scholarly journals Comparison between summertime and wintertime Arctic Ocean primary marine aerosol properties

2012 ◽  
Vol 12 (12) ◽  
pp. 31153-31186 ◽  
Author(s):  
J. Zábori ◽  
R. Krejci ◽  
J. Ström ◽  
P. Vaattovaara ◽  
A. M. L. Ekman ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Temperature ◽  
Arctic Ocean ◽  
Particle Number ◽  
Rate Of Change ◽  
The Arctic ◽  
Size Distributions ◽  
Data Set ◽  
Total Particle Number ◽  
Total Particle

Abstract. Primary marine aerosols (PMA) are an important source of cloud condensation nuclei, and one of the key elements of the remote marine radiative budget. Changes occurring in the rapidly warming Arctic, most importantly the decreasing sea ice extent will alter PMA production and hence the Arctic climate through a set of feedback processes. In light of this, laboratory experiments with Arctic Ocean water during both Arctic winter and summer were conducted and focused on PMA emissions as a function of season and water properties. Total particle number concentrations and particle number size distributions were used to characterize the PMA population. A comprehensive data set from the Arctic summer and winter showed a decrease in PMA concentrations for the covered water temperature (Tw) range between −1 °C and 15 °C. A sharp decrease in PMA emissions for a Tw increase from −1 °C to 4 °C was followed by a lower rate of change in PMA emissions for Tw up to about 6 °C. Near constant number concentrations for water temperatures between 6 °C to 10 °C and higher were recorded. Even though the total particle number concentrations changes for overlapping Tw ranges were consistent between the summer and winter measurements, the distribution of particle number concentrations among the different sizes varied between the seasons. Median particle number concentrations for Dp < 0.125 μm measured during winter conditions were similar (deviation of up to 3%), or lower (up to 70%) than the ones measured during summer conditions (for the same water temperature range). For Dp > 0.125 μm, the particle number concentrations during winter were mostly higher than in summer (up to 50%). The normalized particle number size distribution as a function of water temperature was examined for both winter and summer measurements. An increase in Tw from −1 °C to 10 °C during winter measurements showed a decrease in the peak of relative particle number concentration at about Dp of 0.180 μm, while an increase was observed for particles with Dp > 1 μm. Summer measurements exhibited a relative shift to smaller particle sizes for an increase of Tw in the range 7–11 °C. The differences in the shape of the number size distributions between winter and summer may be caused by different production of organic material in water, different local processes modifying the water masses within the fjord (like sea ice production in winter and increased glacial melt water inflow during summer) and different origin of the dominant sea water mass. Further research is needed regarding the contribution of these factors to the PMA production.

scholarly journals Comparison between summertime and wintertime Arctic Ocean primary marine aerosol properties

2013 ◽  
Vol 13 (9) ◽  
pp. 4783-4799 ◽  
Author(s):  
J. Zábori ◽  
R. Krejci ◽  
J. Ström ◽  
P. Vaattovaara ◽  
A. M. L. Ekman ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Temperature ◽  
Arctic Ocean ◽  
Particle Number ◽  
Number Concentration ◽  
The Arctic ◽  
Particle Number Concentration ◽  
Size Distributions ◽  
Total Particle Number ◽  
Total Particle

Abstract. Primary marine aerosols (PMAs) are an important source of cloud condensation nuclei, and one of the key elements of the remote marine radiative budget. Changes occurring in the rapidly warming Arctic, most importantly the decreasing sea ice extent, will alter PMA production and hence the Arctic climate through a set of feedback processes. In light of this, laboratory experiments with Arctic Ocean water during both Arctic winter and summer were conducted and focused on PMA emissions as a function of season and water properties. Total particle number concentrations and particle number size distributions were used to characterize the PMA population. A comprehensive data set from the Arctic summer and winter showed a decrease in PMA concentrations for the covered water temperature (Tw) range between −1°C and 15°C. A sharp decrease in PMA emissions for a Tw increase from −1°C to 4°C was followed by a lower rate of change in PMA emissions for Tw up to about 6°C. Near constant number concentrations for water temperatures between 6°C to 10°C and higher were recorded. Even though the total particle number concentration changes for overlapping Tw ranges were consistent between the summer and winter measurements, the distribution of particle number concentrations among the different sizes varied between the seasons. Median particle number concentrations for a dry diameter (Dp< 0.125μm measured during winter conditions were similar (deviation of up to 3%), or lower (up to 70%) than the ones measured during summer conditions (for the same water temperature range). For Dp > 0.125μm, the particle number concentrations during winter were mostly higher than in summer (up to 50%). The normalized particle number size distribution as a function of water temperature was examined for both winter and summer measurements. An increase in Tw from −1°C to 10°C during winter measurements showed a decrease in the peak of relative particle number concentration at about a Dp of 0.180μm, while an increase was observed for particles with Dp > 1μm. Summer measurements exhibited a relative shift to smaller particle sizes for an increase of Tw in the range 7–11°C. The differences in the shape of the number size distributions between winter and summer may be caused by different production of organic material in water, different local processes modifying the water masses within the fjord (for example sea ice production in winter and increased glacial meltwater inflow during summer) and different origin of the dominant sea water mass. Further research is needed regarding the contribution of these factors to the PMA production.

