Atmosphere

1551 KiB

Open AccessArticle

Total Gaseous Mercury Concentration Measurements at Fort McMurray, Alberta, Canada

by Matthew T. Parsons, Daniel McLennan, Monique Lapalme, Curtis Mooney, Corinna Watt and Rachel Mintz

Atmosphere 2013, 4(4), 472-493; https://doi.org/10.3390/atmos4040472 - 13 Dec 2013

Cited by 19 | Viewed by 10148

Abstract

Observations are described from total gaseous mercury (TGM) concentrations measured at the Wood Buffalo Environmental Association (WBEA) Fort McMurray—Patricia McInnes air quality monitoring station—from 21 October 2010 through 31 May 2013, inclusively. Fort McMurray is approximately 380 km north-northeast of Edmonton, Alberta, and [...] Read more.

Observations are described from total gaseous mercury (TGM) concentrations measured at the Wood Buffalo Environmental Association (WBEA) Fort McMurray—Patricia McInnes air quality monitoring station—from 21 October 2010 through 31 May 2013, inclusively. Fort McMurray is approximately 380 km north-northeast of Edmonton, Alberta, and approximately 30 km south of major Canadian oil sands developments. The average TGM concentration over the period of this study was 1.45 ± 0.18 ng∙m⁻³. Principal component analysis suggests that observed TGM concentrations are correlated with meteorological conditions including temperature, relative humidity, and solar radiation, and also ozone concentration. There is no significant correlation between ambient concentrations of TGM and anthropogenic pollutants, such as nitrogen oxides (NO_X) and sulphur dioxide (SO₂). Principal component analysis also shows that the highest TGM concentrations observed are a result of forest fire smoke near the monitoring station. Back trajectory analysis highlights the importance of long-range transport, indicating that unseasonably high TGM concentrations are generally associated with air from the southeast and west, while unseasonably low TGM concentrations are a result of arctic air moving over the monitoring station. In general, TGM concentration appears to be driven by diel and seasonal trends superimposed over a combination of long-range transport and regional surface-air flux of gaseous mercury. Full article

(This article belongs to the Special Issue Atmospheric Mercury)

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359 KiB

Open AccessArticle

How Enhancing Atmospheric Monitoring and Modelling can be Effective for the Stockholm Convention on POPs

by Ramon Guardans and Javier Castro-Jiménez

Atmosphere 2013, 4(4), 445-471; https://doi.org/10.3390/atmos4040445 - 05 Dec 2013

Viewed by 6411

Abstract

The presence of toxic substances such as persistent organic pollutants (POPs) in the environment, and in organisms including humans, is a serious public health and environmental problem, even at low levels and poses a challenging scientific problem. The Stockholm Convention on POPs (SC) [...] Read more.

The presence of toxic substances such as persistent organic pollutants (POPs) in the environment, and in organisms including humans, is a serious public health and environmental problem, even at low levels and poses a challenging scientific problem. The Stockholm Convention on POPs (SC) entered into force in 2004 and is a large international effort under the United Nations Environment Programme (UNEP) to facilitate cooperation in monitoring, modeling and the design of effective and fair ways to deal with POPs globally. This paper is a contribution to the ongoing effectiveness evaluation (EE) work aimed at the assessment and enhancement of the effectiveness of the actions undertaken under the SC. First we consider some aspects related to the monitoring of POPs in the environment and then briefly review modeling frameworks that have been used to simulate long range transport (LRT) of POPs. In the final sections we describe the institutional arrangements providing the conditions for this work to unfold now and some suggestions for it in the future. A more effective use of existing monitoring data could be made if scientists who deposited them in publicly available and supervised sites were rewarded in academic and professional terms. We also suggest the development of multi-media, nested, Lagrangian models to improve the understanding of changes over time in the environment and individual organisms. Full article

(This article belongs to the Special Issue Persistent Organic Pollutants (POPs) in the Atmosphere: From Nowadays Background Sites to Hot Spots)

882 KiB

Open AccessArticle

Water Vapor, Temperature and Wind Profiles within Maize Canopy under in-Field Rainwater Harvesting with Wide and Narrow Runoff Strips

by Weldemichael A. Tesfuhuney, Sue Walker, Leon D. Van Rensburg and Colin S. Everson

Atmosphere 2013, 4(4), 428-444; https://doi.org/10.3390/atmos4040428 - 29 Nov 2013

Cited by 8 | Viewed by 7085

Abstract

Micrometeorological measurements were used to evaluate heat and water vapor to describe the transpiration (Ev) and soil evaporation (Es) processes for wide and narrow runoff strips under in-field rainwater harvesting (IRWH) system. The resulting sigmoid-shaped water vapor (ea) in wide and [...] Read more.

