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GFDL Past Events & Seminars - 2010

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Date Speaker Affiliation Title of Presentation
Jan. 6Steve Garner and Ming ZhaoSteve Garner and Ming Zhao
Modeling Studies on Tropical Cyclones and Climate Change
Jan. 7E. DiLorenzoE. DiLorenzo
ENSO and the North Pacific Gyre Oscillation: towards an integrated view of Pacific climate
Jan. 13Tom Knutson and Morris BenderTom Knutson and Morris Bender
Simulating the response of intense Atlantic hurricane activity to 21st century anthropogenic warming
Jan. 14Francis ZwiersFrancis Zwiers
Climate Change Detection and Attribution Methods
Jan. 21Chris FieldChris Field
Climate impacts and ecosystem feedbacks: Building toward the next IPCC assessment
Jan. 27Yi MingYi Ming
Aerosol-induced Changes in Boreal Winter Extratropical Circulation
Jan. 28Dick PeltierDick Peltier
Global Sea Level Rise: Closure of the budget over the GRACE era
Feb. 3Lars HedinLars Hedin
Nutrient Constraints on the Land Carbon Cycle
Feb. 4Nick BondNick Bond
Climate change and fishsticks: Dynamical projections of future walleye pollock populations in the Bering Sea
Feb. 5S. RamachandranS. Ramachandran
Spatiotemporal gradients in aerosol properties and radiative forcing over Bay of Bengal and Arabian Sea
Feb. 5Thomas FrölicherThomas Frölicher
The sensitivity of the coupled carbon cycle-climate system to natural variability and anthropogenic changes: Results from the NCAR CSM1.4-carbon model
Feb. 9Neven Fuckar Final Oral ExamNeven Fuckar Final Oral Exam
Final Oral Exam Sayre Hall Seminar Room
Feb. 17Julian Wang and Xin-Zhong LiangJulian Wang and Xin-Zhong Liang
Integrated Regional Earth System Modeling: Development and Application
Feb. 18Allison SteinerAllison Steiner
Biosphere-Atmosphere Interactions: Controls on regional climate and atmospheric chemistry
Feb. 24Tony BroccoliTony Broccoli
Feb. 24Water and Climate: Science, Policy, and Security in the Face of Change and UncerWater and Climate: Science, Policy, and Security in the Face of Change and Uncer
John Waterbury: Water and Climate: Enduring Collective Action Challenges Bowen Hall Auditorium (next to E-Quad) on Princeton U. campus.
Feb. 25Jery MitrovicaJerry Mitrovica
Ice Sheets, Solid Earth and Sea Level: New Results
Mar. 1Forrestal/Main Campus ShuttleForrestal/Main Campus Shuttle
Mar. 3Water and Climate: Science, Policy, and Security in the Face of Change and UncerWater and Climate: Science, Policy, and Security in the Face of Change and Uncer
Jerry Delli Priscoli: Water, Security and Global Policy Responses Bowen Hall Auditorium (next to E-Quad) on Princeton U. campus.
Mar. 3Stefan GerberStefan Gerber
Modeling Carbon-Nitrogen Interactions in LM3V
Mar. 8Marshall WardMarshall Ward
Informal 0 Group seminar - The Force Balance of Wind-Driven Channel Models
Mar. 10Adam ShowmanAdam Showman
Atmospheric circulation of giant planets inside and outside the Solar System
Mar. 10Water and Climate: Science, Policy, and Security in the Face of Change and UncerWater and Climate: Science, Policy, and Security in the Face of Change and Uncer
Charles Vorosmarty: Climate Uncertainty and Water Resources at the Global Scale Bowen Hall Auditorium (next to E-Quad) on Princeton U. campus.
