Influence of continental advection on aerosol characteristics over Bay of Bengal (BoB) in winter: results from W-ICARB cruise experiment

The transport of aerosols and pollutants from continental India to the adjoining oceanic areas is a major topic of concern and several experimental campaigns have been conducted over the region focusing on aerosol characteristics and their climate implications. The present study analyzes the spectral aerosol optical depth (AOD) variations over Bay of Bengal (BoB) during Winter-Integrated Campaign for Aerosols, gases and Radiation Budget (W-ICARB) from 27 December 2008 to 30 January 2009 and investigates the influence of the adjoining landmass to the marine aerosol field. High AOD₅₀₀ values (>0.7) occurred over northern BoB due to outflow of aerosols and pollutants from the densely populated Indo-Gangetic Plains (IGP); low AOD₅₀₀ (0.1–0.2) was observed in central and southern BoB, far away from the mainland. The Angstrom exponent "α" was observed to be high (>1.2) near coastal waters, indicating relative abundance of accumulation-mode continental aerosols. On the other hand, over southern BoB its values dropped below ~0.7. National Center for Environmental Prediction (NCEP) reanalysis data on winds at 850 and 700 hPa, along with air-mass trajectories calculated using Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, suggested transport of continental aerosols from central and northern India over the BoB. On the other hand, when the ship was crossing the eastern BoB, the aerosol loading was strongly affected by air-masses originating from Southeast Asia, causing an increase in AOD and α. Biomass-burning episodes over the region played an important role in the observed aerosol properties. Terra/Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) AOD₅₅₀ and cruise measured AOD₅₅₀ showed good agreement (<I>R</I>² = 0.86 and 0.77, respectively) over BoB, exhibiting similar AOD and α spatio-temporal variation

Extremely large anthropogenic-aerosol contribution to total aerosol load over the Bay of Bengal during winter season

Ship-borne observations of spectral aerosol optical depth (AOD) have been carried out over the entire Bay of Bengal (BoB) as part of the W-ICARB cruise campaign during the period 27 December 2008–30 January 2009. The results reveal a pronounced temporal and spatial variability in the optical characteristics of aerosols mainly due to anthropogenic emissions and their dispersion controlled by local meteorology. The highest aerosol amount, with mean AOD&lt;sub&gt;500&lt;/sub&gt;&gt;0.4, being even above 1.0 on specific days, is found close to the coastal regions in the western and northern parts of BoB. In these regions the Ångström exponent is also found to be high (~1.2–1.25) indicating transport of strong anthropogenic emissions from continental regions, while very high AOD&lt;sub&gt;500&lt;/sub&gt; (0.39&amp;plusmn;0.07) and &amp;alpha;&lt;sub&gt;380–870&lt;/sub&gt; values (1.27&amp;plusmn;0.09) are found over the eastern BoB. Except from the large &amp;alpha;&lt;sub&gt;380–870&lt;/sub&gt; values, an indication of strong fine-mode dominance is also observed from the AOD curvature, which is negative in the vast majority of the cases, suggesting dominance of an anthropogenic-pollution aerosol type. On the other hand, clean maritime conditions are rather rare over the region, while the aerosol types are further examined through a classification scheme based on the relationship between α and &lt;i&gt;d&lt;/i&gt;&amp;alpha;. It was found that even for the same α values the fine-mode dominance is larger for higher AODs showing the strong continental influence over the marine environment of BoB. Furthermore, there is also an evidence of aerosol-size growth under more turbid conditions indicative of coagulation and/or humidification over specific BoB regions. The results obtained using OPAC model show significant fraction of soot aerosols (~6 %–8 %) over the eastern and northwestern BoB, while coarse-mode sea salt particles are found to dominate in the southern parts of BoB

Effects of Crop Residue Burning on Aerosol Properties, Plume Characteristics, and Long-Range Transport over Northern India

Aerosol emissions from biomass burning are of specific interest over the globe due to their strong radiative impacts and climate implications. The present study examines the impact of paddy crop residue burning over northern India during the postmonsoon (October-November) season of 2012 on modification of aerosol properties, as well as the long-range transport of smoke plumes, altitude characteristics, and affected areas via the synergy of ground-based measurements and satellite observations. During this period, Moderate Resolution Imaging Spectroradiometer (MODIS) images show a thick smoke/hazy aerosol layer below 2-2.5 km in the atmosphere covering nearly the whole Indo-Gangetic Plains (IGP). The air mass trajectories originating from the biomass-burning source region over Punjab at 500 m reveal a potential aerosol transport pathway along the Ganges valley from west to east, resulting in a strong aerosol optical depth (AOD) gradient. Sometimes, depending upon the wind direction and meteorological conditions, the plumes also influence central India, the Arabian Sea, and the Bay of Bengal, thus contributing to Asian pollution outflow. The increased number of fire counts (Terra and Aqua MODIS data) is associated with severe aerosol-laden atmospheres (AOD(500 nm) \u3e 1.0) over six IGP locations, high values of Angstrom exponent (\u3e1.2), high particulate mass 2.5 (PM2.5) concentrations (\u3e100-150 mu gm(-3)), and enhanced Ozone Monitoring Instrument Aerosol Index gradient (similar to 2.5) and NO2 concentrations (similar to 6 x 10(15) mol/cm(2)), indicating the dominance of smoke aerosols from agricultural crop residue burning. The aerosol size distribution is shifted toward the fine-mode fraction, also exhibiting an increase in the radius of fine aerosols due to coagulation processes in a highly turbid environment. The spectral variation of the single-scattering albedo reveals enhanced dominance of moderately absorbing aerosols, while the aerosol properties, modification, and mixing atmospheric processes differentiate along the IGP sites depending on the distance from the aerosol source, urban influence, and local characteristics