scholarly journals Urban aerosol size distributions over the Mediterranean city of Barcelona, NE Spain

2012 ◽  
Vol 12 (7) ◽  
pp. 16457-16492 ◽  
Author(s):  
M. Dall'Osto ◽  
D.C.S. Beddows ◽  
J. Pey ◽  
S. Rodriguez ◽  
A. Alastuey ◽  
...  
Keyword(s):  
Particle Number ◽  
Number Concentration ◽  
Aerosol Size Distribution ◽  
Time Variability ◽  
Small Contribution ◽  
Particle Number Concentration ◽  
Size Distributions ◽  
Total Particle Number ◽  
Total Particle ◽  
One Year

Abstract. Differential mobility particle sizer (DMPS) aerosol concentrations (N13–800) were collected over a one-year-period (2004) at an urban background site in Barcelona, North-Eastern Spain. Quantitative contributions to particle number concentrations of the nucleation (33–38%), Aitken (39–49%) and accumulation mode (18–22%) were estimated. We examined the source and time variability of atmospheric aerosol particles by using both K-means clustering and Positive Matrix Factorization (PMF) analysis. Performing clustering analysis on hourly size distributions, nine K-means DMPS clusters were identified and, by directional association, diurnal variation and relationship to meteorological and pollution variables, four typical aerosol size distribution scenarios were identified: traffic (69% of the time), dilution (15% of the time), summer background conditions (4% of the time) and regional pollution (12% of the time). According to the results of PMF, vehicle exhausts are estimated to contribute at least to 62–66% of the total particle number concentration, with a slightly higher proportion distributed towards the nucleation mode (34%) relative to the Aitken mode (28–32%). Photochemically induced nucleation particles make only a small contribution to the total particle number concentration (2–3% of the total), although only particles larger than 13 nm were considered in this study. Overall the combination of the two statistical methods is successful at separating components and quantifying relative contributions to the particle number population.

scholarly journals Classification of aerosol population type and cloud condensation nuclei properties in a coastal California littoral environment using an unsupervised cluster model

2019 ◽  
Author(s):  
Samuel A. Atwood ◽  
Sonia M. Kreidenweis ◽  
Paul J. DeMott ◽  
Markus D. Petters ◽  
Gavin C. Cornwell ◽  
...  
Keyword(s):  
Cluster Model ◽  
Particle Number ◽  
Cloud Condensation Nuclei ◽  
Sea Breeze ◽  
Northern Coast ◽  
Size Distributions ◽  
Condensation Nuclei ◽  
Entire Study ◽  
Total Particle Number ◽  
Total Particle

Abstract. Aerosol particle and cloud condensation nuclei (CCN) measurements from a littoral location on the northern coast of California at Bodega Bay Marine Laboratory (BML) are presented for approximately six weeks of observations during the CalWater-2015 field campaign. A combination of aerosol microphysical and meteorological parameters was used to classify variability in the properties of the BML surface aerosol using a K-means cluster model. Eight aerosol population types were identified that were associated with a range of impacts from both marine and terrestrial sources. Average measured total particle number concentrations, size distributions, hygroscopicities, and activated fraction spectra between 0.08 % and 1.1 % supersaturation are given for each of the identified aerosol population types, along with meteorological observations and transport pathways during time periods associated with each type. Five terrestrially influenced aerosol population types represented different degrees of aging of the continental outflow from the coast and interior of California and their appearance at the BML site was often linked to changes in wind direction and transport pathway. In particular, distinct aerosol populations, associated with diurnal variations in source region induced by land/sea-breeze shifts, were classified by the clustering technique. A terrestrial type representing fresh emissions, and/or a recent new particle formation event, occurred in approximately 10 % of the observations. Over the entire study period, three marine influenced population types were identified that typically occurred when the regular diurnal land/sea-breeze cycle collapsed and BML was continuously ventilated by air masses from marine regions for multiple days. These marine types differed from each other primarily in the degree of cloud processing evident in the size distributions, and in the presence of an additional large-particle mode for the type associated with the highest wind speeds. One of the marine types was associated with a multi-day period during which an atmospheric river made landfall at BML. The generally higher total particle number concentrations but lower activated fractions of four of the terrestrial types yielded similar CCN number concentrations to two of the marine types for supersaturations below about 0.4 %. Despite quite different activated fraction spectra, the two remaining marine and terrestrial types had CCN spectral number concentrations very similar to each other, due in part to higher number concentrations associated with the terrestrial type.

