scholarly journals Annual variation of methane emissions from forested bogs in West Siberia (2005–2009): a case of high CH<sub>4</sub> and precipitation rate in the summer of 2007

2010 ◽  
Vol 10 (11) ◽  
pp. 27759-27776 ◽  
Author(s):  
M. Sasakawa ◽  
A. Ito ◽  
T. Machida ◽  
N. Tsuda ◽  
Y. Niwa ◽  
...  
Keyword(s):  
Annual Variation ◽  
Co2 Flux ◽  
West Siberia ◽  
Ecosystem Model ◽  
Precipitation Rate ◽  
Monthly Precipitation ◽  
High Concentration ◽  
Ch4 Flux ◽  
Observation Network ◽  
Forested Bog

Abstract. We have been conducting continuous measurements of CH4 and CO2 on a network of towers (JR-STATION: Japan–Russia Siberian Tall Tower Inland Observation Network) located in taiga, steppe, and wetland biomes of Siberia. Here we describe measurements from two forested bog sites, Karasevoe (KRS; 58°15′ N, 82°25′ E) and Demyanskoe (DEM; 59°47′ N, 70°52′ E), in West Siberia from 2005 to 2009. Although both CH4 and CO2 accumulation (ΔCH4 and ΔCO2) during nighttime (duration of 7 h beginning 21:30 LST) at KRS in July 2007 showed an anomalously high concentration, the higher ratios of ΔCH4/ΔCO2 compared with those in other years indicate that a considerably more CH4 flux occurred relative to the CO2 flux in response to large precipitation recorded in 2007 (~2.7 mm d−1 higher than the climatological 1979–1998 base). Estimated seasonal CH4 fluxes based on the ratio of ΔCH4/ΔCO2 and the CASA 3-hourly CO2 flux for the 2005–2009 period exhibited a seasonal variation with a maximum in July at both sites. Annual values of the CH4 emission from the forested bogs around KRS (approx. 7.8×104 km2) calculated from a process-based ecosystem model, Vegetation Integrative Simulator for Trace gases (VISIT), showed inter-annual variation of 0.54, 0.31, 0.94, 0.44, and 0.41 Tg CH4 yr−1 from 2005 to 2009, respectively, with the highest values in 2007. It was assumed in the model that the area flooded with water is proportional to the cumulative anomaly in monthly precipitation rate.

scholarly journals Variation in Soil Properties Regulate Greenhouse Gas Fluxes and Global Warming Potential in Three Land Use Types on Tropical Peat

Atmosphere ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 465 ◽  
Author(s):  
Kiwamu Ishikura ◽  
Untung Darung ◽  
Takashi Inoue ◽  
Ryusuke Hatano
Keyword(s):  
Global Warming ◽  
Soil Moisture ◽  
Groundwater Level ◽  
Global Warming Potential ◽  
C:N Ratio ◽  
Co2 Flux ◽  
Nitrate Content ◽  
N2o Flux ◽  
Ch4 Flux ◽  
In The Beginning

This study investigated spatial factors controlling CO2, CH4, and N2O fluxes and compared global warming potential (GWP) among undrained forest (UDF), drained forest (DF), and drained burned land (DBL) on tropical peatland in Central Kalimantan, Indonesia. Sampling was performed once within two weeks in the beginning of dry season. CO2 flux was significantly promoted by lowering soil moisture and pH. The result suggests that oxidative peat decomposition was enhanced in drier position, and the decomposition acidify the peat soils. CH4 flux was significantly promoted by a rise in groundwater level, suggesting that methanogenesis was enhanced under anaerobic condition. N2O flux was promoted by increasing soil nitrate content in DF, suggesting that denitrification was promoted by substrate availability. On the other hand, N2O flux was promoted by lower soil C:N ratio and higher soil pH in DBL and UDF. CO2 flux was the highest in DF (241 mg C m−2 h−1) and was the lowest in DBL (94 mg C m−2 h−1), whereas CH4 flux was the highest in DBL (0.91 mg C m−2 h−1) and was the lowest in DF (0.01 mg C m−2 h−1), respectively. N2O flux was not significantly different among land uses. CO2 flux relatively contributed to 91–100% of GWP. In conclusion, it is necessary to decrease CO2 flux to mitigate GWP through a rise in groundwater level and soil moisture in the region.

