scholarly journals Towards a method for high vertical resolution measurements of the partial pressure of CO2 within bulk sea ice

2012 ◽  
Vol 58 (208) ◽  
pp. 287-300 ◽  
Author(s):  
N.-X. Geilfus ◽  
B. Delille ◽  
V. Verbeke ◽  
J.-L. Tison
Keyword(s):  
Gas Chromatography ◽  
Sea Ice ◽  
Partial Pressure ◽  
Vertical Resolution ◽  
Gas Chromatograph ◽  
Partial Pressure Of Co2 ◽  
High Vertical Resolution ◽  
Non Destructive ◽  
Standard Gas

AbstractFluxes of atmospheric CO2 have been reported over sea ice during winter and spring. These fluxes are partly driven by the gradient of the CO2 concentration between sea ice and the atmosphere. We present a new non-destructive method to measure the pCO2 of bulk sea ice at its in situ temperature. This method is based on an equilibration procedure between sea ice and a standard gas of known CO2 concentration. The concentration is measured by gas chromatography with a precision of 5%. Tests were performed on artificial standard sea ice and confirmed the reproducibility of the technique in the range of precision of the gas chromatograph. To test the accuracy of this method, the first profiles of pCO2 measured in bulk sea ice are reported and compared with direct in situ measurements of brine pCO2 over depth-integrated intervals.

scholarly journals Uncertainties of the Ocean Heat Content Estimation Induced by Insufficient Vertical Resolution of Historical Ocean Subsurface Observations

2014 ◽  
Vol 31 (6) ◽  
pp. 1383-1396 ◽  
Author(s):  
Lijing Cheng ◽  
Jiang Zhu
Keyword(s):  
Heat Content ◽  
Temporal Distribution ◽  
Observation System ◽  
Cold Bias ◽  
Vertical Resolution ◽  
Convex Shape ◽  
Global Average ◽  
High Vertical Resolution ◽  
The Difference

Abstract Assessment of the upper-ocean (0–700 m) heat content (OHC) is a key task for monitoring climate change. However, irregular spatial and temporal distribution of historical subsurface observations has induced uncertainties in OHC estimation. In this study, a new source of uncertainties in calculating OHC due to the insufficiency of vertical resolution in historical ocean subsurface temperature profile observations was diagnosed. This error was examined by sampling a high-vertical-resolution climatological ocean according to the depth intervals of in situ subsurface observations, and then the error was defined as the difference between the OHC calculated by subsampled profiles and the OHC of the climatological ocean. The obtained resolution-induced error appeared to be cold in the upper 100 m (with a peak of approximately −0.1°C), warm within 100–700 m (with a peak of ~0.1°C near 180 m), and warm when averaged over 0–700-m depths (with a global average of ~0.01°–0.025°C, ~1–2.5 × 1022 J). Geographically, it showed a warm bias within 30°S–30°N and a cold bias at higher latitudes in both hemispheres, the sign of which depended on the concave or convex shape of the vertical temperature profiles. Finally, the authors recommend maintaining an unbiased observation system in the future: a minimal vertical depth bin of 5% of the depth was needed to reduce the vertical-resolution-induced bias to less than 0.005°C on global average (equal to Argo accuracy).

scholarly journals Reconstruction of super-resolution ocean <i>p</i>CO<sub>2</sub> and air–sea fluxes of CO<sub>2</sub> from satellite imagery in the southeastern Atlantic

2015 ◽  
Vol 12 (17) ◽  
pp. 5229-5245 ◽  
Author(s):  
I. Hernández-Carrasco ◽  
J. Sudre ◽  
V. Garçon ◽  
H. Yahia ◽  
C. Garbe ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Partial Pressure ◽  
Sea Surface Temperature ◽  
Ocean Color ◽  
Super Resolution ◽  
In Situ Measurements ◽  
Sea Surface ◽  
Co2 Fluxes ◽  
Partial Pressure Of Co2

Abstract. An accurate quantification of the role of the ocean as source/sink of greenhouse gases (GHGs) requires to access the high-resolution of the GHG air–sea flux at the interface. In this paper we present a novel method to reconstruct maps of surface ocean partial pressure of CO2 ( pCO2) and air–sea CO2 fluxes at super resolution (4 km, i.e., 1/32° at these latitudes) using sea surface temperature (SST) and ocean color (OC) data at this resolution, and CarbonTracker CO2 fluxes data at low resolution (110 km). Inference of super-resolution pCO2 and air–sea CO2 fluxes is performed using novel nonlinear signal processing methodologies that prove efficient in the context of oceanography. The theoretical background comes from the microcanonical multifractal formalism which unlocks the geometrical determination of cascading properties of physical intensive variables. As a consequence, a multi-resolution analysis performed on the signal of the so-called singularity exponents allows for the correct and near optimal cross-scale inference of GHG fluxes, as the inference suits the geometric realization of the cascade. We apply such a methodology to the study offshore of the Benguela area. The inferred representation of oceanic partial pressure of CO2 improves and enhances the description provided by CarbonTracker, capturing the small-scale variability. We examine different combinations of ocean color and sea surface temperature products in order to increase the number of valid points and the quality of the inferred pCO2 field. The methodology is validated using in situ measurements by means of statistical errors. We find that mean absolute and relative errors in the inferred values of pCO2 with respect to in situ measurements are smaller than for CarbonTracker.

