scholarly journals Method to Estimate Water Vapor Supersaturation in the Ambient Activation Process Using Aerosol and Droplet Measurement Data

2018 ◽  
Vol 123 (18) ◽  
Author(s):  
Chuanyang Shen ◽  
Chunsheng Zhao ◽  
Nan Ma ◽  
Jiangchuan Tao ◽  
Gang Zhao ◽  
...  
Keyword(s):  
Water Vapor ◽  
Measurement Data ◽  
Activation Process ◽  
Vapor Supersaturation

scholarly journals Seasonality of tropospheric ozone and water vapor over Delhi, India: a study based on MOZAIC measurement data

2009 ◽  
Vol 62 (2) ◽  
pp. 151-174 ◽  
Author(s):  
Lokesh K. Sahu ◽  
Shyam Lal ◽  
Valérie Thouret ◽  
Herman G. Smit
Keyword(s):  
Water Vapor ◽  
Tropospheric Ozone ◽  
Measurement Data

scholarly journals Long-term observation of midlatitude quasi 2-day waves by a water vapor radiometer

2018 ◽  
Vol 18 (16) ◽  
pp. 12061-12074 ◽  
Author(s):  
Martin Lainer ◽  
Klemens Hocke ◽  
Niklaus Kämpfer
Keyword(s):  
Water Vapor ◽  
Large Fraction ◽  
Dynamical Behavior ◽  
Measurement Data ◽  
Data Set ◽  
Water Vapor Radiometer ◽  
Long Term Observation ◽  
Scientific Value ◽  
High Degree

Abstract. A mesospheric water vapor data set obtained by the middle atmospheric water vapor radiometer (MIAWARA) close to Bern, Switzerland (46.88∘ N, 7.46∘ E) during October 2010 to September 2017 is investigated to study the long-term evolution and variability of quasi 2-day waves (Q2DWs). We present a climatological overview and an insight on the dynamical behavior of these waves with the occurring spectrum of periods as seen from a midlatitude observation site. Such a large and nearly continuous measurement data set as ours is rare and of high scientific value. The core results of our investigation indicate that the activity of the Q2DW manifests in burst-like events and is higher during winter months (November–February) than during summer months (May–August) for the altitude region of the mesosphere (up to 0.02 hPa in winter and up to 0.05 hPa in summer) accessible for the instrument. Single Q2DW events reach at most about 0.8 ppm in the H2O amplitudes. Further, monthly mean Q2DW amplitude spectra are presented and reveal a high-frequency variability between different months. A large fraction of identified Q2DW events (20 %) develop periods between 38 and 40 h. Further, we show the temporal evolution of monthly mean Q2DW oscillations continuously for all months and separated for single months over 7 years. The analysis of autobicoherence spectra gives evidence that Q2DWs are sometimes phase coupled to diurnal oscillations to a high degree and to waves with a period close to 18 h.

scholarly journals Technical note: A method for measuring size-resolved CCN in the atmosphere

2006 ◽  
Vol 6 (3) ◽  
pp. 4879-4895 ◽  
Author(s):  
G. P. Frank ◽  
U. Dusek ◽  
M. O. Andreae
Keyword(s):  
Particle Size ◽  
Water Vapor ◽  
Size Range ◽  
Cloud Condensation Nuclei ◽  
Technical Note ◽  
Condensation Nuclei ◽  
Ambient Aerosols ◽  
Condensation Particle Counter ◽  
Set Up ◽  
Vapor Supersaturation

Abstract. We present a method to investigate cloud condensation nuclei (CCN) concentrations and activation efficiencies as a function of two independent variables, aerosol particle size and water vapor supersaturation. To date, most ambient CCN measurements have been made as the integral (total) CCN concentration as a function of water vapor supersaturation only. However, since CCN properties of aerosol particles are strongly dependent on particle size, as well as on chemical composition, which commonly varies with particle size, more detailed measurements can provide additional important information about the CCN activation. With size-resolved measurements, the effect of particle size on CCN activity can be kept constant, which makes it possible to directly assess the influence of particle chemistry. The instrumental set-up consists of a differential mobility analyzer (DMA) to select particles of a known size, within a narrow size range. A condensation nuclei (CN) counter (condensation particle counter, CPC) is used to count the total number of particles in that size range, and a CCN counter is used to count the number of CCN as a function of supersaturation, in that same size range. The activation efficiency, expressed as CCN/CN ratios, can thus directly be calculated as a function of particle size and supersaturation. We present examples of the application of this technique, using salt and smoke aerosols produced in the laboratory as well as ambient aerosols.

