Update on IAGOS greenhouse gas observations from commercial airliners

2020 ◽  
Author(s):  
Christoph Gerbig ◽  
Harald Franke ◽  
Ralf Stosius ◽  
Florian Obersteiner ◽  
Torsten Gehrlein ◽  
...  
Keyword(s):  
Measurement System ◽  
Uncertainty Estimation ◽  
Research Community ◽  
Trace Gas ◽  
Calibration System ◽  
Core System ◽  
Autonomous Operation ◽  
System A ◽  
Future Extension ◽  
Gas Measurements

<p>Within the framework of the research infrastructure IAGOS (In-service Aircraft for a Global Observing System), a cavity ring-down spectroscopy (CRDS)-based measurement system for the autonomous measurement of the greenhouse gases (GHGs) CO<sub>2</sub> and CH<sub>2</sub>, as well as CO and water vapour is deployed on a Lufthansa Airbus A330 since September 2018. This IAGOS-CORE system is equipped with a two-standard in-flight calibration system, allowing for trace gas measurements to be fully traceable to WMO calibration scales. Various lessons have been learned during the first deployment periods related to the autonomous operation of the system over periods of several months, enabling the future extension of the GHG measurements to aircraft from further airlines. Apart from the presentation of the observations, the presentation will discuss the data quality and uncertainty estimation.</p><p>A further CRDS system for autonomous measurement CO<sub>2</sub> and CH<sub>4</sub> is integrated within the instrumented IAGOS-CARIBIC container deployed on board an Airbus A340 on a bi-monthly schedule since July 2018. By now this system has provided data from more than 30 flights. Data will be presented, and the potential of the observations for research applications will be introduced. Also the availability of IAGOS GHG data to the research community will be discussed.</p>

scholarly journals Soil gas probes for monitoring trace gas messengers of microbial activity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joseph R. Roscioli ◽  
Laura K. Meredith ◽  
Joanne H. Shorter ◽  
Juliana Gil-Loaiza ◽  
Till H. M. Volkmann
Keyword(s):  
Microbial Activity ◽  
Soil Heterogeneity ◽  
Soil Gas ◽  
Microbial Processes ◽  
Trace Gas ◽  
Soil Microbiome ◽  
Sampling System ◽  
Site Specific ◽  
Gas Measurements ◽  
Subsurface Monitoring

AbstractSoil microbes vigorously produce and consume gases that reflect active soil biogeochemical processes. Soil gas measurements are therefore a powerful tool to monitor microbial activity. Yet, the majority of soil gases lack non-disruptive subsurface measurement methods at spatiotemporal scales relevant to microbial processes and soil structure. To address this need, we developed a soil gas sampling system that uses novel diffusive soil probes and sample transfer approaches for high-resolution sampling from discrete subsurface regions. Probe sampling requires transferring soil gas samples to above-ground gas analyzers where concentrations and isotopologues are measured. Obtaining representative soil gas samples has historically required balancing disruption to soil gas composition with measurement frequency and analyzer volume demand. These considerations have limited attempts to quantify trace gas spatial concentration gradients and heterogeneity at scales relevant to the soil microbiome. Here, we describe our new flexible diffusive probe sampling system integrated with a modified, reduced volume trace gas analyzer and demonstrate its application for subsurface monitoring of biogeochemical cycling of nitrous oxide (N2O) and its site-specific isotopologues, methane, carbon dioxide, and nitric oxide in controlled soil columns. The sampling system observed reproducible responses of soil gas concentrations to manipulations of soil nutrients and redox state, providing a new window into the microbial response to these key environmental forcings. Using site-specific N2O isotopologues as indicators of microbial processes, we constrain the dynamics of in situ microbial activity. Unlocking trace gas messengers of microbial activity will complement -omics approaches, challenge subsurface models, and improve understanding of soil heterogeneity to disentangle interactive processes in the subsurface biome.

scholarly journals An evaluation of the performance of chemistry transport models by comparison with research aircraft observations. Part 1: Concepts and overall model performance

