scholarly journals Black carbon in spring aerosols of Moscow urban background

2020 ◽  
Vol 13 (1) ◽  
pp. 233-243 ◽  
Author(s):  
Olga B. Popovicheva ◽  
Elena Volpert ◽  
Nikolay M. Sitnikov ◽  
Marina A. Chichaeva ◽  
Sara Padoan
Keyword(s):  
Wind Speed ◽  
Black Carbon ◽  
Western Europe ◽  
Night Time ◽  
Urban Background ◽  
The North ◽  
Meteorological Observatory ◽  
Remote Sites ◽  
Pollution Accumulation ◽  
Mass Concentrations

Air quality in megacities is recognized as the most important environmental problem. Aerosol pollution by combustion emissions is remaining to be uncertain. Measurements of particulate black carbon (BC) were conducted at the urban background site of Meteorological Observatory (MO) MSU during the spring period of 2017 and 2018. BC mass concentrations ranged from 0.1 to 10 μg m–3, on average 1.5±1.3 and 1.1±0.9 µg/m3 , in 2017 and 2018, respectively. Mean BC concentrations displayed significant diurnal variations with poorly prominent morning peak and minimum at day time. BC mass concentrations are higher at night time due the shallow boundary layer and intensive diesel traffic which results in trapping of pollutants. Wind speed and direction are found to be important meteorological factors affected BC concentrations. BC pollution rose identifies the North as the direction of the preferable pollution. A negative correlation between BC concentrations and wind speed confirms the pollution accumulation preferably in stable weather days. Relation of BC pollution to a number of agriculture fires is distinguishable by air mass transportation from South and South-Est of Russia and Western Europe. Mean season ВС concentrations at rural and remote sites in different world locations are discussed.

scholarly journals The impact of diurnal variations of air traffic on contrail radiative forcing

2007 ◽  
Vol 7 (12) ◽  
pp. 3153-3162 ◽  
Author(s):  
N. Stuber ◽  
P. Forster
Keyword(s):  
Radiative Forcing ◽  
Western Europe ◽  
Analysis Data ◽  
Air Traffic ◽  
Diurnal Variations ◽  
Night Time ◽  
The North ◽  
Framework Programme Project ◽  
Sky Conditions ◽  
The Impact

Abstract. We combined high resolution aircraft flight data from the EU Fifth Framework Programme project AERO2k with analysis data from the ECMWF's integrated forecast system to calculate diurnally resolved 3-D contrail cover. We scaled the contrail cover in order to match observational data for the Bakan area (eastern-Atlantic/western-Europe). We found that less than 40% of the global distance travelled by aircraft is due to flights during local night time. Yet, due to the cancellation of shortwave and longwave effects during daytime, night time flights contribute a disproportional 60% to the global annual mean forcing. Under clear sky conditions the night flights contribute even more disproportionally at 76%. There are pronounced regional variations in night flying and the associated radiative forcing. Over parts of the North Atlantic flight corridor 75% of air traffic and 84% of the forcing occurs during local night, whereas only 35% of flights are during local night in South-East Asia, yet these contribute 68% of the radiative forcing. In general, regions with a significant local contrail radiative forcing are also regions for which night time flights amount to less than half of the daily total of flights. Therefore, neglecting diurnal variations in air traffic/contrail cover by assuming a diurnal mean contrail cover can over-estimate the global mean radiative forcing by up to 30%.

scholarly journals Assessment of wood burning versus fossil fuel contribution to wintertime black carbon and carbon monoxide concentrations in Athens, Greece

2018 ◽  
Vol 18 (14) ◽  
pp. 10219-10236 ◽  
Author(s):  
Athina-Cerise Kalogridis ◽  
Stergios Vratolis ◽  
Eleni Liakakou ◽  
Evangelos Gerasopoulos ◽  
Nikolaos Mihalopoulos ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Black Carbon ◽  
Fossil Fuel ◽  
Road Traffic ◽  
Monitoring Site ◽  
Night Time ◽  
Urban Background ◽  
Wood Burning ◽  
Ambient Concentrations ◽  
Co Concentrations

