The Houston Environmental Aerosol Thunderstorm (HEAT) Project: 2005

1. The Houston Environmental Aerosol Thunderstorm (HEAT) Project: 2005 http://www.met.tamu.edu/ciams/heat/index.html Richard (Dick) Orville with John Nielsen-Gammon, Renyi Zhang, Don Collins and Amy Stuart Dept. of Atmospheric Sciences Texas A&M University College Station, TX Email: rorville@tamu.edu March 15, 2004

2. Introduction: Houston, the Lightning Capital of Texas • National Lightning Detection Network (NLDN) analyzed climatological data (Orville et al. 2001) have indicated a significant CG lightning enhancement (60%) over and near the city of Houston, Texas (pop. 5 million). • The hypothesized causes include: • The urban heat island effect enhancing convection • The petroleum refining operations (49% of the USA capacity) • The sea breeze circulation system and increased CCN/IN concentrations from the multitude of pollution sources in the Houston region.

3. Intracloud Lightning

4. Cloud-to-ground lightning

5. Data and Methods • The National Lightning Detection Network (NLDN) • Detects only CG flashes • 106 sensors (DF/TOA) across the U. S. • Since 1994, the resolution is 500 m, and detection efficiency is ~85% • Created and analyzed lightning flash density maps for different season and time periods

7. E=60%

8. Sea – Heat Island Breeze • From MM5 simulations [Orville et al., 2001], enhanced low-level convergence does not occur without the city. • The main effect is increased thunderstorm initiation directly over the city. • Greater warm season daytime enhancement gives support for this.

9. Pollution • Houston atmosphere is polluted due to the oil refineries and automobiles • Hypothesis: Effect of CCN concentrations on lightning • Higher CCN • Mean drop radius decreased • More small supercooled droplets above 0o C level • Greater volume of mixed phase (ice and supercooled water) • More charge separation • More lightning!

10. Proposed Research • Houston has a significant lightning enhancement during all seasons, but highest in the summer. • Field experiments (CCN/IN, cloud droplet size distributions over Houston), and modeling (separate effects from city, bay, and pollution) should help in determining the relative importance of each factor. • HEAT Project is needed with measurements of total lightning (both cloud-to-ground and intracloud lightning), polarimetric radars, and aircraft sampling of clouds.

11. Houston Environmental Aerosol Thunderstorm (HEAT) Project 2005 • Houston Environmental AerosolThunderstorm Project(HEAT) • DRAFT • Scientific Overview &Operational Plan for HEAT-2004/2005 • Table of Contents:     [ Download PDF ] • Abstract1. Introduction    1.1 Primary Goals of HEAT          Pollution Effects          Urban Heat Island Dynamics          The Effect of a Complex Coastline          Atmospheric Chemistry           Lightning 2. Project Overview3. Scientific Objectives    3.1 Pollution Effects    3.2 Urban Heat Island Dynamics    3.3 The Effect of a Complex Coastline    3.4 Atmospheric Chemistry    3.5 Lightning4. Operation Plan: Daily Schedule and Conduct of Operations    4.1 Briefings    4.2 Conduct of Field Operations and the Operations Center          4.2.1 Operations Center Team          4.2.2 Chief Coordinators and Representatives for the                   Major Components and Observing Systems    4.3 Operations Center Layout • http://www.met.tamu.edu/ciams/heat/index.html

12. Primary Goals of the HEAT Project • Evaluate the pollution effects (small aerosols) and precipitation suppression • Evaluate the urban heat island (UHI) dynamics (e.g. Huff and Changnon 1972) • Evaluate the effect of a complex coastline • Low level convergence • Interaction of sea breeze with UHI • Effect of sea breeze on convection intensity

13. Atmospheric Chemistry: • Thunderstorms are efficient in transporting planetary boundary air to higher levels. Flux of certain atmospheric constituents (CO, CO2, O3, HC, NOx and aerosols) will be measured by aircraft observations into and out of storms. • Lightning: Total lightning (IC and CG) will be measured. Why a 58% enhancement (CG) over urban area?

14. Scientificobjectives • Lightning • Measure the total lightning over Houston • Determine the lightning polarity over Houston • Obtain thunderstorm electric field profiles over Houston and over non-urban environments.

15. (cont) • Cloud microphysics • Objective M1: Mixed-phase region • Objective M2: Cloud droplet spectra • Objective M3: Precipitation drop-size distributions • Objective M4: Pollution effects in the early-storm stages

16. (cont) • Urban heat island dynamics • Objective U1: Urban heat island thermodynamics • Objective U2: Urban wind modification • Objective U3: Urban updraft enhancement • Objective U4: Urban effects on convective storm mergers and lightning production

17. (cont) • The effect of a complex coastline • Objective C1: Sea breeze modification: low level convergence field associated with a complex coastline and its effects on convective initiation • Objective C2: Sea breeze interaction with the Houston heat island • Objective C3: Intensity of sea breeze convection

18. (cont) • Atmospheric chemistry • Objective A1: NOx production by lightning • Objective A2: Transport and fate of pollutants in thunderstorms • Objective A3: Effect of urban thunderstorms on upper tropospheric chemistry

19. Project Overview: Approximate locations of CSU-CHILL polarimetric radar, S-Pol polarimetric radar, NWS WSR-88D radar, upper air sites, TAOS sites, and wind profiler sites. The Houston metro area is outlined in red.

20. Total (CG plus IC) Lightning and Polarimetric Radar Measurements

21. Note that the sensor spacing is closer in the middle of the network and farther apart on the outside of Houston. Green stars = airports with the exception of the green star in the center of Houston.

