Role of the boundary layer in the occurrence and termination of the tropospheric ozone depletion events in polar spring

Cao, Le; Platt, U.; Gutheil, Eva

doi:10.1016/j.atmosenv.2016.02.034

Cited by 18 publications

(46 citation statements)

References 52 publications

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“…Although tropospheric ozone is relatively well mixed in a broad sense, its concentration can vary notably with both time and space depending on the prevailing meteorological conditions. Regional and local surface O 3 con-centrations are affected, for example, by horizontal and vertical advections of pollutants, entrainment from the free troposphere and other boundary layer dynamic processes (Simpson et al, 2007;Cao et al, 2016;Tang et al, 2017;Zhou et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Observations of ozone depletion events in a Finnish boreal forest

et al. 2018

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Abstract. We investigated the concentrations and vertical profiles of ozone over a 20-year period (1996-2016) at the SMEAR II station in southern Finland. Our results showed that the typical daily median ozone concentrations were in the range of 20-50 ppb with clear diurnal and annual patterns. In general, the profile of ozone concentrations illustrated an increase as a function of heights. The main aim of our study was to address the frequency and strength of ozone depletion events at this boreal forest site. We observed more than a thousand of 10 min periods at 4.2 m, with ozone concentrations below 10 ppb, and a few tens of cases with ozone concentrations below 2 ppb. Among these observations, a number of ozone depletion events that lasted for more than 3 h were identified, and they occurred mainly in autumn and winter months. The low ozone concentrations were likely related to the formation of a low mixing layer under the conditions of low temperatures, low wind speeds, high relative humidities and limited intensity of solar radiation.

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Section: Introductionmentioning

confidence: 99%

Observations of ozone depletion events in a Finnish boreal forest

et al. 2018

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“…Figure 1 shows the development of the mixing ratios of ozone and principal bromine species with time. Since this result has been presented and discussed in our previous publications [17,22], we give in the present manuscript only a brief outline of their most important features. It is seen in Figure 1 that ozone starts to drop significantly after day 3 before which the ozone depletion rate is less than 0.1 ppb·h −1 .…”

Section: Resultsmentioning

confidence: 99%

“…It is also assumed in the model that the bromide storage in the acidic ice/snow-covered surfaces is inexhaustible [13,17,22]. Apart from this, the parametrization adopted in the model still requires the prescription of the height of the boundary layer and the surface layer.…”

Section: Mathematical Models and Methodsmentioning

confidence: 99%

“…After implementing a reaction mechanism of ODEs in the box model KINAL (KInetic aNALysis of reaction mechanics) [21] and solving Equation (1), we are able to capture the temporal evolutions of ozone and principal bromine species in the ODE event. The adopted reaction mechanism in the present study is taken from previous studies [13,17,22] and consists of 92 reactions among 39 chemical species. The full reaction mechanism is listed in Table A1 in the Appendix.…”

Section: Mathematical Models and Methodsmentioning

confidence: 99%

“…92 in Table A1 in the Appendix), it is necessary to consider the aerodynamic resistance r a , quasi-laminar resistance r b due to the molecular diffusion, and the surface resistance r c . Parametrization from previous model studies [13,17,22] for these heterogeneous reactions is adopted in the present study. In this parametrization, the wind speed 8 m·s −1 is assumed [28], and a constant value of 10 −5 m is used for the roughness of the ice surface [29][30][31].…”

Section: Mathematical Models and Methodsmentioning

confidence: 99%

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Sensitivity of the Reaction Mechanism of the Ozone Depletion Events during the Arctic Spring on the Initial Atmospheric Composition of the Troposphere

Cao

Jiang

et al. 2016

Atmosphere

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Abstract:Ozone depletion events (ODEs) during the Arctic spring have been investigated since the 1980s. It was found that the depletion of ozone is highly associated with the release of halogens, especially bromine containing compounds. These compounds originate from various substrates such as the ice/snow-covered surfaces in Arctic. In the present study, the dependence of the mixing ratios of ozone and principal bromine species during ODEs on the initial composition of the Arctic atmospheric boundary layer was investigated by using a concentration sensitivity analysis. This analysis was performed by implementing a reaction mechanism representing the ozone depletion and halogen release in the box model KINAL (KInetic aNALysis of reaction mechanics). The ratios between the relative change of the mixing ratios of particular species such as ozone and the variation in the initial concentration of each atmospheric component were calculated, which indicate the relative importance of each initial species in the chemical kinetic system. The results of the computations show that the impact of various chemical species is different for ozone and bromine containing compounds during the depletion of ozone. It was found that CH 3 CHO critically controls the time scale of the complete removal of ozone. However, the rate of the ozone loss and the maximum values of bromine species are only slightly influenced by the initial value of CH 3 CHO. In addition, according to the concentration sensitivity analysis, the reduction of initial Br 2 was found to cause a significant retardant of the ODE while the initial mixing ratio of HBr exerts minor influence on both ozone and bromine species. In addition, it is also interesting to note that the increase of C 2 H 2 would significantly raise the amount of HOBr and Br in the atmosphere while the ozone depletion is hardly changed.

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