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Development of a Lightning NOx Algorithm for WRF-Chem

Development of a Lightning NOx Algorithm for WRF-Chem. Amanda Hopkins Hansen 1 , Henry E. Fuelberg 1 , Kenneth Pickering 2 , Steven Peckham 3. 1 Florida State University 2 NASA Goddard Space Flight Center 3 NOAA Earth System Research Lab Global Systems Division.

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Development of a Lightning NOx Algorithm for WRF-Chem

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  1. Development of a Lightning NOx Algorithm for WRF-Chem Amanda Hopkins Hansen1, Henry E. Fuelberg1, Kenneth Pickering2, Steven Peckham3 1Florida State University 2NASA Goddard Space Flight Center 3NOAA Earth System Research Lab Global Systems Division

  2. An LNOx algorithm for WRF-Chem with Parameterized Convection What are the necessary ingredients? • Flash rate parameterization which we can use in a regional • Model to produce a 2D flash rate • 2) Average NO production per flash • 3) Method of specifying the vertical distribution • of LNOx emissions

  3. Flash Rate Parameterization: Convective Radar Storm Height Futyan and Del Genio, 2007 Convective storm height is used because cloud top height may be several kilometers higher than the height of significant radar signal Fifth order power law for radar top height (above surface) Second order for radar top height above 0 degree isotherm.

  4. LNOx algorithm for WRF-Chem What are the necessary ingredients? Lightning Flash Rate Parameterization • Flash rate (F) can be calculated from the following relation: • F=AHn • Within WRFChem, we will use the relationship determined by Futyan and DelGenio where, • A=7.67 x 10-5 • n=4.8 • Convective storm height above freezing level (H) is found using the 20 dBz contour and the freezing level is obtained from the WRF temperature field. • Radar Reflectivity calculated within WRFChem using 3-D hydrometeors from microphysical scheme (WSM6) coupled with the Kain-Fritsch cumulus parameterization.

  5. DATA WSR-88 Doppler Radar and the Lightning Detection and Ranging (LDAR ) data from Kennedy Space Center (KSC) Doppler Radar Melbourne, Florida KSC LDAR. Sensor 0 is the central LDAR receiver. (After Poehler and Lennon 1979 and Vollmer 2002)

  6. Composite Radar Reflectivity • from KMLB for 3 Aug 2005 • Black contours are LDAR flash • counts in the corresponding • 6 minute radar scan • Red rings are distance (km) from • KMLB radar located: • Lat=28.109 • Lon=-80.650 • LDAR central receiver location: • Lat=28.5386 • Lon=-80.6431

  7. Cross section through approx • 28.4N, Radar Reflectivity • from KMLB for 3 Aug 2005 • Black contours are LDAR flash • counts in the corresponding • 6 minute radar scan NOTE: due to radar scan angle lightning Flashes are seen above the radar signature Depending on the proximity of the storm to The radar

  8. T=19z Radar top=11 km T=17z Radar top=9 km

  9. T=22z Radar top=12 km T=20z Radar top=14 km

  10. WRF-Chem Model and Domain for Testing FSULNOx Mother domain: 36km Nested domain: 12km Eventually we will be using a larger domain Covering the eastern half of the US • Within the WRF-Chem namelist two • User defined options will be added • lighting_opt 0,1 ; turn off, on lightning • Lightning_time_step Lightning Module will be placed in chem/ directory and contains subroutine radar subroutine lightning Module will be called from Chem_driver.F right after emissions.

  11. WRF-Chem Physics Microphysics-WSM6 Cumulus Parameterization-Kain Fritsch eta Long wave & Short wave radiation-RRTM/Dudhia Planetary Boundary Layer-Mellor-Yamada-Janjic (MYJ) Lightning Parameterization will likely be very sensitive to the Microphysics scheme chosen. We may need to perform a sensitivity Study to make sure WSM6 is the scheme to use.

  12. LNOx algorithm for WRF-Chem what are the necessary ingredients? LNOx parameterization • Production rate of NO from both IC and CG lightning: • -500 moles per flash (Ott et al.,in progress) • Vertical Distribution of NO: • -Using LDAR source distributions as a function of radar storm top height above the freezing level we can obtain a percentage of lightning at each vertical level that can be used to distribute the model derived 2-D NO.

  13. Vertical Distribution LDAR Source distribution (range from central receiver 50 km) calculated as an average of lightning sources during storms occurring in June, July, and August from 2004&2005 Boccippio et al., 2000 19 month average from 1997-1998

  14. Freezing Level On average during The summer in Florida Was around 4500m Vertical Distribution as a function of Freezing Level (FL) Peak between 7-8 km Peak ~7 km

  15. Secondary Peak ~14-15 km Secondary Peak between 12-14 km Peak ~9 km Peak between 7-8 km

  16. Verification Simulations for Summer 2004 INTEX-NA period over eastern US and comparisons with aircraft data DC-8 flight track showing the path through the Huntsville, AL storms We have the same data for Kennedy Space Center Plot courtesy of Mike Porter

  17. Verification SCIAMACHY satellite data SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY European Space agency Satellite in orbit in 2004 Primary mission to measure atmospheric trace gases Including tropospheric ozone and NO2 Measurements at relatively high resolution (0.2 nm to 0.5 nm) over a wide range: 240 nm to 1700 nm

  18. Verification IONS-INTEX ozonesonde Network Study Since NOx is a precursor for tropospheric ozone formation; Model ozone will be a good indicator of NOx model performance Ozonesondes launched during the 2004 INTEX field campaign 10 Operational Sites in Eastern US Including Huntsville, AL

  19. Summary • Flash rate parameterization being developed for WRF-Chem usingobserved radar and 3-D lightning mapping array data. • WRF-Chem first will be tested with the Futyan and Del Genio (2007) relationship. • Existing NO production per flash • Vertical distribution of lightning sources will be used to distribute model derived NO from lightning. • Testing of WRF-Chem with lightning will be conducted using aircraft NOx observations from the ICARTT (NASA and NOAA data) experiment from Summer 2004, ozonesondes, and possibly NO2 from satellite.

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