scholarly journals Spatial and temporal variability of urban fluxes of methane, carbon monoxide and carbon dioxide above London, UK

2016 ◽  
Author(s):  
Carole Helfter ◽  
Anja H. Tremper ◽  
Christoforos H. Halios ◽  
Simone Kotthaus ◽  
Alex Bjorkegren ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Air Temperature ◽  
Combustion Efficiency ◽  
Spatial And Temporal Variability ◽  
Co2 Fluxes ◽  
Flux Footprint ◽  
Emissions Inventory ◽  
Carbon Dioxide Co2 ◽  
Cold Starts

Abstract. We report on more than three years of measurements of fluxes of methane (CH4), carbon monoxide (CO) and carbon dioxide (CO2) taken by eddy-covariance in central London, UK. Inter-annual variability in the period 2012–2014 ranged from 36.3 to 40.7 ktons km−2 y−1 for CO2, and from 69 to 75 tons km−2 y−1 for CH4. Mean annual emissions of CO2 (39.1 ± 2.4 ktons km−2 y−1) and CO (89 ± 16 tons km−2 y−1) were consistent (within 1 % and 5 % respectively) with values from the London Atmospheric Emissions Inventory, but measured CH4 (72 ± 3 tons km−2 y−1) was over two-fold larger than the inventory value. Seasonal variability was large for CO with a winter to summer reduction of 69 %. Monthly fluxes of CO were strongly anti-correlated with mean air temperature, and the winter emissions accounted for 45 % of the annual budget. The winter increment in CO emissions was attributed mainly to vehicle cold starts and reduced fuel combustion efficiency. CO2 fluxes were 33 % higher in winter and anti-correlated with mean air temperature, albeit to a lesser extent than for CO. This was attributed to an increased demand for natural gas for heating during the winter. Seasonality in CH4 fluxes was moderate (21 % larger in winter) and linear correlation with air temperature was only statistically significant for certain wind sectors (N, NE, E and W), which was also the case for CO2. Differences in resident population within the flux footprint explained ca. 90 % variability by wind direction in annual CO2 fluxes and 99 % for CH4 (wind sectors excluded from linear regressions: S for CO2; S, SE and E for CH4). Seasonality and proportionality of emissions with respect to population in the outlying wind sectors (S, SE and E) might be masked by constant sources of CO2 and CH4, perhaps of industrial or biogenic origin. To our knowledge, this study is unique given the long-term, continuous dataset of urban CH4 fluxes analysed.

scholarly journals Spatial and temporal variability of urban fluxes of methane, carbon monoxide and carbon dioxide above London, UK

2016 ◽  
Vol 16 (16) ◽  
pp. 10543-10557 ◽  
Author(s):  
Carole Helfter ◽  
Anja H. Tremper ◽  
Christoforos H. Halios ◽  
Simone Kotthaus ◽  
Alex Bjorkegren ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Air Temperature ◽  
Temporal Variability ◽  
Substantial Contribution ◽  
Spatial And Temporal Variability ◽  
Co2 Fluxes ◽  
Atmospheric Emissions ◽  
Ch4 Emissions ◽  
Emissions Inventories

