Seminars and Events
Dr. Frank Raes – Atmospheric Processes Division, Institute for Environment and Sustainability, Joint Research Centre of the European Commission, Ispra, Italy
4/30/09 – 5/4/09
May 1, 2009 – Linkages Between Air Pollution and Climate Change: Science and Policy
Abstract
We used scenarios for reducing emissions of greenhouse gases and air aerosols between 2000 and 2050, scenarios that are considered realistic by policy makers, and we studied their effect on climate and air quality. We used two types of models: the Global Circulation Model ECHAM5 and the Chemical Transport Model TM5.The GCM calculations show how increasing GHG concentrations alone (expected without any climate policy) result in a global annual mean equilibrium temperature increase of 1.20 °C between 2000 and 2030. The equilibrium temperature response due to decreasing aerosols alone (expected by the implementation of a strong air pollution reduction policy) is 0.96 °C. The latter value is globally less than that from increasing GHGs, but it is concentrated in the Northern Hemisphere, where most of the air pollution source regions are located. The combined effect of increasing GHGs and decreasing aerosols leads to a global increase of the equilibrium surface temperature by 2.18 °C, and to more than 4 °C in vast regions of the Northern Hemisphere. Global precipitation will also increase.
With the CTM calculations, we look at the effect of both air pollution policies and greenhouse gas reduction policies. Climate Change policies (e.g. energy efficiency, renewable energies, etc …) have clear co-benefits for air pollution, e.g. reduction of aerosols. However that same reduction of aerosols is shown to largely offset the decrease in radiative forcing obtained by reducing greenhouse gases until at least 2050. Regardless of the policy is used, we expect a faster rate of global warming in the coming decades. Climate policies must be implemented quickly in order to stabilize climate in the long term. In the mean time, policy makers must stress that such implementation will have benefits in the near term, i.e. improved air quality, energy security, etc.
May 4, 2009 – Air Pollution Monitoring From a Mediterranean Cruise Ship from 2007 to Present: Operational Considerations and Some Data and Analysis
Abstract
Cruise ships offer a convenient platform for carrying out routine observations of atmospheric and oceanic parameters. Here I present results from a three year program carried out aboard the cruise ship 'Costa Crociere' which follows a regular track in the Western Mediterranean between April and November. I present the results of measurements of ozone and black carbon aerosols, along with other parameters. Analysis of the data include a study of high ozone levels related to anticyclonic circulation over the Western Mediterranean and subsidence that bring air masses down from altitudes between 1000 and 3500 meters. A second analysis relates to the contribution of local ship emissions to levels of ozone and black carbon aerosols, and the validation of several ship emission inventories. I conclude with a discussion of the advantages and difficulties of carrying out cruise ship programs such as this.
Dr. Peter Lamb – Cooperative Institute for Mesoscale Meteorological Studies and School of Meteorology, The University of Oklahoma, Norman, OK
1/9/2009
January 9, 2009 – Sahel Drought: How Did Mesoscale Weather System Variations Produce the Largest Regional Climate Change in the 20th Century?
Dr. Martin Visbeck – IfM-GEOMAR, Kiel, Germany
12/15/08 – 1/30/09
January 14, 2009 – Observed Changes in the Southern Ocean Winds and Associated Impacts on the Oceans Stratification and Circulation: Are there Lessons for the Role of the Southern Ocean in CO2 Uptake and Paleo Climatic Events?
January 21, 2009 – First Results from the Guinea Dome Tracer Release Experiment (GUTRE) in the Tropical North Atlantic Oxygen Minimum Zone
Dr. Nathan Taylor – University of British Columbia, Vancouver, Canada
12/1/08 – 12/5/08
December 4, 2008 - A Multistock Age-Structured Assessment Model of Atlantic Bluefin Tuna: Integrating Stock Composition, Conventional and Electronic Tagging Data
Dr. Fred Jopp – Institute of Zoology, Free University of Berlin, Germany and Visiting Professor, Department of Biology, University of Miami, Coral Gables, FL, USA
11/24/08
November 24, 2008 – Modeling the Aquatic Food Web Structure of the Everglades
Prof. Daniel Rosenfeld — Program of Atmospheric Studies, Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
11/14/08
November 14, 2008 – Floods or Droughts: How do Aerosols Affect Precipitation?