Micrometeorological measurements were used to evaluate heat and water vapor to describe the transpiration (Ev) and soil evaporation (Es) processes for wide and narrow runoff strips under in-field rainwater harvesting (IRWH) system. The resulting sigmoid-shaped water vapor (ea) in wide and narrow runoff strips varied in lower and upper parts of the maize canopy. In wide runoff strips, lapse conditions of ea extended from lowest measurement level (LP) to the upper middle section (MU) and inversion was apparent at the top of the canopy. The virtual potential temperature (θv) profile showed no difference in middle section, but the lower and upper portion (UP) had lower in narrow, compared to wide, strips, and LP-UP changes of 0.6 K and 1.2 K were observed, respectively. The Ev and Es within the canopy increased the ea concentration as determined by the wind order of magnitude. The ea concentration reached peak at about 1.6 kPa at a range of wind speed value of 1.4–1.8 m∙s⁻¹ and 2.0–2.4 m∙s⁻¹ for wide and narrow treatments, respectively. The sparse maize canopy of the wide strips could supply more drying power of the air in response to atmospheric evaporative demand compared to narrow strips. This is due to the variation in air flow in wide and narrow runoff strips that change gradients in ea for evapotranspiration processes. Full article

(This article belongs to the Special Issue Agrometeorology: From Scientific Analysis to Operational Application)

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329 KiB

Open AccessArticle

Comparison between Vegetation and Rainfall of Bioclimatic Ecoregions in Central Africa

by Sonfack Rousvel, Nzeukou Armand, Lenouo Andre, Siddi Tengeleng, Tchakoutio Sandjon Alain and Kaptue Armel

Atmosphere 2013, 4(4), 411-427; https://doi.org/10.3390/atmos4040411 - 13 Nov 2013

Cited by 23 | Viewed by 5314

Abstract

This paper investigates the relationship between the Normalized Difference Vegetation Index (NDVI) and extracted rainfall in the Global Precipitation Climatology Project (GPCP) in Central Africa between latitudes 15°S and 20°N and longitudes 0°E and 31°E. Monthly NDVI and GPCP datasets for the period [...] Read more.

This paper investigates the relationship between the Normalized Difference Vegetation Index (NDVI) and extracted rainfall in the Global Precipitation Climatology Project (GPCP) in Central Africa between latitudes 15°S and 20°N and longitudes 0°E and 31°E. Monthly NDVI and GPCP datasets for the period 1982–2000 have been used. The Index of Segmentation of Fourier Components (ISFC) has been applied on the NDVI dataset to segment Central Africa into four bioclimatic ecoregions (BCERs). In order to compare the differential response of vegetation growth to rainfall, an analysis of the inter-annual, intra-annual and seasonal variability for each BCER has been carried out, and the correlations between NDVI and rainfall have been assessed. The plot of the annual cycles of both variables revealed a coherent onset, peak and decay, with a time lag of 1 month for almost all the zones, except the zones, semi-desert and steppe, where a season of short and intense rainfall was observed. The correlation coefficients computed between the two variables are relatively high, especially in brush-grass savannah, where they reach up to 0.90 at a time lag of 1 month. The phenological transition points and phases show that the range between the +1 and -1 time lags corresponds to the duration of the maturity of vegetation. Overall, there is a strong similarity between temporal patterns of NDVI and rainfall, showing that the NDVI can be considered a sensitive indicator of the interannual variability of rainfall. Full article

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347 KiB

Open AccessArticle

Use of Traditional Weather/Climate Knowledge by Farmers in the South-Western Free State of South Africa: Agrometeorological Learning by Scientists

by Gugulethu Zuma-Netshiukhwi, Kees Stigter and Sue Walker

Atmosphere 2013, 4(4), 383-410; https://doi.org/10.3390/atmos4040383 - 13 Nov 2013

Cited by 65 | Viewed by 16833

Abstract

The variety of natural indicators, associated with weather forecasting and climate prediction, as used by farmers in the South-Western Free State province of South Africa, is described. Most farmers in this area were not familiar with the application of weather forecasts/climate predictions for [...] Read more.