Abstract. The scope of this study was to estimate the contribution of fossil fuel and wood burning combustion to black carbon (BC) and carbon monoxide (CO) during wintertime, in Athens. For that purpose, in situ measurements of equivalent black carbon (eBC) and CO were simultaneously conducted in a suburban and an urban background monitoring site in Athens during the 3 months of winter 2014–2015. For the deconvolution of eBC into eBC emitted from fossil fuel (BCff) and wood burning (BCwb), a method based on the spectral dependency of the absorption of pure black carbon and brown carbon was used. Thereafter, BCwb and BCff estimated fractions were used along with measured CO concentrations in a multiple regression analysis, in order to quantify the contribution of each one of the combustion sources to the ambient CO levels. For a comparative analysis of the results, we additionally estimated the wood burning and fossil fuel contribution to CO, calculated on the basis of their CO ∕ NOx emission ratios. The results indicate that during wintertime BC and CO are mainly emitted by local sources within the Athens Metropolitan Area (AMA). Fossil fuel combustion, mainly from road traffic, is found to be the major contributor to both eBC in PM2.5 and CO ambient concentrations in AMA. However, wintertime wood burning makes a significant contribution to the observed eBC (of about 30 %) and CO concentrations (on average, 11 and 16 % of total CO in the suburban and urban background sites respectively). Both BC and CO from biomass burning (BCwb and COwb, respectively) present a clear diurnal pattern, with the highest concentrations during night-time, supporting the theory of local domestic heating being their main source.

scholarly journals Comparison of measured residential black carbon levels outdoors and indoors with fixed-site monitoring data and with dispersion modelling

2020 ◽  
Author(s):  
Olena Gruzieva ◽  
Antonios Georgelis ◽  
Niklas Andersson ◽  
Tom Bellander ◽  
Christer Johansson ◽  
...  
Keyword(s):  
Time Series ◽  
Black Carbon ◽  
Health Effects ◽  
Dispersion Model ◽  
Monitoring Data ◽  
Dispersion Modelling ◽  
Night Time ◽  
Urban Background ◽  
Site Monitoring

AbstractEpidemiologic studies on health effects of air pollution usually rely on time-series of ambient monitoring data or on spatially modelled levels. Little is known how well these estimate residential outdoor and indoor levels. We investigated the agreement of measured residential black carbon (BC) levels outdoors and indoors with fixed-site monitoring data and with levels calculated using a Gaussian dispersion model. One-week residential outdoor and indoor BC measurements were conducted for 15 families living in central Stockholm. Time-series from urban background and street-level monitors were compared to these measurements. The observed weekly concentrations were also standardized to reflect annual averages, using urban background levels, and compared spatially to long-term levels as estimated by dispersion modelling. Weekly average outdoor BC level was 472 ng/m3 (range 261–797 ng/m3). The corresponding fixed-site urban background and street levels were 313 and 1039 ng/m3, respectively. Urban background variation explained 50% of the temporal variation in residential outdoor levels averaged over 24 h. Modelled residential long-term outdoor levels were on average comparable with the standardized measured home outdoor levels, and explained 49% of the spatial variability. The median indoor/outdoor ratio across all addresses was 0.79, with no difference between day and night time. Common exposure estimation approaches in the epidemiology of health effects related to BC displayed high validity for residencies in central Stockholm. Urban background monitored levels explained half of the outdoor day-to-day variability at residential addresses. Long-term dispersion modelling explained half of the spatial differences in outdoor levels. Indoor BC concentrations tended to be somewhat lower than outdoor levels.

Representativeness and variability of PM2.5 mass concentrations and black carbon near traffic and urban background monitoring stations/Repräsentativität und Variabilität von PM2.5-Massenkonzentrationen und schwarzem Kohlenstoff in der Nähe von Verkehrs- und städtischen Luftgütemessstationen.

