|
October 2007
An
overview of projects throughout the organization
Chemical
weather forecasting. An interdisciplinary
team of NCAR scientists is launching a major new
program known as Atmospheric Composition Remote Sensing
and Prediction (ACRESP). The program will focus on
integrating satellite data into Earth system models
and determining what new satellite observations will
be required in the future to address key science
questions. The initiative, which is led by Dave
Edwards
(ESSL/ACD) with researchers in ESSL/CGD and CISL/IMAGe,
is expected to encompass additional NCAR laboratories
in time. It also involves the wider university and
agency community. Funding comes from the NCAR directorate
and NASA.
An important component of the new program is the
development of a chemical weather forecasting capability
that is analogous to weather forecasting. Such outlooks
could eventually provide communities with several
days’ notice of high levels of smog, particulate
matter, or other air quality issues important to
human health. Field campaigns that look at atmospheric
chemistry and air quality will also have access to
chemical forecasts for aircraft flight planning.
Chemical weather forecasting will require a better
understanding of the evolution of ozone, particulates,
and other pollutants, as well as the local impact
of pollutants transported from distant sources. The
research can reveal connections between climate change
and regional air quality.
The scientists plan to integrate data from satellites,
aircraft, and ground stations into global and regional
chemistry transport models such as MOZART (Model
for Ozone and Related Chemical Tracers), and CAM-Chem
and WRF-Chem (the chemistry versions of the Community
Atmosphere Model and Weather Research and Forecasting
model), using the Data Assimilation Research Testbed
(DART). Satellite observations play a key role in
chemical weather forecasts because they are able
to provide a large-scale view of the evolving distributions
of pollutants.
Other activities within ACRESP will investigate the
ways that current satellite data can be used to evaluate
and perhaps improve the performance of Earth system
models. These same models will be used to simulate
the observations of future satellite instruments,
thereby helping researchers determine which prospective
instruments and measurements would be most useful
in shedding light on important atmospheric processes.
The ultimate goal is to provide NCAR and the wider
community with a laboratory that will help in the
design of future satellite missions.
Alfvén
waves observed. ESSL/HAO’s Steve
Tomczyk published a paper in the August 31 issue of Science
documenting the first observations of elusive oscillations
in the Sun’s corona (outer layer) known as
Alfvén waves.
The waves transport energy outward from the surface
of the Sun. Unlike other waves, they do not lead
to large-intensity fluctuations in the corona, making
them difficult to detect. In addition, their velocity
shifts are small and not easily spotted. Although
they have been detected in the heliosphere outside
the Sun, they had never before been viewed within
the corona.
Steve and a team of researchers that included Scott
McIntosh (Southwest Research Institute) and Phil
Judge (ESSL/HAO) used the Coronal Multichannel Polarimeter,
or CoMP, to gather and analyze light from the Sun’s
corona. CoMP, which utlilizes a telescope at the
National Solar Observatory in Sacramento Peak, New
Mexico, tracks magnetic activity around the entire
edge of the Sun and collects data with unusual speed.
The instrument enabled the research team to capture
intensity, velocity, and polarization images of the
solar corona. The images revealed Alfvén waves
that moved in trajectories aligned with magnetic
fields and traveled as fast as nearly 2,500 miles
(4,000 kilometers) per second.
The discovery is expected to give researchers more
insight into the fundamental behavior of solar magnetic
fields, eventually leading to a fuller understanding
of how the Sun affects Earth and the solar system.
For more information, click
here.
Scientists have observed elusive
oscillations in the Sun’s corona, known
as Alfvén waves, for the first time.
In this image, made by NCAR’s CoMP instrument,
the oscillations of the plasma velocity are
made clearer by filtering the velocity data
to show only oscillations that recur periodically
every five minutes. (Image courtesy Steve Tomczyk
and Scott McIntosh.) |
Hazardous plumes. For
several years, RAL scientists have worked with Department of Homeland Security
officials to create fine-resolution models that can simulate the tracks of hazardous
plumes through the atmosphere. Now they are looking at the problem in a different
way: detecting a hazardous plume and backtracking to the source of the plume.
The goals of this approach are to fully map out the area that may be affected
by the plume, gain insights into the material being released into the atmosphere,
and possibly determine who is releasing the material. If an industrial plant
is on fire, for example, researchers can use the model to help determine the
rate at which toxins are being released and the area that should be evacuated.