The variety of natural indicators, associated with weather forecasting and climate prediction, as used by farmers in the South-Western Free State province of South Africa, is described. Most farmers in this area were not familiar with the application of weather forecasts/climate predictions for agricultural production, or with other science-based agrometeorological products. They relied almost fully on their experience and traditional knowledge for farming decision making. The indicators for traditional knowledge are demonstrated here in broad terms, relying on the stories and indications from observations and years of experience of their use by the farmers. These means of engagement with the natural environment, are skills not well understood by most scientists, but useful to the farmers. They range from the constellation of stars, animal behavior, cloud cover and type, blossoming of certain indigenous trees, appearance and disappearance of reptiles, to migration of bird species and many others. It is suggested that some short-term traditional forecasts/predictions may be successfully merged with science-based climate predictions. The traditional knowledge and its use, reported on in this paper, is what scientists learned from farmers. Berkes was right that scholars have wasted too much time and effort on a science versus traditional knowledge debate; we should reframe it instead as a science and traditional knowledge dialogue and partnership. The complications of a changing climate make this even more necessary. Full article

(This article belongs to the Special Issue Agrometeorology: From Scientific Analysis to Operational Application)

846 KiB

Open AccessArticle

A Methodology to Infer Crop Yield Response to Climate Variability and Change Using Long-Term Observations

by Mustapha El-Maayar and Manfred A. Lange

Atmosphere 2013, 4(4), 365-382; https://doi.org/10.3390/atmos4040365 - 08 Nov 2013

Cited by 18 | Viewed by 6837

Abstract

A new methodology to extract crop yield response to climate variability and change from long-term crop yield observations is presented in this study. In contrast to the existing first-difference approach (FDA), the proposed methodology considers that the difference in value between crop yields [...] Read more.

A new methodology to extract crop yield response to climate variability and change from long-term crop yield observations is presented in this study. In contrast to the existing first-difference approach (FDA), the proposed methodology considers that the difference in value between crop yields of two consecutive years reflects necessarily the contributions of climate and management conditions, especially at large spatial scales where both conditions may vary significantly from one year to the next. Our approach was applied to remove the effect of non-climatic factors on crop yield and, hence, to isolate the effect of the observed climate change between 1961 and 2006 on three widely crops grown in three Mediterranean countries—namely wheat, corn and potato—using national-level crop yield observations’ time-series. Obtained results show that the proposed methodology provides us with a ground basis to improve substantially our understanding of crop yield response to climate change at a scale that is relevant to large-scale estimations of agricultural production and to food security analyses; and therefore to reduce uncertainties in estimations of potential climate change effects on agricultural production. Furthermore, a comparison of outputs of our methodology and FDA outputs yielded a difference in terms of maize production in Egypt, for example, that exceeds the production of some neighbouring countries. Full article

(This article belongs to the Special Issue Agrometeorology: From Scientific Analysis to Operational Application)

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758 KiB

Open AccessArticle

A Study on the Use of a Statistical Analysis Model to Monitor Air Pollution Status in an Air Quality Total Quantity Control District

by Edward Ming-Yang Wu and Shu-Lung Kuo

Atmosphere 2013, 4(4), 349-364; https://doi.org/10.3390/atmos4040349 - 07 Nov 2013

Cited by 12 | Viewed by 7545

Abstract

The air quality in Taiwan, at present, is determined by a pollution standard index (PSI) that is applied to areas of possible serious air pollution and Air Quality Total Quantity Control Districts (AQTQCD). Many studies, both in Taiwan and in other countries have [...] Read more.

The air quality in Taiwan, at present, is determined by a pollution standard index (PSI) that is applied to areas of possible serious air pollution and Air Quality Total Quantity Control Districts (AQTQCD). Many studies, both in Taiwan and in other countries have examined the characteristics and levels of air pollution with PSI. This study uses air quality data collected from eight automatic air quality monitoring stations in an AQTQCD in central Taiwan and discusses the correlation between air quality variables with statistical analysis in an attempt to accurately reflect the difference of air quality observed by each monitoring station as well as to establish an air quality classification system suitable for the whole Taiwan. After using factor analysis (FA), seven air pollutants are grouped into three factors: organic, photochemical, and fuel. These three factors are the dominant ones in regards to the air quality of central Taiwan. Cluster analysis is used to classify air quality in central Taiwan into five clusters to present different characteristics and pollution degrees of air quality. This research results should serve as a reference for those involved in the review of air quality management effectiveness and/or the enactment of management control strategies. Full article

