scholarly journals Imprint of large-scale atmospheric transport patterns on sea-salt records in northern Greenland ice cores

2001 ◽  
Vol 106 (D20) ◽  
pp. 23977-23984 ◽  
Author(s):  
Hubertus Fischer

2019 ◽  
Vol 116 (30) ◽  
pp. 14910-14915 ◽  
Author(s):  
Joseph R. McConnell ◽  
Nathan J. Chellman ◽  
Andrew I. Wilson ◽  
Andreas Stohl ◽  
Monica M. Arienzo ◽  
...  

Lead pollution in Arctic ice reflects large-scale historical changes in midlatitude industrial activities such as ancient lead/silver production and recent fossil fuel burning. Here we used measurements in a broad array of 13 accurately dated ice cores from Greenland and Severnaya Zemlya to document spatial and temporal changes in Arctic lead pollution from 200 BCE to 2010 CE, with interpretation focused on 500 to 2010 CE. Atmospheric transport modeling indicates that Arctic lead pollution was primarily from European emissions before the 19th-century Industrial Revolution. Temporal variability was surprisingly similar across the large swath of the Arctic represented by the array, with 250- to 300-fold increases in lead pollution observed from the Early Middle Ages to the 1970s industrial peak. Superimposed on these exponential changes were pronounced, multiannual to multidecadal variations, marked by increases coincident with exploitation of new mining regions, improved technologies, and periods of economic prosperity; and decreases coincident with climate disruptions, famines, major wars, and plagues. Results suggest substantial overall growth in lead/silver mining and smelting emissions—and so silver production—from the Early through High Middle Ages, particularly in northern Europe, with lower growth during the Late Middle Ages into the Early Modern Period. Near the end of the second plague pandemic (1348 to ∼1700 CE), lead pollution increased sharply through the Industrial Revolution. North American and European pollution abatement policies have reduced Arctic lead pollution by >80% since the 1970s, but recent levels remain ∼60-fold higher than at the start of the Middle Ages.



2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Christoph Mayer ◽  
Astrid Lambrecht ◽  
Hans Oerter ◽  
Margit Schwikowski ◽  
Elisa Vuillermoz ◽  
...  

The precipitation conditions in central Karakoram are investigated on the basis of snow samples from high elevated snow pits at Urdok glacier from 2006 and the analysis of atmospheric transport trajectories in combination with the general, large scale pressure distribution. Our analysis shows that accumulation at the high elevated regions of the central Karakoram is dominated by the west wind circulation (WWC). Incursions of the South Asian monsoon (SAM) occur sometimes during the summer months accompanied by strong precipitation but play a minor role for the total accumulation amount. Dust layers found in the snow pits show a rare earth elements signature which indicates that the dust very likely originates from the arid regions of western China and Central Asia. Our trajectory calculations based on NCEP/NCAR reanalysis data confirm that especially during late spring and early summer the westerly flow is redirected over the Tarim basin to reach central Karakoram from an East/Southeast direction. The preservation of the layer structure and the clear seasonal signals in the snow pits indicate that locations above 5200 m in central Karakoram will be suitable places for retrieving longer climate records from ice cores.



Author(s):  
Yeny A. Tobon ◽  
Danielle El Hajj ◽  
Samantha Seng ◽  
Ferdaous Bengrad ◽  
Myriam Moreau ◽  
...  

Sodium chloride (NaCl) is the main constituent of sea-salt aerosols. During atmospheric transport, sea-salt aerosols can interact with gases and other particles including secondary aerosols containing ammonium sulfate ((NH4)2SO4). This...



2008 ◽  
Vol 8 (10) ◽  
pp. 2811-2832 ◽  
Author(s):  
K. Zhang ◽  
H. Wan ◽  
M. Zhang ◽  
B. Wang

Abstract. The radioactive species radon (222Rn) has long been used as a test tracer for the numerical simulation of large scale transport processes. In this study, radon transport experiments are carried out using an atmospheric GCM with a finite-difference dynamical core, the van Leer type FFSL advection algorithm, and two state-of-the-art cumulus convection parameterization schemes. Measurements of surface concentration and vertical distribution of radon collected from the literature are used as references in model evaluation. The simulated radon concentrations using both convection schemes turn out to be consistent with earlier studies with many other models. Comparison with measurements indicates that at the locations where significant seasonal variations are observed in reality, the model can reproduce both the monthly mean surface radon concentration and the annual cycle quite well. At those sites where the seasonal variation is not large, the model is able to give a correct magnitude of the annual mean. In East Asia, where radon simulations are rarely reported in the literature, detailed analysis shows that our results compare reasonably well with the observations. The most evident changes caused by the use of a different convection scheme are found in the vertical distribution of the tracer. The scheme associated with weaker upward transport gives higher radon concentration up to about 6 km above the surface, and lower values in higher altitudes. In the lower part of the atmosphere results from this scheme does not agree as well with the measurements as the other scheme. Differences from 6 km to the model top are even larger, although we are not yet able to tell which simulation is better due to the lack of observations at such high altitudes.