22. Radar Systems • NCAR S-Pol radar • CSU-CHILL Research radar • NWS WSR-88D Operational weather radar • Texas A&M, NSSL, OU, Texas Tech mobile C- band radars (2)

23. Aircraft Systems • University of Wyoming King Air • WMI Lear Jet • North Dakota Citation • Airborne chemistry instrumentation (Baylor) • HIAPER

24. Balloon Sounding Units • MGLASS Units (2) • Mobile electrical sounding units (2) • TAOS units • Upper air sounding station

25. Lightning Detection • National Lightning Detection Network (NLDN) for CG lightning (in place since 1989) • Lightning Detection and Ranging (LDAR II) network (Funded September 2003; NSF) to detect total lightning (IC and CG)

26. Conclusions • Field observing systems in HEAT (2005) will include • Radar systems • Surface mesonet systems • Aircraft • Balloon sounding units • Lightning detection and mapping arrays • All lightning discharges are detected • Cloud-to-ground • Intracloud • Up to several thousand locations for an individual flash • Location accuracy of 50 to 100 meters • Charge layers can be identified • Flash type can be identified

27. The Beginning!

28. Time of Arrival Lightning Mapping System (LDAR II) Radiation occurs at time t, at location (x, y, z) • Measure time RF pulse arrives at multiple stations • Determine position and time of source • Locate hundreds to thousands of sources per flash Radiation arrives at station i at time ti, location (xi, yi, zi)

29. Layout of LDAR II Plots Altitude vs. Time (Color Coded) Number of LDAR II Points vs. Height Altitude vs. x Plan View (x vs. y) Altitude vs. y

30. LDAR II Image of an airplane avoiding thunderstorms 20 Minutes of Data Plane Flying 400 MPH at 30,000 ft

31. Intra-Cloud Lightning

32. Cloud-to-Ground Lightning

35. LDAR-II Antenna – FAA Facility in Texas Ground Mount

37. LDAR-II Antenna -Roof of DFWAirport

39. Note that the sensor spacing is closer in the middle of the network and farther apart on the outside of Houston. Green stars = airports with the exception of the green star in the center of Houston.

40. 3D/2D Lightning Mapping - LDAR II • Most advanced lightning detection capability in the world • In 1997, GAI and NASA entered into a technology transfer agreement (NASA had been using VHF lightning detection for many years) • In 1999, GAI and NMT began a collaboration that lead to the future commercialization of LDAR II (NMT had developed a similar VHF lightning detection sensor with slightly different technology) • 3-Dimensional mapping within network perimeter • 100-200 meter or better location accuracy • Greater than 95% expected flash detection efficiency • Reduces to 2-dimensional mapping well outside of the network (~150 km) • 2 km or better location accuracy • Greater than 90% expected flash detection efficiency

41. Conclusions • Field observing systems in HEAT (2005) will include • Radar systems • Surface mesonet systems • Aircraft • Balloon sounding units • Lightning detection and mapping arrays • All lightning discharges are detected • Cloud-to-ground • Intracloud • Up to several thousand locations for an individual flash • Location accuracy of 50 to 100 meters • Charge layers can be identified • Flash type can be identified

42. The Beginning!

44. Lightning sensor for cloud-to-ground lightning • Installation for experimental use at Texas A&M

45. Goals: Document ambient pollution levels, vertical atmospheric thermodynamic structure and E-fields Instruments: King air, T-28, MGLASS, mobile electrical sounding units Option I: No Storm/Before Storm Initiation/Before Storm Enters Domain (including Sea Breeze) Harris County Sea Breeze Front

46. Goals: Document storm cloud droplet spectra, ice nuclei content, and amount of supercooled water; E-field measurements inside/outside of storm Instruments: T-28, mobile electricalsounding units Option II:Isolated Urban Storm

47. Goals: Document cloud droplet spectra, ice nuclei content, amount of supercooled water, and E-fields in/near convective cores for an urban and one environmental storm. Instruments: T-28, mobile electrical sounding units Harris County Galveston Bay N Option III:Isolated Environmental and Urban Storms in Coexistence

48. Goals:Document cloud droplet spectra, ice nuclei content, amount of supercooled water, and E-fields in/near convective cores for urban and environmental portions of the system. Sample before, during, and after propagating through Houston. Instruments: T-28, mobile electrical sounding units Option IV:Storm System Transgressing Study Area (i.e., squall line)

49. Title:“The Houston Environmental Aerosol Thunderstorm (HEAT) Project” Principal Investigators: Richard Orville, John Nielsen-Gammon, Renyi Zhang, and Don Collins (Texas A&M University) Proposed Co-investigators: Danny Rosenfeld (Hebrew University), William Woodley (Woodley, Inc.), Earle Williams (MIT), John Helsdon and Andy Detwiler (South Dakota Tech), Steve Rutledge (Colorado State), Paul Krehbiel (New Mexico Tech), Maribeth Stolzenburg and Tom Marshall (U. of Mississippi), Walt Lyons (FMA, Inc.), Ron Holle, Ken Cummins, and Nick Demetriades (Global Atmospherics, Inc.), David Rust and Don MacGorman (National Severe Storms Laboratory), Bill Read and Steve Allen (National Weather Service, Houston), Daewon Byun (University of Houston), J. G. Hudson (Desert Research Institute, Nevada), J. Marshall Shepherd (NASA-Goddard), Gary Huffines (U.S. Air Force), NCAR-MMM personnel to be determined, Lead Institutions: Texas A&M University and the National Center for Atmospheric Research (NCAR) Project Period: Four years (2003-2007); field program (summer 2005)