Deliverables
Draft: April 18, 2005
There is a strong need to reduce uncertainty in estimates of radiative forcing
of climate and climate change by aerosols. The DOE Atmospheric Science Program
is a major component of a larger national and international program addressing
this issue. In particular, in addition to research on aerosol properties and
processes affecting climate forcing, there is a need to represent aerosol
processes, properties, and influences on clouds and radiation in large-scale
climate models. While such modeling is beyond the scope of ASP, it requires
the products of ASP research in evaluating such large-scale influences. In
particular this effort requires models and parameterizations of the pertinent
aerosol properties and processes, that is, numerical descriptions of these
processes that can be incorporated in such large scale models, together with
assessments of the accuracy of such models and parameterizations. These
requirements drive research that is conducted within ASP and also the
deliverables of the Program. These deliverables are distinguished into two
categories:
Science deliverables are specific advances that form the scientific basis for
program deliverables. Science deliverables range from data sets (from field
and laboratory studies) comprising the primary results of these studies, to
scientific papers published in the peer-reviewed literature that document the
findings on which ASP models and parameterizations are based and the associated
uncertainties. These science deliverables will generally be completed in a
given funding cycle; the current funding cycle extends over FY 2005-FY
2007.
Program deliverables are the products that will be delivered by the program as
a whole. These program deliverables incorporating these advances in
science will generally be completed in following three-year funding cycle,
i.e., during FY 2008-FY 2010.
This document introduces the ASP Program Deliverables and the ASP Science
Deliverables that are needed to support those Program Deliverables.
PROGRAM DELIVERABLES
Models and parameterizations suitable for representing aerosol
properties and processes required to compute aerosol radiative forcing of
climate in large-scale climate models, together with an assessment of their
accuracy and limitations.
Models and parameterizations relating aerosol light scattering and
absorption, including dependence on relative humidity and other
controlling variables, to aerosol chemical and microphysical properties.
Models and parameterizations relating cloud microphysical
properties and dependence on controlling variables, to concentration,
and chemical and microphysical properties of pre-cloud aerosol.
Models and parameterizations relating the evolution of aerosol
composition and microphysical properties, and optical and cloud
nucleating properties, to concentrations of precursor gases, properties of the
pre-existing aerosol, cloud processing, and other controlling variables.
SCIENCE DELIVERABLES
1. FIELD MEASUREMENTS
Measurements of concentrations and properties of aerosols and aerosol
precursors and other pertinent variables (e.g., insolation, meteorological and
micrometeorological data) suitable for developing and/or evaluating model-based
representation of the processes controlling the loading and properties of
atmospheric aerosols especially pertinent to their direct and indirect
radiative forcing.
These data sets will be intensive in space, time, and multivariate,
encompassing multiple measurements by multiple techniques, permitting highly
differentiated examination of interrelations between aerosol properties and
governing processes and development of qualitative and quantitative
descriptions of aerosol processes in the atmosphere.
Specific deliverables
Data sets from G-1 aircraft flights during ASP field campaigns, including documentation and visualization tools. Measurements include atmospheric state parameters, concentrations of core gas-phase species (CO, SO2, O3, NO, NO2, NOy, etc), and aerosol properties, together with other pertinent data (location, altitude, etc.). Data are to be provided in customary physical units and readily usable format and documented with appropriate calibrations and uncertainties. [Hubbe, Springston]
A merged data set of all the surface observations made during the ASP field
experiments on a uniform time grid.
Data set of vertical profiles of aerosol optical properties in "curtains"
under the Flight International Lear Jet. These properties include (a) Aerosol
backscatter coefficient at 532 nm and 1064 nm; (b) Aerosol extinction
coefficient at 532 nm; and (c) Aerosol depolarization (%) at 532 nm and 1064
nm. These deliverables would be provided for measurements acquired as part of
the ASP 2006 Megacity Aerosol eXperiment in Mexico city (MAX-Mex), the Aerosol
Processing in Cumuliform Clouds experiment, and proposed future ASP missions as
requested by the ASP science team. [Hostetler]
Comparisons of measurements of aerosol optical properties with optical
properties calculated from measured aerosol size distributions, aerosol
morphology, and chemical composition, together with assessment of
uncertainties. [optical properties working group]
Determination of the evolution of aerosol microphysical and optical
properties during well defined Lagrangian or quasi-Lagrangian situations, and
comparison with model calculations of such evolution. [multiple
investigators]
Measurements of aerosol size-distribution and aerosol hygroscopicity and
volatility pertinent to size-resolved aerosol mixing state and composition
[Wang] and comparison with model calculations of such properties.
