Deep Convective Clouds and Chemistry (DC3) Field Experiment

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Deep Convective Clouds and Chemistry (DC3) Field
Experiment
Principal Investigators Mary Barth (NCAR), Bill
Brune (PSU), Chris Cantrell(NCAR), Steve
Rutledge (CSU)
Steering Committee Ken Pickering Jim
Crawford Laura Pan Andrew Heymsfield Don
Lenschow Owen Cooper Andy Weinheimer Paul
Krehbiel Jeff Stith Alan Fried
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DC3 Characterize the effects of continental,
midlatitude deep convection on the transport and
transformation of ozone and its precursors

1. Processing in the convection,
2. Processing in the anvil
3. Processing in the convective outflow 12-48 hours
   later
4. Contrast different types of convection and
   different emission regions

http//utls.tiimes.ucar.edu/Science/dc3.shmtl
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Ancillary Objectives of DC3

1. Halogen Chemistry in the UTLS
2. Determine mass fluxes of air and trace gases into
   and out of the storm,
3. Cloud electrification and lightning discharge
   processes
4. Effects of deep convection on UT water vapor
5. Convective processing of aerosols and their
   impact on water and ice particles

http//utls.tiimes.ucar.edu/Science/dc3.shmtl
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A Storm Penetrating Aircraft (SPA) can help reach
these objectives

• Processing of trace gases in the convection,
• Processing in the anvil (mid to lower regions)
• Cloud electrification and lightning discharge
  processes
• Effects of deep convection on UT water vapor
• Convective processing of aerosols and their
  impact on water and ice particles

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Importance of Production of NOx by Lightning
Barth et al., 2006, submitted to JGR
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Cross Section of CO
CO used as a tracer of boundary layer air
ppbv
Barth et al., 2006, submitted to JGR
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Soluble Species and Their Fate in Deep Convection
Total CH2O mixing ratios gas cloud water
rain ice snow hail
Barth et al., 2006, submitted to JGR
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Transects across Anvil
Disagreement among models, but no observations
available
Barth et al., 2007, in preparation
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Priority Instruments on a SPA to Understand
Convective Processing of Constituents

• NO
• 150 lbs., 10 pptv detection limit, and 0.5-sec
  time response
• (courtesy of Andy Weinheimer, NCAR)
• CO
• Soluble Species
• Formaldehyde, Hydrogen Peroxide, Nitric Acid

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Ozone in the UT/LS region is important for
climate change and for affecting the UV radiation
reaching the Earths surface. Deep convection
alters the composition of the UT/LS
region. Important precursors of O3 are NOx, HOx,
and the HOx precursors.
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Previous Studies of Convection and Chemistry

• Comprehensive cloud and lightning with a fair
  amount of chemistry information
• STERAO, EULINOX, ELCHEM, TROCCINOX, SCOUT
• Comprehensive chemistry with little cloud and
  lightning information
• INTEX, TRACE-P

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Goals of DC3
1. To quantify the impact of continental,
midlatitude convective storm dynamics, multiphase
chemistry, lightning, and physics on the
transport of chemical constituents to the upper
troposphere,
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Goals of DC3
2. To determine the role of anvil dynamics,
multiphase chemistry, microphysics, radiation,
and electrification on the chemical composition
of convective outflow,
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Goals of DC3
3. To determine the effects of convectively-pertur
bed air masses on ozone and its related chemistry
in the midlatitude upper troposphere and lower
stratosphere 12-48 hours after the near
convection region is sampled,
CO at z 10.6 km 00 Z 15 June 1985
06 Z 15 June 1985
Modeling study showing convectively-transported
CO advection downwind of active convection. From
Park et al. (2004)
12 Z 15 June 1985
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Goals of DC3
4. To contrast the influence of different surface
emission rates on the composition of convective
outflow.
NOx emissions
Isoprene emissions
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Ancillary Goals of DC3

1. To determine partitioning of reactive halogen and
   reservoir species in the UTLS
2. To determine the mass fluxes of air and trace
   gases into and out of the storm, including
   entrainment (determine fraction of boundary layer
   air that reaches LS, UT determine fraction
   entrained determine what part of the boundary
   layer is ingested by the storm determine
   quantity of stratospheric ozone entrained into
   anvil)
3. To improve our understanding of cloud
   electrification and lightning discharge processes
   
4. 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
5. To connect aerosol and cloud droplet and ice
   particle number concentrations with convection
   characteristics and trace gas convective
   processing

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Facilities

• High altitude aircraft HIAPER
• Low altitude aircraft NASA DC-8 or C-130
• Ground based dual Doppler and polarimetric radars
• Lightning mapping arrays
• Others
• Ground precipitation network
• Discussion of other aircraft (A-10, DOE G-1)

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Setting
Annual Average Precipitation

• Summer 2009
• 6 week period
• start and stop times are still being determined
• Northeast Colorado and Central Oklahoma and
  Northern Alabama
• Sufficient ground-based facilities
• Likelihood of convection occurring in one of the
  three places is good
• Contrast different environments (long-lived,
  shear storms vs airmass storms high cloud bases
  vs low cloud bases low chemical emissions vs
  higher emissions)

JJA Lightning
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Northeastern Colorado

• Facilities
• CHILL and PAWNEE radars in place
• Need portable LMA installed

• Chemistry
• Agricultural emissions
• Denver emissions likely to be sampled
• Convection
• Variety of single, multi and super cell
  convection
• Lightning peaks in July

Figure from Brenda Dolan (CSU)
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Oklahoma

• Facilities
• LMA in place
• Have both Doppler and polarimetric radars
• Chemistry
• Urban emissions from Oklahoma City
• Agricultural emissions nearby
• Isoprene emissions in eastern Oklahoma

• Convection
• large storms dominate in May and June (tornado
  season)
• air mass storms dominate in July and August
• Lightning peaks in late June

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Northern Alabama

• Facilities
• LMA in place
• Have radars, ozone lidar, ozonesondes
• Chemistry
• High biogenic emissions
• Convection
• Shear-induced convection in May airmass
  thunderstorms during June, July, August
• Peak lightning in July

Radar ranges and LMA location
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Recommendations from Recent Workshop

• Prefer to sample isolated convection for
  analyzing convective processing of chemical
  species
• Base aircraft near Oklahoma City
• Central location can easily fly to NE CO or
  N.AL longer endurance because of lower elevation
  (than JeffCo)
• Preliminary studies of forecasting convective
  plume downwind
• Need to address specific issues

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Working Groups

1. Climatology (O. Cooper)
2. Forecasting Convection and Downwind Plumes
   (M. Weisman)
3. Airborne Platforms (A. Fried)
4. Ground-based Platforms (D. MacGorman, S.
   Rutledge)
5. Flight Plans to address Science Goals (D.
   McKenna)
6. Satellite Data Contribution (L. Pan)
7. Linking Models and Observations (K. Pickering)
8. Education and Outreach (D. Rogers, S. Rutledge)

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Timeline

• Working Groups address specific issues (now
  Sept)
• PIs and steering committee incorporate
  information into Science Plan and Experimental
  Design Overviews
• Decisions on specific issues
• Draft of documents by Oct/Nov
• Submit proposal to NSF/OFAP by Jan 2007