d. Peer Review at George Mason University
Due to the sensitivity of the notification process, the significance of the followup epidemiological studies, and the intense interest of the atmospheric science community, the DHS convened a panel of experts in the fields of meteorological and turbulent diffusion modeling to review the DoD and CIA work. The panel, consisting of Richard Anthes, University Corporation for Atmospheric Research; Bruce Hicks and Will Pendergrass, National Oceanic and Atmospheric Administration; and Steven Hanna, George Mason University, participated in a meeting at George Mason University in Fairfax, Virginia on November 45, 1997. The primary purpose of the panel discussion was to assess the scientific credibility of the Khamisiyah modeling results publicly released in July 1997, with an additional assessment of the modeling methodology and model selection. The panel members received a copy of the draft technical report one week before the meeting.
At the meeting, a CIA contractor briefed the Pit demolition, the Dugway rocket tests, and the Edgewood and Dugway agent evaporation tests. Meteorological modelers briefed their models’ capabilities, supporting publications, configurations, and modeling results and performance measures. Dispersion modelers from the CIA (NUSSE4), NSWC (VLSTRACK), and DTRA (HPAC/SCIPUFF) presented their analyses of the Pit release and an overview of their model’s validation.
The panel prepared a December 11, 1997, report, "Comments by Peer Review Panel on Khamisiyah Modeling Report and Presentations on 45 November 1997" (Anthes et al., 1997). On the question of using outputs from several independent meteorological and dispersion models to determine the area within which ground personnel were at risk of exposure, the panel stated: "The panel endorses the DoD decision to base its estimates of potentiallyaffected personnel on the union of all the model outputs."
The panel discouraged using computationally inexpensive operational models and suggested using stateoftheart highresolution models with the fewest physical limitations and assumptions. In addition, the panel commented on the significance of several topics, including spatially and temporallyvarying atmospheric stability, accurate mixinglayer heights, and inconsistencies in the dispersion models’ results using the same nominal meteorological input data. On modeling strategy and the selection of models, the panel noted:
The panel also issued these findings on the dispersion models:
C. REFINED KHAMISIYAH ANALYSES (FOR 2000 MODELING)
1. Introduction
In addition to the issues raised by the George Mason University panel, agent removal effects (e.g., decay and vapor deposition) also required serious consideration. The July 1997 results did not fully represent the agent removal effects because empirical data was lacking and more inclusive hazard areas were preferred. The Senate Special Investigative Unit on Gulf War Illnesses also identified these omissions in its August 1998 report. Other deficiencies in the 1997 modeling are as follows:
Inconsistencies In Dispersion Calculations For Same Source And Same Meteorology
Dosage patterns for the July 1997 VLSTRACK and HPAC/SCIPUFF model runs based on the same meteorological input showed a discrepancy (Figures A58 and A59). Dispersion results strongly depend on the puff tracking heights for nearsurface releases. For all runs conducted prior to the November 1997 George Mason University panel review meeting, VLSTRACK used either the puff centroid or the height of interest as the effective tracking height, while HPAC/SCIPUFF used the maximum of the centroid and 0.6 cloud vertical sigma. Subsequent to the review meeting, NSWC ran VLSTRACK using the HPAC/SCIPUFF nearsurface tracking algorithm, which resulted in plumes with trajectories quite consistent with the corresponding HPAC/SCIPUFF output (Figures A58 and A60). NSWC has since proposed a vertical tracking and splitting algorithm using the maximum of the centroid and 0.6 cloud sigma.
Figure
A58. HPAC/COAMPS4 predicted fourday cumulative
dosage contours
Figure
A60. VLSTRAC/COAMPS4 predicted fourday cumulative
dosage contours (revised tracking height)
Inconsistency in the Source Term
Because of the pressure to release modeling results quickly, the July 1997 simulations used inconsistent source terms (e.g., the internal evaporation algorithm for VLSTRACK versus the DPG evaporation curve for HPAC/SCIPUFF). A common source characterization, the DPG evaporation curve, was used for all subsequent simulations.
Therefore, the DHS intensified its efforts to obtain more refined exposure assessments. The inconsistencies in the puff tracking algorithm and the source term mentioned above were resolved for the refined (2000) modeling. In addition the following sections describe in detail the improvements made to meteorological modeling and the unit location and personnel data. The results are more refined estimates of possible exposure to servicemembers from the demolition in the Khamisiyah Pit.
2. Refined Meteorological Modeling
a. Models’ Improvements
Since 1997, several new simulations of MM5, OMEGA, and COAMPS were made to update the description of the mesoscale meteorological conditions near Khamisiyah. The largescale fields used to initialize the mesoscale models and to provide the lateral boundary conditions are largely the same as those used in the 1997 modeling. The improvements made to COAMPS, OMEGA, and MM5 are described below.
1) COAMPS. As mentioned before (Table A9) in 1997, in addition to the baseline analysis (Run COAMPS 7), alternative COAMPS analyses were performed that consisted of (Westphal et al., 1999):
The baseline analysis was used in the 2000 modeling. In 1997, however, COAMPS 4 was chosen for dispersion modeling based on comparison to the ground soot patterns due to bunker explosions. COAMPS 4 is equivalent to running COAMPS in pure forecast mode with no data assimilation. The peer review panel questioned the decision because intuitively a datadenial run should give inferior results. Furthermore, the COAMPS developers also recommended the use of the baseline analysis. Therefore, COAMPS 7 was used in the 2000 Modeling.
2) OMEGA. The following improvements incorporated into OMEGA version 3.7 used for the 2000 modeling:
See Bacon et al., (2000) for OMEGA 3.7’s application to the Khamisiyah analysis.
3) MM5. The new MM5 reanalysis consisted of four sixday simulations using continuous data assimilation (see Table A13). As with the spring 1997 reanalysis, NCAR performed these simulations with different options for the PBL parameterizations and global data for lateral boundary conditions and assimilation. In addition, a simulation was made with a variation in the surface roughness length. This simulation was motivated by the fact many mesoscale models historically have employed a default roughness length of about 10 cm for desert. This value may be appropriate for some southwestern US deserts with large brush and scrub trees, but surface roughness less than 1 cm probably is more appropriate for barren desert with scattered, limited vegetation (e.g., Oke, 1987). Thus, in Simulations 1, 2, and 3, the lower values of desert roughness length were employed to be consistent with the surface conditions of the Arabian desert (1 cm for vegetated desert and 0.5 cm for unvegetated desert). In Simulation 4, otherwise the same as Simulation 1, 10 cm was used.
Table A13. Configurations for MM5 simulations
Simulation Number 
LargeScale 
BoundaryLayer Parameterization 
Desert Roughness Length (cm) 
1 
TOGA/ECMWF 
MR 
~ 1 
2 
NCEP 
MR 
~ 1 
3 
TOGA/ECMWF 
Blackadar 
~ 1 
4 
TOGA/ECMWF 
MR 
~ 10 
Systematic performance evaluation shows Simulation 2 performed slightly better than the rest. To quantify model performance, the mean error (ME), the mean absolute error (MAE), and the root mean square error (RMSE) are calculated for predictions of wind speed, wind direction, temperature, and dew point temperature:
(Equation
A34)