Gefahrstoffe ◽  
2019 ◽  
Vol 79 (06) ◽  
pp. 217-226
Author(s):  
H. D. Alas ◽  
S. Pfeifer ◽  
A. Wiesner ◽  
B. Wehner ◽  
K. Weinhold ◽  
...  
Keyword(s):  
Air Pollution ◽  
Black Carbon ◽  
Urban Areas ◽  
Mass Concentration ◽  
Spatial Distributions ◽  
Urban Background ◽  
Regular Monitoring ◽  
The City ◽  
Mass Concentrations ◽  
Monitoring Stations

Mobile measurements of PM2.5 and black carbon (BC) mass concentrations were performed near regular monitoring stations in order to gain deeper understanding of the drivers of pedestrian exposure to traffic-related air pollution. The following investigations have been done: A) Yearlong measurements in an area around a street canyon approximately 3 km airline distance from the city center of Leipzig showed that the spatial distributions of both pollutants are elevated during wintertime. The patterns of the BC mass concentration, however, consistently showed a strong influence from traffic emissions in the street, while the PM2.5 mass concentration was more dependent on the regional background and less on urban sources. B) Measurements in the city of Dresden near two regular monitoring stations, one at a roadside and one in urban background areas revealed differences between the two in terms of the BC mass concentrations, with slightly higher concentrations at the traffic area. However, no significant differences between the spatial distributions of PM2.5 mass concentrations were observed. The background measurements of the PM2.5 mass concentrations seem to be generally representative for the residential area. C) Measurements near a regular monitoring station located at a junction of the inner-city ring road of Leipzig showed that it is representative of its immediate vicinity in terms of BC mass concentrations. However, the PM2.5 mass concentration varied by a factor 2, reaching the highest levels near in the central tram station about 200 m away. The central tram station seems to significantly influence the PM2.5 mass concentration. These results of the three studies provide a better understanding of the variability of these two parameters in urban areas in Leipzig and Dresden, helping local policy makers to interpret better the measured air pollution.

scholarly journals Spectral and statistical analysis of wind spectrum for Ali Al-Gharbi area in Iraq

2019 ◽  
pp. 1649-1657
Author(s):  
Taghreed Ali Abbas ◽  
Monim Hakim Khalaf ◽  
Amani I. Altmimi
Keyword(s):  
Fourier Transform ◽  
Statistical Analysis ◽  
Wind Speed ◽  
Spectral Density ◽  
Wind Direction ◽  
Time Interval ◽  
Night Time ◽  
The North ◽  
Specific Parameter ◽  
One Year

The spectrum known represented as a relationship that’s plotted between the magnitudes or energy for a specific parameter vs. its frequency, the wind spectrum is presented as the sum of wind speed created by events divided either in space, in time, or both. This paper presents a wind speed spectrum demonstration inAli Al-Gharbi location in Iraq. The aim of the present paper is to analysis the wind speed and direction by employing the FFT (Fast Fourier Transform) therefore field measurement of wind speed and direction were collected for one year from Dec 2014 to Dec 2015 in the time interval of 10 minutes at heights of 10, 30 and 50meters. From the performance of the FFT it was found that the values of the peak which contains the highest spectral density was (226236.282 m/sec) at the frequency of (2 Hz) on the 50 m height level throughout the night time but the lowest was (115863.7 m/sec) at the frequency of (2 Hz) at the 10 m height throughout the night time. The dominant wind direction at the area was from west-Northwest and the north-Northwest. The wind speed during morning hours was higher than that at the night time.