scholarly journals The surface layer observed by a high-resolution sodar at DOME C, Antarctica

2014 ◽  
Vol 56 (5) ◽  
Author(s):  
Stefania Argentini ◽  
Igor Petenko ◽  
Angelo Viola ◽  
Giangiuseppe Mastrantonio ◽  
Ilaria Pietroni ◽  
...  
Keyword(s):  
Surface Layer ◽  
Gravity Waves ◽  
High Frequency ◽  
Vertical Resolution ◽  
High Vertical Resolution ◽  
One Year ◽  
Atmospheric Gravity ◽  
Radiation Measurements ◽  
High Range

<p>One year field experiment has started on December 2011 at the French - Italian station of Concordia at Dome C, East Antarctic Plateau. The objective of the experiment is the study of the surface layer turbulent processes under stable/very stable stratifications, and the mechanisms leading to the formation of the warming events. A sodar was improved to achieve the vertical/time resolution needed to study these processes. The system, named Surface Layer sodar (SL-sodar), may operate both in high vertical resolution (low range) and low vertical resolution (high range) modes. <em>In situ</em> turbulence and radiation measurements were also provided in the framework of this experiment. A few preliminary results, concerning the standard summer diurnal cycle, a summer warming event, and unusually high frequency boundary layer atmospheric gravity waves are presented.</p>

scholarly journals CO<sub>2</sub> and CH<sub>4</sub> in sea ice from a subarctic fjord under influence of riverine input

2014 ◽  
Vol 11 (23) ◽  
pp. 6525-6538 ◽  
Author(s):  
O. Crabeck ◽  
B. Delille ◽  
D. Thomas ◽  
N.-X. Geilfus ◽  
S. Rysgaard ◽  
...  
Keyword(s):  
Sea Ice ◽  
Partial Pressure ◽  
Gas Content ◽  
Atmospheric Methane ◽  
Riverine Input ◽  
River Input ◽  
Partial Pressure Of Co2 ◽  
Minor Portion ◽  
Ch4 Concentration ◽  
A Minor

Abstract. We present the CH4 concentration [CH4], the partial pressure of CO2 (pCO2) and the total gas content in bulk sea ice from subarctic, land-fast sea ice in the Kapisillit fjord, Greenland. Fjord systems are characterized by freshwater runoff and riverine input and based on δ18O data, we show that > 30% of the surface water originated from periodic river input during ice growth. This resulted in fresher sea-ice layers with higher gas content than is typical from marine sea ice. The bulk ice [CH4] ranged from 1.8 to 12.1 nmol L−1, which corresponds to a partial pressure ranging from 3 to 28 ppmv. This is markedly higher than the average atmospheric methane content of 1.9 ppmv. Evidently most of the trapped methane within the ice was contained inside bubbles, and only a minor portion was dissolved in the brines. The bulk ice pCO2 ranged from 60 to 330 ppmv indicating that sea ice at temperatures above −4 °C is undersaturated compared to the atmosphere (390 ppmv). This study adds to the few existing studies of CH4 and CO2 in sea ice, and we conclude that subarctic seawater can be a sink for atmospheric CO2, while being a net source of CH4.

scholarly journals Reconstruction of super-resolution fields of ocean <i>p</i>CO<sub>2</sub> and air–sea fluxes of CO<sub>2</sub> from satellite imagery in the Southeastern Atlantic

2015 ◽  
Vol 12 (2) ◽  
pp. 1405-1452 ◽  
Author(s):  
I. Hernández-Carrasco ◽  
J. Sudre ◽  
V. Garçon ◽  
H. Yahia ◽  
C. Garbe ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Partial Pressure ◽  
Sea Surface Temperature ◽  
Super Resolution ◽  
In Situ Measurements ◽  
Sea Surface ◽  
Co2 Fluxes ◽  
Ocean Colour ◽  
Partial Pressure Of Co2

Abstract. The knowledge of Green House Gases GHGs fluxes at the air–sea interface at high resolution is crucial to accurately quantify the role of the ocean in the absorption and emission of GHGs. In this paper we present a novel method to reconstruct maps of surface ocean partial pressure of CO2, pCO2, and air–sea CO2 fluxes at super resolution (4 km) using Sea Surface Temperature (SST) and Ocean Colour (OC) data at this resolution, and CarbonTracker CO2 fluxes data at low resolution (110 km). Inference of super-resolution of pCO2, and air–sea CO2 fluxes is performed using novel nonlinear signal processing methodologies that prove efficient in the context of oceanography. The theoretical background comes from the Microcanonical Multifractal Formalism which unlocks the geometrical determination of cascading properties of physical intensive variables. As a consequence, a multiresolution analysis performed on the signal of the so-called singularity exponents allows the correct and near optimal cross-scale inference of GHGs fluxes, as the inference suits the geometric realization of the cascade. We apply such a methodology to the study offshore of the Benguela area. The inferred representation of oceanic partial pressure of CO2 improves and enhances the description provided by CarbonTracker, capturing the small scale variability. We examine different combinations of Ocean Colour and Sea Surface Temperature products in order to increase the number of valid points and the quality of the inferred pCO2 field. The methodology is validated using in-situ measurements by means of statistical errors. We obtain that mean absolute and relative errors in the inferred values of pCO2 with respect to in-situ measurements are smaller than for CarbonTracker.