Dr. Daniel J. Vimont – Atmospheric and Ocean Sciences Department, University of Wisconsin, Madison, WI
6/8/08 – 6/14/08
June 8, 2008 – Meridional Modes in the Climate System: Dynamics, Impacts and Predictability in the Pacific and Atlantic
Abstract
The dynamics of tropical “Meridional Modes” are discussed, as well as their role in Atlantic and Pacific climate variability. Meridional modes are dynamical “modes” of variability that can be identified from simple coupled models of the tropical ocean / atmosphere system, as well as through statistical analysis of ocean / atmosphere variability in the tropical Pacific and Atlantic. Meridional modes emerge as dominant modes of covariability between the atmosphere and ocean due to a positive feedback between surface winds, evaporation, and SST (the WES feedback). Although the WES feedback destabilizes the meridional mode, it is not likely that these modes are linearly unstable in nature. Instead, some sort of external forcing is likely required for their excitation.
Tropical meridional modes play an important role in generating and influencing climate variability in the Pacific and Atlantic. In the Pacific, meridional mode variations provide a mechanism through which mid-latitude atmospheric variability can influence ENSO. Timing of the Pacific meridional mode may influence ENSO amplitude and phase locking to the seasonal cycle. In the Atlantic, the meridional mode can be excited by a number of climatic variations, including ENSO, the North Atlantic Oscillation, and high-latitude oceanic variations. The latter connection leads to predictability of the Atlantic Meridional Mode during the Atlantic hurricane season.
Dr. Maureen Conte – Bermuda Institute of Ocean Sciences, Bermuda
3/12/09
March 12, 2008 — Weather in the Ocean Abyss: Particle Rain, Storms, and Hurricanes
Abstract
The Oceanic Flux Program sediment traps off Bermuda have continuously measured the deep ocean particle flux since the late 1970s, with a >95% temporal coverage at 3200m depth. The early OFP discovery of a seasonal cycle in deep particle flux clearly demonstrated that the deep ocean was directly coupled to the overlying surface environment via the particle flux, laying to rest the (then) widely held view of the abyssal ocean as an invariant, largely isolated realm. In the 30 years since, the OFP time-series has clearly shown that deep ocean environment is closely linked to upper ocean variability occurring on time-scales of days to decades. In fact, the deep particle flux- analogous to atmospheric precipitation- follows a strongly skewed (gamma) frequency distribution with transient flux "rainstorms", which occur most predominately in the late fall and spring when surface stratification is weak and variable. On longer time-scales, deep particle flux exhibits no long term trend but is weakly inversely correlated with the wintertime North Atlantic Oscillation (NAO) Index. This correlation reflects the greater frequency of transient, high flux events in years when the wintertime NAO Index is low, suggesting a direct influence of increased wintertime storminess on the efficiency of the biological pump.
Prof. Daniel Rosenfeld — Program of Atmospheric Studies, Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
10/1/07 — 10/2/07
October 2, 2007 - Simulation of Hurricane Response to Supression of Warm Rain by Sub-Micron Aerosols
Ernest Lewis — Brookhaven National Laboratory,
Atmospheric Sciences Division, Upton, NY
4/22/07 — 4/24/07
April 23, 2007 — Sea Salt Aerosol 101
Abstract
Sea salt aerosol is the dominant aerosol component over most of
Earth's surface and accounts for the majority of aerosol
emissions to the atmosphere globally. Sea salt aerosol
particles act as cloud condensation nuclei, scatter light, and
serve as a sink for gases and smaller aerosol particles. Thus
they can affect the hydrological cycle, Earth's radiation
balance, geochemical cycling of elements, and the size
distribution of other aerosol components. This lecture provides
an introduction to sea salt aerosol and discusses its
importance, its properties, and the size range of particles of
which it is comprised. The role of sea salt aerosol in
atmospheric processes is examined and estimates are presented
for concentrations and fluxes of sea salt aerosol and their
dependences on particle size, wind speed, and other factors.
April 24, 2007 — Sea Salt Aerosol: Advanced Topic
Abstract
The size-dependent production flux of sea salt aerosol is of primary importance in quantifying sea salt aerosol and its role in various atmospheric processes. In this lecture methods that have been utilized to infer this flux are reviewed, and estimates based on some of these methods are examined in detail. Topics to be discussed include size-dependent sea salt aerosol concentrations, oceanic whitecap ratios, laboratory results of sea salt aerosol production, and the proposed dependences of the production flux on wind speed and other factors. The confidence that can be placed in these estimates is evaluated, and the state of knowledge of the size-dependent sea salt aerosol production flux is summarized.