Origins and Evolution of the North American Stable Peace

2020 ◽  
Author(s):  
David G. Haglund
Keyword(s):  
International Relations ◽  
North American ◽  
Western Europe ◽  
Regional Security ◽  
Interstate Relations ◽  
American Experience ◽  
Back Seat ◽  
The North ◽  
Security Communities ◽  
Primary Focus

Interstate relations among the North American countries have been irenic for so long that the continent is often assumed to have little if anything to contribute to scholarly debates on peaceful change. In good measure, this can be attributed to the way in which discussions of peaceful change often become intertwined with a different kind of inquiry among international relations scholars, one focused upon the origins and denotative characteristics of “pluralistic security communities.” Given that it is generally (though not necessarily accurately) considered that such security communities first arose in Western Europe, it is not difficult to understand why the North American regional-security story so regularly takes an analytical back seat to what is considered to be the far more interesting European one. This article challenges the idea that there is little to learn from the North American experience, inter alia by stressing three leading theoretical clusters within which can be situated the scholarly corpus of works attempting to assess the causes of peaceful change on the continent. Although the primary focus is on the Canada–US relationship, the article includes a brief discussion of where Mexico might be said to fit in the regional-security order.

scholarly journals Striking forest revival at the end of the Roman Period in north-western Europe

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
C. Lambert ◽  
A. Penaud ◽  
M. Vidal ◽  
C. Gandini ◽  
L. Labeyrie ◽  
...  
Keyword(s):  
North Atlantic ◽  
Western Europe ◽  
Anthropogenic Activities ◽  
Sedimentary Environment ◽  
Pollen Grains ◽  
Roman Period ◽  
Freshwater Microalgae ◽  
Environmental Signals ◽  
The North ◽  
North Western

AbstractThe Holocene period (last 11,700 years BP) has been marked by significant climate variability over decadal to millennial timescales. The underlying mechanisms are still being debated, despite ocean–atmosphere–land connections put forward in many paleo-studies. Among the main drivers, involving a cluster of spectral signatures and shaping the climate of north-western Europe, are solar activity, the North Atlantic Oscillation (NAO) varying atmospheric regimes and North Atlantic oceanic gyre dynamics. Over the last 2500 years BP, paleo-environmental signals have been strongly affected by anthropogenic activities through deforestation and land use for crops, grazing, habitations, or access to resources. Palynological proxies (especially pollen grains and marine or freshwater microalgae) help to highlight such anthropogenic imprints over natural variability. Palynological analyses conducted in a macro-estuarine sedimentary environment of north-western France over the last 2500 years BP reveal a huge and atypical 300 year-long arboreal increase between 1700 and 1400 years BP (around 250 and 550 years AD) that we refer to as the ‘1.7–1.4 ka Arboreal Pollen rise event’ or ‘1.7–1.4 ka AP event’. Interestingly, the climatic 1700–1200 years BP interval coincides with evidence for the withdrawal of coastal societies in Brittany (NW France), in an unfavourable socio-economic context. We suggest that subpolar North Atlantic gyre strengthening and related increasing recurrence of storminess extremes may have affected long-term coastal anthropogenic trajectories resulting in a local collapse of coastal agrarian societies, partly forced by climatic degradation at the end of the Roman Period.

Further Investigation upon the Water Movements in the English Channel. Drift-Bottle Experiments in the Summers of 1927, 1928 and 1929, with Critical Notes on Drift-Bottle Experiments in General.

1930 ◽  
Vol 17 (1) ◽  
pp. 241-275 ◽  
Author(s):  
J. N. Carruthers
Keyword(s):  
Wind Speed ◽  
North Sea ◽  
English Channel ◽  
The North ◽  
Different Types ◽  
The North Sea ◽  
The Common ◽  
Relationship Of ◽  
Great Simplicity ◽  
Simple Surface

In July–August of three different years common surface-floating bottles were set adrift at International Station E2 (49° 27' N.—4° 42' W.). With them, various types of drag-fitted bottles were also put out. The journeys accomplished are discussed, and the striking differences as between year and year in the case of the common surface floaters, and as between the different types in the same year, are commented upon in the light of the prevailing winds. An inter-relationship of great simplicity is deduced between wind speed and the rate of travel of simple surface floating bottles up-Channel and across the North Sea from the results of experiments carried out in four different summers.