Is the water vapor supersaturation distribution Gaussian?

2021 ◽  
Author(s):  
Subin Thomas ◽  
Prasanth Prabhakaran ◽  
Will Cantrell ◽  
Raymond A. Shaw
Keyword(s):  
Water Vapor ◽  
Large Eddy Simulation ◽  
Gaussian Distribution ◽  
Numerical Study ◽  
Mixing Model ◽  
Large Eddy Simulations ◽  
Mixing Processes ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Vapor Supersaturation

AbstractWater vapor supersaturation in the atmosphere is produced in a variety of ways, including the lifting of a parcel or via isobaric mixing of parcels. However, irrespective of the mechanism of production, the water vapor supersaturation in the atmosphere has typically been modeled as a Gaussian distribution. In the current theoretical and numerical study, the nature of supersaturation produced by mixing processes is explored. The results from large eddy simulation and a Gaussian mixing model reveal the distribution of supersaturations produced by mixing to be negatively skewed. Further, the causes of skewness are explored using large eddy simulations (LES) and the Gaussian mixing model (GMM). The correlation in forcing of temperature and water vapor fields is recognized as playing a key role.

scholarly journals Mass-based hygroscopicity parameter interaction model and measurement of atmospheric aerosol water uptake

2013 ◽  
Vol 13 (2) ◽  
pp. 717-740 ◽  
Author(s):  
E. Mikhailov ◽  
S. Vlasenko ◽  
D. Rose ◽  
U. Pöschl
Keyword(s):  
Water Vapor ◽  
Sodium Chloride ◽  
Ammonium Sulfate ◽  
Water Uptake ◽  
Malonic Acid ◽  
Atmospheric Aerosol ◽  
Interaction Model ◽  
Inorganic Particles ◽  
Vapor Supersaturation ◽  
Good Agreement

Abstract. In this study we derive and apply a mass-based hygroscopicity parameter interaction model for efficient description of concentration-dependent water uptake by atmospheric aerosol particles with complex chemical composition. The model approach builds on the single hygroscopicity parameter model of Petters and Kreidenweis (2007). We introduce an observable mass-based hygroscopicity parameter κm which can be deconvoluted into a dilute hygroscopicity parameter (κm0) and additional self- and cross-interaction parameters describing non-ideal solution behavior and concentration dependencies of single- and multi-component systems. For reference aerosol samples of sodium chloride and ammonium sulfate, the κm-interaction model (KIM) captures the experimentally observed concentration and humidity dependence of the hygroscopicity parameter and is in good agreement with an accurate reference model based on the Pitzer ion-interaction approach (Aerosol Inorganic Model, AIM). Experimental results for pure organic particles (malonic acid, levoglucosan) and for mixed organic-inorganic particles (malonic acid – ammonium sulfate) are also well reproduced by KIM, taking into account apparent or equilibrium solubilities for stepwise or gradual deliquescence and efflorescence transitions. The mixed organic-inorganic particles as well as atmospheric aerosol samples exhibit three distinctly different regimes of hygroscopicity: (I) a quasi-eutonic deliquescence & efflorescence regime at low-humidity where substances are just partly dissolved and exist also in a non-dissolved phase, (II) a gradual deliquescence & efflorescence regime at intermediate humidity where different solutes undergo gradual dissolution or solidification in the aqueous phase; and (III) a dilute regime at high humidity where the solutes are fully dissolved approaching their dilute hygroscopicity. For atmospheric aerosol samples collected from boreal rural air and from pristine tropical rainforest air (secondary organic aerosol) we present first mass-based measurements of water uptake over a wide range of relative humidity (1–99.4%) obtained with a new filter-based differential hygroscopicity analyzer (FDHA) technique. For these samples the concentration dependence of κm can be described by a simple KIM model equation based on observable mass growth factors and a total of only six fit parameters summarizing the combined effects of the dilute hygroscopicity parameters, self- and cross-interaction parameters, and solubilities of all involved chemical components. One of the fit parameters represents κm0 and can be used to predict critical dry diameters for the activation of cloud condensation nuclei (CCN) as a function of water vapor supersaturation according to Köhler theory. For sodium chloride and ammonium sulfate reference particles as well as for pristine rainforest aerosols consisting mostly of secondary organic matter, we obtained good agreement between the KIM predictions and measurement data of CCN activation. The application of KIM and mass-based measurement techniques shall help to bridge gaps in the current understanding of water uptake by atmospheric aerosols: (1) the gap between hygroscopicity parameters determined by hygroscopic growth measurements under sub-saturated conditions and by CCN activation measurements at water vapor supersaturation, and (2) the gap between the results of simplified single parameter models widely used in atmospheric or climate science and the results of complex multi-parameter ion- and molecule-interaction models frequently used in physical chemistry and solution thermodynamics (e.g., AIM, E-AIM, ADDEM, UNIFAC, AIOMFAC).