Chemical content of secondary organic aerosol (SOA); concentration of gaseous
SOA precursors and oxidants. [Molina]
Measurements by proton-transfer ion-trap mass spectrometry time-of-flight
mass spectrometry chemical identity and concentration of SOA and gaseous SOA
precursors. [Alexander]
Characterization by a variety of microscopic and spectroscopic techniques of
chemical, hygroscopic, and morphological properties of bulk aerosol and
individual particles. [Laskin]
Characterization by near-edge x-ray absorption spectra of atmospheric
particles that do or do not contain soot (black carbon, BC); determination of
the extent to which x-ray microscopy imaging can be used to quantify the mixing
state of BC particles. [Gilles]
Measurements by liquid-phase chromatography of filter samples of
concentrations total organic carbon and water soluble organic carbon in
aerosols in conjunction with characterization of humic-like substances in these
aerosols. [Lee]
Characterization of field collected organic aerosol particles pertinent to
relationships between chemical structure and physical (hygroscopic and optical)
properties. [Finlayson-Pitts]
CCN data set--concentrations active at at least 10 different supersaturations
every few seconds throughout the research portions of all research flights in
MASE. The entire range of supersaturations should span 1-0.02%. [Hudson]
Measurements of aerosol absorption using a photoacoustic and photothermal
interferometric techniques. [Arnott, Sedlacek].
Determination of black carbon and organic carbon aerosol mass and optical
properties. [Paulson]
Determination of aerosol mean lifetimes and black carbon washout rates.
[Gaffney]
Chemical characterization for activated and non-activated aerosols.
[Berkowitz and Jobson]
Chemical and size characterization of aerosols following their passage
through cumuliform clouds. [Berkowitz and Berg]
Examples of possible derived products
Identification of mechanisms by which gas-phase precursors are converted to
condensed phase material by secondary atmospheric reaction, e.g., acid
catalyzed reaction and the responsible reagent substances.
Determination of rates and yields of aerosol processes such as secondary
organic aerosol formation and conversion of hydrophobic to hydrophilic
aerosol.
Identification of conditions under which new particle formation occurs in the
atmosphere, the responsible nucleating substances, threshold conditions, and
the like.
2. LABORATORY STUDIES
Laboratory measurements of concentrations and properties of aerosols and
aerosol precursors and other pertinent variables (e.g., insolation,
meteorological and micrometeorological data) suitable for determination of
derived products such as rate constants and mechanisms, suitable for
incorporation in and/or evaluation of model-based representation of the
processes controlling the amount and properties of atmospheric aerosols
especially pertinent to their direct and indirect radiative forcing.
These studies examine aerosol properties and of their evolution under
controlled laboratory conditions, together with a specification of those
conditions, permitting qualitative and quantitative descriptions of aerosol
processes in the atmosphere, their rates, and their dependence on governing
conditions.
Specific deliverables
Determination of physical and chemical properties of BC particles subjected
to surface oxidation and coating with organic and inorganic species.
Examination of effect of soot morphology and chemistry on hydroscopic and
optical properties. [Davidovits]
Smog chamber data for acid-catalyzed SOA formation from a variety of parent
VOCs, including molecular speciation by mass spectrometry and hygroscopicity
characterization. [Seinfeld]
Characterization by a variety of microscopic and spectroscopic techniques of
chemical, hygroscopic, and morphological properties of bulk aerosol and
individual particles produced under controlled laboratory conditions . [Laskin]
Characterization of organic particles produced under controlled laboratory
conditions to determine structure-physical (hygroscopic and optical) properties
relationships for SOA and nitrate particles. [Finlayson-Pitts]
Rate constants for reactions of OH, NO3, and O3 with various particulate
organic compounds including molecular tracers commonly used for organic sources
suitable for modeling atmospheric oxidation rates of primary particulate
emissions. [Ziemann]
Identification of non-volatile, semi-volatile, and volatile products formed
from organic particle oxidation by OH, NO3, and O3, and the reaction mechanisms
suitable for developing quantitative predictions of the effect of oxidation on
hygroscopicity and CCN activity. [Ziemann]
Laboratory measurements of the chemical identity and rate of production
secondary organic aerosols (SOA) and their precursors. [Alexander]
Derived products
Identification of mechanisms of aerosol formation, e.g., acid
catalyzed reaction.
Determination of rates and yields of aerosol processes, and dependence on
controlling variables, for processes such as secondary organic aerosol
formation and conversion of hydrophobic to hydrophilic aerosol.
3. INSTRUMENT DEVELOPMENT
Development of new instruments and methods for measurement of properties of
atmospheric aerosols pertinent to direct and indirect radiative forcing and
precursors of these aerosols pertinent to their formation and evolution.
These activities design, construct, deploy, evaluate, and determine the
accuracy of new instruments and methods for measurement of properties of
atmospheric aerosols (especially properties pertinent to direct and indirect
radiative forcing) and precursor species, including comparison with alternative
measurement approaches.
Deliverables consist of accounts (publications, reports, design specifications)
of these research activities and data sets resulting from deployment and
evaluation of these instruments and methods.
Specific deliverables
Proton transfer reaction - ion trap mass spectrometer for rapid,
real-time aircraft speciation and quantification of gas-phase organics.
[Alexander/Jobson]
Particle into liquid sampler - oxidative/conductimetric analyzer for rapid,
real-time aircraft measurement of aerosol organic carbon. [Lee]
Coupled mobility particle sizer - chemical ionization mass spectrometer for
speciation of organics in aerosol particles. [McMurry]
Fluorimetric system for rapid, real-time aircraft measurement of gaseous
hydroperoxyl radical, hydroperoxides, and ammonia. [Lloyd]
Multi-channel aerosol mobility size spectrometer for rapid determination of
particle size distributions in aircraft measurements. [Wang]
Polar nephelometer to measure aerosol angular scattering and polarization.