scholarly journals Potential Evapotranspiration Reduction and Its Influence on Crop Yield in the North China Plain in 1961–2014

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Wanlin Dong ◽  
Chao Li ◽  
Qi Hu ◽  
Feifei Pan ◽  
Jyoti Bhandari ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Crop Yield ◽  
North China Plain ◽  
North China ◽  
Potential Evapotranspiration ◽  
The North ◽  
The North China Plain ◽  
Sunshine Hours ◽  
Humidity Index

Climate change has caused uneven changes in hydrological processes (precipitation and evapotranspiration) on a space-temporal scale, which would influence climate types, eventually impact agricultural production. Based on data from 61 meteorological stations from 1961 to 2014 in the North China Plain (NCP), the spatiotemporal characteristics of climate variables, such as humidity index, precipitation, and potential evapotranspiration (ET0), were analyzed. The sensitivity coefficients and contribution rates were applied to ET0. The NCP has experienced a semiarid to humid climate from north to south due to the significant decline of ET0 (−13.8 mm decade−1). In the study region, 71.0% of the sites showed a “pan evaporation paradox” phenomenon. Relative humidity had the most negative influence on ET0, while wind speed, sunshine hours, and air temperature had a positive effect on ET0. Wind speed and sunshine hours contributed the most to the spatiotemporal variation of ET0, followed by relative humidity and air temperature. Overall, the key climate factor impacting ET0 was wind speed decline in the NCP, particularly in Beijing and Tianjin. The crop yield in Shandong and Henan provinces was higher than that in the other regions with a higher humidity index. The lower the humidity index in Hebei province, the lower the crop yield. Therefore, potential water shortages and water conflict should be considered in the future because of spatiotemporal humidity variations in the NCP.

scholarly journals Mechanisms for a remote response to Asian anthropogenic aerosol in boreal winter

2019 ◽  
Vol 19 (14) ◽  
pp. 9081-9095 ◽  
Author(s):  
Laura J. Wilcox ◽  
Nick Dunstone ◽  
Anna Lewinschal ◽  
Massimo Bollasina ◽  
Annica M. L. Ekman ◽  
...  
Keyword(s):  
North Pacific ◽  
Western Europe ◽  
Large Temperature ◽  
Boreal Winter ◽  
Far Field ◽  
Anthropogenic Aerosols ◽  
Local Circulation ◽  
The North ◽  
The North Pacific ◽  
Circulation Changes

Abstract. Asian emissions of anthropogenic aerosols and their precursors have increased rapidly since 1980, with half of the increase since the pre-industrial era occurring in this period. Transient experiments with the HadGEM3-GC2 coupled model were designed to isolate the impact of Asian anthropogenic aerosols on global climate in boreal winter. It is found that this increase has resulted in local circulation changes, which in turn have driven decreases in precipitation over China, alongside an intensification of the offshore monsoon flow. No large temperature changes are seen over China. Over India, the opposite response is found, with decreasing temperatures and increasing precipitation. The dominant feature of the local circulation changes is an increase in low-level convergence, ascent, and precipitation over the Maritime Continent, which forms part of a tropical Pacific-wide La Niña-like response. HadGEM3-GC2 also simulates pronounced far-field responses. A decreased meridional temperature gradient in the North Pacific leads to a positive Pacific–North American circulation pattern, with associated temperature anomalies over the North Pacific and North America. Anomalous northeasterly flow over northeast Europe drives advection of cold air into central and western Europe, causing cooling in this region. An anomalous anticyclonic circulation over the North Atlantic causes drying over western Europe. Using a steady-state primitive equation model, LUMA, we demonstrate that these far-field midlatitude responses arise primarily as a result of Rossby waves generated over China, rather than in the equatorial Pacific.

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