Mar. 11Ronald CohenRonald Cohen
Fires, farms, and trucks: perspectives from space on changes to atmospheric nitrogen
Mar. 16Brown Bag Seminar John Dunne and Ryan RykaczewskiBrown Bag Seminar John Dunne and Ryan Rykaczewski
Decoupling of the temperature-nutrient relationship in the California Current Ecosystem with Global Warming
Mar. 18Sumant NigamSumant Nigam
Droughts over the US Great Plains: A key role for Atlantic basin temperatures
Mar. 18Brown Bag Seminar - Mary Glackin DUSBrown Bag Seminar - Mary Glackin, DUS
NOAA Climate Services Line Office
Mar. 25Professor Ted ShepherdProfessor Ted Shepherd
The role of stratospheric dynamics in chemistry-climate coupling
Mar. 31Eric LeibenspergerEric Leibensperger
Climate Response to Changing US Aerosol Sources
Apr. 1A. R. RavishankaraA. R. Ravishankara
Ozone depletion, Montreal protocol, climate change and nitrous oxide: musings on science and policy
Apr. 2Michael OppenheimerMichael Oppenheimer
Why two-degrees?: policy origins, scientific rationale
Apr. 5Axel LauerAxel Lauer
The impact of global warming on marine boundary layer clouds over the eastern Pacific - A regional model study
Apr. 8Jennifer LoganJennifer Logan
Insights into the transport characteristics of the GEOS assimilated fields from analysis of satellite data for CO in the tropical upper troposphere
Apr. 13Dr. Ian Fenty, MITDr. Ian Fenty, MIT
Hydrographic Preconditioning for Sea Ice in the Labrador Sea
Apr. 14Water and Climate: Science, Policy, and Security in the Face of Change and UncerWater and Climate: Science, Policy, and Security in the Face of Change and Uncer
Kathleen Miller: Science, Politics and Crystal Balls - Building Effective Approaches to Water Adaptation Planning Robertson Hall - Bowl l on Princeton U. campus.
Apr. 14Isaac HeldIsaac Held
The recalcitrant component of global warming
Apr. 15Prof. Stewart PragerProf. Stewart Prager
Fusion Energy: Accomplishments and Remaining Challenges
Apr. 15Christopher Wolfe, Scripps Inst. OceanographyChristopher Wolfe, Scripps Inst. Oceanography
The mid-depth stratification of eddying ocean models
Apr. 22 Bill Cotton Bill Cotton
Aerosol impacts on clouds and storms
Apr. 27Freddy Bouchet (CNLS Los Alamos)Freddy Bouchet (CNLS Los Alamos)
Non-equilibrium statistical mechanics of atmosphere and ocean flows
Apr. 28Hamish RamsayHamish Ramsay
The effects of relative and absolute sea surface temperature on tropical cyclone potential intensity using a single column model
Apr. 29Ming XueMing Xue
Convection-resolving deterministic and ensemble forecasts with radar data assimilation
May. 5Prof. Cheng-Ta ChenProf. Cheng-Ta Chen
Regional model downscaling of tropical cyclone activity in the Northwest Pacific basin
May. 6Ming-Jen YangMing-Jen Yang
The Catastrophic Typhoon Morakot (2009) on Taiwan: Observational and Modeling Aspects
May. 7Sophie ZhangSophie Zhang
A Model Study of the Slope/Shelf Circulation and Cross-Slope/Shelf Transport in the Western Antarctic Peninsula and Marguerite Bay
May. 10Caroline MullerCaroline Muller
Relationship Between Tropical Precipitation and Water Vapor in Current Climate and Under Warming
May. 10 Ruben van Hooidonk Ruben van Hooidonk
Using GCMs to predict coral bleaching
May. 11GFDL 5K RaceGFDL 5K Race
5 K Race
May. 12John LanzanteJohn Lanzante
Differing Rates of Surface & Tropospheric Warming: Demystifying a Controversy
May. 13Thomas StockerThomas Stocker
Towards IPCC AR5 - The Physical Science Basis: Science Gaps, Structure of the Report, and Schedule of Production
May. 14James BoothJames Booth
Examination of the influence of SST in the Gulf Stream region on individual midlatitude storms using synoptic models and data from a reanalysis product In Sayre Hall, Room 312
May. 17Jingqiu MaoJingqiu Mao
Chemistry of Hydrogen Oxide Radicals (HOx) in the Troposphere: From Arctic Spring to North America Summer
May. 19Gabriel VecchiGabriel Vecchi
Long-lead seasonal hurricane forecasts
May. 19Steve Mayle, GFDL, and Craig Piotrowski, Princeton UniversityPrinceton University Facilities Project Management Office
Status update on several GFDL facilities projects.
