Towards quantifying the glacial runoff signal in the freshwater input to Tyrolerfjord–Young Sound,NE Greenland

Terrestrial freshwater runoff strongly influences physical and biogeochemical processes at the fjord scale and can have global impacts when considered at the Greenland scale. We investigate the performance of the HIRHAM5 regional climate model over the catchments delivering freshwater to Tyrolerfjord and Young Sound by comparing to the unique Greenland Ecological Monitoring database of in situ observations from this region. Based on these findings, we estimate and discuss the fraction of runoff originating from glacierized and non-glacierized land delivered at the daily scale between 1996 and 2008. We find that glaciers contributed on average 50–80% of annual terrestrial runoff when considering different sections of Tyrolerfjord–Young Sound, but snowpack depletion on land and consequently runoff happens about one month earlier in the model than observed in the field. The temporal shift in the model is a likely explanation why summer surface salinity in the inner fjord did not correlate to modelled runoff.     

Soil-atmosphere trace gas exchange in semiarid and arid zones

A review is presented on trace gas exchange of CH4, CO, N2O, and NOx arising from agriculture and natural sources in the world's semiarid and arid zones due to soil processes. These gases are important contributors to the radiative forcing and the chemistry of the atmosphere. Quantitative information is summarized from the available studies. Between 5 and 40% of the global soil-atmosphere exchange for these gases (CH4, CO, N2O, and NOx) may occur in semiarid and arid zones, but for each of these gases there are fewer than a dozen studies to support the individual estimates, and these are from a limited number of locations. Significant differences in the biophysical and chemical processes controlling these trace gas exchanges are identified through the comparison of semiarid and arid zones with the moist temperate or wet/dry savanna land regions. Therefore, there is a poorly quantified understanding of the contribution of these regions to the global trace gas cycles and atmospheric chemistry. More importantly, there is a poor understanding of the feedback between these exchanges, global change, and regional land use and air pollution issues. A set of research issues is presented.     

A simple model for estimating emissions of volatile organic compounds from grass and cut grass in urban airsheds and its application to two Australian cities

Grass, and particularly cut grass, recently has been shown to emit significant amounts of volatile organic compounds (VOCs) into the atmosphere. Some components of these emissions are highly reactive and may contribute to photochemical smog in urban areas. A simple model for estimating the VOC emissions from grass and for grass cutting that allows these processes to be included in urban/regional emissions inventories is presented here. Using previous work and recent literature values, estimates are made of these biogenic volatile organic compound (BVOC) emissions for two typical urban airsheds, those including the cities of Sydney and Melbourne in Australia. Grass and cut grass could contribute approximately 2% for Sydney and 3% for Melbourne of the total VOCs emitted into these urban atmospheres annually. These contributions could rise to 4 and 5%, respectively, during the weekends of the summer growing season and, thus, could contribute to weekday/weekend ozone differences. It is recommended that the emissions of BVOCs from grass and cut grass be included in urban and global emissions inventories so that more accurate predictions of smog chemistry can be determined.     

Test of the Multi Increment Sampling® Method on 14 Playgrounds

The Capital Region of Denmark tested the Multi Increment Sampling^® (MIS) technology at 14 children's playgrounds in the region to assess whether the method provides representative test results and an improved foundation for risk assessment. The purpose of the investigation was to determine whether the previous uses of the playground areas have led to soil contamination that poses a health risk to its current users (children). The unpaved areas of the playgrounds were divided into decision units based on historical data along with the expected patterns of movement from its users. The samples from each unit consisted of 45 to 100 increments were collected from three depths within the upper one‐half meter. Furthermore, triplicate samples were taken from the upper sampling depth in at least one unit for quality control purposes. The investigation results showed excellent consistency between the pollution parameters and contamination levels in different decision units for each playground. The decision units where high levels of soil contamination exist coincide well with the previous site history. The MIS method has proven to be expensive and time consuming. However, in the future it will be easier to implement as we gain more experience with use of this method.  ©2016 Wiley Periodicals, Inc.     

Deltas,freshwater discharge,and waves along the Young Sound,NE Greenland

A wide range of delta morphologies occurs along the fringes of the Young Sound in Northeast Greenland due to spatial heterogeneity of delta regimes. In general, the delta regime is related to catchment and basin characteristics (geology, topography, drainage pattern, sediment availability, and bathymetry), fluvial discharges and associated sediment load, and processes by waves and currents. Main factors steering the Arctic fluvial discharges into the Young Sound are the snow and ice melt and precipitation in the catchment, and extreme events like glacier lake outburst floods (GLOFs). Waves are subordinate and only rework fringes of the delta plain forming sandy bars if the exposure and fetch are optimal. Spatial gradients and variability in driving forces (snow and precipitation) and catchment characteristics (amount of glacier coverage, sediment characteristics) as well as the strong and local influence of GLOFs in a specific catchment impede a simple upscaling of sediment fluxes from individual catchments toward a total sediment flux into the Young Sound.     

A Simple Model for Estimating Emissions of Volatile Organic Compounds from Grass and Cut Grass in Urban Airsheds and Its Application to Two Australian Cities

Abstract

Grass, and particularly cut grass, recently has been shown to emit significant amounts of volatile organic compounds (VOCs) into the atmosphere. Some components of these emissions are highly reactive and may contribute to photochemical smog in urban areas. A simple model for estimating the VOC emissions from grass and for grass cutting that allows these processes to be included in urban/regional emissions inventories is presented here. Using previous work and recent literature values, estimates are made of these biogenic volatile organic compound (BVOC) emissions for two typical urban airsheds, those including the cities of Sydney and Melbourne in Australia. Grass and cut grass could contribute ～2% for Sydney and 3% for Melbourne of the total VOCs emitted into these urban atmospheres annually. These contributions could rise to 4 and 5%, respectively, during the weekends of the summer growing season and, thus, could contribute to weekday/weekend ozone differences. It is recommended that the emissions of BVOCs from grass and cut grass be included in urban and global emissions inventories so that more accurate predictions of smog chemistry can be determined.