The project findings and conclusions concerning the efficacy of regional strategies are to be used by the EPA, States, and a possible future regional commission to support development of the policies and legislation needed to provide consistent, coordinated SIPs along the Northeast Corridor, and for the potential implementation of regional control measures. Detailed descriptions of meteorol- ogy data and meteorology, data preprocessing can be found in Milich etal. The following approach was adopted for evaluating the candidate episodes against these criteria and for ultimately selecting the episodes for modeling. August 6- August 16, High pressure systems moved across the east coast during much Episode 9. Also, reactivity measures may counterbalance the negative impact of NOX controls in New York City and other areas that show a similar response. PF’s contain partially processed data required as Input to higher level processors.
Within the Corridor, along-Corridor flow occurred on seven days with variable flow on other days. Selective catalytic reduction SCR was applied to all utility combustion sources. This page is intentionally left blank. This reduction trans- lates to a 5 percent reduction in overall VOC emissions. Meteorology input data consist of the regular hourly surface and upper-air observations from the U. These values are chemically equilibrated with each other before use by the ROM.
Flow into much of the Corridor was from the southwest on eight days and from the northwest on other days. It is noteworthy that the observed and modeled patterns in Figure resemble each other: Detroit, Pittsburgh, Charleston, and Danville.
A detailed description of the meteorological conditions and ambient ozone levels during the four episodes selected for simulation is provided in Appendices D, E, and F. Both the mobile and stationary area source inventories include emissions for three separate day types: The second reactivity reduction measure was the conversion of the entire Northeast Corridor highway fleet to percent methanol fuel vehicles.
Hourly emission rates for mobile sources are computed by using a daily average temperature value for each individual grid cell. The episode with the highest total was ranked first, etc. Thus, if biogenics are actually near the high end of the uncertainty range, then additional controls providing reduc- tions in emissions beyond those in CS19 will be needed in many of the Northeast cities.
Such a broad strategy may be needed to reduce interurban and intraregional impacts associated with ozone and precursor transport. These latter two pollutants are not affected by the range in diurnal temperature changes. The objectives of the ambient evaluation were 1 to examine overall evaluation statistics to determine whether a general bias exists in the model calculations, 2 to look at spatial patterns of maximum concentration to determine whether a spatial bias exists, and 3 to examine the model’s applicability for determining UAM boundary conditions.
Controls were added for four new point source categories and to generic non-CTG point sources. These coefficients can no longer be equated with physical quantities; they are purely mathematical entities related specifically to the form of the finite difference algorithms used by the ROM. The above statistics include all grid points regardless of the wind direction.
Mean residuals versus wind persistence for the UAM boundary; positive values are over- prediction, negative values are underprediction.
Daam-Episode 16 (part 2)
Transition regime – high pressure along east coast extending SE and NW: Concentration estimates are grid cell horizontal and vertical average values for each layer. For analyzing spatial patterns, an objective contouring algorithm was used to produce computer graphics depicting concentration fields based on the gridded ROM data 3.
Predictions for the different strategies and the future, baseline scenario were analyzed and inter-compared relative to the strategic issues. Mean concentrations for all daytime hours agreed to within 5 ppb less than 10 percent error. Diurnal NOX emission rates for mobile sources contain large variations due to the assumed traffic pattern.
Individuals participating in the project are listed in Appendix B. As noted in Section 1.
Regional Ozone Modeling for Northeast Transport (ROMNET) Project Final Report
ApexCourt for Salaries to Imaams. If the number of reporting sites was the same for two or more episodes, epsiode episode with the highest maximum hourly concentration was ranked first; the episode with the lowest concen- tration was ranked last.
A processor at any given stage, however, must wait until all processors from lower stages along its input data paths have been completed.
The urban-scale analyses are to be conducted by the States as part of the SIP process. Surface emissions are specified as a mass flux through the bottom of layer 1. Near Boston, the modeled and observed concentrations agreed closely as noted by the placement of the ppb contour on both plots.
A stationary front extending from a low over central Indiana stretched eastward to northern Virginia and merged into a surface trough that stretched northeastward along the Atlantic seaboard.
आर्यावर्त लायें – Malegaon-trial
Overestimates by the model continued throughout Group 2. The region showing the greatest underestimate in the upper values was Group 3, an area removed from the extensive metropolitan area along the Northeast Corridor. Only daytime values LSI to LSI were included in the evaluation because nighttime observations are influenced by localized processes that often include scavenging of ozone by NO emissions and therefore do not reflect vertically-integrated ozone concentrations in layeM eppisode the ROM Schere and Wayland, Within the Corridor, along-Corridor flow was noted on only three days with recirculation conditions on two days.
For the portion of the evaluation concerned with general statistics, gridded ozone values were interpolated to actual monitoring locations using a biquintic interpolation scheme Lamb, that is consistent with the methodology used in the model.
Because the primary focus of trie study was the Northeast Corridor, the selection of episodes focused on conditions in this portion of the domain. Muj13W32 Sonia and Nazeeb. The following approach was adopted for evaluating the candidate episodes against these criteria and for ultimately selecting the episodes for modeling.
Although the time scale of output concentrations is 30 minutes, ROM predictions are aggregated into 1-hour average concentrations. Within the cloud, the chemical processes of ambient pollutant species are suddenly altered by the presence of liquid water and the attendant attenuation layek sunlight.