Colloidal meteorological processes in the formation of precipitation

Findeisen, W; Volken, Esther; Giesche, Alena; Brönnimann, Stefan

doi:10.1127/metz/2015/0675

Cited by 44 publications

(41 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Approximately 2 % of the freezing events in our experiments occurred by contact freezing between −16.2 and −34.8 • C. Contact freezing occurred when a frozen droplet grew in size, due to the Wegener-Bergeron-Findeisen process (Findeisen, 1938), and caused the freezing of a neighbouring unfrozen droplet. When calculating concentrations of INPs, contact freezing events were excluded.…”

Section: Droplet Freezing Techniquementioning

confidence: 79%

“…Mineral dust is transported to the atmosphere by wind erosion, which is sensitive to factors like soil composition, soil moisture, and wind velocity (Ginoux et al, 2001). Mineral dust has been identified as an important contributor to the atmospheric INP population in many field and laboratory studies (Atkinson et al, 2013;Boose et al, 2016;Chen et al, 2018;Conen et al, 2011;Connolly et al, 2009;Creamean et al, 2013;DeMott et al, 2015;Eastwood et al, 2008;Hill et al, 2016;Kaufmann et al, 2016;Klein et al, 2010;Murray et al, 2012;Niedermeier et al, 2010;Niemand et al, 2012;O'Sullivan et al, 2014;Prenni et al, 2009a, b;Rangel-Alvarado et al, 2015;Steinke et al, 2016;Wex et al, 2014;Wheeler et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ice nucleating particles in the marine boundary layer in the Canadian Arctic during summer 2014

et al. 2019

View full text Add to dashboard Cite

Abstract. Ice nucleating particles (INPs) in the Arctic can influence climate and precipitation in the region; yet our understanding of the concentrations and sources of INPs in this region remain uncertain. In the following, we (1) measured concentrations of INPs in the immersion mode in the Canadian Arctic marine boundary layer during summer 2014 on board the CCGS Amundsen, (2) determined ratios of surface areas of mineral dust aerosol to sea spray aerosol, and (3) investigated the source region of the INPs using particle dispersion modelling. Average concentrations of INPs at −15, −20, and −25 ∘C were 0.005, 0.044, and 0.154 L−1, respectively. These concentrations fall within the range of INP concentrations measured in other marine environments. For the samples investigated the ratio of mineral dust surface area to sea spray surface area ranged from 0.03 to 0.09. Based on these ratios and the ice active surface site densities of mineral dust and sea spray aerosol determined in previous laboratory studies, our results suggest that mineral dust is a more important contributor to the INP population than sea spray aerosol for the samples analysed. Based on particle dispersion modelling, the highest concentrations of INPs were often associated with lower-latitude source regions such as the Hudson Bay area, eastern Greenland, or north-western continental Canada. On the other hand, the lowest concentrations were often associated with regions further north of the sampling sites and over Baffin Bay. A weak correlation was observed between INP concentrations and the time the air mass spent over bare land, and a weak negative correlation was observed between INP concentrations and the time the air mass spent over ice and open water. These combined results suggest that mineral dust from local sources is an important contributor to the INP population in the Canadian Arctic marine boundary layer during summer 2014.

show abstract

Section: Droplet Freezing Techniquementioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Ice nucleating particles in the marine boundary layer in the Canadian Arctic during summer 2014

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Rossow and Schiffer, 1991), their temperature (warm, cold) or their cloud particle phase (liquid, mixed-phase: both liquid and ice, ice). Especially for intermediate altitudes, these classification criteria overlap: ice particles may sediment into warm cloud layers, updraughts can transport liquid water droplets into colder cloud regions and droplet formation may produce liquid water content in a cold, formerly glaciated cloud (Findeisen et al, 2015;Korolev, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…2, adapted from Korolev, 2007). The first scenario represents an intermediate vertical velocity (1 m s −1 ; blue lines), where the Wegener-BergeronFindeisen process (Findeisen et al, 2015) is triggered above the altitude marked by the blue line (note that the temperature decreases with increasing altitude), which leads to full glaciation of the cloud. At that point, the relative humidity over water falls below 100 % (RH w < 100 %), as more and more water vapour is consumed by the many small liquid cloud droplets.…”