scholarly journals Mass-based hygroscopicity parameter interaction model and measurement of atmospheric aerosol water uptake

2011 ◽  
Vol 11 (11) ◽  
pp. 30877-30918
Author(s):  
E. Mikhailov ◽  
V. Merkulov ◽  
S. Vlasenko ◽  
D. Rose ◽  
U. Pöschl
Keyword(s):  
Water Vapor ◽  
Sodium Chloride ◽  
Relative Humidity ◽  
Aqueous Phase ◽  
Water Uptake ◽  
Atmospheric Aerosol ◽  
Interaction Model ◽  
Interaction Parameters ◽  
Vapor Supersaturation ◽  
Good Agreement

Abstract. In this study we derive and apply a mass-based hygroscopicity parameter interaction model for efficient description of concentration-dependent water uptake by atmospheric aerosol particles. The model approach builds on the single hygroscopicity parameter model of Petters and Kreidenweis (2007). We introduce an observable mass-based hygroscopicity parameter κm, which can be deconvoluted into a dilute intrinsic hygroscopicity parameter (κm,∞) and additional self- and cross-interaction parameters describing non-ideal solution behavior and concentration dependencies of single- and multi-component systems. For sodium chloride, the κm-interaction model (KIM) captures the observed concentration and humidity dependence of the hygroscopicity parameter and is in good agreement with an accurate reference model based on the Pitzer ion-interaction approach (Aerosol Inorganic Model, AIM). For atmospheric aerosol samples collected from boreal rural air and from pristine tropical rainforest air (secondary organic aerosol) we present first mass-based measurements of water uptake over a wide range of relative humidity (1–99%) obtained with a new filter-based differential hygroscopicity analyzer (FDHA) technique. By application of KIM to the measurement data we can distinguish three different regimes of hygroscopicity in the investigated aerosol samples: (I) A quasi-eutonic regime at low relative humidity (~60% RH) where the solutes co-exist in an aqueous and non-aqueous phase; (II) a gradually deliquescent regime at intermediate humidity (~60%–90% RH) where different solutes undergo gradual dissolution in the aqueous phase; and (III) a dilute regime at high humidity (≳90% RH) where the solutes are fully dissolved approaching their dilute intrinsic hygroscopicity. The characteristic features of the three hygroscopicity regimes are similar for both samples, while the RH threshold values vary as expected for samples of different chemical composition. In each regime, the concentration dependence of κm can be described by a simple KIM model equation based on observable mass growth factors and six fit parameters summarizing the combined effects of the dilute intrinsic hygroscopicity and interaction parameters of all involved chemical components. One of the fit parameters represents κm,∞ and can be used to predict CCN activation diameters as a function of water vapor supersaturation. For sodium chloride reference particles as well as for pristine rainforest aerosols consisting mostly of secondary organic matter, we obtained good agreement between the predicted and measured critical diameters of CCN activation. The application of KIM and mass-based measurement techniques shall help to bridge gaps in the current understanding of water uptake by atmospheric aerosols: (1) the gap between hygroscopicity parameters determined by HTDMA (hygroscopicity tandem differential mobility analyzer) or FDHA measurements under sub-saturated conditions and by CCN measurements at water vapor supersaturation, and (2) the gap between the results of simplified single parameter models widely used in atmospheric or climate science and the results of complex multi-parameter ion- and molecule-interaction models frequently used in physical chemistry and thermodynamics (AIM, E-AIM, UNIFAC, AIOMFAC etc.).