scholarly journals GLOBAL CHANGES IN THE SEA ICE COVER AND ASSOCIATED SURFACE TEMPERATURE CHANGES

2016 ◽  
Vol XLI-B8 ◽  
pp. 469-479
Author(s):  
Josefino C. Comiso
Keyword(s):  
Global Warming ◽  
Sea Ice ◽  
Surface Temperature ◽  
Ice Cover ◽  
Rate Of Change ◽  
The Arctic ◽  
Global Changes ◽  
Data Set ◽  
Time Period ◽  
The Antarctic

The trends in the sea ice cover in the two hemispheres have been observed to be asymmetric with the rate of change in the Arctic being negative at &minus;3.8&thinsp;% per decade while that of the Antarctic is positive at 1.7&thinsp;% per decade. These observations are confirmed in this study through analyses of a more robust data set that has been enhanced for better consistency and updated for improved statistics. With reports of anthropogenic global warming such phenomenon appears physically counter intuitive but trend studies of surface temperature over the same time period show the occurrence of a similar asymmetry. Satellite surface temperature data show that while global warming is strong and dominant in the Arctic, it is relatively minor in the Antarctic with the trends in sea ice covered areas and surrounding ice free regions observed to be even negative. A strong correlation of ice extent with surface temperature is observed, especially during the growth season, and the observed trends in the sea ice cover are coherent with the trends in surface temperature. The trend of global averages of the ice cover is negative but modest and is consistent and compatible with the positive but modest trend in global surface temperature. A continuation of the trend would mean the disappearance of summer ice by the end of the century but modelling projections indicate that the summer ice could be salvaged if anthropogenic greenhouse gases in the atmosphere are kept constant at the current level.

scholarly journals Pelagic occurrences of the ice amphipod Apherusa glacialis throughout the Arctic

2020 ◽  
Vol 42 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Erin H Kunisch ◽  
Bodil A Bluhm ◽  
Malin Daase ◽  
Rolf Gradinger ◽  
Haakon Hop ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Atlantic Water ◽  
The Arctic ◽  
Size Distributions ◽  
The Arctic Ocean ◽  
Complex Life History ◽  
Different Depths ◽  
Young Of The Year ◽  
Occurrence Records

Abstract Apherusa glacialis is a common, sea ice-associated amphipod found throughout the Arctic Ocean and has long been considered permanently associated with the sea ice habitat. However, pelagic occurrences of A. glacialis have also been reported. It was recently suggested that A. glacialis overwinters at depth within the Atlantic-water inflow near Svalbard, to avoid being exported out of the Arctic Ocean through the Fram Strait. This study collated pelagic occurrence records over a 71-year period and found that A. glacialis was consistently found away from its presumed sea ice habitat on a pan-Arctic scale, in different depths and water masses. In the Svalbard region, A. glacialis was found in Atlantic Water both in winter and summer. Additionally, we analyzed A. glacialis size distributions throughout the year, collected mostly from sea ice, in order to elucidate potential life cycle strategies. The majority of young-of-the-year A. glacialis was found in the sea ice habitat during spring, supporting previous findings. Data on size distributions and sex ratios suggest a semelparous lifestyle. A synchronous seasonal vertical migration was not evident, but our data imply a more complex life history than previously assumed. We provide evidence that A. glacialis can no longer be regarded as an autochthonous sympagic species.

scholarly journals Arctic freshwater fluxes: sources, tracer budgets and inconsistencies

2019 ◽  
Author(s):  
Alexander Forryan ◽  
Sheldon Bacon ◽  
Takamasa Tsubouchi ◽  
Sinhué Torres-Valdés ◽  
Alberto C. Naveira Garabato
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Control Volume ◽  
The Arctic ◽  
Freshwater Flux ◽  
Data Set ◽  
Freshwater Fluxes ◽  
Pacific Waters ◽  
The Arctic Ocean ◽  
Geochemical Tracer

