Quantification of topographic venting of boundary layer air to the free troposphere

Henne, Stephan; Furger, Markus; Nyeki, S.; Steinbacher, Martin; Neininger, B.; Wekker, Stephan F. J. De; Dommen, Josef; Spichtinger, N.; Stohl, Andreas; Prévôt, A. S. H.

doi:10.5194/acp-4-497-2004

Cited by 184 publications

(153 citation statements)

References 46 publications

(42 reference statements)

Supporting

Mentioning

142

Contrasting

Unclassified

Order By: Relevance

“…These observations are in agreement with studies showing that air masses transported from the ML can favour new particle formation in the FT (Twohy et al, 2002;Rose et al, 2015). Henne et al (2004) described events where long-range transported anthropogenic emissions have been identified on the Jungfraujoch research station, as well as events where slope winds contribute to the transportation of urban emissions from the ML into the FT.…”

Section: Introductionsupporting

confidence: 81%

See 1 more Smart Citation

Experimental Evidence of the Feeding of the Free Troposphere with Aerosol Particles from the Mixing Layer

Freney¹,

Sellegri²,

Asmi³

et al. 2016

Aerosol Air Qual. Res.

View full text Add to dashboard Cite

Aerosol particles emitted by both natural and anthropogenic sources have direct and indirect radiative impacts. Within the planetary mixing layer (ML), these particles are subjected to a large number of removal processes, e.g., rain, sedimentation, coagulation, and thus have a relatively short lifetime. Once aerosols are transported into the free troposphere (FT), their atmospheric lifetime increases significantly and they tend to be representative of large spatial areas. The work presented here shows evidence of anthropogenic emissions being transported from the ML to the FT during a cold period in February 2012. Using a wide range of in-situ measurements of aerosol chemical and physical properties at the Puy de Dome (PUY) station, as well as LIDAR measurements (at the Cezeaux site) of atmospheric back scattering we studied the exchange between the ML and the FT. Criteria used to identify when the PUY station was sampling in the ML or in the FT included mixing layer height estimates from LIDAR measurements, trace gas measurements, and air mass trajectories. Within the FT, we observed a gradual change in aerosol physical properties with increases in aerosol mass concentrations of up to 2 times the starting concentration, as well as increases in the number of larger particles (particle diameter >150 nm). Aerosol chemical properties showed increases in organic and nitrate particles. A series of linear fits were made through the data providing information on how different parameters change as a function of time. The impact of these changing aerosol properties are discussed in relation to the potential influence on aerosol direct and indirect effects. This work presents a unique combination of observations, and provide valuable data for future model validation.

show abstract

Section: Introductionsupporting

confidence: 81%

“…Slope/valley winds in mountainous areas (Henne et al, 2004) turbulence and vertical exchange all play central roles in the interactions between the ML and FT (McKendry and Lundgren, 2000). In addition, periods of heavy pollution or photochemical smog are generally associated with anticyclonic conditions.…”

Section: Introductionmentioning

confidence: 99%

Experimental Evidence of the Feeding of the Free Troposphere with Aerosol Particles from the Mixing Layer

Freney¹,

Sellegri²,

Asmi³

et al. 2016

Aerosol Air Qual. Res.

View full text Add to dashboard Cite

show abstract

“…This can be attributed to the larger integrated air mass sampled by the FTIR instrument (and thus vertical and horizontal averaging). The FTIR data are less sensitive to "local" events such as thermally-induced vertical transport of CO from the valleys (Henne et al, 2004). Also clear sky conditions are needed to perform the FTIR measurements whereas 2 to 6 % of NDIR CO measurements are associated with (cloudy) South Föhn events (Zellweger et al, 2003).…”

Section: Raw Datasetsmentioning

confidence: 99%

“…Due to its unique location, the year-round accessibility, and the excellent infrastructure, the Jungfraujoch research station is well suited for long-term ground-based monitoring of trace gas mixing ratio trends in the free troposphere. However, the site is also intermittently influenced by polluted boundary layer air (Zellweger et al, 2003) reaching the site during föhn or thermally-induced vertical transport conditions (Henne et al, 2004). The area influencing JFJ was recently compared with other European background monitoring sites and the site was categorized as "mostly remote" .…”

Section: Study Site Jungfraujochmentioning

confidence: 99%

1997–2007 CO trend at the high Alpine site Jungfraujoch: a comparison between NDIR surface in situ and FTIR remote sensing observations