If terrorists release dangerous chemical, biological, or radioactive (CBR) substances,
first responders can use the models both to evacuate residents in the path of
the plume and to determine where the terrorists were operating.
RAL’s Paul Bieringer and George
Bierberbach
are heading up the project, known as Sensor Data
Fusion. Other scientists on the team include Francois Vandenberghe, Andrzej
Wyszogrodzki,
and Rong-Shyang Sheu (all in RAL), and Jeff
Weil (ESSL/MMM).
Their aim is to assimilate observations of winds, temperatures, and other atmospheric
properties, along with measurements from CBR sensors, into transport and dispersion
models. These models, which are capable of operating at horizontal grid increments
of 5 to 10 meters (16 to 33 feet), will ultimately improve the hazard prediction
capabilities of the departments of Defense and Homeland Security. Funding for
the project comes from the Defense Threat Reduction Agency.
WACCM
reaches higher. NCAR’s Whole-Atmosphere
Community Climate Model (WACCM) is a comprehensive
numerical model that spans the range of altitude
from Earth’s surface to the outer atmosphere.
An interdivisional effort in ESSL, WACCM incorporates
HAO’s modeling of the upper atmosphere, ACD’s
modeling of the middle atmosphere’s chemistry,
and CGD’s modeling of atmospheric dynamics
and the lowest portion of
the atmosphere.
Hanli Liu (HAO/TIIMES) and a team of colleagues are
working to increase WACCM’s reach to higher
altitudes. Over the past year, they’ve extended
the model from 87 miles (140 kilometers) to 310 mi
(500 km). The new domain now incorporates the
upper thermosphere (fourth layer of the atmosphere).
The team’s next step is to include the ionosphere
(the ionized region of the thermosphere) in WACCM.
When the work is complete in about a year, researchers
will have a more complete model of the whole atmosphere,
which they’ll begin using to tackle scientific
problems.
The integrated model will help scientists better
understand climate change throughout the whole atmosphere.
This is especially important because carbon dioxide
emissions impact the upper atmosphere as well as
the lower. The model will also provide scientists
with a numerical tool to connect tropospheric climate
with space weather and to study lower and upper atmospheric
coupling.
Nitrogen
and climate. A team of researchers in ESSL/CGD,
led by Peter Thornton, is expanding our understanding
of the climate system by adding the nitrogen cycle
to the Community Climate System Model (CCSM). Nitrogen
has critical influences on the atmosphere, in part
because it enables plants to grow and take in carbon
dioxide.
Preliminary research, now in press, with the land
component of CCSM shows that nitrogen has complex
and sometimes conflicting impacts on global warming.
One of the most important findings is that the limited
supply of nitrogen, an essential plant nutrient,
will restrict the ability of plants to absorb carbon
dioxide from the atmosphere. Whereas carbon-only
models have indicated that plants would partially
offset warming temperatures by thriving in a world
of higher atmospheric carbon dioxide levels,
the new research indicates that plants won’t
have the requisite nitrogen to grow as much as climate
scientists thought.
Although that is bad news for the planet, it is partially
offset by another preliminary finding. Peter and
his colleagues are discovering that increased levels
of atmospheric carbon dioxide, and associated climate
change, will stimulate more uptake of carbon on land.
That is because in a warmer and, in some places,
wetter climate, decomposition will provide plants
with more nitrogen, which will boost plant growth.
In contrast, previous carbon-only models had
predicted reduced uptake of carbon on land.
The results of this complex line of research, including
an examination of the interplay between nitrogen
and land cover changes, won’t be resolved for
at least several months. Early indications, however,
show that carbon dioxide levels in the atmosphere
are likely to rise at least somewhat more quickly
than indicated by carbon-only models, including those
cited by the Intergovernmental Panel on Climate Change.
Another likely result is that tropical ecosystems
will play an especially critical role in absorbing
rising amounts of carbon dioxide.
In this issue...
Ice
in clouds
Surprise
finding in the desert
Tackling
disasters in an energy-restricted Boulder
Jeffco
bears fruit
Short
Takes
Getting
their paws wet
Delphi
Question
Random
profile: Chris Golubieski
Just One Look
Staff Notes home page | News Center
|
