Meteorology of the great dun fell cloud experiment 1993

Colvile, R. N.; Bower, Keith; Choularton, T. W.; Gallagher, Martin; Beswick, K.M.; Arends, B. G.; Kos, G.P.A.; Wobrock, W.; Schell, D.; Hargreaves, K. J.; Storeton-West, Robert; Cape, J. N.; Jones, Brian M.; Wiedensohler, Alfred; Hansson, H.‐C.; Wendisch, Manfred; Acker, K.; Wieprechtj, W.; Pahl, S.; Winkler, P.; Berner, A.; Kruisz, C.; Gieray, R.

doi:10.1016/s1352-2310(96)00177-x

Cited by 36 publications

(8 citation statements)

References 20 publications

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“…These indicators are summarised in Table 6. In agreement with the criteria suggested by Colvile et al (1997) such as the conservation of gas phase and particle phase tracers, the agreement of the measured cloud LWC with the adiabatic LWC and the cloud droplet size distribution characteristics, the observations generally support the conclusion that no significant entrainment occurred during the three measurement periods selected for detailed analysis. However, the detailed model that includes the micro-physics as described in the contribution of indicates that entrainment may have been possible as it would possible explain differences observed between the cloud physical measurements and model predictions, especially with regard to the liquid water content.…”

Section: A Consideration On Entrainment Indicatorssupporting

confidence: 86%

FEBUKO and MODMEP: Field measurements and modelling of aerosol and cloud multiphase processes

Herrmann

Wolke

Mueller

et al. 2005

Atmospheric Environment

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An overview of the two FEBUKO aerosol-cloud interaction field experiments in the Thu¨ringer Wald (Germany) in October 2001 and 2002 and the corresponding modelling project MODMEP is given. Experimentally, a variety of measurement methods were deployed to probe the gas phase, particles and cloud droplets at three sites upwind, downwind and within an orographic cloud with special emphasis on the budgets and interconversions of organic gas and particle phase constituents. Out of a total of 14 sampling periods within 30 cloud events three events (EI, EII and EIII) are selected for detailed analysis. At various occasions an impact of the cloud process on particle chemical composition such as on the organic compounds content, sulphate and nitrate and also on particle size distributions and particle mass is observed. Moreover, direct phase transfer of polar organic compound from the gas phase is found to be very important for the understanding of cloudwater composition.For the modelling side, a main result of the MODMEP project is the development of a cloud model, which combines a complex multiphase chemistry with detailed microphysics. Both components are described in a fine-resolved particle/ drop spectrum. New numerical methods are developed for an efficient solution of the entire complex model. A further development of the CAPRAM mechanism has lead to a more detailed description of tropospheric aqueous phase organic chemistry. In parallel, effective tools for the reduction of highly complex reaction schemes are provided. Techniques are provided and tested which allow the description of complex multiphase chemistry and of detailed microphysics in multidimensional chemistry-transport models. r

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Section: A Consideration On Entrainment Indicatorssupporting

confidence: 86%

FEBUKO and MODMEP: Field measurements and modelling of aerosol and cloud multiphase processes

Herrmann

Wolke

Mueller

et al. 2005

Atmospheric Environment

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“…To investigate the influence of a cloud on SOA formation, a specific protocol allowing cloud generation with a lifetime close to droplet lifetime in the atmosphere (∼ 2-30 min, Colvile et al, 1997) in the presence of light was designed. Clouds were generated by adding water vapour into the chamber up to saturation: at 22 • C, ca.…”

Section: Cloud Generationmentioning

confidence: 99%

“…Complementary to FTIR measurements, a proton-transfer time of flight mass spectrometer (PTR-ToF-MS 8000, Ionicon Analytik ® ) was used for online gas-phase measurements in the m/z range 10-200 including isoprene, the sum of MACR and MVK, 3-methylfuran (3 M-F), acetaldehyde, the sum of glycolaldehyde and acetic acid, acrolein, acetone, hydroxyacetone, Table 1. Comparisons of cloud properties between clouds generated in CESAM (23 clouds) and atmospheric clouds (Colvile et al, 1997;Herrmann, 2003).…”