1998 ◽  
Vol 26 ◽  
pp. 156-160 ◽  
Author(s):  
Richard Hodgkins ◽  
Martyn Tranter

The chemical composition of snow and meltwater in the 13 km2 catchment of Scott Turnerbreen, Svalbard, was investigated during the spring and summer of 1993. This paper assesses the provenance of solute in the snowpack and its impact on runoff chemistry. Dry snow contains 420μeql-1 of solute, is slightly acidic (pH 5.4) and is dominated by Na+ and Cl-. Wet snow is more dilute (total concentration 340μeql-1), and less acidic (pH 5.9). This is consistent with the elution of ions from the snowpack by meltwater. Snowpack solute can be partitioned into the following fractions: sea-salt aerosol, acid aerosol and crustal. About 98% of snowpack solute is sea salt, yielding 22000 kg km-2a-1. The behaviour of snowpack-derived Cl- in runoff is distinctive, peaking at over 800 μeql-1 early in the melt season as runoff picks up, before declining quasi-exponentially. This represents the discharge of snowmelt concentrated by elution within the snowpack which subsequently becomes relatively dilute. A solute yield of 140 kg km-2 a-1 can be attributed to anthropogenically generated acid aerosols, representing long-range atmospheric transport of pollutants, a potential contributor to Arctic runoff acidification.



1998 ◽  
Vol 32 (6) ◽  
pp. 1039-1048 ◽  
Author(s):  
I.J Beverland ◽  
J.M Crowther ◽  
M.S.N Srinivas ◽  
M.R Heal


2016 ◽  
Author(s):  
Weihua Chen ◽  
Xuemei Wang ◽  
Jason Blake Cohen ◽  
Shengzhen Zhou ◽  
Zhisheng Zhang ◽  
...  

Abstract. Measurements of size-resolved aerosols from 0.25 to 18 μm were conducted at three sites (urban, suburban and background sites) and used in tandem with an atmospheric transport model to study the size distribution and formation of atmospheric aerosols in southern China during the monsoon season (May–June) in 2010. The mass distribution showed the majority of chemical components were found in the smaller size bins (< 2.5 μm). Sulfate, was found to be strongly correlated with aerosol water, and anti-correlated with atmospheric SO2, hinting at aqueous-phase reactions being the main formation pathway. Nitrate was the only major species that showed a bi-modal distribution at the urban site, and was dominated by the coarse mode in the other two sites, suggesting that an important component of nitrate formation is chloride depletion of sea salt transported from the South China Sea. In addition to these aqueous-phase reactions and interactions with sea salt aerosols, new particle formation, chemical aging, and long-range transport from upwind urban or biomass burning regions were also found to be important in at least some of the sights on some of the days. This work therefore summarizes the different mechanisms that significantly impact the aerosol chemical composition during the Monsoon over southern China.



2015 ◽  
Vol 15 (6) ◽  
pp. 9767-9813 ◽  
Author(s):  
R. Paugam ◽  
M. Wooster ◽  
S. R. Freitas ◽  
M. Val Martin

Abstract. Landscape fires produce smoke containing a very wide variety of chemical species, both gases and aerosols. For larger, more intense fires that produce the greatest amounts of emissions per unit time, the smoke tends initially to be transported vertically or semi-vertically close by the source region, driven by the intense heat and convective energy released by the burning vegetation. The column of hot smoke rapidly entrains cooler ambient air, forming a rising plume within which the fire emissions are transported. This characteristics of this plume, and in particular the height to which it rises before releasing the majority of the smoke burden into the wider atmosphere, are important in terms of how the fire emissions are ultimately transported, since for example winds at different altitudes maybe quite different. This difference in atmospheric transport then may also affect the longevity, chemical conversion and fate of the plumes chemical consituents, with for example very high plume injection heights being associated with extreme long-range atmospheric transport. Here we review how such landscape-scale fire smoke plume injection heights are represented in larger scale atmospheric transport models aiming to represent the impacts of wildfire emissions on component of the Earth system. The use of satellite Earth observation (EO) data is commonly used for this, and detail the EO datasets capable of being used to remotely assess wildfire plume height distributions and the driving characteristics of the causal fires. We also discus both the physical mechanisms and dynamics taking place in fire plumes, and investigate the efficiency and limitations of currently available injection height parameterizations. Finally, we conclude by suggestion some future parameterization developments and ideas on EO data selection that maybe relevant to the instigation of enhanced methodologies aimed at injection height representation.



2012 ◽  
Vol 8 (3) ◽  
pp. 1653-1685 ◽  
Author(s):  
P. Brohan ◽  
R. Allan ◽  
E. Freeman ◽  
D. Wheeler ◽  
C. Wilkinson ◽  
...  

Abstract. The current assessment that twentieth-century global temperature change is unusual in the context of the last thousand years relies on estimates of temperature changes from natural proxies (tree-rings, ice-cores etc.) and climate model simulations. Confidence in such estimates is limited by difficulties in calibrating the proxies and systematic differences between proxy reconstructions and model simulations. As the difference between the estimates extends into the relatively recent period of the early nineteenth century it is possible to compare them with a reliable instrumental estimate of the temperature change over that period, provided that enough early thermometer observations, covering a wide enough expanse of the world, can be collected. One organisation which systematically made observations and collected the results was the English East-India Company (EEIC), and their archives have been preserved in the British Library. Inspection of those archives revealed 900 log-books of EEIC ships containing daily instrumental measurements of temperature and pressure, and subjective estimates of wind speed and direction, from voyages across the Atlantic and Indian Oceans between 1789 and 1834. Those records have been extracted and digitised, providing 273 000 new weather records offering an unprecedentedly detailed view of the weather and climate of the late eighteenth and early nineteenth centuries. The new thermometer observations demonstrate that the large-scale temperature response to the Tambora eruption and the 1809 eruption was modest (perhaps 0.5 °C). This provides a powerful out-of-sample validation for the proxy reconstructions – supporting their use for longer-term climate reconstructions. However, some of the climate model simulations in the CMIP5 ensemble show much larger volcanic effects than this – such simulations are unlikely to be accurate in this respect.



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