May. 21Dr. Y. MiyazawaDr. Y. Miyazawa
Japan Coastal Ocean Predictability Experiment: the Development of Parallel Ensemble Kalman Filter using the parallelized Princeton Ocean Model
May. 24Cheryl LoganCheryl Logan
Predicting Climate Change Effects on Marine Species: Integrating Physiology into Marine Ecosystem Models
May. 26Yi MingYi Ming
absorbing aerosols: from radiative forcing to hydrological response
Jun. 1Yi HuangYi Huang
Spectral fingerprinting of climate forcing and feedback
Jun. 4S. N. TripathiS. N. Tripathi
Understanding the heterogeneity in aerosol characteristics over the Indo-Gangetic Basin - an observational portrayal
Jun. 7Geert Jan van OldenborghGeert Jan van Oldenborgh
Verification of Temperature and Precipitation Trends in Climate Models
Jun. 9Junfeng LiuJunfeng Liu
New developments in aerosol and cloud chemistry simulation in AM3: towards a chemistry-climate study on inter-continental transport of air pollution.
Jun. 10Siegfried SchubertSiegfried Schubert
Some results on the nature and potential predictability of drought on monthly to decadal time scales
Jun. 16Leo Oey and Yu-Lin ChangLeo Oey and Yu-Lin Chang
Loop Current and BP Oil Spill
Jun. 17Alex HallAlex Hall
Constraining Climate Feedbacks with Observations
Jul. 8Craig Piotrowski, Princeton University Office of Design and ConstructionGFDL Data Silo Area Schematic Design Review
Review AKF Schematic Design for GFDL Data Silo Area Construction Project
Jul. 12Andrea RayAndrea Ray
Pikas and dams and droughts: Creating regional-scale climate assessments for management & planning
Jul. 14Nikos HatzianastassiouNikos Hatzianastassiou
Tendencies of shortwave radiation budget beyond 2000, global dimming and brightening and possible implications for climate
Jul. 15Prof Yuh-Lang LinProf Yuh-Lang Lin
A Review of Cloud Microphysics Schemes used in Atmospheric Models
Jul. 26Eco System GroupEco System group
Aug. 11John AustinJohn Austin
Long term projections of stratospheric ozone
Aug. 12Alexandr KhainAlexandr Khain
Simulation of mesoscale phenomena (including TC) using models with spectral bin microphysics (SBM)
Aug. 18Janet NyeJanet Nye
The role of Atlantic multidecadal variability and the Gulf Stream in determining the spatial distribution of Northwest Atlantic fish stocks
Aug. 25Anand GnanadesikanAnand Gnanadesikan
Linking Marine Ecosystem and Climate Variability: Recent Results
Sep. 15Emily FischerU of WashingtonImporting ozone precursors and aerosols to the North American free troposphere: an analysis of peroxyacetyl nitrate (PAN) and aerosol observations from Mount Bachelor
Abstract: This talk will have two components, and there is something for everyone. We will begin with an analysis of the first consistent multi-year springtime measurements of peroxyacetyl nitrate (PAN) over the U.S. Pacific Northwest. PAN is an important constituent in the global atmosphere, responsible for redistributing reactive nitrogen. A limited number of case studies indicate that the NOx released from the thermal decomposition of imported PAN may represent a significant source of O3 to the eastern Pacific free troposphere. If changes in Asian NOx emissions are impacting O3 over North America, we expect a relatively larger parallel increase in PAN over the eastern Pacific. We will discuss factors driving the observed interannual variability in PAN at Mount Bachelor, including temperature and biomass burning. We will also explore whether consistent free tropospheric PAN observations could be the keystone to understanding increasing springtime O3 mixing ratios over western North America. The latter portion of this talk will present measurements of aerosol optical properties made at Mount Bachelor during spring 2008 and spring 2009. The overarching goal of this second project is to increase our understanding of how aging impacts the optical properties of Asian aerosols, particularly biomass burning smoke, industrial pollution and dust. We will explore two questions by examining 7 aerosol plumes of Asian origin observed at Mount Bachelor. 1) Are differences in the intensive optical properties of Asian aerosols observed over the western U.S. linked to variations in composition? 2) How do the aerosol optical properties observed in plumes of Asian origin over the western U.S. differ from those observed closer to the Asian source region?