Abstract. The traditionally divergent perspectives of the Arctic Ocean freshwater budget provided by control volume-based and geochemical tracer-based approaches are reconciled, and the sources of inter-approach inconsistencies identified, by comparing both methodologies using an observational data set of the circulation and water mass properties at the basin's boundary in summer 2005. The control volume-based and geochemical estimates of the Arctic Ocean (liquid) freshwater fluxes are 147 &amp;pm; 42 mSv (1 Sv = 106 m3 s−1) and 140 &amp;pm; 67 mSv, respectively, and are thus in agreement. Examination of meteoric, sea ice and seawater contributions to the freshwater fluxes reveals near equivalence of the net freshwater flux out of the Arctic and the meteoric source to the basin, and a close balance between the transport of solid sea ice and ice-derived meltwater out of the Arctic and the freshwater deficit in the seawater from which the sea ice has been frozen out. Inconsistencies between the two approaches are shown to stem from the distinction between "Atlantic" and "Pacific" waters based on tracers in geochemical tracer-based calculations. The definition of Pacific waters is found to be particularly problematic, because of the non-conservative nature of the inorganic nutrients underpinning that definition, as well as the low salinity characterising waters entering the Arctic through Bering Strait - which makes them difficult to isolate from meteoric sources.

scholarly journals Urban aerosol number size distributions

2003 ◽  
Vol 3 (5) ◽  
pp. 5139-5184 ◽  
Author(s):  
T. Hussein ◽  
A. Puustinen ◽  
P. P. Aalto ◽  
J. M. Mäkelä ◽  
K. Hämeri ◽  
...  
Keyword(s):  
Particle Number ◽  
Number Concentration ◽  
Building Construction ◽  
Traffic Density ◽  
Urban Aerosol ◽  
Size Distributions ◽  
Accumulation Mode ◽  
Total Particle Number ◽  
Total Particle ◽  
Aitken Mode

Abstract. Aerosol number size distributions were measured continuously in Helsinki, Finland from 5 May 1997 to 28 February 2003. The daily, monthly and annual patterns were investigated. The temporal variation of the particle number concentration was seen to follow the traffic density. The highest total particle number concentrations were usually observed during workdays; especially on Fridays, and the lower concentrations occurred during weekends; especially Sundays. Seasonally, the highest total number concentrations were usually observed during winter and spring and the lowest during June and July. More than 80\\% of the particle number size distributions were tri-modal: nucleation mode (Dp < 30 nm), Aitken mode (20–100 nm) and accumulation mode (Dp > 90 nm). Less than 20% of the particle number size distributions have either two modes or consisted of more than three modes. Two different measurement sites are used; in the first place (Siltavuori, 5 May 1997–5 March 2001), the overall means of the integrated particle number concentrations were 7100 cm−3, 6320 cm−3, and 960 cm−3, respectively, for nucleation, Aitken, and accumulation modes. In the second site (Kumpula, 6 March 2001–28 February 2003) they were 5670 cm−3, 4050 cm−3, and 900 cm−3. The total number concentration in nucleation and Aitken modes were usually significantly higher during weekdays than during weekends. The variations in accumulation mode were less pronounced. The smaller concentrations in Kumpula were mainly due to building construction and also slight overall decreasing trend during these years. During the site changing a period of simultaneous measurements over two weeks were performed showing nice correlation in both sites.

scholarly journals Urban aerosol size distributions over the Mediterranean city of Barcelona, NE Spain

2012 ◽  
Vol 12 (22) ◽  
pp. 10693-10707 ◽  
Author(s):  
M. Dall'Osto ◽  
D.C.S. Beddows ◽  
J. Pey ◽  
S. Rodriguez ◽  
A. Alastuey ◽  
...  
Keyword(s):  
Particle Number ◽  
Number Concentration ◽  
Aerosol Size Distribution ◽  
Time Variability ◽  
Small Contribution ◽  
Particle Number Concentration ◽  
Size Distributions ◽  
Total Particle Number ◽  
Total Particle ◽  
One Year