scholarly journals Annual follow-up of gross diffusive carbon dioxide and methane emissions from a boreal reservoir and two nearby lakes in Québec, Canada

2011 ◽  
Vol 8 (1) ◽  
pp. 41-53 ◽  
Author(s):  
M. Demarty ◽  
J. Bastien ◽  
A. Tremblay
Keyword(s):  
Carbon Budget ◽  
Ghg Emissions ◽  
Co2 Flux ◽  
Reliable Estimate ◽  
Minor Importance ◽  
Layer Model ◽  
Thin Boundary Layer ◽  
Ch4 Flux ◽  
Annual Carbon

Abstract. Surface water pCO2 and pCH4 measurements were taken in the boreal zone of Québec, Canada, from summer 2006 to summer 2008 in Eastmain 1 reservoir and two nearby lakes. The goal of this follow-up was to evaluate annual greenhouse gas (GHG) emissions, including spring emissions (N.B. gross emissions for reservoir), through flux calculations using the thin boundary layer model. Our measurements underscored the winter CO2 accumulation due to ice cover and the importance of a reliable estimate of spring diffusive emissions as the ice breaks up. We clearly demonstrated that in our systems, diffusive CH4 flux (in terms of CO2 equivalent) were of minor importance in the GHG emissions (without CH4 accumulation under ice), with diffusive CO2 flux generally accounting for more than 95% of the annual diffusive flux. We also noted the extent of spring diffusive CO2 emissions (23% to 52%) in the annual carbon budget.

scholarly journals Climate and site management as driving factors for the atmospheric greenhouse gas exchange of a restored wetland

2013 ◽  
Vol 10 (1) ◽  
pp. 39-52 ◽  
Author(s):  
M. Herbst ◽  
T. Friborg ◽  
K. Schelde ◽  
R. Jensen ◽  
R. Ringgaard ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Carbon Sink ◽  
Stocking Density ◽  
Co2 Flux ◽  
Co2 Uptake ◽  
Site Management ◽  
Restored Wetland ◽  
Ch4 Flux ◽  
Annual Variations ◽  
Vegetation Height

Abstract. The atmospheric greenhouse gas (GHG) budget of a restored wetland in western Denmark was established for the years 2009–2011 from eddy covariance measurements of carbon dioxide (CO2) and methane (CH4) fluxes. The water table in the wetland, which was restored in 2002, was unregulated, and the vegetation height was limited through occasional grazing by cattle and grass cutting. The annual net CO2 uptake varied between 195 and 983 g m−2 and the annual net CH4 release varied between 11 and 17 g m−2. In all three years the wetland was a carbon sink and removed between 42 and 259 g C m−2 from the atmosphere. However, in terms of the full annual GHG budget (assuming that 1 g CH4 is equivalent to 25 g CO2 with respect to the greenhouse effect over a time horizon of 100 years) the wetland was a sink in 2009, a source in 2010 and neutral in 2011. Complementary observations of meteorological factors and management activities were used to explain the large inter-annual variations in the full atmospheric GHG budget of the wetland. The largest impact on the annual GHG fluxes, eventually defining their sign, came from site management through changes in grazing duration and animal stocking density. These changes accounted for half of the observed variability in the CO2 fluxes and about two thirds of the variability in CH4 fluxes. An unusually long period of snow cover in 2010 had the second largest effect on the annual CO2 flux, whose interannual variability was larger than that of the CH4 flux. Since integrated CO2 and CH4 flux data from restored wetlands are still very rare, it is concluded that more long-term flux measurements are needed to quantify the effects of ecosystem disturbance, in terms of management activities and exceptional weather patterns, on the atmospheric GHG budget more accurately.