Section: Measurementsmentioning

confidence: 99%

Secondary organic aerosol formation from isoprene photooxidation during cloud condensation–evaporation cycles

et al. 2016

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Abstract. The impact of cloud events on isoprene secondary organic aerosol (SOA) formation has been studied from an isoprene ∕ NOx ∕ light system in an atmospheric simulation chamber. It was shown that the presence of a liquid water cloud leads to a faster and higher SOA formation than under dry conditions. When a cloud is generated early in the photooxidation reaction, before any SOA formation has occurred, a fast SOA formation is observed with mass yields ranging from 0.002 to 0.004. These yields are 2 and 4 times higher than those observed under dry conditions. When the cloud is generated at a later photooxidation stage, after isoprene SOA is stabilized at its maximum mass concentration, a rapid increase (by a factor of 2 or higher) of the SOA mass concentration is observed. The SOA chemical composition is influenced by cloud generation: the additional SOA formed during cloud events is composed of both organics and nitrate containing species. This SOA formation can be linked to the dissolution of water soluble volatile organic compounds (VOCs) in the aqueous phase and to further aqueous phase reactions. Cloud-induced SOA formation is experimentally demonstrated in this study, thus highlighting the importance of aqueous multiphase systems in atmospheric SOA formation estimations.

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“…Several field experiments have exploited the fact that unsaturated air may become saturated and form clouds ("flow-through reactors") as it flows over a mountaintop, returning to an unsaturated state again when it descends the mountain (e.g., Heinold et al 2005;Colvile et al 1997). However, most such studies focused on the chemical composition of air rather than on quantifying the amount of lifting.…”

Section: Introductionmentioning

confidence: 99%

Analysis and Application of Sheppard’s Airflow Model to Predict Mechanical Orographic Lifting and the Occurrence of Mountain Clouds

Kleissl

Honrath

Henriques³

2006

Journal of Applied Meteorology and Climatology

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Mechanically driven orographic lifting is important for air pollution dispersion and weather prediction, but the small dimensions of mountain peaks often prevent numerical weather models from producing detailed forecasts. Mechanical lifting in stratified flow over mountains and associated thermodynamic processes were quantified and evaluated using Sheppard's model to estimate the dividing-streamline height z t . The model was based on numerical weather model profile data and was evaluated using ground-based measurements on a tall, axisymmetric mountaintop for which the nondimensional mountain height h ND ϭ hN/U ϱ is frequently between 1 and 10 (here h is mountain height, N is Brunt-Väisälä frequency, and U ϱ is upstream horizontal wind speed). Sheppard's formula was successful in predicting water vapor saturation at the mountaintop, with a false-prediction rate of 14.5%. Wind speed was found to be strongly related to the likelihood of forecast errors, and wind direction, season, and stratification did not play significant roles. The potential temperature (water vapor mixing ratio) at z t in the sounding was found to be slightly smaller (larger) than at the mountaintop, on average, indicating less lifting than predicted and/or turbulent mixing with higher-altitude air during parcel ascent. Detailed analysis revealed that this difference is a result of less lifting than predicted for small U ϱ /(Nh), whereas Sheppard's model predicts the relative increase in uplift with increasing U ϱ /(Nh) correctly for U ϱ /(Nh) Ͼ 0.2.

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Meteorology of the great dun fell cloud experiment 1993

Cited by 36 publications

References 20 publications

FEBUKO and MODMEP: Field measurements and modelling of aerosol and cloud multiphase processes

FEBUKO and MODMEP: Field measurements and modelling of aerosol and cloud multiphase processes

Secondary organic aerosol formation from isoprene photooxidation during cloud condensation–evaporation cycles

Analysis and Application of Sheppard’s Airflow Model to Predict Mechanical Orographic Lifting and the Occurrence of Mountain Clouds

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