Dils

Cui²,

Henne

et al. 2011

Atmos. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

Abstract. Within the atmospheric research community, there is a strong interest in integrated datasets, combining data from several instrumentations. This integration is complicated by the different characteristics of the datasets, inherent to the measurement techniques. Here we have compared two carbon monoxide time series (1997 till 2007) acquired at the high-Alpine research station Jungfraujoch (3580 m above sea level), with two well-established measurement techniques, namely in situ surface concentration measurements using Non-Dispersive Infrared Absorption technology (NDIR), and ground-based remote sensing measurements using solar absorption Fourier Transform Infrared spectrometry (FTIR). The profile information available in the FTIR signal allowed us to extract an independent layer with a top height of 7.18 km above sea level, appropriate for comparison with our in situ measurements. We show that, even if both techniques are able to measure free troposphere CO concentrations, the datasets exhibit marked differences in their overall trends (−3.21 ± 0.03 ppb year −1 for NDIR vs.−0.8 ± 0.4 ppb year −1 for FTIR). Removing measurements that are polluted by uprising boundary layer air has a strong impact on the NDIR trend (now −2.62 ± 0.03 ppb year −1 ), but its difference with FTIR remains significant. Using the LAGRANTO trajectory model, we show that both measurement techniques are influenced by different source regions and therefore are likely subject to exhibit significant differences in their overall trend behaviour. However the observation that the NDIR-FTIR trend difference is as significant before as after 2001 is at odds with available emission databases which claim a significant Asian CO increase after 2001 only.

show abstract

“…Three primary mechanisms can loft pollutants from the boundary layer to the free troposphere: (1) airstreams such as the warm conveyor belt (WCB) that are associated with middle latitude cyclones (Bey et al, 2001;Cooper et al, 2002;Hannan et al, 2003;Kiley and Fuelberg, 2006), (2) orographic lifting (Henne et al, 2004;Chen et al, 2009;Ding610 C. A. Klich and H. E. Fuelberg: Transport of CO in a middle latitude cyclone latitudes (Stohl et al, 2002), distinct maxima are located off the east coasts of North America and Asia (Stohl, 2001;Eckhardt et al, 2004). The long-range synoptic-scale WCBrelated transport of atmospheric pollutants has been studied across both the Pacific Ocean (e.g., Jaffe et al, 1999;Yienger et al, 2000;Bey et al, 2001;Carmichael et al, 2003;Heald et al, 2003;Jacob et al, 2003;Liu et al, 2003;Cooper et al, 2004) and Atlantic Ocean (Stohl and Trickl, 1999;Cooper et al, 2001Cooper et al, , 2002Naja et al, 2003;Li et al, 2005;Fehsenfeld et al, 2006;Singh et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

The role of horizontal model resolution in assessing the transport of CO in a middle latitude cyclone using WRF-Chem

Klich

Fuelberg

2014

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. We use the Weather Research and Forecasting with Chemistry (WRF-Chem) online chemical transport model to simulate a middle latitude cyclone in East Asia at three different horizontal resolutions (45, 15, and 5 km grid spacing). The cyclone contains a typical warm conveyor belt (WCB) with an embedded squall line that passes through an area having large surface concentrations (> 400 ppbv) of carbon monoxide (CO). Model output from WRF-Chem is used to compare differences between the large-scale CO vertical transport by the WCB (the 45 km simulation) with the smaller-scale transport due to its convection (the 5 km simulation). Forward trajectories are calculated from WRF-Chem output using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. At 45 km grid spacing, the WCB exhibits gradual ascent, lofting surface CO to 6-7 km. Upon reaching the warm front, the WCB and associated CO ascend more rapidly and later turn eastward over the Pacific Ocean. Convective transport at 5 km resolution with explicitly resolved convection occurs much more rapidly, with surface CO lofted to altitudes greater than 10 km in 1 h or less. We also compute CO vertical mass fluxes over specified areas and times to compare differences in transport due to the different grid spacings. Upward CO flux exceeds 110 000 t h −1 in the domain with explicit convection when the squall line is at peak intensity, while fluxes from the two coarser resolutions are an order of magnitude smaller. Specific areas of interest within the 5 km domain are defined to compare the magnitude of convective transport to that within the entire 5 km region. Although convection encompasses only a small portion of the 5 km domain, it is responsible for ∼ 40 % of the upward CO transport. We also examine the vertical transport due to a short wave trough and its associated area of convection, not related to the cyclone, that lofts CO to the upper troposphere. Results indicate that fine-scale resolution with explicitly resolved convection is important when assessing the vertical transport of surface emissions in areas of deep convection.

show abstract

Quantification of topographic venting of boundary layer air to the free troposphere

Cited by 184 publications

References 46 publications

Experimental Evidence of the Feeding of the Free Troposphere with Aerosol Particles from the Mixing Layer

Experimental Evidence of the Feeding of the Free Troposphere with Aerosol Particles from the Mixing Layer

1997–2007 CO trend at the high Alpine site Jungfraujoch: a comparison between NDIR surface in situ and FTIR remote sensing observations

The role of horizontal model resolution in assessing the transport of CO in a middle latitude cyclone using WRF-Chem

Contact Info

Product

Resources

About