Improvement of CO2 Separation Performance by Blended Aqueous Solutions of DEA+AMP in Hollow Fiber Membrane Contactor (HFMC)

2012 ◽  
Vol 512-515 ◽  
pp. 2308-2316 ◽  
Author(s):  
Zhen Wang ◽  
Meng Xiang Fang ◽  
Shui Ping Yan ◽  
Yi Li Pang ◽  
Zhong Yang Luo
Keyword(s):  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Co2 Flux ◽  
Positive Influence ◽  
Separation Performance ◽  
Co2 Absorption ◽  
Membrane Contactor ◽  
Fiber Membrane ◽  
High Concentration ◽  
Carbon Dioxide Co2

Absorption of carbon dioxide (CO2) by blended diethanolamine (DEA) + 2-amino-2- methyl-1-propanol (AMP) and single DEA solvents were compared using hollow fiber membrane contactor (HFMC). Experimental results showed AMP additive has positive influence to improve CO2 absorption flux and the optimum AMP/DEA mass concentration ratio is between 0.2 and 0.4. Decreasing gas liquid ratio could greatly promote CO2 absorption, and operating temperature has weak effect on CO2 flux. Besides, large CO2 flux can be achieved with high concentration of DEA+0.2AMP solution due to the decrease of liquid phase resistance to mass transfer, but the optimal DEA concentration was recommended to be about 15% for DEA+0.2AMP solution considering the costs of amines in HFMC.

Studying the spatial and seasonal variability of greenhouse gases across West Siberia: large-scale mobile measurement campaigns of 2018-2019

2020 ◽  
Author(s):  
Mikhail Arshinov ◽  
Boris Belan ◽  
Denis Davydov ◽  
Artem Kozlov ◽  
Alexander Fofonov ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Large Scale ◽  
Seasonal Pattern ◽  
West Siberia ◽  
Small Scale ◽  
Seasonal Cycles ◽  
Ocean Optics ◽  
Atmospheric Physics ◽  
Mixing Ratios ◽  
Observation Network

&lt;p&gt;The continuous ground-based measurements of greenhouse gases carried out in Siberia in the past two decades allowed the long-term trends, as well as the diurnal and seasonal cycles of CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; to be derived for this poorly studied region (Belikov et al., 2019). To date, these in-situ observations are made at the joint Japan-Russia Siberian Tall Tower Inland Observation Network (JR-STATION) consisted of 6 automated stations that should be maintained several times per year. In late October to early November 2018, we have undertaken the first mobile campaign to derive a distribution of CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; concentrations at high spatial resolution while traveling to the sites of the above network. For that, we used a commercially available GHG CRDS analyzer (G4301, Picarro Inc., Santa Clara, CA, USA) installed in an off-road vehicle (Arshinov et al., 2019). Over one trip, the instrument were driven over 7000 km throughout the study area.&lt;/p&gt;&lt;p&gt;In March, June, August, and October 2019 we have performed four more campaigns along the same route. This enabled the seasonal pattern of CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; concentrations to be obtained over a huge area of West Siberia between 54.5&amp;#176; and 63.2&amp;#176; north latitude and between 62.3&amp;#176; and 85.0&amp;#176; east longitude, as well as to reveal a large- and small-scale spatial heterogeneity in CH&lt;sub&gt;4&lt;/sub&gt; mixing ratios particularly over wetland regions. We plan to continue mobile campaigns to cover interannual variations.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;This work was supported by the Ministry of Science and Higher Education of the Russian Federation under State Contract No. 14.616.21.0104 (ID No RFMEFI61618X0104).&lt;/p&gt;&lt;p&gt;Belikov, D.; Arshinov, M.; Belan, B.; Davydov, D.; Fofonov, A.; Sasakawa, M.; Machida, T. Analysis of the Diurnal, Weekly, and Seasonal Cycles and Annual Trends in Atmospheric CO&lt;sub&gt;2&lt;/sub&gt;&amp;#160;and CH&lt;sub&gt;4&lt;/sub&gt;&amp;#160;at Tower Network in Siberia from 2005 to 2016. Atmosphere&amp;#160;2019,&amp;#160;10, 689.&lt;/p&gt;&lt;p&gt;Arshinov, M.Yu.; Belan B.D.;&amp;#160;Davydov D.K.; &amp;#160;Kozlov A.V.,&amp;#160;Fofonov A.V.,&amp;#160;and&amp;#160; Arshinova&amp;#160;V.&amp;#160;Heterogeneity of the spatial distribution of CO&lt;sub&gt;2&lt;/sub&gt;&amp;#160;and CH&lt;sub&gt;4&lt;/sub&gt;&amp;#160;concentrations in the atmospheric surface layer over West Siberia: October-November 2018, Proc. SPIE 11208, 25th International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics, 1120831 (18 December 2019);https://doi.org/10.1117/12.2539205&lt;/p&gt;

scholarly journals Nature of extreme precipitation over Ukraine in the 21st century