Dr. Omar Torres — Joint Center for Earth Systems
Technology, University of Maryland Baltimore County, MD
3/24/07 — 3/26/07
March 27, 2007 — The Global Distributions of Dust and Smoke: Measuring Aerosol Absorption with OMI Observations
Abstract
There is great interest in the radiative properties of aerosols, especially those aerosols that absorb solar radiation. The dominant absorbing aerosol species in the atmosphere are mineral dust, derived largely from arid regions, and black and organic carbon, emitted by natural and anthropogenic combustion processes. The long-held view that the effect of aerosols in the global radiative balance was one of just cooling is currently being re-evaluated. Observational evidence as well as important theoretical analyses, indicate that the absorption of solar radiation by soot-containing and organic aerosols may in fact contribute to warming the atmosphere. In addition to the well-documented climate role of aerosol absorption, recent research indicates that absorbing aerosols may also have an effect on the hydrological cycle as it inhibits cloud formation and prevents or delays the onset of precipitation.
The discovery of the capability to detect aerosol absorption from space using near-UV observations was one the most important breakthroughs of the last decade in aerosol remote sensing from space. The technique, developed from analysis of observations by the TOMS instrument has been extensively used for the global mapping of absorbing aerosols. Aerosol absorption can be measured from space in the near UV by taking advantage of the interaction between Rayleigh scattering and particle absorption. The result of this radiative transfer interaction is a unique signal that clearly detects the presence of absorbing aerosols under most observing conditions: clear skies over water and land surfaces (including deserts), mixed with clouds or above them, and aerosols over ice and snow covered surfaces.
For soot-containing aerosols, the near-UV aerosol absorption signal is a proxy of an important radiative transfer effect of significance not just in the near-UV but also in the visible and near-IR. I will discuss the application of the near-UV method to measurements by the Ozone Monitoring Instrument (OMI). Results of the observed spatial and temporal variability of aerosol absorption will be shown. I will also discuss the results of a comparison analysis using AERONET observations.
Dr. Paul Ginoux — Geophysical Fluid Dynamics
Laboratory, National Oceanic and Atmospheric Administration,
Princeton, NJ
3/13/07 — 3/14/07
March 14, 2007 — African Dust and North Atlantic Climate: Positive Feedback Between Dust and the Azores Anticyclone
Dr. William K.M. Lau— Laboratory for Atmospheres,
NASA, Goddard Space Flight Center, Greenbelt, MD
6/14/06 — 6/18/06
June 15, 2006 — Aerosol-Water Cycle Interaction: A New Challenge for Monsoon Climate Research
Dr. Fritz Schott — IfM-GEOMAR, Leibniz-Institut
für Meereswissenschaften, Kiel, Germany
3/28/06 — 4/13/06
April 7, 2006 — Tropical Atlantic Variability: Observations vs. Models and Assimilations
Prof. Yuli D. Chashechkin — Laboratory of Fluid Mechanics, Institute for Problems in Mechanics, Russian Academy of Sciences, 101/1 Prospect Vernadskogo, Moscow 117526 2/28/06 — 3/14/06
March 2, 2006 — About Resolvability of Governing Equations: Generation of 2D and 3D Periodic Internal Waves (Linear and Slightly Non-Linear Theory and Lab Experiments)
March 7, 2006 — 2D Wave and Vortex Wakes Past Uniformly Moving Plates and Cylinders: Formation of Streaky Structures, Soaring Interfaces with Vortex Pairs and Vortex Systems
March 8, 2006 — 3D Diffusion Induced Boundary Currents; Double Diffusive Convection
March 10, 2006 — On the Problem of Measurements of Oceanic Parameters and Optimization of Measurement Protocol
Prof. Stanley D. Gedzelman — Department of Earth and
Atmospheric Sciences, The City College of New York, 138th
Street & Convent Avenue, New York, NY 10031
1/26/06
January 26, 2006 — The Sky in Art
Dr. Ron Miller — NASA, Goddard Institute for Space Studies, Department of Physics, Columbia University, New York, NY
12/7/05
December 7, 2005 — How Much Dust is in the Wind and How Does it Affect Climate?