Input data automation to model evaporation loss in an Argentinian vineyard using a coupled water, vapor and heat flow model

2021 ◽  
Author(s):  
Arij Chmeis ◽  
Johanna Blöcher ◽  
Michal Kuráž
Keyword(s):  
Water Vapor ◽  
Heat Flow ◽  
Flow Field ◽  
Flow Model ◽  
Initial Conditions ◽  
Measurement Data ◽  
Climatic Data ◽  
Missing Measurements ◽  
Evaporation Losses ◽  
Heat Flow Model

<p>Water resources in arid regions around the world are under a lot of strain due to extremely low precipitation rates and very high evaporation. In addition to water scarcity, irrigation methods can be quite inefficient. For example, over-irrigation beyond soil saturation can cause many problems, such as increase in soil salinity and decrease in productive soil capacity.<br><br>This research aims to investigate evaporation losses in a vineyard in San Juan province, Argentina. Trucks are used to deliver irrigation water to the raisin-producing vineyard, which ends up being over-flooded due to poor irrigation schedules, making the process highly costly.<br>For the estimation of evaporation losses, we use a coupled water, vapor, and heat flow model implemented in DRUtES software, Kuraz and Blöcher (2020). The model’s top boundary condition solves the surface energy balance. For that we need the solar radiation as input, which we compute based on equations suggested in the FAO Irrigation and Drainage guideline No. 56 and by Saito et al. (2006).</p><p>Due to the lack of measurement data  on the study site, soil hydraulic and thermal properties are estimated. We neglect the effect of soil organic matter in the water retention model  and assume a homogenous type of soil for the thermodynamic model. While climatic data is available from a nearby meteorological station, access to backdated files is not possible. This limits our choice of simulation period. To solve this issue, we create Python codes that produce automated daily procedures to access the weather servers. This transcribed data record is then used as input for DRUtES configuration files. We also establish communication with sensors installed in the soil using Python-script automation, in order to rectify missing measurements and use them as the model’s initial conditions.</p><p>The result is output records that simulate pressure heads and water content distribution across the flow field over the simulated period. We present a system that describes the flow field allowing us to calculate evaporation rate changes with time, thereby optimizing the irrigation process according to soil and plant needs. This can be a helpful decision-making tool for farmers.</p>

scholarly journals Uji Spesifikasi Pengukuran PM10 Dengan EPAM5000 dan BAM 1020 Terhadap Kelembaban Udara

2022 ◽  
Vol 20 (2) ◽  
pp. 242-251
Author(s):  
Andi Sulistiyono ◽  
Rendi Septa Davi
Keyword(s):  
Water Vapor ◽  
Correlation Analysis ◽  
Strong Correlation ◽  
Measurement Data ◽  
Atmospheric Conditions ◽  
Optic Sensor ◽  
Air Stream ◽  
Time Period ◽  
Measurement Results ◽  
Night Period

PM10 merupakan salah satu aerosol yang merupakan bagian dari partikel pencemar. Keberadaannya menempati  volume ruang di atmosfer dengan konsentrasi yang selalu tergabung dengan materi lainnya dan dipengaruhi oleh kondisi atmosfer setempat. Pengukuran PM10 pada periode waktu siang dan malam dengan menggunakan EPAM5000 dan BAM1020 telah dilakukan untuk mengetahui specifikasi alat terhadap hasil pengukuran pada responnya terhadap unsur cuaca (kelembaban). Data hasil pengukuran dan analisis korelasi menunjukkan bahwa terdapat perbedaan pada hasil ukur konsentrasi PM10 pada periode malam pada EPAM5000 dan BAM1020 yang disebabkan oleh perbedaan pendukung instrument pada aliran udara masuk.  Adanya smart heather pada BAM1020 berfungsi untuk mengontrol kadar uap air dari aliran udara yang dihisap sedangan pada EPAM5000 udara yang dihisap langsung diukur kosentrasinya sehingga hasil ukur konsentrasi PM10 pada EPAM5000 lebih tinggi karena masih mengandung banyak uap air (aerosol hidroskopis). Adanya menu Manual Zero atau Auto Zero pada EPAM5000 untuk membersihkan optic sensor dan mereset menjadi 0 mg/m3. Pada periode malam, partikulat PM10 akan bergabung dengan uap air menyebabkan konsentrsi yang terukur pada EPAM5000 tinggi. Hal ini diperkuat oleh hasil korelasi menunjukkan bahwa nilai PM10 berkorelasi kuat terhadap kelembaban data pengukuran EPAM5000. Untuk ini perlu adanya metode untuk memisahkan PM10 dan materi lainnya (uap air) agar didapatkan nilai konsentarsi yang sebenarnya untuk menentukan kebijakan terkait kondisi udara yang terjadi.ABSTRACTPM10 is one of the aerosols which is part of polluting particles. Its existence occupies a volume of space in the atmosphere with a concentration that is always combined with other materials and is influenced by local atmospheric conditions. Measurement of PM10 in the time period of day and night using EPAM5000 and BAM1020 has been carried out to determine the specifications of the instrument on the measurement results in response to weather elements (humidity). Measurement data and correlation analysis indicate that there are differences in the results of measuring PM10 concentrations in the night period on EPAM5000 and BAM1020 due to differences in instrument support in the intake air flow. The presence of a smart heather on the BAM1020 functions to control the water vapor content of the sucked air stream, while on the EPAM5000 the air that is sucked is directly measured so that the concentration of PM10 on EPAM5000 is higher because it still contains a lot of water vapor (hydroscopic aerosol). There is a Manual Zero or Auto Zero menu on the EPAM5000 to clean the optical sensor and reset it to 0 mg/m3. During the night period, PM10 particulates will combine with water vapor causing concentrations measured at high EPAM5000. This is confirmed by the correlation results showing that the PM10 value has a strong correlation to the humidity of the EPAM5000 measurement data. For this, it is necessary to have a method for separating PM10 and other materials (water vapor) in order to obtain the actual concentration value to determine policies related to air conditions that occur.