2018 ◽  
pp. 36-45
Author(s):  
V. F. Martazinova ◽  
O. Shchehlov
Keyword(s):  
Comparative Analysis ◽  
Extreme Precipitation ◽  
Daily Precipitation ◽  
Human Life ◽  
Precipitation Amount ◽  
Precipitation Rate ◽  
Monthly Precipitation ◽  
Threshold Values ◽  
Precipitation Regime ◽  
Carpathian Region

The article examines the state of precipitation over the territory of Ukraine over recent decades. Through the example of central months of the seasons differences in monthly and average daily precipitation amounts for the period of 2000-2014 are shown. Within the most territory of Ukraine summer precipitation is almost twice as high as spring and autumn one. During all seasons the greatest amount of precipitation is observed in the Carpathian region. Distribution of average long-term precipitation values over the rest of the territory coincides in spring, summer and autumn: the highest precipitation values are observed in the western and north-western parts and decrease to the south-east. The article studies a yearly precipitation rate at low-land and mountain meteorological stations. It proposes to separate criteria of precipitation extremality depending on the regions. All extreme daily precipitation can be divided into the following categories: > 20-30 mm / day, > 30-50 mm / day, > 50 mm / day. Each category of extreme precipitation has its a certain economic risk, but the third class can cause not only economic risks, but also risks associated with human life and activities. The distinct feature of the present-day precipitation consists in redistribution of precipitation in the middle of the months, when a daily precipitation rate increases together with intervals between heavy rains. In order to analyze the changes of precipitation regime, the approach of dividing the rates of monthly precipitation amount by the rates of extreme and non-extreme precipitation is proposed. A comparative analysis of daily precipitation in different seasons and over different climatic periods was also carried out. The article studies the proportion of daily precipitation of up to 15 mm and the one exceeding 15 mm forming a part of monthly rates of precipitation over the territory of Ukraine. In January, rainfalls exceeding 15 mm make up from 5-10 % of the total amount of monthly precipitation, except the Carpathian region and the southwestern regions of Ukraine where those exceed 20-25 %. In spring, the amount of rainfalls increases and its percentage of the monthly precipitation amount is around 20 % over most of the regions. Until summer, the amount of rainfalls increases and in July its percentage is 50-70 %. Until autumn, the amount of those starts decreasing, however, the percentage of rainfalls is almost twice as high as in spring, and for most of the regions it is about 30-40 %. Such breakdown of the monthly precipitation rates into two components allows determination during a period in question of precipitation amounts we have each month. The maximum daily precipitation amounts serve as an important indicator of the precipitation regime which shows the potential danger from extreme precipitation. For different regions the threshold values of the upper limit of rainfalls taken as a maximum daily value for the period of 2000-2014 differ. In winter and spring time, the limit of rainfalls amount per day usually hits 20-30 mm for the most territory of the country. At the same time there are certain areas where the limit values of the daily rainfalls rate reach 40-50 mm. The most significant rainfalls are observed in summer. Despite the fact that the territory of such rainfalls is quite patchy, nevertheless, those areas where precipitation rate over one day may reach 70 mm are the most vulnerable and have high risks for human life and activities. In autumn, the threshold values are 30-40 mm. The breakdown of the rates of monthly precipitation amount into extreme and non-extreme ones allows determination in future of whether the precipitation regime changes because of extreme or non-extreme values. Also, in the long run, a comparative analysis of the rates of showers and weak rainfalls in the late 20th and early 21st centuries can be carried out and a tendency of precipitation regime seasonal change over the next decade can be obtained which will help us to identify vulnerable regions suffering from extreme precipitation rates.

scholarly journals Insights from year-long measurements of air–water CH<sub>4</sub> and CO<sub>2</sub> exchange in a coastal environment

2019 ◽  
Vol 16 (5) ◽  
pp. 961-978 ◽  
Author(s):  
Mingxi Yang ◽  
Thomas G. Bell ◽  
Ian J. Brown ◽  
James R. Fishwick ◽  
Vassilis Kitidis ◽  
...  
Keyword(s):  
Wind Speed ◽  
Co2 Flux ◽  
Open Water ◽  
Gas Transfer ◽  
Co2 Efflux ◽  
Water Sector ◽  
Transfer Velocity ◽  
Ch4 Flux ◽  
Gas Transfer Velocity