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863 KiB

Open AccessArticle

Concentration and Size Distribution of Fungi Aerosol over Oceans along a Cruise Path during the Fourth Chinese Arctic Research Expedition

by Juan Yu, Qihou Hu, Zhouqing Xie, Hui Kang, Ming Li, Zheng Li and Peipei Ye

Atmosphere 2013, 4(4), 337-348; https://doi.org/10.3390/atmos4040337 - 05 Nov 2013

Cited by 13 | Viewed by 6003

Abstract

Bioaerosol can act as nuclei and thus may play an important role in climate change. During the Fourth Chinese National Arctic Research Expedition (CHINARE 2010) from July to September 2010, the concentrations and size distributions of airborne fungi, which are thought to be [...] Read more.

Bioaerosol can act as nuclei and thus may play an important role in climate change. During the Fourth Chinese National Arctic Research Expedition (CHINARE 2010) from July to September 2010, the concentrations and size distributions of airborne fungi, which are thought to be one of important bioaerosols, in the marine boundary layer were investigated. The concentrations of airborne fungi varied considerably with a range of 0 to 320.4 CFU/m³. The fungal concentrations in the marine boundary layer were significantly lower than those in most continental ecosystems. Airborne fungi over oceans roughly displayed a decreasing trend with increasing latitudes. The mean concentrations of airborne fungi in the region of offshore China, the western North Pacific Ocean, the Chukchi Sea, the Canada Basin, and the central Arctic Ocean were 172.2 ± 158.4, 73.8 ± 104.4, 13.3 ± 16.2, 16.5 ± 8.0, and 1.2 ± 1.0 CFU/m³, respectively. In most areas airborne fungi showed a unimodal size distribution pattern, with the maximum proportion (about 36.2%) in the range of 2.1~3.3 µm and the minimum proportion (about 3.5%) in the range of 0.65~1.1 µm, and over 50% occurred on the fine size (<3.3 µm). Potential factors influencing airborne fungal concentrations, including the origin of air mass, meteorological conditions, and sea ice conditions, were discussed. Full article

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1781 KiB

Open AccessArticle

Palmitic Acid on Salt Subphases and in Mixed Monolayers of Cerebrosides: Application to Atmospheric Aerosol Chemistry

by Ellen M. Adams and Heather C. Allen

Atmosphere 2013, 4(4), 315-336; https://doi.org/10.3390/atmos4040315 - 10 Oct 2013

Cited by 56 | Viewed by 9792

Abstract

Palmitic acid (PA) has been found to be a major constituent in marine aerosols, and is commonly used to investigate organic containing atmospheric aerosols, and is therefore used here as a proxy system. Surface pressure-area isotherms (π-A), Brewster angle microscopy (BAM), and vibrational [...] Read more.

Palmitic acid (PA) has been found to be a major constituent in marine aerosols, and is commonly used to investigate organic containing atmospheric aerosols, and is therefore used here as a proxy system. Surface pressure-area isotherms (π-A), Brewster angle microscopy (BAM), and vibrational sum frequency generation (VSFG) were used to observe a PA monolayer during film compression on subphases of ultrapure water, CaCl₂ and MgCl₂ aqueous solutions, and artificial seawater (ASW). π-A isotherms indicate that salt subphases alter the phase behavior of PA, and BAM further reveals that a condensation of the monolayer occurs when compared to pure water. VSFG spectra and BAM images show that Mg²⁺ and Ca²⁺ induce ordering of the PA acyl chains, and it was determined that the interaction of Mg²⁺ with the monolayer is weaker than Ca²⁺. π-A isotherms and BAM were also used to monitor mixed monolayers of PA and cerebroside, a simple glycolipid. Results reveal that PA also has a condensing effect on the cerebroside monolayer. Thermodynamic analysis indicates that attractive interactions between the two components exist; this may be due to hydrogen bonding of the galactose and carbonyl headgroups. BAM images of the collapse structures show that mixed monolayers of PA and cerebroside are miscible at all surface pressures. These results suggest that the surface morphology of organic-coated aerosols is influenced by the chemical composition of the aqueous core and the organic film itself. Full article

(This article belongs to the Special Issue Atmospheric Surfactants and Humic-like Substances)

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Atmosphere, Volume 4, Issue 4 (December 2013) – 9 articles , Pages 315-493

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