Sep. 16Yuqing WangU of HawaiiDynamical Downscaling of Western North Pacific Tropical Cyclone Genesis by the IPRC Regional Climate model
Abstract Dynamical downscaling with a regional climate model (RCM) has been widely used for climate change assessment, seasonal predictions, understanding of climate processes and regional climate predictability (see the review by Wang et al. 2004). By this approach, a high-resolution limited area model is driven by relatively coarse resolution reanalysis or output of a coarse resolution global model to produce more detailed regional features. This has been approved to be particularly useful for the study of extreme climate events, including tropical cyclones. There have been several studies using RCMs to investigate the possible impact of global warming on the activity of tropical cyclones in different ocean basins. Knutson et al. (2007) demonstrated how well a nested regional atmospheric model driven by the reanalysis reproduced the recent multidecadal increase of Atlantic hurricane activity. However, the hurricane counts in the model were very sensitive to how strong the large-scale nudging in the interior of their model was. In this talk, following a brief review in the dynamical downscaling of tropical cyclone genesis, the performance of the regional atmospheric model (IRAM) developed at the International Pacific Research Center (IPRC) in reproducing the tropical cyclone genesis over the Northwest Pacific has been evaluated. The NCEP/NCAR reanalysis is used to provide both initial and lateral boundary conditions to the IRAM, which was run at a horizontal resolution of 0.3o lat/lon. The weekly mean Reynolds SST was used as the lower boundary conditions for the model over the ocean. Simulations for 17 years from 1990 to 2006 are analyzed in the study. The model was initialized at June 1 and integrated continuously through November 30 for each year without the use of any interior nudging. The model TCs are located and tracked using an objective algorithm previously developed by Stowasser et al. (2007) for the IRAM. The results show that the model reproduced not only the mean seasonal cycle but also the interannual variability of tropical cyclones in the Northwest Pacific realistically. The correlation coefficients between the modeled and observed annual tropical cyclone counts and the power dissipation index reach 0.82 and 0.74, respectively. The correlation coefficient between the modeled and observed seasonal cycle reaches 0.92. Further, the model also reproduced the spatial distributions of genesis locations and frequency occurrence reasonably well. Further experiments for the Northwest Pacific TC genesis in response to SST anomalies over the eastern Indian Ocean show that the model can reproduce the observed response quite well. Therefore, the results demonstrate that given accurate large-scale circulation from an ocean-atmospheric coupled global model, the IRAM can be used to provide skillful dynamical downscaling for seasonal prediction and climate change projection of tropical cyclone genesis over the Northwest Pacific.
Sep. 29Angelique Melet DieudonneLEGI/MEOM (CNRS), Grenoble, FranceSolomon Sea circulations and water mass transformations
Sep. 30Michela BiasuttiLDEOUnderstanding changes in Sahel precipitation, or linking regional and global climate change
The Sahel, the semi-arid region of Africa just south of the Sahara desert, has experienced such a prolonged and devastating drought in recent decades as to be often cited in the non-scientific literature as an example of the perils of global warming. In this talk I will review current knowledge on the origin of drought in 20th Century Sahel and will present the projections for future changes in the seasonal evolution of Sahel rainfall in response to increasing greenhouse gases. Throughout the talk, I will emphasize the link of regional droughts and pluvials to global-scale climate anomalies and the consensus of the CMIP3 models. In this framework, we can interpret the projected delay and shortening of the rainy season in the Sahel as a regional manifestation of a global delay in the seasonal cycle of global precipitation and SST. While a phase delay in high latitude temperatures in response to CO2 had been simulated before, the delay of the global monsoon is a new result, one that might help increase our understanding and confidence in regional projections of tropical rainfall. Finally, I will describe two possible mechanisms for the global phase changes in surface temperature (a direct forcing by greenhouse gases and high latitude sea ice changes) and provide some preliminary analysis of their expected role.