Abstract. Air–water CH4 and CO2 fluxes were directly measured using the eddy covariance technique at the Penlee Point Atmospheric Observatory on the southwest coast of the United Kingdom from September 2015 to August 2016. The high-frequency, year-long measurements provide unprecedented detail on the variability of these greenhouse gas fluxes from seasonal to diurnal and to semi-diurnal (tidal) timescales. Depending on the wind sector, fluxes measured at this site are indicative of air–water exchange in coastal seas as well as in an outer estuary. For the open-water sector when winds were off the Atlantic Ocean, CH4 flux was almost always positive (annual mean of ∼0.05 mmol m−2 d−1) except in December and January, when CH4 flux was near zero. At times of high rainfall and river flow rate, CH4 emission from the estuarine-influenced Plymouth Sound sector was several times higher than emission from the open-water sector. The implied CH4 saturation (derived from the measured fluxes and a wind-speed-dependent gas transfer velocity parameterization) of over 1000 % in the Plymouth Sound is within range of in situ dissolved CH4 measurements near the mouth of the river Tamar. CO2 flux from the open-water sector was generally from sea to air in autumn and winter and from air to sea in late spring and summer, with an annual mean flux of near zero. A diurnal signal in CO2 flux and implied partial pressure of CO2 in water (pCO2) are clearly observed for the Plymouth Sound sector and also evident for the open-water sector during biologically productive periods. These observations suggest that coastal CO2 efflux may be underestimated if sampling strategies are limited to daytime only. Combining the flux data with seawater pCO2 measurements made in situ within the flux footprint allows us to estimate the CO2 transfer velocity. The gas transfer velocity and wind speed relationship at this coastal location agrees reasonably well with previous open-water parameterizations in the mean but demonstrates considerable variability. We discuss the influences of biological productivity, bottom-driven turbulence and rainfall on coastal air–water gas exchange.

Gas emissions from dairy barnyards

2016 ◽  
Vol 56 (3) ◽  
pp. 355 ◽  
Author(s):  
J. M. Powell ◽  
P. A. Vadas
Keyword(s):  
Co2 Flux ◽  
N2o Flux ◽  
Sand Soil ◽  
Gas Emissions ◽  
Nutrient Runoff ◽  
Ch4 Flux ◽  
Before And After ◽  
Health Need ◽  
Carbon Dioxide Co2 ◽  
Cow Comfort

Dairy cattle spend considerable time in outside barnyards. Nine barnyards were constructed to examine impacts of surface materials (bark, sand, soil) and timing of cattle corralling (before and after 3–14-day corralling periods) on fluxes of carbon dioxide (CO2), methane (CH4), ammonia (NH3), nitrous oxide (N2O) and CO2 equivalents (CO2eq). Surface, year, and surface*year interactions accounted for 64%, 6% and 16% of CO2 flux variability. Average CO2 flux from bark (2552 mg/m2.h) was 3.1–3.9 times greater than from sand or soil, especially after bark replenishment. Timing, year, timing*year and surface*year accounted for 40%, 17%, 14%, and 17% of CH4 variability. Average CH4 flux after corralling (10.6 mg/m2.h) was 3.8 times greater than before corralling, and 5.2 times greater the year following bark replenishment. Timing accounted for 67% of NH3 variability. After corralling, NH3 fluxes (1622 µg/m2.h) were 95 times greater than before corralling. Timing, surface, surface*timing and timing*year accounted for 33%, 10%, 24% and 13% of N2O variability. Average N2O flux after corralling (2252 µg/m2.h) was 3.7 times greater than before corralling. Surface and surface*year accounted for 71% and 16% of CO2eq variability. Average CO2eq flux from bark (3188 mg/m2.h) was 2.5–3.0 times greater than sand or soil. Greatest CO2eq flux occurred the year after bark replenishment. Tradeoffs between gas emissions, nutrient runoff and leaching, and cow comfort and health need to be assessed more fully before recommending beneficial practices for barnyard surface type and management.

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