[Paulson/Liou]
Photothermal interferometer system for direct measurement of aerosol
absorption. [Sedlacek]
Ultrafiltration-spectrophotometric method for the characterization and quantitative determination of the highly absorbing "humic-like" substances in aerosol particles. [Marley]
4. MODELS, MODULES, AND PARAMETERIZATIONS
Modules representing chemical reactions and microphysical processes of
atmospheric aerosols suitable for incorporation in large-scale chemical
transport models and climate models representing direct and indirect radiative
forcing by atmospheric aerosols, together with estimates of their
uncertainties, as determined by evaluation in field measurement campaigns
and/or laboratory studies.
Models are a key transferable product of research conducted in this program,
serving as input to investigators examining aerosol radiative forcing and
climate response to this and other forcings on regional global scales. As
aerosol properties and processes are inherently local, emphasis is given to
development and evaluation of modules, computer codes that describe aerosol
properties and the evolution of these properties on local scales, so-called
box-models or zero-dimensional models. However it is essential that such models
be capable of being applied in higher-dimensional models, both for purpose of
evaluating model performance using data from ASP field measurements and other
sources, and for assuring the utility of these modules as components of
higher-dimensional models.
Specific deliverables
A new cloud microphysics module capable of tracking transformations of cloud
condensation nuclei inside cloud droplets. This new module linked with both a
detailed cloud resolving model (CRM) and a Lagrangian parcel framework will
provide benchmark simulations for evaluating simplified treatments of aerosol
processing used in large-scale models, including WRF-Chem. [Ovtchinnikov,
Easter]
A parameterization for atmospheric new particle formation enhanced by organic
acids. [McGraw]
A parameterization for coupled nucleation and growth rates in the presence of
background aerosol, suitable for incorporation into chemical transport and
climate models, for assessment studies, and for interpretation of field
measurements. The accuracy of this parameterization will be tested using box
models and plume dispersion models and through comparisons with field
measurements. [McGraw]
Fully-explicit mechanisms for secondary organic aerosol (SOA) formation along
with a repository of measured and estimated kinetic, mechanistic,
thermodynamic, and spectroscopic data. [Madronich]
Comprehensive SOA-inorganic model representation of gas-particle
partitioning, acid-catalyzed SOA chemistry, and physical properties.
[Madronich, Seinfeld, Zaveri]
Size- and composition-resolved gas-aerosol Lagrangian box-model incorporating
laboratory findings on SOA formation, BC aging, and heterogeneous chemistry.
[Zaveri]
Box, column, and 3-D model evaluation and interpretation of MAX-Mex field
observations. [Atherton, Fast, Kotamarthi, Madronich, Wright/Schwartz, Zaveri]
A fully-coupled meteorology-chemistry-aerosol model, WRF-chem, that has been
evaluated by field measurements will be made publicly available to the
atmospheric and global climate modeling communities via the Weather Research
and Forecasting (WRF) model framework. [Fast]
Simulated 3-D fields of aerosol mass, size distribution, composition,
optical properties, and radiative forcing using WRF-chem that have been
evaluated with ASP measurements made during the 2004 International Consortium
of Atmospheric Research on Transport and Transformation Project (ICARRT) and
2006 Megacity Aerosol Experiment in Mexico City (MAX-Mex) field campaigns will
be made available to other scientists for further analysis. [Fast]
A single-column module for treating cloud processing of pollutants which
efficiently uses cloud-scale transport and microphysical information from a
cloud-resolving model. [Ghan, Easter, Berg]
A parameterized cumulus scheme designed to represent the effects of
cumuliform clouds on the regional-scale redistribution of aerosols and changes
to their optical properties following transport through clouds. [Berg, Zaveri,
Berkowitz]
A coupled column aerosol-chemistry-pbl dynamics and radiation model. This
will have detailed chemistry of the gas phase, aerosol phase, organic and
inorganic aerosols, highly resolved PBL with 2.5 level PBL closure model and
RRTM radiation model. [Kotamarthi]
A regional scale coupled model for aerosol-chemistry (full suite of gas phase
and aerosol chemistry), meteorology ( MM5/WRF) , and radiation suitable for
evaluating regional scale climate change issues. [Kotamarthi]
5. DISSEMINATION OF RESEARCH RESULTS
Self documenting, publicly accessible data archive
Publicly available descriptions and codes of aerosol evolution modules,
together with pertinent documentation
Peer reviewed accounts of research published in appropriate scientific
journals
Special issues of appropriate scientific journals
Special sessions in national and international meetings of appropriate
scientific societies
Ashley Williamson
Climate Change Research Division
Germantown Building
U.S. Department of Energy SC-23.3
1000 Independence Avenue SW
Washington DC 20585 - 1290
(301) 903-3120
Fax: (301) 903-8519
Email: Ashley.Williamson@science.doe.gov |