Abstract. We report on more than 3 years of measurements of fluxes of methane (CH4), carbon monoxide (CO) and carbon dioxide (CO2) taken by eddy-covariance in central London, UK. Mean annual emissions of CO2 in the period 2012–2014 (39.1 ± 2.4 ktons km−2 yr−1) and CO (89 ± 16 tons km−2 yr−1) were consistent (within 1 and 5 % respectively) with values from the London Atmospheric Emissions Inventory, but measured CH4 emissions (72 ± 3 tons km−2 yr−1) were over two-fold larger than the inventory value. Seasonal variability was large for CO with a winter to summer reduction of 69 %, and monthly fluxes were strongly anti-correlated with mean air temperature. The winter increment in CO emissions was attributed mainly to vehicle cold starts and reduced fuel combustion efficiency. CO2 fluxes were 33 % higher in winter than in summer and anti-correlated with mean air temperature, albeit to a lesser extent than for CO. This was attributed to an increased demand for natural gas for heating during the winter. CH4 fluxes exhibited moderate seasonality (21 % larger in winter), and a spatially variable linear anti-correlation with air temperature. Differences in resident population within the flux footprint explained up to 90 % of the spatial variability of the annual CO2 fluxes and up to 99 % for CH4. Furthermore, we suggest that biogenic sources of CH4, such as wastewater, which is unaccounted for by the atmospheric emissions inventories, make a substantial contribution to the overall budget and that commuting dynamics in and out of central business districts could explain some of the spatial and temporal variability of CO2 and CH4 emissions. To our knowledge, this study is unique given the length of the data sets presented, especially for CO and CH4 fluxes. This study offers an independent assessment of "bottom-up" emissions inventories and demonstrates that the urban sources of CO and CO2 are well characterized in London. This is however not the case for CH4 emissions which are heavily underestimated by the inventory approach. Our results and others point to opportunities in the UK and abroad to identify and quantify the "missing" sources of urban methane, revise the methodologies of the emission inventories and devise emission reduction strategies for this potent greenhouse gas.

scholarly journals Controls of carbon dioxide concentrations and fluxes above central London

2011 ◽  
Vol 11 (5) ◽  
pp. 1913-1928 ◽  
Author(s):  
C. Helfter ◽  
D. Famulari ◽  
G. J. Phillips ◽  
J. F. Barlow ◽  
C. R. Wood ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Stability ◽  
Co2 Fluxes ◽  
Night Time ◽  
Flux Footprint ◽  
Carbon Dioxide Fluxes ◽  
Emissions Inventory ◽  
Building Height ◽  
Street Level ◽  
Significant Difference

Abstract. Eddy-covariance measurements of carbon dioxide fluxes were taken continuously between October 2006 and May 2008 at 190 m height in central London (UK) to quantify emissions and study their controls. Inner London, with a population of 8.2 million (~5000 inhabitants per km2) is heavily built up with 8% vegetation cover within the central boroughs. CO2 emissions were found to be mainly controlled by fossil fuel combustion (e.g. traffic, commercial and domestic heating). The measurement period allowed investigation of both diurnal patterns and seasonal trends. Diurnal averages of CO2 fluxes were found to be correlated with traffic but also exhibited an inverse dependency on atmospheric stability in the near-neutral range, with higher fluxes coinciding with unstable stratification during most seasons and perhaps reflecting how changes in heating-related natural gas consumption and, to a lesser extent, photosynthetic activity controlled the seasonal variability. Despite measurements being taken at ca. 22 times the mean building height, coupling with street level was adequate, especially during daytime. Night-time saw a higher occurrence of stable or neutral stratification, especially in autumn and winter, which resulted in data loss in post-processing and caused the tower to become decoupled from street level. CO2 fluxes observed at night were not always correlated with traffic counts, probably reflecting this decoupling, but also the fact that at night heating was always a larger source than traffic. No significant difference was found between the annual estimate of net exchange of CO2 for the expected measurement footprint and the values derived from the National Atmospheric Emissions Inventory (NAEI), with daytime fluxes differing by only 3%. This agreement with NAEI data also supported the use of the simple flux footprint model which was applied to the London site; this also suggests that individual roughness elements did not significantly affect the measurements due to the large ratio of measurement height to mean building height.

scholarly journals Tower and Aircraft Eddy Covariance Measurements of Water Vapor, Energy, and Carbon Dioxide Fluxes during SMACEX

2005 ◽  
Vol 6 (6) ◽  
pp. 954-960 ◽  
Author(s):  
J. H. Prueger ◽  
J. L. Hatfield ◽  
T. B. Parkin ◽  
W. P. Kustas ◽  
L. E. Hipps ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Water Vapor ◽  
Eddy Covariance ◽  
Spatial And Temporal Variability ◽  
Co2 Fluxes ◽  
Sensible Heat ◽  
Carbon Dioxide Fluxes ◽  
Crop Growth Stage ◽  
Aircraft Flux Measurements ◽  
Carbon Dioxide Co2

