre-seasonal ambient climate conditions.
  Time: 12:00 pm - 1:00 pm
  Location: Smagorinsky Seminar Room
• October 18, 2012: Evaluation and Regime-dependent Error Diagnosis of Cloud and Water Vapor Simulations in Climate Models Using NASA A-Train Satellite Observations
  Jonathan Jiang and Hui Su (Jet Propulsion Lab, Pasadena, CA)
  Using NASA "A-Train" satellite observations, we evaluate the accuracy of cloud water content (CWC) and water vapor mixing ratio (H2O) outputs from ~20 climate models submitted to the CMIP5, and assess improvements relative to their counterparts for the earlier CMIP3. We find more than half of the models show improvements from CMIP3 to CMIP5 in simulating column-integrated cloud amount, while changes in water vapor simulation are insignificant. For the CMIP5 models, the model spreads and their differences from the observations are much larger in the upper troposphere than in the lower or middle troposphere. Numerical scores are used to compare model performances in regards of to spatial mean, variance and distribution of CWC and H2O over the tropical oceans. Model performances at each pressure level are ranked according to the average of all the relevant scores for that level. We further developed a diagnostic framework to decompose the cloud simulation errors into the large-scale errors, cloud parameterization errors and co-variation errors. We find that the cloud parameterization errors contribute predominantly to the total errors for all models.
  Time: 2:00 pm - 3:15 pm
  Location: Smagorinsky Seminar Room
• October 31, 2012: TBA
  Marian Westley guest (TBA)
  TBA
  Time: 12:00 pm - 1:15 pm
  Location: Smagorinsky Seminar Room
• November 1, 2012: TBA
  Vernon Morris (Howard University)
  TBA
  Time: 2:00 pm - 3:15 pm
  Location: Smagorinsky Seminar Room
• November 7, 2012: Toward a new approach to Ocean Energetics: introducing the concept of Dynamical Potential Energy
  Fabien Roquet (Stockholm University, Sweden)
  Toward a new approach to Ocean Energetics: introducing the concept of Dynamical Potential Energy
  Time: 12:00 pm - 1:00 pm
  Location: Smagorinsky Seminar Room
• November 8, 2012: TBA
  Randal Koster (NASA)
  TBA
  Time: 2:00 pm - 3:00 pm
  Location: Smagorinsky Seminar Room
• November 14, 2012: TBA
  Charles Stock (GFDL)
  TBA
  Time: 12:00 pm - 1:00 pm
  Location: Smagorinsky Seminar Room
• November 15, 2012: TBA
  Oliver Buhler (NYU)
  TBA
  Time: 2:00 pm - 3:15 pm
  Location: Smagorinsky Seminar Room
• November 28, 2012: TBA
  Rachel Licker (Woodrow Wilson School at Princeton)
  TBA
  Time: 12:00 pm - 1:15 pm
  Location: Smagorinsky Seminar Room
• November 29, 2012: Insights into the relationship between regional radiative forcing and climate response
  Drew T. Shindell (NASA-GISS)
  While forcings such as those due to increasing greenhouse gases or changing solar irradiance are relatively uniform geographically, forcing by aerosols, ozone and land-use are highly inhomogeneous. This talk will explore some recent analysis attempting to better understand how this uneven distribution of forcing affects climate response. I will discuss results from simulations with the GISS GCM driven by localized regional forcings that help indicate how temperature and precipitation response is affected by both the type and location of forcing. Using GISS CMIP5 simulations driven by single forcing agents, I will then examine how the various agents affect the response of particular regional climate features including the location of the ITCZ and the rate of Southern Ocean overturning. Finally, results from a larger set of the new generation of CMIP5/ACCMIP composition-climate models will be examined to see how the response to highly inhomogeneous forcing compares with the response to greenhouse gas forcing and to evaluate the robustness of the regional forcing/response relationships across the models.
  Time: 2:00 pm - 3:15 pm
  Location: Smagorinsky Seminar Room
• December 12, 2012: TBA
  Ilya V. Buynevich (Temple University)
  TBA
  Time: 12:00 pm - 1:00 pm
  Location: Smagorinsky Seminar Room
• January 10, 2013: TBA
  Alexander Khain (Hebrew University of Jerusalem)
  TBA
  Time: 2:00 pm - 3:30 pm
  Location: Smagorinsky Seminar Room
• January 17, 2013: TBA
  Annemarie Carlton (Rutgers)
  TBA
  Time: 2:00 pm - 3:15 pm
  Location: Smagorinsky Seminar Room
• January 24, 2013: TBA
  Glenn Tallia (Section Chief in NOAA's General Counsel's office)
  TBA
  Time: 2:00 pm - 3:15 pm
  Location: Smagorinsky Seminar Room
• March 14, 2013: TBA
  Paul Durack (Lawrence Livermore National Laboratory)
  TBA
  Time: 2:00 pm - 3:15 pm
  Location: Smagorinsky Seminar Room
• March 21, 2013: TBA
  Ray Pierrehumbert (University of Chicago)
  TBA
  Time: 2:00 pm - 3:15 pm
  Location: Smagorinsky Seminar Room
• March 27, 2013: Diagnosis of Seasonally Dependent Predictability in Observations and CM2.5
  Xiaosong Yang (UCAR)
  Diagnosis of Seasonally Dependent Predictability in Observations and CM2.5
  Time: 12:00 pm - 1:15 pm
  Location: Smagorinsky Seminar Room

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