UTLS - Science - DC3 Field Campaign

Deep Convective Clouds & Chemistry

Experiment (DC3)

Principal Investigators

Contact PI:
Mary Barth
NCAR- ACD
303-497-8186

William Brune
PSU
814-865-3286

Chris Cantrell
NCAR- ACD
303-497-1479

Steven Rutledge
CSU
970-491-8283

Steering Committee
(includes those above)

Jim Crawford
NASA-Langley
757-864-7231

Owen Cooper
NOAA- CSD &
CU-CIRES
303-497-3599

Alan Fried
NCAR-EOL
303-497-1475

Andrew Heymsfield
NCAR-MMM
303-497-8943

Paul Krehbiel
NMT
505-835-5215

Donald Lenschow
NCAR-MMM
303-497-8903

Laura Pan
NCAR-ACD &
NCAR-TIIMES
303-497-1467

Kenneth Pickering
NASA-Goddard
301-405-7639

Jeffrey Stith
NCAR-EOL
303-497-1032

Andy Weinheimer
NCAR-ACD
303-497-1444

The DC3 Field Experiment will characterize the effect of midlatitude, continental convection on the transport and transformation of ozone and its precursors. Along with measurements of hydrogen oxide radicals, their precursors, and nitrogen oxides in both the inflow and outflow regions of deep convection, measurements of cloud microphysical properties, storm kinematics, and lightning discharges will be conducted. These measurements are planned for the central United States during summer 2010 where remote continental regions can be contrasted to anthropogenically-influenced regions.

Motivation

Ozone in the UTLS region is important for climate change and for affecting the UV radiation reaching the Earth's surface.

Ozone is produced from NO_x and HO_x radicals. Thus, quantifying the sources of NO_x and HO_x in the upper troposphere is key to understanding the climate implications of upper tropospheric O₃.

Deep convection alters the composition of the UTLS region.

Important precursors of O₃ are NO_x, HO_x, and the HO_x precursors.

DC3 will give us:

• Comprehensive chemistry on board NSF/NCAR HIAPER and NASA DC-8 aircraft
• Comprehensive storm information from ground-based Doppler and polarimetric radars
• Outstanding information on lightning location from lightning mapping arrays

Science Goals

Quantify the impact of continental, midlatitude convective storm dynamics, multiphase chemistry, lightning, and physics on the transport of chemical constituents to the upper troposphere

• Can we locate the source of NO within the storm in relation to the kinematics, and the location of the lightning and microphysical structure?

• Can we determine the production of NO_x from intracloud lightning in relation to that from cloud-to-ground lightning?

• Can we accurately represent all processes affecting constituents?

• Do the results vary depending on the type of convection

Determine the mass fluxes of air and trace gases into and out of the storm, including entrainment from the boundary layer, mid-troposphere, and stratosphere

• What fraction of the boundary layer air reaches the upper troposphere?

• What’s the degree of entrainment?

• What part of the boundary layer is ingested into the storm?

Determine the effects of convectively-perturbed air masses on ozone and its related chemistry in the midlatitude upper troposphere and lower stratosphere near the convective cores (in the anvil region) and further downwind, 12-48 hours after the near convection region is sampled

• In the anvil, does the scattering of actinic fluxes significantly affect concentrations?

• What role does adsorption of gases onto ice play in affecting the chemistry?

• What chemical aging occurs in the convective outflow? Is O₃ produced (and how much)?

Contrast the influence of different surface emission rates on the composition of convective outflow

• Is more O₃ produced in convective outflow when the convection occurs over relatively clean regions?

• What is the importance of biogenic hydrocarbons (e.g. isoprene) on the chemical aging in convective outflow regions?

Ancillary Goals

• To improve our understanding of cloud electrification and lightning discharge processes (in relation to NO production; contrasting differences among different convective regimes)

• To investigate the role of deep convection in contributing to the UT water vapor and in the transport of water vapor into the lowermost stratosphere

• To connect aerosol and cloud droplet and ice particle number concentrations with convection characteristics and trace gas convective processing

• To determine partitioning of reactive halogen and reservoir species in the UTLS

Experimental Design

High Altitude Aircraft

(e.g. NSF/NCAR G-V) outfitted with gas-phase and aerosol characterization instrumentation to sample convective outflow

Low Altitude Aircraft

(e.g. NASA DC-8) configured with in situ and remote gas, aerosol, liquid and ice characterization instruments to sample inflow region, mid-troposphere, and locate downwind plumes

Ground based facilities

To measure winds, hydrometeors, lightning characteristics, thermodynamics, and species profiles
Utilize (existing) ground based networks to sample in diverse precipitation, lightning and background chemistry regimes:

Northeast Colorado

• CSU CHILL Radar
• S-Band Doppler
• Polarimetric Radar
• Portable Lightning Mapping Array
  

Central Oklahoma

• S-band Doppler
• Polarimetric Radar (KOUN)
• Phased Array Radar (PAR)
• SMART-R C-Band
• Doppler Mobile Radar
• Lightning Mapping Array

Northern Alabama

• ARMOR Radar – Doppler & Polarimetric
• Lightning Mapping Array
  

Meetings

• Planning Workshop - 10-12 April 2006

• Meeting - September 2005

Documents

• AGU Poster- December 2006 (pdf)

• Scoping Paper (pdf)