scholarly journals CO<sub>2</sub> and CH<sub>4</sub> in sea ice from a subarctic fjord

2014 ◽  
Vol 11 (3) ◽  
pp. 4047-4083 ◽  
Author(s):  
O. Crabeck ◽  
B. Delille ◽  
D. N. Thomas ◽  
N. X. Geilfus ◽  
S. Rysgaard ◽  
...  
Keyword(s):  
Sea Ice ◽  
Partial Pressure ◽  
Atmospheric Methane ◽  
Arctic Sea ◽  
Partial Pressure Of Co2 ◽  
Ice Conditions ◽  
Minor Portion ◽  
Ch4 Concentration ◽  
Field Campaigns ◽  
A Minor

Abstract. We present CH4 concentration [CH4] and the partial pressure of CO2 (pCO2) in bulk sea ice from subarctic, land-fast sea ice in the Kapisillit fjord, Greenland. The bulk ice [CH4] ranged from 1.8 to 12.1 nmol L−1, which corresponds to a partial pressure range of 3 to 28 ppmv. This is markedly higher than the average atmospheric methane content of 1.9 ppmv. Most of the trapped methane within the sea ice was evidently contained inside bubbles, and only a minor portion was dissolved in the brine. The bulk ice pCO2 ranged from 60 to 330 ppmv showing that sea ice at temperatures above −4 °C is under-saturated compared to the atmosphere (390 ppmv). Our study adds to the few existing studies of CH4 and CO2 in sea ice and concludes that sub-arctic sea can be a sink for atmospheric CO2, while being a net source of CH4. Processes related to the freezing and melting of sea ice represents large unknowns to the exchange of CO2 but also CH4. It is therefore imperative to assess the consequences of these unknowns through further field campaigns and targeted research under other sea ice conditions at both hemispheres.

Continuous non-destructive determination of nitrogenase activity in microbial cultures

1975 ◽  
Vol 21 (7) ◽  
pp. 980-983 ◽  
Author(s):  
T. A. Larue ◽  
W. G. W. Kurz ◽  
C. Mallard
Keyword(s):  
Gas Chromatography ◽  
Gas Flow ◽  
Nitrogenase Activity ◽  
Microbial Cultures ◽  
Non Destructive

The dinitrogen fixing enzyme nitrogenase (nitrogen:(acceptor) oxidoreductase) (EC 1.7.99.2) is monitored by its ability to reduce acetylene to ethylene. Low, non-inhibitory concentrations of acetylene (~10−7 mol/litre) are mixed with the gas flow aerating microbial cultures, and acetylene and ethylene in the effluent gas are determined by gas chromatography. The procedure is safe, simple and is carried out in situ without disturbing the growing culture. Transient changes in nitrogenase activity are easily detected. The technique may be automated.

In-situ automatic observations of ice thickness of seas

2012 ◽  
Vol 19 (3) ◽  
pp. 583-592 ◽  
Author(s):  
Yinke Dou ◽  
Xiaomin Chang
Keyword(s):  
Sea Ice ◽  
New Technologies ◽  
Capacitive Sensor ◽  
Automatic Monitoring ◽  
Ice Thickness ◽  
In Situ Observation ◽  
Glacier Surface ◽  
Sea Ice Thickness ◽  
Surface Ice

Abstract Ice thickness is one of the most critical physical indicators in the ice science and engineering. It is therefore very necessary to develop in-situ automatic observation technologies of ice thickness. This paper proposes the principle of three new technologies of in-situ automatic observations of sea ice thickness and provides the findings of laboratory applications. The results show that the in-situ observation accuracy of the monitor apparatus based on the Magnetostrictive Delay Line (MDL) principle can reach ±2 mm, which has solved the “bottleneck” problem of restricting the fine development of a sea ice thermodynamic model, and the resistance accuracy of monitor apparatus with temperature gradient can reach the centimeter level and research the ice and snow substance balance by automatically measuring the glacier surface ice and snow change. The measurement accuracy of the capacitive sensor for ice thickness can also reach ±4 mm and the capacitive sensor is of the potential for automatic monitoring the water level under the ice and the ice formation and development process in water. Such three new technologies can meet different needs of fixed-point ice thickness observation and realize the simultaneous measurement in order to accurately judge the ice thickness.

Sign in / Sign up

Export Citation Format

Share Document