Interannual Variability of BVOC Emissions in an Alpine City

Kaser, L.; Peron, Arianna; Graus, M.; Striednig, Marcus; Wohlfahrt, Georg; Juráň, Stanislav; Karl, T.

doi:10.5194/acp-2021-851

Cited by 5 publications

(7 citation statements)

References 59 publications

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“…Indeed, the opposite behaviour is seen, and CO2 emissions decrease with increasing temperature as demand for building heating falls. Although anthropogenic emissions far outweigh any biogenic contributions to the observed CO2 fluxes, it is possible to identify biogenic signals in other gases at IAO (Karl et al, 2018;Kaser et al, 2021).…”

Section: Carbon Dioxide Exchangementioning

confidence: 99%

Energy and mass exchange at an urban site in mountainous terrain – the Alpine city of Innsbruck

Ward

Rotach

Gohm

et al. 2022

Preprint

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Abstract. This study represents the first detailed analysis of multi-year near-surface turbulence observations for an urban area located in highly complex terrain. Using four years of eddy covariance measurements over the Alpine city of Innsbruck, Austria, the effects of the urban surface, orographic setting and mountain weather on energy and mass exchange are investigated. In terms of surface controls, findings for Innsbruck are in accordance with previous studies at city-centre sites. The available energy is partitioned mainly into net storage heat flux and sensible heat flux (each comprising about 40 % of the net radiation, Q*, during summer daytimes). The latent heat flux is small by comparison (only about 10 % of Q*) due to the small amount of vegetation present but increases for short periods (6–12 h) following rainfall. Additional energy supplied by anthropogenic activities and heat released from the large thermal mass of the urban surface helps to support positive sensible heat fluxes in the city all year round. Annual observed CO2 fluxes (5.1 kg C m−2 y−1) correspond well to both modelled emissions and expectations based on findings at other sites with a similar proportion of vegetation. The net CO2 exchange is dominated by anthropogenic emissions from traffic in summer and building heating in winter. In contrast to previous urban observational studies, the effect of the orography is examined here. Innsbruck’s location in a steep-sided valley results in marked diurnal and seasonal patterns in flow conditions. A typical valley-wind circulation is observed (in the absence of strong synoptic forcing) with moderate up-valley winds during daytime, weaker down-valley winds at night (and in winter) and near-zero wind speeds around the times of the twice-daily wind reversal. Due to Innsbruck’s location north of the main Alpine crest, south foehn events frequently have a marked effect on temperature, wind speed, turbulence and pollutant concentration. Warm, dry foehn air advected over the surface can lead to negative sensible heat fluxes both inside and outside the city. Increased wind speeds and intense mixing during foehn (turbulent kinetic energy often exceeds 5 m2 s−2) help to ventilate the city, illustrated here by low CO2 mixing ratio. Radiative exchange is also affected by the orography, for example incoming shortwave radiation is blocked by the terrain at low solar elevation. Interpretation of the dataset is complicated by distinct temporal patterns in flow conditions and the combined influences of the urban environment, terrain and atmospheric conditions. The analysis presented here reveals how Innsbruck’s mountainous setting impacts the near-surface conditions in multiple ways, highlighting the similarities with previous studies in much flatter terrain and examining the differences, in order to begin to understand interactions between urban and orographic processes.

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Section: Carbon Dioxide Exchangementioning

confidence: 99%

Energy and mass exchange at an urban site in mountainous terrain – the Alpine city of Innsbruck

Ward

Rotach

Gohm

et al. 2022

Preprint

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“…Temperature, wind speed, atmospheric pressure, and humidity are all important meteorological variables in the formation, development, and depletion of ozone. Figure 4 shows the annual plots of ozone concentrations (top, 1), followed by solar radiation, clear sky photolysis frequencies of NO 2 and O 3 (2), daily maximum PBLH (3), and afternoon wind speeds in black and air temperature in red (bottom, 4) from the UTEP/CAMS 12 monitoring site showing their seasonal behavior. In Figure 4 (1), the blue line marks the hourly 71 ppbv of O 3 concentrations.…”

Section: Impacts Of Pbl On High Ozone Eventsmentioning

confidence: 99%

“…Tropospheric ozone (O 3 ) is one of the most significant photooxidants formed by sunlight-driven photochemical reactions of nitrogen oxides (NO x ) and volatile organic compounds (VOCs) [1,2]. Ozone plays a central role in atmospheric chemistry, and more generally, the O 3 distribution and concentration strongly impact atmospheric temperature.…”