Abstract A network of eddy covariance (EC) and micrometeorological flux (METFLUX) stations over corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] canopies was established as part of the Soil Moisture–Atmosphere Coupling Experiment (SMACEX) in central Iowa during the summer of 2002 to measure fluxes of heat, water vapor, and carbon dioxide (CO2) during the growing season. Additionally, EC measurements of water vapor and CO2 fluxes from an aircraft platform complemented the tower-based measurements. Sensible heat, water vapor, and CO2 fluxes showed the greatest spatial and temporal variability during the early crop growth stage. Differences in all of the energy balance components were detectable between corn and soybean as well as within similar crops throughout the study period. Tower network–averaged fluxes of sensible heat, water vapor, and CO2 were observed to be in good agreement with area-averaged aircraft flux measurements.

S. I. Engine Pollution Control Using Low-Cost Palletized Catalytic Converter

Volume 2 ◽  
2004 ◽  
Author(s):  
Madhuri Jakkaraju ◽  
Vasudha Patri
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Pollution Control ◽  
Noble Metals ◽  
Fossil Fuel ◽  
Catalytic Converter ◽  
Low Cost ◽  
Hydrocarbon Emissions ◽  
Oxides Of Nitrogen ◽  
Carbon Dioxide Co2

I. C. Engines consume large amounts of fossil fuel emitting harmful pollutants like carbon monoxide (CO), unburnt hydrocarbons (UBHC), and oxides of nitrogen (NOx). By using a catalytic converter (CC), the carbon monoxide, hydrocarbon emissions can be transformed into less harmful carbon dioxide (CO2) & water vapor (H2O). Currently available CC’s are using costly noble metals like platinum (pt), palladium (pd), rhodium (rh) etc., hence making them expensive. This paper deals with the use of low-cost palletized silver coated alumina as the catalyst element in a CC. In this study, alumina and silver were used in the ratio of 10:1. All tests have been conducted on a stationary S.I. Engine at a constant speed of 1500 r.p.m with and without CC. Also, the performance of the palletized CC in combination with promoters like Bismuth, Cerium and Lanthanum was tested which have shown better results than silver alone as the coating element. It has been experimentally determined that the CO emissions have dropped from 7.25 (% vol) to 3.03(% vol) and the HC values have reduced from 350 ppm to 190 ppm.

scholarly journals Variability of dissolved CO<sub>2</sub> in the Pang and Lambourn Chalk rivers

2007 ◽  
Vol 11 (1) ◽  
pp. 328-339 ◽  
Author(s):  
J. Griffiths ◽  
J. Nutter ◽  
A. Binley ◽  
N. Crook ◽  
A. Young ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Seasonal Variation ◽  
Surface Waters ◽  
Temporal Variability ◽  
Stream Water ◽  
Spatial And Temporal Variability ◽  
Dissolved Carbon ◽  
Dissolved Carbon Dioxide ◽  
Borehole Water ◽  
Carbon Dioxide Co2

Abstract. This paper presents the results of a two-year field campaign to determine the spatial and temporal variability of groundwater interaction with surface waters in two Cretaceous Chalk catchments (the Pang and Lambourn) in the Upper Thames in Berkshire, UK, based on measurement of dissolved carbon dioxide (CO2). Average stream water concentrations of dissolved CO2 were up to 35 times the concentration at atmospheric equilibrium. Mean groundwater concentrations of 85 and 70 times the atmospheric equilibrium were determined from borehole water sampled in the Pang and Lambourn respectively. Diurnal and seasonal variation of in-stream concentration of dissolved CO2 is not significant enough to mask the signal from groundwater inputs.

scholarly journals Quantitative Fluxes of the Greenhouse Gases CH4 and CO2 from the Surfaces of Selected Polish Reservoirs