Oct. 6Lorenzo PolvaniStratospheric ozone depletion: the main driver of 20th Century atmospheric circulation changes in the Southern Hemisphere
Oct. 7Jim RandersonU of Cal - IrvineThe role of fire in climate-carbon cycle feedbacks
Oct. 14Richard BirdseyDept. of Agriculture -Forest ServiceForest Disturbance and Carbon Dynamics of North America
Most forests of the world are recovering from a past disturbance: 3% of the total forest area is disturbed each year by fire, pests, and weather. The net sequestration or loss of CO2 by forests after disturbance follows a predictable pattern determined by age, site, climate, and other factors. Forests of North America are currently a net carbon (C) sink due primarily to re-growth of previously harvested or abandoned forests. Projections of the future changes in C sources and sinks critically depend on understanding of the causes of past disturbances, the impacts of those disturbances, and scenarios of future disturbances. Observations indicate that tree mortality has increased significantly in North America over the last decade, the result of natural forest dynamics (aging) and increasing damage from climate and natural disturbance. Given the increasing significance of current and projected natural disturbances, what are the interactions with climate and the C cycle at regional and global scales?
Oct. 20Daniel GoldbergGFDL/AOS The response of grounded ice to ocean temperature forcing in a coupled ice sheet-ice shelf-ocean cavity model
Oct. 20Steve RintoulCSIRO Hobart AustraliaSouthern Ocean Physics and Observations
Oct. 21Jonathan GregoryMet Office Hadley CenterKinetic energy analysis of the response of the Atlantic meridional overturning circulation to CO2-forced climate change
Atmosphere-ocean general circulation models (AOGCMs) predict a weakening of the Atlantic meridional overturning circulation (AMOC) in response to anthropogenic forcing of climate, but there is a large model uncertainty in the magnitude of the predicted change. The weakening of the AMOC is generally understood to be the result of increased buoyancy input to the north Atlantic in a warmer climate, leading to reduced convection and deep water formation. Consistent with this idea, model analyses have shown empirical relationships between the AMOC and the meridional density gradient, but this link is not direct because the large-scale ocean circulation is essentially geostrophic, making currents and pressure gradients orthogonal. Analysis of the budget of kinetic energy (KE) instead of momentum has the advantage of excluding the dominant geostrophic balance. Diagnosis of the KE balance of the HadCM3 AOGCM and its low-resolution version FAMOUS shows that KE is supplied to the ocean by the wind and dissipated by viscous forces in the global mean of the steady-state control climate, and the circulation does work against the pressure-gradient force, mainly in the Southern Ocean. In the Atlantic Ocean, however, the pressure-gradient force does work on the circulation, especially in the high-latitude regions of deep water formation. During CO2-forced climate change, we demonstrate a very good temporal correlation between the AMOC strength and the rate of KE generation by the pressure-gradient force in 50-70N of the Atlantic Ocean in each of nine contemporary AOGCMs, supporting a buoyancy-driven interpretation of AMOC changes. To account for this, we describe a conceptual model, which offers an explanation of why AOGCMs with stronger overturning in the control climate tend to have a larger weakening under CO2 increase.