2003 ◽  
Vol 3 (5) ◽  
pp. 1609-1631 ◽  
Author(s):  
D. Brunner ◽  
J. Staehelin ◽  
H. L. Rogers ◽  
M. O. Köhler ◽  
J. A. Pyle ◽  
...  
Keyword(s):  
Quantitative Methods ◽  
Climate Models ◽  
Model Performance ◽  
Average Concentration ◽  
Convective Transport ◽  
Trace Gas ◽  
Atmospheric Conditions ◽  
Time Step ◽  
Research Aircraft ◽  
Gas Measurements

Abstract. A rigorous evaluation of five global Chemistry-Transport and two Chemistry-Climate Models operated by several different groups in Europe, was performed. Comparisons were made of the models with trace gas observations from a number of research aircraft measurement campaigns during the four-year period 1995-1998. Whenever possible the models were run over the same four-year period and at each simulation time step the instantaneous tracer fields were interpolated to all coinciding observation points. This approach allows for a very close comparison with observations and fully accounts for the specific meteorological conditions during the measurement flights. This is important considering the often limited availability and representativity of such trace gas measurements. A new extensive database including all major research and commercial aircraft measurements between 1995 and 1998, as well as ozone soundings, was established specifically to support this type of direct comparison. Quantitative methods were applied to judge model performance including the calculation of average concentration biases and the visualization of correlations and RMS errors in the form of so-called Taylor diagrams. We present the general concepts applied, the structure and content of the database, and an overall analysis of model skills over four distinct regions. These regions were selected to represent various atmospheric conditions and to cover large geographical domains such that sufficient observations are available for comparison. The comparison of model results with the observations revealed specific problems for each individual model. This study suggests the further improvements needed and serves as a benchmark for re-evaluations of such improvements. In general all models show deficiencies with respect to both mean concentrations and vertical gradients of important trace gases. These include ozone, CO and NOx at the tropopause. Too strong two-way mixing across the tropopause is suggested to be the main reason for differences between simulated and observed CO and ozone values. The generally poor correlations between simulated and measured NOx values suggest that in particular the NOx input by lightning and the convective transport from the polluted boundary layer are still not well described by current parameterizations, which may lead to significant differences in the spatial and seasonal distribution of NOx in the models. Simulated OH concentrations, on the other hand, were found to be in surprisingly good agreement with measured values.

scholarly journals The high Arctic in extreme winters: vortex, temperature, and MLS and ACE-FTS trace gas evolution

2008 ◽  
Vol 8 (3) ◽  
pp. 505-522 ◽  
Author(s):  
G. L. Manney ◽  
W. H. Daffer ◽  
K. B. Strawbridge ◽  
K. A. Walker ◽  
C. D. Boone ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Lower Stratosphere ◽  
High Arctic ◽  
Trace Gas ◽  
Satellite Measurements ◽  
Broadband Emission ◽  
Gas Measurements ◽  
Chemistry Experiment ◽  
Very High ◽  
Good Agreement

Abstract. The first three Arctic winters of the ACE mission represented two extremes of winter variability: Stratospheric sudden warmings (SSWs) in 2004 and 2006 were among the strongest, most prolonged on record; 2005 was a record cold winter. Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Campaigns were conducted at Eureka (80° N, 86° W) during each of these winters. New satellite measurements from ACE-Fourier Transform Spectrometer (ACE-FTS), Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), and Aura Microwave Limb Sounder (MLS), along with meteorological analyses and Eureka lidar temperatures, are used to detail the meteorology in these winters, to demonstrate its influence on transport, and to provide a context for interpretation of ACE-FTS and validation campaign observations. During the 2004 and 2006 SSWs, the vortex broke down throughout the stratosphere, reformed quickly in the upper stratosphere, and remained weak in the middle and lower stratosphere. The stratopause reformed at very high altitude, near 75 km. ACE measurements covered both vortex and extra-vortex conditions in each winter, except in late-February through mid-March 2004 and 2006, when the strong, pole-centered vortex that reformed after the SSWs resulted in ACE sampling only inside the vortex in the middle through upper stratosphere. The 2004 and 2006 Eureka campaigns were during the recovery from the SSWs, with the redeveloping vortex over Eureka. 2005 was the coldest winter on record in the lower stratosphere, but with an early final warming in mid-March. The vortex was over Eureka at the start of the 2005 campaign, but moved away as it broke up. Disparate temperature profile structure and vortex evolution resulted in much lower (higher) temperatures in the upper (lower) stratosphere in 2004 and 2006 than in 2005. Satellite temperatures agree well with lidar data up to 50–60 km, and ACE-FTS, MLS and SABER show good agreement in high-latitude temperatures throughout the winters. Consistent with a strong, cold upper stratospheric vortex and enhanced radiative cooling after the SSWs, MLS and ACE-FTS trace gas measurements show strongly enhanced descent in the upper stratospheric vortex in late January through March 2006 compared to that in 2005.