Quantifying the effect of SVOC condensation on cloud droplet number in different airmass types

2020 ◽  
Author(s):  
Liine Heikkinen ◽  
Samuel Lowe ◽  
Cheng Wu ◽  
Diego Aliaga ◽  
Wei Huang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Size Distribution ◽  
Cloud Droplet ◽  
Ambient Air ◽  
Population Characteristics ◽  
Basis Set ◽  
Activation Process ◽  
Multiple Model ◽  
Aerosol Composition ◽  
Data Set

<p>Clouds are made of droplets that arise from the activation of suitable aerosol particles (termed cloud condensation nuclei, CCN). In the activation process, water vapor saturation ratio exceeds a critial ratio enabling CCN runaway-growth to cloud droplet sizes. The number concentration of cloud droplets (CDNC) is highly dependent on the aerosol population properties (size distribution and composition), relative humidity, and the vertical wind component. While the activation of CCN consisting of non-volatile particulate matter is fairly well understood, the same process involving semi-volatile organic vapors (SVOCs) has received less attention despite their significant presence in ambient air. A recent cloud parcel modeling study shows substanial CDNC enhancement due to SVOC condensation (Topping <em>et al</em>., 2013). Surprisingly, the topic has not been widely investigated nor the results replicated with other cloud parcel models (CPM). Thus, in the current study we seek to quantify the CDNC enhancement by SVOC condensation using a recently developed CPM framework (Lowe <em>et al.</em>, 2020, <em>in prep</em>.). Moreover, the CPM initialization is performed, for the first time, with state-of-the art measurement data including measured SVOC data for multiple airmass types.</p><p>Here, the CPM, which uses spectral microphysics for the simulation of CCN activation and hydrometeor growth, also includes a SVOC condensation equation analogous to those of water vapor. Equilibrium initialization of the SVOC volatility basis set (VBS) partitioning coefficients is performed iteratively, and constrained by the organic to inorganic ratio in the particle phase determined by ambient measurements performed at the Chacaltaya Global Atmospheric Watch (GAW) Station located at 5240 m a.s.l. in the Bolivian Andes, in spring 2018. The uniquely comprehensive data set recorded, which tracks all of the relevant aerosol population characteristics in near real-time, reveals a high degree of variability in aerosol composition, size distribution and loading depending on the air mass origin. Lagrangian backward simulations during the measurement period at Chacaltaya GAW reveal at least 18 significantly different airmass origins (Aliaga <em>et al.</em>, 2020, <em>in prep.</em>). Such variability served multiple model initialization scenarios for individual case studies. We will show a suite of CDNC enhancements by SVOC condensation under different initialization scenarios actualized in data recorded at Chacaltaya GAW Station, including airmasses originating from the Amazon (biomass burning and biogenic VOCs), Andean plateau (volcanic activity), and La Paz/El Alto metropolitan areas (anthropogenic emissions).</p><p><strong>References:</strong></p><div>Topping, D., Connolly, P. and McFiggans, G., 2013. Cloud droplet number enhanced by co-condensation of organic vapours. <em>Nature Geoscience</em>, <em>6</em>(6), p.443.</div>

scholarly journals Long-term observations of cloud condensation nuclei over the Amazon rain forest – Part 2: Variability and characteristics of biomass burning, long-range transport, and pristine rain forest aerosols