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 286
Author(s):  
Renata Gruca-Rokosz
Keyword(s):  
Carbon Dioxide ◽  
Greenhouse Gases ◽  
Water Column ◽  
Co2 Fluxes ◽  
Ch4 Flux ◽  
Chamber Method ◽  
Tropical Reservoirs ◽  
Se Poland ◽  
Carbon Dioxide Co2 ◽  
Eutrophic Reservoirs

Research carried out in the years 2009–2011 and 2018–2019 sought to determine the magnitudes of fluxes of methane (CH4) and carbon dioxide (CO2) from the surfaces of three eutrophic reservoirs in SE Poland. The “static chamber” method was deployed at five or six stations located along the reservoirs, where the water column at its deepest slightly exceeds 2 m. Obtained values for the fluxes of CH4 varied across a wide (0–2513.48 mmol·m−2·d−1) range, with many of these values therefore exceeding those characteristics for large tropical reservoirs. The reservoirs studied were not found to differ significantly in terms of average CH4 flux, however. Where obtained values for CO2 fluxes in the range from −10.96 to 621.69 mmol·m−2·d−1 were concerned, most fell within the range given for temperate-zone reservoirs, while differences between reservoirs were noted for average values in this case.

scholarly journals EMISI GAS KARBON DIOKSIDA (CO2) PADA PERKEBUNAN KELAPA SAWIT (Elaeis guineensis Jacq) YANG DITUMPANGSARI DENGAN TANAMAN PANGAN DI LAHAN GAMBUT

2017 ◽  
Vol 7 (2) ◽  
pp. 35
Author(s):  
Muhammad Ridha Pahlipi ◽  
Ervina Aryanti ◽  
Mokhamad Irfan ◽  
Indah Permanasari ◽  
Ahmad Taufiq Arminudin
Keyword(s):  
Carbon Dioxide ◽  
Soil Temperature ◽  
Air Temperature ◽  
Palm Oil ◽  
Oil Palm ◽  
Carbon Dioxide Emissions ◽  
Elaeis Guineensis ◽  
Block Design ◽  
Random Block Design ◽  
Carbon Dioxide Co2

Peat land conversion into oil palm plantations leads was increased emissions of carbon dioxide (CO2). Plants on peat land and environmental conditions believed to be factors in the emission of carbon dioxide (CO2). The porpuse of this research was determined the emissions of carbon dioxide (CO2) in oil palm plantations are intercropped with cropping crop on peat land and the influence of environmental factors on the emission of carbon dioxide (CO2). This research was conducted in September 2015 until April 2016 in Rimbo Panjang village, Subdiscrict Tambang, District of Kampar, Province of Riau. Cropping crop used were corn and soybeans. The method used in this study was a Random Block Design with four treatments and four replications. The treatments were palm - berau, palm oil - corn, palm oil - soybean, palm oil – intercropping (soybean – maize). Parameters measured were carbon dioxide (CO2), soil temperature, air temperature, the temperature of the lid, the depth of the water table and soil pH. The results showed that carbon dioxide emissions (CO2) in oil palm plantations are intercropped with cropping crop (corn and soybeans) were not significantly different. The influence of air temperature, soil temperature, the temperature of the lid, and the depth of the ground water level were inversely and  insignificant to the emission of carbon dioxide (CO2). As for getting nearly neutral pH, the emission of carbon dioxide (CO2) is increasing, but insignificant.

scholarly journals National Greenhouse Gas Emissions Inventory – Romania

2010 ◽  
Vol 67 (2) ◽  
Author(s):  
Marian PROOROCU ◽  
Sorin DEACONU ◽  
Mihaela SMARANDACHE
Keyword(s):  
Carbon Dioxide ◽  
Greenhouse Gas ◽  
Kyoto Protocol ◽  
Fossil Fuels ◽  
Ghg Emissions ◽  
Great Probability ◽  
Emissions Inventory ◽  
National Inventory ◽  
Commitment Period ◽  
Carbon Dioxide Co2

