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Some measurements of the vertical distribution of ozone in the atmospheric boundary layer
2037
Discussions
SOME MEASUREME~S OF THE VERTICAL DISTRIBUTION OF OZONE IN THE ATMOSPHERIC BOUNDARY LAYER*
hypothesis. We can infer the vertical distribution of ozone through the equation
The study described in the paper suggests that the authors might have enough information to test one explanation for the diurnal variation of surface ozone levels. Recent papers (Ott and Lyons, 1977; Johnson and Singh, 1977) show that there is a strong correlation between mixed layer height and surface ozone concentrations in the forenoon hours. This indicates that surface ozone levels are the result of entrainment of ozone from “reservoirs” aloft. We can construct a simple model for this process as follows. Assuming negligible photochemical production and scavenging of ozone the conservation equation for the ozone concentration in the well mixed daytime PBL can bc written as
In Equation (1) h is the mixed layer height, C is the ozone concentration in the mixed layer, and C, is the concentration above the mixed layer. The equation states that the variation of ozone concentration is the result of entrainment (the term on the right) at the top of the mixed layer. It is clear that a measurement of the vertical ozone profile C,(z) before mixing, and simultaneous measurements of mixed layer height and surface ozone concentration would be sufficient to test the
* Van Dop H., Guicherit R. and Lanting R. W. (1977) Atmospheric Ennironment 11,65-71.
PLUME RISE FROM MULTIPLE SOURCES: A NEW MODEL* This paper is an ingenious, logical method of simplifying the evaluation of multiple plume problems, and it should be helpful to many who are struggling with the complex problem of refining the theoretical treatment of diffusion from large stationary sources. It is also reassuring to see that an approach which is quite different in several respects from Bri8gs’ work gives essentially similar results. The formulation of course suffers from the same deficiencies as other multiple source plume rise equations, namely that it is not easy to see how well it may apply to the * Anfossi D., Bonino G., Bossa F. and Richiardone (1978) Atmospheric Environ~nt 12, 1821-1826.
R.
The mixed layer height can be estimated using Holzworth’s technique if direct measurements have not been made. We can explain the strong correlation between C and h if we take C, = C, + a(z - ho), where Co is the initial surface concentration. Then, the solution of (1) can be readily written as C=Co+;(h-h,)?
In (3), he is the nocturnal boundary layer height. If he and C, are small, C becomes pro~~ional to h This would exptain the results presented by Ott and Lyons (1977). From a reading of the paper WCbelieve that Van Doper al. (1977) have enough data (not presented in the paper) to test an important explanation for diurnal ozone concentration variations. Ontarfo Ministry OJthe Environment 880 Bay Street, 4th Floor Toronto, Ontario, Canada MSS 128
A. VENKATRAM
REFERENCES Johnson W. and Singh B. S. (1977) Ozone maximums aloR : Their origin and importance. Joint Cont on Appkatlons of Air PoWon ~et~ro~y, November 29-Dtxxmber 2, f977, Salt Lake City, Utah. Lyons W. and Ott S. (1977) Further evidence of long-range photochemical oxidant transport inferred from acoustic sounder data. Ibid. 33-38.
more complex (and common) situations where the stack co~guration and wind o~~tation do not fit simple geometry, but the authors cannot be faulted for this. I do disagree, however, with the implication that WChave a “high degree of knowledge” about plume behavior from single sources. indeed, we have a fairly large volume of data, but we seIdom have adequate definition of the metrological structure to go with it. In fact, the paper is yet another indication of the need for carefully-designed field experiments, rather than blind dependence upon theoretical work. The fact is that there are almost no decent data on the behavior of multiple plumes in the literature, and multiple plumes are the rule rather than the exception. Meteorological Evaluation Service. Inc. MAYNARDE. SMITH 134 Broadway Amityvifie, N. Y. 11701, U.S.A.
Discussions
SOME MEASUREME~S OF THE VERTICAL DISTRIBUTION OF OZONE IN THE ATMOSPHERIC BOUNDARY LAYER*
hypothesis. We can infer the vertical distribution of ozone through the equation
The study described in the paper suggests that the authors might have enough information to test one explanation for the diurnal variation of surface ozone levels. Recent papers (Ott and Lyons, 1977; Johnson and Singh, 1977) show that there is a strong correlation between mixed layer height and surface ozone concentrations in the forenoon hours. This indicates that surface ozone levels are the result of entrainment of ozone from “reservoirs” aloft. We can construct a simple model for this process as follows. Assuming negligible photochemical production and scavenging of ozone the conservation equation for the ozone concentration in the well mixed daytime PBL can bc written as
In Equation (1) h is the mixed layer height, C is the ozone concentration in the mixed layer, and C, is the concentration above the mixed layer. The equation states that the variation of ozone concentration is the result of entrainment (the term on the right) at the top of the mixed layer. It is clear that a measurement of the vertical ozone profile C,(z) before mixing, and simultaneous measurements of mixed layer height and surface ozone concentration would be sufficient to test the
* Van Dop H., Guicherit R. and Lanting R. W. (1977) Atmospheric Ennironment 11,65-71.
PLUME RISE FROM MULTIPLE SOURCES: A NEW MODEL* This paper is an ingenious, logical method of simplifying the evaluation of multiple plume problems, and it should be helpful to many who are struggling with the complex problem of refining the theoretical treatment of diffusion from large stationary sources. It is also reassuring to see that an approach which is quite different in several respects from Bri8gs’ work gives essentially similar results. The formulation of course suffers from the same deficiencies as other multiple source plume rise equations, namely that it is not easy to see how well it may apply to the * Anfossi D., Bonino G., Bossa F. and Richiardone (1978) Atmospheric Environ~nt 12, 1821-1826.
R.
The mixed layer height can be estimated using Holzworth’s technique if direct measurements have not been made. We can explain the strong correlation between C and h if we take C, = C, + a(z - ho), where Co is the initial surface concentration. Then, the solution of (1) can be readily written as C=Co+;(h-h,)?
In (3), he is the nocturnal boundary layer height. If he and C, are small, C becomes pro~~ional to h This would exptain the results presented by Ott and Lyons (1977). From a reading of the paper WCbelieve that Van Doper al. (1977) have enough data (not presented in the paper) to test an important explanation for diurnal ozone concentration variations. Ontarfo Ministry OJthe Environment 880 Bay Street, 4th Floor Toronto, Ontario, Canada MSS 128
A. VENKATRAM
REFERENCES Johnson W. and Singh B. S. (1977) Ozone maximums aloR : Their origin and importance. Joint Cont on Appkatlons of Air PoWon ~et~ro~y, November 29-Dtxxmber 2, f977, Salt Lake City, Utah. Lyons W. and Ott S. (1977) Further evidence of long-range photochemical oxidant transport inferred from acoustic sounder data. Ibid. 33-38.
more complex (and common) situations where the stack co~guration and wind o~~tation do not fit simple geometry, but the authors cannot be faulted for this. I do disagree, however, with the implication that WChave a “high degree of knowledge” about plume behavior from single sources. indeed, we have a fairly large volume of data, but we seIdom have adequate definition of the metrological structure to go with it. In fact, the paper is yet another indication of the need for carefully-designed field experiments, rather than blind dependence upon theoretical work. The fact is that there are almost no decent data on the behavior of multiple plumes in the literature, and multiple plumes are the rule rather than the exception. Meteorological Evaluation Service. Inc. MAYNARDE. SMITH 134 Broadway Amityvifie, N. Y. 11701, U.S.A.