The thrust measurement system research for combined nozzle in small space

2018 ◽  
Vol 41 (4) ◽  
pp. 1149-1159
Author(s):  
Yonghua Lu ◽  
Jing Li ◽  
Xiang Zhang ◽  
Yang Li
Keyword(s):  
Measurement System ◽  
Force Sensor ◽  
Test Method ◽  
Small Space ◽  
System A ◽  
Calibration Experiment ◽  
Different Types ◽  
Thrust Measurement ◽  
Nozzle Thrust ◽  
Thrust Forces

For measuring the thrust of combined nozzles in satellite thruster with a small space, the test method that the nozzle directly sprays on the load baffle is employed in this paper. The key problem is how to design the positions of 10 load baffles and how to construct the measurement system. A set of complete and automatic nozzle thrust measurement system is designed and built, and the influence of the load baffle applied on the flow field of nozzles is analyzed using the software FLUENT. Furthermore, the load surface locations of the sensors for the different types of nozzles are analyzed. We draw the conclusion that the load baffle position should range from 4–8 mm for the I-type nozzle and range in 6–12 mm for II-type and III-type nozzle. The correction coefficients of the thrust forces for all channels of the measurement system are determined in the calibration experiment. The uncertainty of measurement system is estimated and the error source of the measurement system is traced. We found that the systematic uncertainty is mainly contributed by the A-type uncertainty which is related with the nozzle dimension and its inner structure. The B-type uncertainty of system is contributed by the force sensor.

scholarly journals Boundary Detection and Enhancement of Islanding Operation Investigation Under Fault Condition

2017 ◽  
Author(s):  
Aref Pouryekta ◽  
Vigna K. Ramachandaramurthy ◽  
Sanjeevikumar Padmanaban ◽  
Lucian MIHET-POPA
Keyword(s):  
Distribution Systems ◽  
Dynamic Performance ◽  
Boundary Detection ◽  
Sensitivity Factor ◽  
Voltage Sensitivity ◽  
Autonomous Operation ◽  
System A ◽  
Autonomous Mode ◽  
Dynamic Voltage ◽  
Islanding Operation

Distribution systems can form islands when faults occur. Each island represents a subsection with variable boundaries subject to the location of a fault(s) in the system. A subsection with variable boundaries is referred to as island in this paper. For operation in autonomous mode, it is imperative to detect the island configurations and stabilize these subsections. This paper presents a novel scheme for the detection of islanding boundaries and stabilizing the system during autonomous operation. In the first stage, a boundary detection method is proposed to detect the configuration of the island. In the second stage a dynamic voltage sensitivity factor (DVSF) is proposed to assess the dynamic performance of the system. In the third stage, a wide area load shedding program is adopted based on DVSF to shed the load in weak busbars and stabilize the system. The proposed scheme is validated and tested on a generic 18-bus system using a combination of EMTDC/PSCAD and MATLAB softwares.

Atmospheric trace gas measurements at Palmer Station, Antarctica: 1982?83

1984 ◽  
Vol 2 (1) ◽  
pp. 65-81 ◽  
Author(s):  
E. Robinson ◽  
W. L. Bamesberger ◽  
F. A. Menzia ◽  
A. S. Waylett ◽  
S. F. Waylett
Keyword(s):  
Trace Gas ◽  
Palmer Station ◽  
Gas Measurements ◽  
Atmospheric Trace Gas
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