Section: Introductionmentioning

confidence: 99%

Classification of Arctic, midlatitude and tropical clouds in the mixed-phase temperature regime

et al. 2017

View full text Add to dashboard Cite

Abstract. The degree of glaciation of mixed-phase clouds constitutes one of the largest uncertainties in climate prediction. In order to better understand cloud glaciation, cloud spectrometer observations are presented in this paper, which were made in the mixed-phase temperature regime between 0 and −38 • C (273 to 235 K), where cloud particles can either be frozen or liquid. The extensive data set covers four airborne field campaigns providing a total of 139 000 1 Hz data points (38.6 h within clouds) over Arctic, midlatitude and tropical regions. We develop algorithms, combining the information on number concentration, size and asphericity of the observed cloud particles to classify four cloud types: liquid clouds, clouds in which liquid droplets and ice crystals coexist, fully glaciated clouds after the Wegener-BergeronFindeisen process and clouds where secondary ice formation occurred. We quantify the occurrence of these cloud groups depending on the geographical region and temperature and find that liquid clouds dominate our measurements during the Arctic spring, while clouds dominated by the WegenerBergeron-Findeisen process are most common in midlatitude spring. The coexistence of liquid water and ice crystals is found over the whole mixed-phase temperature range in tropical convective towers in the dry season. Secondary ice is found at midlatitudes at −5 to −10 • C (268 to 263 K) and at higher altitudes, i.e. lower temperatures in the tropics. The distribution of the cloud types with decreasing temperature is shown to be consistent with the theory of evolution of mixedphase clouds. With this study, we aim to contribute to a large statistical database on cloud types in the mixed-phase temperature regime.

show abstract

“…Clouds consisting of too many small cloud droplets, however, are less likely to produce raindrops due to coalescence, leaving longer-lived clouds (the so-called "cloud lifetime hypotheses, " see Albrecht, 1989). A characteristic of these clouds could be that they need a trigger to initiate other precipitation formation processes such as the Wegener-Bergeron-Findeisen process (Findeisen, 2015). Such a trigger could be regional effects like orographic lifting.…”

Section: Discussionmentioning

confidence: 99%

A Rigorous Statistical Assessment of Recent Trends in Intensity of Heavy Precipitation Over Germany

Passow

Donner

2019

Front. Environ. Sci.

View full text Add to dashboard Cite

Comprehensive and robust statistical estimates of trends during heavy precipitation events are essential in understanding the impact of past and future climate changes in the hydrological cycle. However, methods commonly used in extreme value statistics (EVS) are often unable to detect significant trends, because of their methodologically motivated reduction of the sample size and strong assumptions regarding the underlying distribution. Here, we propose linear quantile regression (QR) as a complementary and robust alternative to estimating trends in heavy precipitation events. QR does not require any assumptions on the underlying distribution and is also able to estimate trends for the full span of the distribution without any reduction of the available data. As an example, we study here a very dense and homogenized data set of daily precipitation amounts over Germany for the period between 1951 and 2006 to compare the results of QR and the so-called block maxima approach, a classical method in EVS. Both methods indicate an overall increase in the intensity of heavy precipitation events. The strongest trends can be found in regions with an elevation of about 500 m above sea level. In turn, larger spatial clusters of moderate or even decreasing trends can only be found in Northeastern Germany. In conclusion, both methods show comparable results. QR, however, allows for a more flexible and comprehensive study of precipitation events.

show abstract

Colloidal meteorological processes in the formation of precipitation

Cited by 44 publications

References 2 publications

Ice nucleating particles in the marine boundary layer in the Canadian Arctic during summer 2014

Ice nucleating particles in the marine boundary layer in the Canadian Arctic during summer 2014

Classification of Arctic, midlatitude and tropical clouds in the mixed-phase temperature regime

A Rigorous Statistical Assessment of Recent Trends in Intensity of Heavy Precipitation Over Germany

Contact Info

Product

Resources

About