Oct. 28Jerry MitrovicaHarvardIce Sheets, Sea Level and the Solid Earth: New Results
Nov. 4Guy BrasseurGerman Climate Service Center, Hamburg, GermanyFrom Climate Research to Earth System Management: The Role of Climate Services
Nov. 9INCITE User MeetingRemote Computing User Meeting
ORNL INCITE user meeting
Nov. 16Stephen KleinPCMDI/LLNLAtmospheric Convection in Observations and Models
Atmospheric convection is an enduring problem in climate service. With this talk, I address two questions of current interest: (1) What do observations tell us about the conditions that favor the transition from shallow to deep convection over land? and (2) What improvements in the simulation of tropical convection might be achieved by moderate increases in the horizontal resolution of climate models?
Nov. 17Jonathan Mitchell of UCLASuperrotation in the Solar System
Superrotation in the Solar System
Nov. 18Duncan WinghamCentre for Polar Observations and ModelingThe West Antarctic Ice Sheet retreat: The ephemera of climate variability or something more serious?
The notion that the West Antarctic Ice Sheet has a configuration that is unstable to small perturbations at its margins is an old one. Recent records showing that the Amundsen Sea sector of the ice sheet is retreating, coupled with the observation that a large scale retreat of the ice sheet will result in several meters of sea level rise, now make it important that the detailed mechanics of the instability mechanism are fully understood. This seminar will review the observational record from the 1990's that lead to the view that the ice sheet is retreating at an accelerating rate. It will consider whether the notion of instability is sufficient to explain the phenomenon, or whether it is more likely that external ocean 'forcing' better explains the observations. I will argue that the present configuration is not one of irreversible retreat, and that the important question to understand today is whether the recent increase in oceanographic heat flux to the base of the ice sheet at its grounding line is simply a decadal fluctuation, or a longer term, secular trend that will necessarily then result in irreversible retreat.
Nov. 23Gaea OrientationGaea OrientationGaea Orientation
Dec. 1 Gualtiero Badin Boston University Lateral mixing by submesoscale processes in the ocean
Dec. 7Alexis BergLOCEAN IPSLToward an integrated modelling of crop-climate interactions: including tropical croplands in a land surface model
Toward an integrated modelling of crop-climate interactions: including tropical croplands in a land surface model
Dec. 8Seung-Ki MinEnvironment Cananda TorontoDetecting human influence on precipitation extremes
During the past decades, heavy precipitation events have become more intense over a large part of the Northern Hemisphere land area. It has been suggested that human-induced increase in greenhouse gases may be partly responsible for the observed intensification of extreme precipitation in line with the increased water holding capacity of atmosphere with warming. However, because of the limited observational availability, most previous studies have examined only the potential detectability through model-model comparisons. Here we compare observed and multi-model simulated extreme precipitation changes using an optimal fingerprinting technique, and provide the first evidence that human influence has contributed to the observed intensification of heavy precipitation events during the latter half of the 20th century. Model projected changes and their impacts may nevertheless be underestimated because models tend to underestimate the observed increase in heavy precipitation with warming.
Dec. 9Susan SolomonESRLTimescales and Processes in Climate Change: Transience, Persistence, Irreversibility, and the Surprising Roles of Different Gases
Emissions of a broad range of greenhouse gases of varying lifetimes contribute to global climate change. Carbon dioxide displays exceptional persistence that renders its warming nearly irreversible for more than a thousand years. This talk focusses on explaining the physical reasons for this behavior, and its consequences for global climate change. I will also show that the warming due to non-CO2 greenhouse gases, while not irreversible, persists notably longer than the anthropogenic changes in the greenhouse gas concentrations themselves. This occurs because the persistence of warming depends not just on the decay of a given greenhouse gas concentration but also on climate system behavior, particularly the time scales of heat transfer linked to the ocean. For carbon dioxide and methane, non-linear optical absorption effects also play a smaller but significant role in prolonging the warming. In effect, dampening factors that slow temperature increase during periods of increasing concentration also slow the loss of energy from the Earth's climate system if radiative forcing is reduced. Implications for future global climate change and human choices will be explored.
Dec. 15Stephanie DownesAOSTBA
Dec. 16Malin PinskyStanfordWhy abundant and widespread marine species are not more resilient to collapse: clues from population genetics and global fisheries