Long-Term (1951–2007) Rainfall Trends around Six Indian Cities: Current State, Meteorological, and Urban Dynamics

The present study focuses on analyzing the precipitation trends over six Indian cities during the summer monsoon (June–September) covering the period 1951–2007 and also attempting to investigate possible urban forcing and dynamics by examining the variation in precipitation in the upwind and downwind directions. The analysis shows negative trends in the total number of rainy days over Hyderabad (−10.4%), Kanpur (−7.1%), Jaipur (−10.5%), and Nagpur (−4.8%) and positive trends over Delhi (7.4%) and Bangalore (22.9%). On the other hand, decreases of −21.3%, −5.9%, −14.2%, and −14.6% in seasonal rainfall are found over Delhi, Hyderabad, Jaipur, and Kanpur, respectively, whereas Bangalore and Nagpur show 65.8% and 13.5% increase. The lesser rainfall and rainy days, along with the mostly declining trend, in the downwind directions of the cities may imply an urban influence in precipitation associated with the increased anthropogenic emissions due to expansion of the urban areas and the increase of population. However, the large spatiotemporal variability of precipitation and the lack of statistical significance in the vast majority of the trends do not allow the extraction of safe conclusion concerning the aerosol-precipitation interactions around Indian cities

Improved Satellite Retrievals of NO2 and SO2 over the Canadian Oil Sands and Comparisons with Surface Measurements

Satellite remote sensing is increasingly being used to monitor air quality over localized sources such as the Canadian oil sands. Following an initial study, significantly low biases have been identified in current NO2 and SO2 retrieval products from the Ozone Monitoring Instrument (OMI) satellite sensor over this location resulting from a combination of its rapid development and small spatial scale. Air mass factors (AMFs) used to convert line-of-sight "slant" columns to vertical columns were re-calculated for this region based on updated and higher resolution input information including absorber profiles from a regional-scale (15 km 15 km resolution) air quality model, higher spatial and temporal resolution surface reflectivity, and an improved treatment of snow. The overall impact of these new Environment Canada (EC) AMFs led to substantial increases in the peak NO2 and SO2 average vertical column density (VCD), occurring over an area of intensive surface mining, by factors of 2 and 1.4, respectively, relative to estimates made with previous AMFs. Comparisons are made with long-term averages of NO2 and SO2 (2005-2011) from in situ surface monitors by using the air quality model to map the OMI VCDs to surface concentrations. This new OMI-EC product is able to capture the spatial distribution of the in situ instruments (slopes of 0.65 to 1.0, correlation coefficients of greater than 0.9). The concentration absolute values from surface network observations were in reasonable agreement, with OMI-EC NO2 and SO2 biased low by roughly 30%. Several complications were addressed including correction for the interference effect in the surface NO2 instruments and smoothing and clear-sky biases in the OMI measurements. Overall these results highlight the importance of using input information that accounts for the spatial and temporal variability of the location of interest when performing retrievals

Federal water recreation in Colorado: comprehensive view and analysis, miscellaneous report

This report was prepared as a Masters thesis.Bibliography: page 85

Volatilidad en los precios de los commodities y su relación con el crecimiento económico.

Tesis de EconomiaEn este trabajo se caracteriza la relación entre la volatilidad de los precios de los commodities y el crecimiento económico de los países. Se trabajó con un panel de 74 países para el periodo 1970-2014. Bajo los métodos de MCO y Regresión por cuantiles se encontró que existe una relación negativa entre la volatilidad de los precios de los commodities y el crecimiento económico. Posteriormente, bajo el método de PVAR se encontró evidencia que dicha relación negativa podría ser causal. Por otro lado, no se encontró evidencia de una causalidad bi-direciconal entre el crecimiento y la volatilidad, es decir, no se encontró evidencia de que el crecimiento tenga un efecto sobre la volatilidad de los precios de los commodities

Propuesta De Un Sistema De Tratamiento De Los Lixiviados Generados En El Relleno Sanitario De Daule

En la actualidad Daule cuenta con su relleno sanitario conformado por 4 trincheras de las cuales una está en operación, otra en etapa inicial de construcción y los 2 restantes en etapas de diseño. El relleno está ubicado cerca del recinto Yolán en la vía Los Lojas; la cual es lugar de siembra y cultivo de arroz donde dicha zona se ve afectada por la descarga de los contaminantes, lixiviados, del relleno sanitario después de pasar por un filtro de arena que al parecer no es suficiente para disminuir el grado de contaminación hacia un canal próximo a los cultivos. A razón de esta problemática se propone una alternativa para tratar los lixiviados del relleno sanitario a fin de parar con la contaminación de los arrozales. La alternativa consta de un sistema de tuberías con el fin de recoger a la vez de enviar los lixiviados desde cada trinchera hacia sus piscinas donde se almacenará para luego ser llevada de regreso al relleno a través de una bomba esparciéndolo a través de aspersores para ser evaporado en el ambiente donde el remanente volverá a introducirse en las trincheras para repetirse el ciclo.GuayaquilIngeniería Civi