Jennifer Gebelein — Florida International
University, Miami, Florida
11/15/02
November 15, 2001 — Coral Reef Change — An Integrated approach Using Land and Reef Remotely Sensed Data
Abstract
Maps of coral reefs and adjacent land areas are needed by
natural resource managers around the world. These managers are
making daily decisions that impact the health of coral reefs
and the economies of the communities that depend on them. In a
new NASA funded project, remote sensing is being used to
analyze not only coral reef communities but also the adjacent
land masses that can potentially effect the health of those
reef systems. Dr. Jennifer Gebelein at Florida International
University is beginning the effort to map and analyze these
adjacent land masses using Landsat 7 imagery. Mapped areas on
the adjacent land will focus on features of the land
environment that may be potentially threatening for reef
systems including rivers, wetlands, agriculture and urban
areas. This is a collaborative effort with researchers from
FIU, Johnson Space Center, USF, GSFC, ICLARM, and United
Nations Environmental Programme World conservation Monitoring
Centre (&NEP-WCMC). Then this effort is completed these
maps will be distributed by UNEP-WCMC and ReefBase in support
of the activities of international development agencies and
local resource managers.
Georgy Golitsyn — Director, A.M. Obukhov
Institute of Atmospheric Physics, RAS Moscow, Russia —
Distinguished Visiting Scientist
1/8/02 — 2/7/02
Daniel Rosenfeld — Professor Ring Department of Atmospheric Sciences, Institute of Earth Sciences, Hebrew University of Jerusalem, Israel
2/13/02 -2/16/02
February 14, 2002 — Impacts of Aerosols on Convective Clouds and Precipitation
Abstract
Measurements of the Tropical Rainfall Measuring Mission
satellite made it possible to observe simultaneously cloud drop
size, cloud water content, and precipitation. Conspicuous
streaks of clouds with reduced droplet size and with lack of
precipitation were observed and associated with plumes of
aerosols ingested into the clouds. The aerosols were mostly
anthropogenic emissions in the form of smoke from burning
vegetation, urban and industrial air pollution. These aerosols
suppress precipitation by reducing the size of cloud drops and
the rate that they can merge into raindrops and freeze onto ice
precipitation particles.
Sahara desert dust was found to have similar effect on clouds, although with some important differences because of the large sizes of the particles and their ice nucleating activity. Feedback loops between aerosols and precipitation are identified, such as less rainfall allowing more fires and rising dust, further suppressing the rainfall. This provides a mechanism of desertification and prolongation of droughts. Because much of the energy that propels the global circulation comes from latent heat release, tempering with the precipitation can also affect the global circulation, including storm tracks.
William Cooper — Professor, Department of Chemistry, Center for Marine Sciences, Wilmington, NC
3/5/02-3/8/02
March 6, 2002 — Recent Studies on Hydrogen Peroxide Cycling in Oligotrophic Marine Water: Bermuda Atlantic Time Series Station (BATS)
March 7, 2002 — Treatment of Ballast Water Using Ozone: An Experiment on a 120,000 Ton Oil Tanker
Willard Pierson — Professor, New York City College
3/10/02-3/20/02
March 13, 2002 — Recent Successes in the EOS Program: Needed Research on Unanswered Questions About These Spacecraft and What They Can Do
Abstract
The EOS (or the Earth Observing System) program has had a
number of very import successes during the past few years. Some
are (1) the ability to predict the tides for the deep ocean to
within 2 cm rms, (2) the measurement of the winds by means of
QuickSCAT within undoubtedly an error of less than 2 m/s rms
for the range of wind speeds from 3 to 20 m/s or 10% rms for
winds from 20 m/s to 30 m/s, (3) the use of QuickScat winds
operationally By NCEP and (4) the results of the Tropical
Rainfall Measuring Mission are clearly bound to present very
import results on the cloud structure and rainfall patterns in
tropical cyclones. These successes are illustrated by various
products.
However there are a few questions still to be answered concerning the properties of these remote sensing systems and concerning future applications for them. For example, the geophysical Model Function for QuickSCAT may have very small systematic errors for wind direction that will be difficult to identify and eliminate. Also a way to prove that winds greater than about 20 m/s are correctly recovered is difficult to do because not very many independent verifications by buoys are available and the measurements are obscured by the effects of heavy rain and thick clouds. When ADEOS II to is eventually placed in orbit the passive microwave systems on it will help to solve this particular problem.
Radar altimeters have been successful in solving the problem of the global tides as described in a book by David Edgar Cartwright. The remaining problems have to do with the detailed analysis of the tides in coastal areas and internal tides. Radar altimeter theory involves the convolution of three functions. One represents the radar wave form. The next is the antenna pattern effect. The last is the effect of the waves. It is probably possible to show that this last effect is incorrectly treated and that a better model would make it possible to obtain information on the crests of the very high waves on the ocean.