2018 ◽  
Vol 18 (14) ◽  
pp. 10289-10331 ◽  
Author(s):  
Mira L. Pöhlker ◽  
Florian Ditas ◽  
Jorge Saturno ◽  
Thomas Klimach ◽  
Isabella Hrabě de Angelis ◽  
...  
Keyword(s):  
Water Vapor ◽  
Long Range ◽  
Biomass Burning ◽  
Rain Forest ◽  
Cloud Condensation Nuclei ◽  
Long Range Transport ◽  
Accumulation Mode ◽  
Range Transport ◽  
Mass Fractions ◽  
Vapor Supersaturation

Abstract. Size-resolved measurements of atmospheric aerosol and cloud condensation nuclei (CCN) concentrations and hygroscopicity were conducted over a full seasonal cycle at the remote Amazon Tall Tower Observatory (ATTO, March 2014–February 2015). In a preceding companion paper, we presented annually and seasonally averaged data and parametrizations (Part 1; Pöhlker et al., 2016a). In the present study (Part 2), we analyze key features and implications of aerosol and CCN properties for the following characteristic atmospheric conditions: Empirically pristine rain forest (PR) conditions, where no influence of pollution was detectable, as observed during parts of the wet season from March to May. The PR episodes are characterized by a bimodal aerosol size distribution (strong Aitken mode with DAit ≈ 70 nm and NAit ≈ 160 cm−3, weak accumulation mode with Dacc ≈ 160 nm and Nacc≈ 90 cm−3), a chemical composition dominated by organic compounds, and relatively low particle hygroscopicity (κAit≈ 0.12, κacc ≈ 0.18). Long-range-transport (LRT) events, which frequently bring Saharan dust, African biomass smoke, and sea spray aerosols into the Amazon Basin, mostly during February to April. The LRT episodes are characterized by a dominant accumulation mode (DAit ≈ 80 nm, NAit ≈ 120 cm−3 vs. Dacc ≈ 180 nm, Nacc ≈ 310 cm−3), an increased abundance of dust and salt, and relatively high hygroscopicity (κAit≈ 0.18, κacc ≈ 0.35). The coarse mode is also significantly enhanced during these events. Biomass burning (BB) conditions characteristic for the Amazonian dry season from August to November. The BB episodes show a very strong accumulation mode (DAit ≈ 70 nm, NAit ≈ 140 cm−3 vs. Dacc ≈ 170 nm, Nacc ≈ 3400 cm−3), very high organic mass fractions (∼ 90 %), and correspondingly low hygroscopicity (κAit≈ 0.14, κacc ≈ 0.17). Mixed-pollution (MPOL) conditions with a superposition of African and Amazonian aerosol emissions during the dry season. During the MPOL episode presented here as a case study, we observed African aerosols with a broad monomodal distribution (D ≈ 130 nm, NCN,10 ≈ 1300 cm−3), with high sulfate mass fractions (∼ 20 %) from volcanic sources and correspondingly high hygroscopicity (κ< 100 nm ≈ 0.14, κ>100nm≈ 0.22), which were periodically mixed with fresh smoke from nearby fires (D ≈ 110 nm, NCN,10 ≈ 2800 cm−3) with an organic-dominated composition and sharply decreased hygroscopicity (κ<150nm≈ 0.10, κ>150nm≈ 0.20). Insights into the aerosol mixing state are provided by particle hygroscopicity (κ) distribution plots, which indicate largely internal mixing for the PR aerosols (narrow κ distribution) and more external mixing for the BB, LRT, and MPOL aerosols (broad κ distributions). The CCN spectra (CCN concentration plotted against water vapor supersaturation) obtained for the different case studies indicate distinctly different regimes of cloud formation and microphysics depending on aerosol properties and meteorological conditions. The measurement results suggest that CCN activation and droplet formation in convective clouds are mostly aerosol-limited under PR and LRT conditions and updraft-limited under BB and MPOL conditions. Normalized CCN efficiency spectra (CCN divided by aerosol number concentration plotted against water vapor supersaturation) and corresponding parameterizations (Gaussian error function fits) provide a basis for further analysis and model studies of aerosol–cloud interactions in the Amazon.

Sign in / Sign up

Export Citation Format

Share Document