As a Party to the United Nations Framework Convention on Climate Change (UNFCCC), and its Kyoto Protocol, Romania is required to elaborate, regularly update and submit the national GHG Inventory. In compliance with the reporting requirements, Romania submitted in 2010 its ninth version of the National Inventory Report (NIR) covering the national inventories of GHG emissions/removals for the period 1989-2008. The inventories cover all sectors: Energy, Industrial Processes, Solvent and other product use, Agriculture, LULUCF and Waste. The direct GHGs included in the national inventory are: Carbon dioxide (CO2); Methane (CH4); Nitrous oxide (N2O); Hydrofluorocarbons (HFCs); Perfluorocarbons (PFCs); Sulphur hexafluoride (SF6). The emissions trend over the 1989-2008 period reflects the changes characterized by a process of transition to a market economy. With the entire economy in transition, some energy intensive industries reduced their activities and this is reflected in the GHG emissions reduction. Energy represents the most important sector in Romania, accounting for about 69% of the total national GHG emissions in 2008. The most significant anthropogenic greenhouse gas is the carbon dioxide. The decrease of CO2 emissions is caused by the decline of the amount of fossil fuels burnt in the energy sector, as a consequence of activity decline. According to the figures, there is a great probability for Romania to meet the Kyoto Protocol commitments on the limitation of the GHG emissions in the 2008-2012 commitment period.

scholarly journals Warming enhances carbon dioxide and methane fluxes from Red Sea seagrass (<i>Halophila stipulacea</i>) sediments

2019 ◽  
Author(s):  
Celina Burkholz ◽  
Neus Garcias-Bonet ◽  
Carlos M. Duarte
Keyword(s):  
Carbon Dioxide ◽  
Red Sea ◽  
Seawater Temperature ◽  
Isotopic Signature ◽  
Feedback Mechanism ◽  
Maximum Temperature ◽  
Co2 Fluxes ◽  
Seagrass Meadows ◽  
Halophila Stipulacea ◽  
Carbon Dioxide Co2

Abstract. Seagrass meadows are autotrophic ecosystems storing carbon in their biomass and sediments, but they have also been shown to be sources of carbon dioxide (CO2) and methane (CH4). Seagrasses can be negatively affected by increasing seawater temperatures, but the effects of warming on CO2 and CH4 fluxes in seagrass meadows have not yet been reported. Here, we examine the effect of two disturbances on air-seawater fluxes of CO2 and CH4 in Red Sea Halophila stipulacea communities compared to adjacent unvegetated sediments using cavity ring-down spectroscopy. We first characterized CO2 and CH4 fluxes in vegetated and adjacent unvegetated sediments, and then experimentally examined their response, along with that of the C isotopic signature of CO2 and CH4, to gradual warming from 25 °C (winter seawater temperature) to 37 °C, 2 °C above current maximum temperature. In addition, we assessed the response to prolonged darkness, thereby providing insights into the possible role of suppressing plant photosynthesis in supporting CO2 and CH4 fluxes. We detected distinct differences between vegetated and unvegetated sediments, with the vegetated sediments supporting 6-fold higher CO2 fluxes, and 10- to 100-fold higher CH4 fluxes. Warming led to an increase in net CO2 and CH4 fluxes, reaching average fluxes of 10,422.18 ± 2,570.12 µmol CO2 m−2 d−1 and 88.11 ± 15.19 µmol CH4 m−2 d−1, while CO2 and CH4 fluxes decreased over time in sediments maintained at 25 °C. Prolonged darkness led to an increase in CO2 fluxes but a decrease in CH4 fluxes in vegetated sediments. These results add to previous research identifying Red Sea seagrass meadows as a significant source of CH4, while also indicating that sublethal warming may lead to increased emissions of greenhouse gases from seagrass meadows, providing a feedback mechanism that may contribute to further enhance global warming.

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