Although. the presently available QuickSCAT data are extremely good, certain properties of the model function need to be investigated more carefully and the parameters that define the variance of the sample values need to be checked by an analysis of the actual data. QuickSCAT and TRMM complement each other. The radar on TRMM that describes the vertical structure of the clouds and rainfall patterns is most interesting from the point of view of studying the circulation and cloud structure in a tropical hurricane. One of the great difficulties in using TRMM data along with QuickSCAT data is that it is difficult to find cases where both kinds of measurements were made at nearly the same time. Some examples are given and some of the difficulties in analyzing the data are described.
March 18, 2002 — Wave Forecasting and Needed Research
on Nonlinear Waves
Abstract
There are a number of models for forecasting waves over the
oceans of the world. They differ in detail. When the same wind
field us used to generate the results of the various models the
spectra they predict are not the same. A way to intercompare
these various models for a sufficiently long time as to verify
which one is superior and how well they actually predict wave
properties, either in the hindcast or prediction mode, is
needed. The result of some of these comparisons area described.
Even if a model could be perfected, it would not be able to describe many of the properties of actual waves because it would be essentially for a linear model. Some way to describe the nonlinear properties of waves adequately needs to be developed and applied to a wave forecasting model and to practical applications.
Various experiments are discussed that indicate that the problem of describing the nonlinear properties of waves and of obtaining solutions that describe waves on the ocean is very difficult. They have shown at times contradictory results. These experiments are briefly reviewed, and additional laboratory experiments are described.
Eric Kraus — Former Director, CIMAS
3/10/02-3/14/02
Hal Batchelder — Associate Professor, Oregon State University
3/24/02-3/28/02
March 25,2002 — Individual-Based Modeling of Zooplankton: Where Behavior, Physiology, and Physics Meet
March 27, 2002 — The U.S. Globec Northeast Pacific Program: Overview, Goals, and Mid-Life Results
Arnold Gordon— Associate Director,
Lamont-Doherty Earth Observatory of Colombia University
3/31/02-4/7/02
April 3, 2002 — For the Global Thermohaline Circulation, Little Things May Mean A Lot
William Collins — Scientist III, National Center for Atmospheric Research
5/14/02-5/19/02
May 15,2002 — Modeling Aerosols with Assimilation of Observations
Abstract
A new method for simulating aerosols combines chemical
transport modeling with assimilation of aerosol observations.
The assimilation enhances the fidelity of the model on short
space and time-scales. It can also help improve the simulation
of long-range transport. The assimilation procedures adjust the
aerosol loading in the model for consistency with
satellite-retrieved aerosol optical depth. The model produces
global time-dependent three-dimensional distributions of
sea-salt, sulfate, soil-dust, and carbonaceous aerosols. The
system produced aerosol forecasts for the Indian Ocean
Experiment (INDOEX) in 1999 and the Aerosol Characterization
Experiment (ACE-Asia) in 2001.
The assimilation has been combined with radiative transfer codes to estimate the aerosol radiative forcing. For INDOEX, the calculations show that natural and anthropogenic aerosols reduce the surface insolation over much of the Indian subcontinent by 15 to 20%. The aerosol forcing is as large or larger than other heat sources and sinks, for example shortwave cloud forcing, which are currently included in standard meteorological models. The reduction in insolation is accompanied by an enhancement in atmospheric solar absorption by as much as 130%. Most of this absorption is contributed by the effects of carbonaceous aerosols. The implications of these findings for modeling of regional and global climate are discussed.
May 16, 2002 — Climate Sensitivity to Radiative Effects of Upper Tropospheric Water Vapor
Abstract
Approximately 60-70% of the natural greenhouse effect and 70-80% of the radiative feedback to doubling carbon dioxide are due to water vapor. A substantial fraction of the Earth's thermal radiation is emitted in far-infrared wavelengths between 15 and 100 microns. Some of the strongest radiative interactions with water vapor occur in the far-infrared rotation band. Despite its importance for the climate system, this part of the spectrum was last measured from space over 25 years ago. We illustrate why new measurements would help improve GCMs using the NCAR Community Atmosphere Model (CAM). We have updated the infrared absorption and emission by water vapor to bring CAM into agreement with modern line-by-line calculations. The main changes in the radiative heating rates are associated with line and continuum absorption in the rotation band. The effects of the rotation band are especially important in the upper troposphere. These changes interact strongly with the convective parameterizations in CAM, leading to significant changes in the simulated thermodynamic state. The changes in the mean climate and climate sensitivity are discussed in light of current uncertainties in the water vapor continuum. We discuss the prospects for testing GCM parameterizations of far-infrared radiation using a new generation of NASA satellite instruments.