Section: Introductionmentioning

confidence: 99%

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Multi-Scale Atmospheric Emissions, Circulation and Meteorological Drivers of Ozone Episodes in El Paso-Juárez Airshed

et al. 2021

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Ozone pollution has been prevalent in the El Paso-Juárez Airshed (EPJA), especially in the past few decades, and it has been on the rise recently. The spatial and temporal distribution of the tropospheric ozone and several key meteorological factors that influence its concentration has not been adequately understood. Therefore, this investigation comprehensively examined 57 high and 48 low ozone episodes occurring in this region during 2013–2019. We found that the interannual ozone concentration in EPJA was strongly affected by anthropogenic emissions. On the other hand, seasonal ozone variations are due to meteorological variables (among them, solar radiation, planetary boundary layer, and winds) in addition to biogenic emission factors. High ozone events are characterized by calm winds, shallow planetary boundary layer (PBL), whereas low ozone events were marked with strong winds, precipitation, and deep PBL. Synoptic and mesoscale wind patterns for these ozone episodes were identified and characterized. Most of the high ozone episodes occurred when an anticyclonic circulation aloft was associated with a 500-mile middle and upper tropospheric high-pressure region over the EPJA. During these events, stable air masses with convective available potential energies (CAPE) values of less than 450 J/kg were found. The importance of surface topography is illustrated by the fact that stations close to the Rio Grande River show a bimodal distribution of wind direction according to the valley axis. High ozone episodes occur with a surface easterly wind that is decoupled from winds above the Franklin mountains.

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“…Atmospheric VOCs have both natural and anthropogenic sources [5,6]. They play a central role in the production of the tropospheric ozone (O 3 ) and secondary organic aerosol (SOA), together with nitrogen oxides (NO x ) and solar radiation, and influence the atmospheric chemistry, air quality, and climate processes.…”

Section: Introductionmentioning

confidence: 99%

Air Quality Assessment in the Central Mediterranean Sea (Tyrrhenian Sea): Anthropic Impact and Miscellaneous Natural Sources, including Volcanic Contribution, on the Budget of Volatile Organic Compounds (VOCs)

et al. 2021

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The results of air pollution assessment during a 2017 cruise of the research ship “Minerva Uno” in the Tyrrhenian Sea are reported. Volatile Organic Compounds (VOCs), Oxygenated Volatile Organic Compounds (OVOCs), and pollutants such as nitrogen oxides, ozone, and sulphur dioxide were monitored throughout the cruise. The shallow waters at ten sites of the investigated area were also analyzed. Organic compounds such as n-alkanes showed a bimodal distribution with a maximum at C5–C6 and C10–C11 at sites the most affected by anthropic impact, whereas remote sites showed a unimodal distribution with maximum at C10–C11. The most abundant atmospheric OVOC was acetone (3.66 μg/m3), accounting for 38%; formaldehyde (1.23 μg/m3) and acetaldehyde (0.99 μg/m3) made up about 22–29% of the total. The influence of some natural sources as volcanoes, in the southern part of the Tyrrhenian Sea near the Aeolian arc was studied. This source did not induce any noticeable effect on the total amount of hydrocarbons nor on the levels of trace gases such as CFCs, whereas the trends of sulphur dioxide seemed to confirm a possible contribution. The impact of underwater emissions was observed near the Panarea and Vulcano islands, where lower pHs, high levels of Fe and Mn, and diagnostic of vent activity, were measured.

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Interannual Variability of BVOC Emissions in an Alpine City

Cited by 5 publications

References 59 publications

Energy and mass exchange at an urban site in mountainous terrain – the Alpine city of Innsbruck

Energy and mass exchange at an urban site in mountainous terrain – the Alpine city of Innsbruck

Multi-Scale Atmospheric Emissions, Circulation and Meteorological Drivers of Ozone Episodes in El Paso-Juárez Airshed

Air Quality Assessment in the Central Mediterranean Sea (Tyrrhenian Sea): Anthropic Impact and Miscellaneous Natural Sources, including Volcanic Contribution, on the Budget of Volatile Organic Compounds (VOCs)

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