Abstract. Differential mobility particle sizer (DMPS) aerosol concentrations (N13-800) were collected over a one-year-period (2004) at an urban background site in Barcelona, North-Eastern Spain. Quantitative contributions to particle number concentrations of the nucleation (33–39%), Aitken (39–49%) and accumulation mode (18–22%) were estimated. We examined the source and time variability of atmospheric aerosol particles by using both K-means clustering and Positive Matrix Factorization (PMF) analysis. Performing clustering analysis on hourly size distributions, nine K-means DMPS clusters were identified and, by directional association, diurnal variation and relationship to meteorological and pollution variables, four typical aerosol size distribution scenarios were identified: traffic (69% of the time), dilution (15% of the time), summer background conditions (4% of the time) and regional pollution (12% of the time). According to the results of PMF, vehicle exhausts are estimated to contribute at least to 62–66% of the total particle number concentration, with a slightly higher proportion distributed towards the nucleation mode (34%) relative to the Aitken mode (28–32%). Photochemically induced nucleation particles make only a small contribution to the total particle number concentration (2–3% of the total), although only particles larger than 13 nm were considered in this study. Overall the combination of the two statistical methods is successful at separating components and quantifying relative contributions to the particle number population.

How do synoptic conditions affect Liquid Water Path over the sea-ice-free Arctic Ocean during ACLOUD?

2021 ◽  
Author(s):  
Leif-Leonard Kliesch ◽  
Elena Ruiz Donoso ◽  
Birte Kulla ◽  
Melanie Lauer ◽  
Mario Mech ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Liquid Water ◽  
The Arctic ◽  
Liquid Water Path ◽  
Data Set ◽  
Water Path ◽  
Airborne Measurements ◽  
Normal Period ◽  
Synoptic Conditions

&lt;p&gt;Despite the strong influence of cloud liquid water on the radiative budget, the knowledge of its amount and variability in the Arctic is rather limited. The Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign took place from May 22 to June 28, 2017 and offers the possibility to investigate the Liquid Water Path (LWP) during various environmental conditions. In this period synoptic conditions were characterized as a cold air outbreak, warm air advection resulting in a period of warm conditions, and a normal period with conditions in between the cold and warm period. Deployed on the research aircraft Polar 5, the Microwave Radar/radiometer for Arctic Clouds (MiRAC) collected downward observations of radar reflectivity and Brightness Temperatures (T&lt;sub&gt;b&lt;/sub&gt;) over sea-ice-free ocean from aircraft altitudes above 2.8 km. From T&lt;sub&gt;b&lt;/sub&gt; a unique high-resolution data set of cloud LWP over remote sea-ice-free Arctic ocean is retrieved. The airborne microwave retrieved LWP is compared with LWP retrieved from visible/near-infrared techniques taken on board the aircraft as well as with two different satellite products. The respective uncertainties and the agreement among the different techniques are discussed. &amp;#160;&lt;/p&gt;&lt;p&gt;The different cloud situations observed during the three ACLOUD periods are investigated to identify differences in LWP distribution from the airborne measurements. To analyze the representativity of the limitation to specific flight tracks, continuous ground-based observations at Ny-&amp;#197;lesund, ERA5 reanalysis, and simulations with the ICON model are used. While in general the airborne sampling seems to be representative for the larger region systematic difference in LWP amount between the different products occurs which will be discussed in this presentation.&lt;/p&gt;

scholarly journals GLOBAL CHANGES IN THE SEA ICE COVER AND ASSOCIATED SURFACE TEMPERATURE CHANGES

2016 ◽  
Vol XLI-B8 ◽  
pp. 469-479 ◽  
Author(s):  
Josefino C. Comiso
Keyword(s):  
Global Warming ◽  
Sea Ice ◽  
Surface Temperature ◽  
Ice Cover ◽  
Rate Of Change ◽  
The Arctic ◽  
Global Changes ◽  
Data Set ◽  
Time Period ◽  
The Antarctic

The trends in the sea ice cover in the two hemispheres have been observed to be asymmetric with the rate of change in the Arctic being negative at &minus;3.8&thinsp;% per decade while that of the Antarctic is positive at 1.7&thinsp;% per decade. These observations are confirmed in this study through analyses of a more robust data set that has been enhanced for better consistency and updated for improved statistics. With reports of anthropogenic global warming such phenomenon appears physically counter intuitive but trend studies of surface temperature over the same time period show the occurrence of a similar asymmetry. Satellite surface temperature data show that while global warming is strong and dominant in the Arctic, it is relatively minor in the Antarctic with the trends in sea ice covered areas and surrounding ice free regions observed to be even negative. A strong correlation of ice extent with surface temperature is observed, especially during the growth season, and the observed trends in the sea ice cover are coherent with the trends in surface temperature. The trend of global averages of the ice cover is negative but modest and is consistent and compatible with the positive but modest trend in global surface temperature. A continuation of the trend would mean the disappearance of summer ice by the end of the century but modelling projections indicate that the summer ice could be salvaged if anthropogenic greenhouse gases in the atmosphere are kept constant at the current level.

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