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Laura?Tositti Linda?Pieri Erika?BrattichEmail authorView authors OrcID profile Silvia?Parmeggiani Francesca?Ventura 《Journal of Atmospheric Chemistry》2018,75(1):97-121
This study provides an analysis of a five-year time series chemical composition of the bulk deposition (2009–2013), collected within a farm surrounded by industrial and urban settlements in a semi-rural area of the Po Valley, with the aim of characterizing potential emission sources affecting precipitation composition at the site. Most monitoring efforts in this region, recognized as one of the most polluted in the world both due to the intense industrialisation and urbanisation as well as to frequent air stagnation conditions, are presently devoted more to gaseous and particulate pollutants than to precipitation chemistry. The bulk deposition samples were very concentrated in chemical species, both acidic and alkaline, high compared to other polluted sites in the world and to locations in the same district. The mean ions concentrations (in μeq l?1) are: NO3 ? (243) > SO4 2? (220) > PO4 3? (176) > Cl? (153) > NO2 ? (29) > F? (2.6); NH4 + (504) > Ca2+ (489) > K+ (151) > Na+ (127) > Mg2+ (127). pH data shows a trend toward slightly alkaline conditions attributed to the large presence of ammonium and crustal elements, in spite of high concentrations of nitrates and sulphates. The relevant concentrations of Ca2+ and Mg2+ further suggests that these alkaline conditions might be due to the correspondingly significant concentrations of carbonates/bicarbonates in our dataset. While back-trajectories analysis suggests the stronger importance of local resuspension over long-range transport, statistical analyses on ion composition highlight the key role exerted by agricultural activity, especially in the case of NH4 +, K+, Ca2+ and PO4 3? (especially linked to fertilisation practices and soil resuspension due to mechanical operations). Apart from Na+ and Cl? ions which correlate well as expected, indicating their likely common origin from marine salt, the identification of the origin of the other ions is very complex due to the contribution of diverse local sources, such as industrial and residential settlements. 相似文献
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Jamal Jokar Arsanjani Linda See Amin Tayyebi 《International Journal of Digital Earth》2016,9(9):873-891
Global land cover (LC) maps have been widely employed as the base layer for a number of applications including climate change, food security, water quality, biodiversity, change detection, and environmental planning. Due to the importance of LC, there is a pressing need to increase the temporal and spatial resolution of global LC maps. A recent advance in this direction has been the GlobeLand30 dataset derived from Landsat imagery, which has been developed by the National Geomatics Center of China (NGCC). Although overall accuracy is greater than 80%, the NGCC would like help in assessing the accuracy of the product in different regions of the world. To assist in this process, this study compares the GlobeLand30 product with existing public and online datasets, that is, CORINE, Urban Atlas (UA), OpenStreetMap, and ATKIS for Germany in order to assess overall and per class agreement. The results of the analysis reveal high agreement of up to 92% between these datasets and GlobeLand30 but that large disagreements for certain classes are evident, in particular wetlands. However, overall, GlobeLand30 is shown to be a useful product for characterizing LC in Germany, and paves the way for further regional and national validation efforts. 相似文献
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Linda O. Mearns 《Climatic change》2003,60(1-2):1-6
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The appropriate level of spatial resolution for climate scenarios is a key uncertainty in climate impact studies and regional integrated assessments. To the extent that such uncertainty may affect the magnitude of economic estimates of climate change, it has implications for the public policy debates concerning the efficiency of CO2 control options. In this article, we investigate the effects that different climate scenario resolutions have on economic estimates of the impacts of future climate changeon agriculture in the United States. These results are derived via a set of procedures and an analytical model that has been used previously in climate change assessments. The results demonstrate that the spatial scale of climate scenarios affects the estimates of both regional changes in crop yields and the economic impact on the agricultural sector as a whole. An assessment based on the finer scale climatological information consistently yielded a less favorable assessment of the implications of climate change. Regional indicators of economic activity were of opposite sign in some regions, based on the scenario scale. Such differences in economic magnitudes or signs are potentially important in examining whether past climate change assessments may misstate the economic consequences of such changes. The results reported here suggest that refinement of the spatial scale of scenarios should be carefully considered in future impacts research. 相似文献
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GIS Methodology for Characterizing Historical Conditions of the Willamette River Flood Plain, Oregon
Doug R Oetter Linda R Ashkenas Stanley V Gregory Paula J Minear 《Transactions in GIS》2004,8(3):367-383
Recent environmental developments have stimulated an interest in conservation and restoration of the historical Willamette River flood plain, both to protect against flooding and to provide wildlife habitat. In order to best utilize scarce resources, we characterized historical and modern river channel and flood‐plain conditions to evaluate changes and help prioritize restoration sites. Using cartographic and photographic data sources, we developed a Geographic Information System (GIS) to map active channels, side channels, islands and tributaries for four separate dates, as well as riparian and flood‐plain vegetation characteristics for pre‐European settlement and modern time periods. Coverages based on flood records and other boundaries were used to partition the flood plain into spatial subsets for analysis. The GIS allowed comparisons between historical and present conditions for a variety of environmental factors. Much of the pre‐settlement channel complexity has been removed. Total channel length in 1995 was 26% less than in 1850, with almost 58% of the river's side channels disconnected from the system. In addition, we found a 72% loss of flood‐plain forest from 1850 to 1995, since it was converted to agricultural and urban land uses. Selected river and flood‐plain variables were made available for a spatial model to prioritize potential locations for flood‐plain restoration. 相似文献