Conditions of the Simulations

Background Information   Meteorological Initial Conditions   Chemical Initial Conditions 

 Output   Output for Soluble Species


Background Information

Journal papers describing the 10 July 1996 storm are as follows:

Dye, J. E., B. A. Ridley, K. Baumann, W. C. Skamarock, M. C. Barth, M. Venticinque, E. Defer, P. Blanchet, C. Thery, P. Laroche, G. Hubler, D. D. Parrish, T. Ryerson, M. Trainer, G. Frost, J. S. Holloway, F. C. Fehsenfeld, A. Tuck, T. Matejka, D. Bartels, S. A. Rutledge, T. Lang, J. Stith, R. Zerr, 2000:  An Overview of the STERAO--Deep Convection Experiment with Results for the 10 July Storm, J. Geophys. Res., 105, 10,023-10,045. (PDF)

Skamarock, W. C., J. Powers, M. C. Barth, J. E. Dye, T. Matejka, D. Bartels, K. Baumann, J. Stith, D. D. Parrish, and G. Hubler, 2000: Numerical simulations of the 10 July STERAO/Deep Convection Experiment Convective System:  Kinematics and transport, J. Geophys. Res., 105, 19,973--19,990. (PDF)

Barth, M. C., A. L. Stuart, and W. C. Skamarock, 2001:  Numerical simulations of the July 10 Stratospheric-Tropospheric Experiment: Radiation, Aerosols and Ozone/Deep Convection storm:  Redistribution of soluble tracers, J. Geophys. Res., 106, 12,381-12,400. (PDF)

Skamarock, W. C., J. E. Dye, E. Defer, M. C. Barth, J. L. Stith, B. A. Ridley, and K. Baumann, 2003:  Observational- and Modeling-Based budget of lightning-produced NOx in a continental thunderstorm, J. Geophys. Res., 108(D10), 4305, doi10.1029/2002JD002163. (PDF)


Dye et al. (2000) describe the observed storm.

Skamarock et al. (2000) describe simulations of tracer transport.  The simulation discussed in this paper will be repeated for the intercomparison case.  The observed CO and O3 concentrations shown in this paper will be used to evaluate the participating models.

Skamarock et al. (2003) describe an analysis of lightning-produced NOx.  The analyzed CO, O3, and NOx fluxes (analyzed from the measurements) will be used to evaluate the participating models.

Barth et al. (2001) describe transport of soluble tracers.


Please simulate the following tracers:

CO, O3, NO, NO2 (or NOx), and tracer-NOx.  tracer-NOx is NOx which is only transported in the simulation.
Other species may also be simulated, if so desired.

Optional tracers to simulate:
HNO3, H2O2, and CH2O to examine the fate of soluble tracers. 
These can be simulated either with or without chemistry.  Because measurements of these 3 species were not made in the anvil of the storm nor in the precipitation, comparisons of these model results will be done only among models.  A link to the initial concentrations of these species is provided below. 

The following initial conditions are taken from Skamarock et al. (2000, 2003).  The altitudes provided are values above ground level and match the model levels presented in Skamarock et al. (2000).  If you need initial conditions at other altitudes, simply perform a linear interpolation.


Meteorological Initial Conditions:

Sounding data is contained in a Html version, or ASCII version  table.

To initiate convection, place 3 positively buoyant thermals aligned NW to SE and spaced approximately 20 km apart, following these equations.
θ' = 0.5 Δθ (cos(πr) + 1)          for r < 1

r is the distance from (xr, yr, zr) where xr = yr = 10 km and zr = 1.5 km.  Δθ = 3 K

The surface pressure is 860 mb.  Storm speed is us = 1.5 m/s, vs = -5.5 m/s .

Chemistry Initial Conditions:

Vertical profiles are contained in a Html version or ASCII version table.

Ice Nuclei (IN) initial concentration:  0.1 cm-3.
Condensation Nuclei (CN) concentrations are provided in the following table.  These values are from the WP3D NOAA aircraft.  Altitudes are given in km, mean sea level.  The surface is 1.5 km, m.s.l..  The data are average CN values out-of-cloud for the specific altitude ± 0.5 km.

z
(km, m.s.l.)
 CN
(cm-3)
1.5
 6609
2.7
 4388
4.0
 410
5.0
 195
6.0
 108
6.5
 128

Above 6.5 km, m.s.l. set CN concentrations to 128 cm-3.  Those who simulate aerosols have assumed a log-normal distribution (Dmean = 50-100 nm, std dev = 2.0 in boundary layer; Dmean = 10-30 nm, std dev = 1.5-1.7 above boundary layer) composed of ammonium bisulfate.  There are no measurements to confirm these assumptions, but they are quite reasonable for the location.

You are strongly encourage to predict CO, O3 and NOx mixing ratios.  In addition, the soluble species H2O2, CH2O and HNO3 can be predicted to examine both transport and scavenging.