(Equation
A35)


(Equation
A36)

where M_{i} and O_{i} are the i^{th} pair of model prediction and observation, and N is the total number of pairs. Separate statistics were calculated for
In addition, NCAR made the following improvements to MM5:
Warner and Sheu (2000) provide further details of how NCAR applied MM5 to the Khamisiyah analysis.
b. Khamisiyah’s Predicted Flow Fields
Figures A61 through A72 show the surface wind vectors the three mesoscale models produced for the 2000 Khamisiyah analysis every 24 hours for 1200 UTC March 10, 1991, through 1200 UTC March 13, 1991. Wind vectors are plotted only at every half degree for legibility, although the model resolution is much higher. Moreover, the surface wind fields refer to 10, 40, and 30 m above the ground for COAMPS, MM5, and OMEGA, respectively.
At the time of the release (near 1200 UTC March 10, 1991), all three models produce nearsurface winds out of the northwest over Khamisiyah (Figures A61, A62, and A63). Furthermore, these figures also show the sea breeze effect that drives wind flow counter to the prevailing circulation over the Persian Gulf’s northern coast. Consistent with the earlier predictions, the lowlevel flow south of Khamisiyah shifts from the northwest to the northnortheast over the next 24 hours (i.e., 1200 UTC March 10, 1991, through 1200 UTC March 11, 1991). Figures A64, A65, and A66, reflect this shift, which is consistent with the evolving largescale conditions. Comparing the individual plots, we see the nearsurface flow fields are fairly consistent with the plume trajectories generated in 1997, and individual model differences are generally limited to locations exterior to the hazard area footprint.
Figure
A61. 2000 MM5 Grid 3 predicted
wind fields for 1200 UTC March 10, 1991
Figure
A62. 2000 COAMPS Grid 3 predicted
wind fields for 1200 UTC March 10, 1991
Figure
A63. 2000 OMEGA Grid 3 predicted
wind fields for 1200 UTC March 10, 1991
Figure
A64. 2000 MM5 Grid 3 predicted
wind fields for 1200 UTC March 11, 1991
Figure
A65. 2000 COAMPS Grid 3 predicted
wind fields for 1200 UTC March 11, 1991
Figure
A66. 2000 OMEGA Grid 3 predicted
wind fields for 1200 UTC March 11, 1991
Between 1200 UTC March 11, 1991, and 1200 UTC March 12, 1991, the lowlevel pressure gradient over the Khamisiyah region intensified, shifting the winds more easterly (Figures A67, A68, and A69). Over the next 24 hours (1200 UTC March 12, 1991, through 1200 UTC March 13, 1991), the models show weak cyclonic circulation driven by the surface low pressure over the area (Figures A70, A71, and A72).
Figure
A67. 2000 MM5 Grid 3 predicted
wind fields for 1200 UTC March 12, 1991
Figure
A68. 2000 COAMPS Grid 3 predicted
wind fields for 1200 UTC March 12, 1991
Figure
A69. 2000 OMEGA Grid 3 predicted
wind fields for 1200 UTC March 12, 1991
Figure
A70. 2000 MM5 Grid 3 predicted
wind fields for 1200 UTC March 13, 1991
Figure
A71. 2000 COAMPS Grid 3 predicted
wind fields for 1200 UTC March 13, 1991
Figure
A72. 2000 OMEGA Grid 3 predicted
wind fields for 1200 UTC March 13, 1991