2011 - Cooperative Institute for Research in Environmental Sciences ...

We greatly expanded the holdings in our last-millennium
temperature database (now called the last 2+ millennium
paleoclimate network) through the inclusion of several
gridded data products—including the National Centers
for Environmental Prediction (NCAP) and the National
Center for Atmospheric Research (NCAR) gridded
temperature reanalysis data; selected variables from the
2010 millennium simulations of the Max Planck Institute
for Meteorology Comprehensive COSMOS (Community
Earth System Models) Earth System Model; and the Had-
CRUT3v combined global land and ocean surface temperature
data. This has expanded the spatial coverage of
the existing 92-point reconstructions and 1,209 site proxy
data already in the network. It also increased the temporal
coverage of the network and allowed linkages to be made
between the paleoclimatic records and modern instrumental
observations. Researchers and others interested in
later-Holocene climate can now find a complete set of data
tools needed to calibrate and make temperature reconstructions,
and can compare these with the accumulated
high-resolution reconstructions in NOAA-Paleoclimatology’s
archive.
CSV-02 Mechanism and Forcings
of Climate Variability
n CSD-03 Chemistry, Radiative Forcing, and Climate
n CSD-12 Emissions and Atmospheric Composition
n CSD-13 Kinetics and Photochemical Studies
n PSD-01 Modeling of Seasonal to Interannual Variability
n PSD-02 Understanding and Predicting Subseasonal Variations
and their Implications for Longer-Term Climate Variability
n GMD-04 Climate Forcing
CSD-03Chemistry,RadiativeForcing,andClimate
FEDERAL LEADS: SUSAN SOLOMON, THOMAS B. RYERSON,
KAREN ROSENLOF, STEVEN BROWN AND DAN MURPHY
CIRES LEAD: CHRISTINE ENNIS
NOAA Goal 2: Climate
Project Goal: Observe and model the radiative forcing due to
stratospheric ozone changes and tropospheric radiatively active
gases. Carry out upper-troposphere airborne experiments
and diagnostic analyses that characterize the dynamical and
chemical processes influencing the radiative balance in the
global atmosphere. Quantify the chemical and optical properties
that determine the lifetimes, abundances and trends of
greenhouse gases. Use passive cloud observations to develop
techniques that can be used to estimate cloud properties.
Milestone 1. Add ice habit information to cloud parcel
modeling. Impact: Ice formation and growth is a critical
and highly uncertain process for both precipitation and
the radiative properties of clouds. A better description of
ice habits will allow better calculations of both ice crystal
growth and sedimentation.
The fundamental physical processes that maintain su-
108 CIRES Annual Report 2011
percooled liquid in observed Arctic mixed-phase clouds
are poorly constrained. To isolate the factors that control
ice/liquid partitioning during the ascent of an air parcel,
detailed model studies were performed with ice nucleation
by deposition and immersion freezing and ice habit
evolution. Effects on ice and liquid water evolution in an
updraft were explored as a function of ice nucleus (IN)
concentration and nucleation mode, updraft velocity,
properties of cloud condensation nuclei and assumption
about ice particle shape (habit). For most conditions, ice
and liquid coexist and increase simultaneously, and only
at high IN concentrations or low updraft velocities do ice
particles grow at the expense of droplets. The impact of the
ice nucleation mode on ice/liquid distribution depends
on the temperature and supersaturation regime. The assumption
of spherical ice particles instead of non-spherical
habits leads to substantially smaller predicted ice masses.
It is concluded that updraft velocity, IN concentrations and
particle shape can impact ice/liquid distribution to similar
extents. The work will be continued by exploring different
hypotheses on freezing (stochastic versus singular) using
literature data from laboratory studies within the same
model framework.
Product: Ervens, B, G Feingold, K Sulia, and JY Harrington,
The impact of microphysical parameters, ice
nucleation mode, and habit growth on the ice/liquid
partitioning in mixed-phase Arctic clouds, submitted to
J. Geophys. Res.
Milestone 2. In the CalNex 2010 Field Campaign, survey
a wide variety of different sources of directly emitted
gas and aerosol species (e.g., carbon dioxide, methane,
nitrous oxide, halocarbons and particle-phase soot) that
affect atmospheric radiative forcing. Impact: The planned
suite of measurements includes both short-lived and
long-lived forcing agents, and will provide survey data
for anthropogenic, agricultural, biogenic and geologic
sources of these radiatively important trace species. These
data will provide additional independent evaluation of
newly developed greenhouse gas inventories in California
and better define source sector emissions strengths for
directly emitted greenhouse gases.
During CalNex 2010, the research vessel Atlantis and
the NOAA WP-3D research aircraft were deployed to
characterize emissions of climate forcing agents and their
precursors. Particular attention was paid to commercial
marine vessels, which have been identified by the California
Air Resources Board as significant sources of greenhouse
gas emissions (CO2) and important climate-forcing
aerosol species (e.g., black carbon). In cooperation with
the Maersk Shipping Line, an experiment was conducted
that examined the effect on ship emissions of switching to
low-sulfur marine fuels and slow-steaming (traveling at
slower speeds) when a large containership was outside
of and then within 24 miles of the California coast.
Figure 1 (from Lack et al., submitted in 2011) shows that
the two regulatory strategies are very effective at reducing
stack emissions from these vessels. A separate experiment
with a much smaller vessel showed similar results (Cappa
et al., submitted in 2011).
Research Vessel Atlantis was also deployed within
California’s harbors of Los Angeles, Long Beach, San
Francisco and Oakland to survey the levels of important
climate-forcing agents in these industrial regions with the
goal of verifying current emission inventories. Similarly,
the WP-3D research aircraft was flown on flight tracks