Output:

Simulate storm and tracers for about 3 hours.  The results from the model simulations will be compared to observations measured in the anvil of the storm.  Please provide the following results:

1.  Peak updraft velocities as a function of time and location.  Email an ASCII file with this data and I will plot it alongside results from other participants.

2.  Radar reflectivity (dBZ) cross sections that can be compared to Figures 6 and 7 in Skamarock et al. (2000).
    A. x-y cross section (W-E, N-S) at
      a) z = 4.5 km m.s.l.  (3 km above ground level) at
         1) t = 2312 UTC (approximately 1 hour after start of simulation)
         2) t = 0128 UTC (approximately 9000 s after start of simulation)
      b) z = 10.5 km m.s.l.   (9 km above ground level) at
         1) t = 2312 UTC (approximately 1 hour after start of simulation)
         2) t = 0128 UTC (approximately 9000 s after start of simulation)

    B.  xy-z cross section  (NW-SE, top-bottom) at
      a) t  = 2312 UTC (approximately 1 hour after start of simulation)
      b) t = 0128 UTC (approximately 9000 s after start of simulation)

This cross section is along the line of cells.  In Skamarock et al. (2000) the cross section was placed at a 130 deg angle from north (-40 degrees from east)  -- note that the 9000 s simulation cross-section is at a 115 degree angle from north.  Choose the angle that best fits your simulation.

Code to calculate radar reflectivity using bulk-water microphysics

Fortran code to interpolate model results to a cross section

Email output files of values so that I can plot the results consistently with other participants.  Be sure to provide a height and horizontal coordinate (either in email or in the attached file).  Be sure to explain the format of your output file.

3.  Volume mixing ratios (ppbv) across the anvil for CO, O3, and NOx :
  1. During the multicellular stage of the storm (~1 hour into the simulation) at approximately 10 km downwind of the southeasternmost cell (with a SW-NE orientation)
  2. Approximately 1/2 hour later at ~50 km downwind of the southeasternmost cell (with a N-S orientation)

These observations are shown in Dye et al. (2000) Figure 9 and Skamarock et al. (2000) Figure 11.
Email an ASCII file with these results and I will plot it alongside results from other participants.

4.  Vertical cross section of particle concentration (per liter), CO (ppbv), O3 (ppbv), NO (pptv), and NOx (pptv) at  approximately 6000 s and 50-60 km downwind of convective core.  See Figure 1 of Skamarock et al. (2003) for location of observed analysis plane.  The analyzed measurements are shown in Figure 4 of Skamarock et al. (2003).  If your model does not predict particle concentration, use one of the following methods for determining the particle concentration:

If the water reservoir is assumed to have the same size particles, then
N = q/M
where q = mixing ratio (kg/kg) of water reservoir and M = mass of particle = ρparticle * π/6 * (Dparticle)3
If the water reservoir has an assumed size distribution, then
N = ∫ (N(D) dD

Email output files of values so that I can plot the results consistently with other participants.  Be sure to provide a height and horizontal coordinate (either in email or in the attached file).  Be sure to explain the format of your output file.

5.  Fluxes of air mass (kg/s/m2), CO (moles/s/m2) and NOx (moles/s/m2) integrated over the anvil through the analysis plane (see #3) divided by the cross-sectional area of the anvil.  Provide instantaneous and cumulative flux densities at 10 minute intervals between 1 hour and 2 hours of the integration.  The analyzed observations of flux densities are given in Table 1 of Skamarock et al. (2003).

How to do the flux calculation:  3 slides explaining geometry and flux calculation

Email these results in an ASCII file.


Output for Soluble Species:

1.  Volume mixing ratios (ppbv) across the anvil for HNO3, H2O2 and CH2O :
  1. During the multicellular stage of the storm (~1 hour into the simulation) at approximately 10 km downwind of the southeasternmost cell (with a SW-NE orientation)
  2. Approximately 1/2 hour later at ~50 km downwind of the southeasternmost cell (with a N-S orientation)
Email an ASCII file with these results and I will plot it alongside results from other participants.

2.  Vertical cross section of HNO3 (ppbv), H2O2 (ppbv), and CH2O (ppbv) at  approximately 6000 s and 50-60 km downwind of convective core.  See Figure 1 of Skamarock et al. (2003) for location of observed analysis plane. 

Email output files of values so that I can plot the results consistently with other participants.  Be sure to provide a height and horizontal coordinate (either in email or in the attached file).  Be sure to explain the format of your output file.

3.  Fluxes of HNO3, H2O2 and CH2O ((moles/s/m2) integrated over the anvil through the analysis plane (see above) divided by the cross-sectional area of the anvil.  Provide instantaneous and cumulative flux densities at 10 minute intervals between 1 hour and 2 hours of the integration.   If needed, see flux calculation slides (link in #5 above).

Email these results in an ASCII file.

Send email to barthm@ucar.edu.


Last updated:  February 18, 2005