scholarly journals Intercomparison of in-situ aircraft and satellite aerosol measurements in the stratosphere

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Oscar S. Sandvik ◽  
Johan Friberg ◽  
Bengt G. Martinsson ◽  
Peter F. J. van Velthoven ◽  
Markus Hermann ◽  
...  
Keyword(s):  
Stratospheric Aerosol ◽  
Aerosol Composition ◽  
Tropospheric Aerosol ◽  
Lidar Measurements ◽  
Northern Hemispheric ◽  
Extratropical Tropopause ◽  
Passenger Aircraft ◽  
First Time

Abstract Aerosol composition and optical scattering from particles in the lowermost stratosphere (LMS) have been studied by comparing in-situ aerosol samples from the IAGOS-CARIBIC passenger aircraft with vertical profiles of aerosol backscattering obtained from the CALIOP lidar aboard the CALIPSO satellite. Concentrations of the dominating fractions of the stratospheric aerosol, being sulphur and carbon, have been obtained from post-flight analysis of IAGOS-CARIBIC aerosol samples. This information together with literature data on black carbon concentrations were used to calculate the aerosol backscattering which subsequently is compared with measurements by CALIOP. Vertical optical profiles were taken in an altitude range of several kilometres from and above the northern hemispheric extratropical tropopause for the years 2006-2014. We find that the two vastly different measurement platforms yield different aerosol backscattering, especially close to the tropopause where the influence from tropospheric aerosol is strong. The best agreement is found when the LMS is affected by volcanism, i.e., at elevated aerosol loadings. At background conditions, best agreement is obtained some distance (>2 km) above the tropopause in winter and spring, i.e., at likewise elevated aerosol loadings from subsiding aerosol-rich stratospheric air. This is to our knowledge the first time the CALIPSO lidar measurements have been compared to in-situ long-term aerosol measurements.

scholarly journals Coherence of long-term stratospheric ozone vertical distribution time series used for the study of ozone recovery at a northern mid-latitude station

2011 ◽  
Vol 11 (10) ◽  
pp. 4957-4975 ◽  
Author(s):  
P. J. Nair ◽  
S. Godin-Beekmann ◽  
A. Pazmiño ◽  
A. Hauchecorne ◽  
G. Ancellet ◽  
...  
Keyword(s):  
Time Series ◽  
Stratospheric Ozone ◽  
Stratospheric Aerosol ◽  
Data Sets ◽  
Zero Bias ◽  
Lidar Measurements ◽  
Relative Differences ◽  
Difference Time

Abstract. The coherence of stratospheric ozone time series retrieved from various observational records is investigated at Haute-Provence Observatory (OHP–43.93° N, 5.71° E). The analysis is accomplished through the intercomparison of collocated ozone measurements of Light Detection and Ranging (lidar) with Solar Backscatter UltraViolet(/2) (SBUV(/2)), Stratospheric Aerosol and Gas Experiment II (SAGE~II), Halogen Occultation Experiment (HALOE), Microwave Limb Sounder (MLS) on Upper Atmosphere Research Satellite (UARS) and Aura and Global Ozone Monitoring by Occultation of Stars (GOMOS) satellite observations as well as with in situ ozonesondes and ground-based Umkehr measurements performed at OHP. A detailed statistical study of the relative differences of ozone observations over the whole stratosphere is performed to detect any specific drift in the data. On average, all instruments show their best agreement with lidar at 20–40 km, where deviations are within ±5 %. Discrepancies are somewhat higher below 20 and above 40 km. The agreement with SAGE II data is remarkable since average differences are within ±1 % at 17–41 km. In contrast, Umkehr data underestimate systematically the lidar measurements in the whole stratosphere with a near zero bias at 16–8 hPa (~30 km). Drifts are estimated using simple linear regression for the data sets analysed in this study, from the monthly averaged difference time series. The derived values are less than ±0.5 % yr−1 in the 20–40 km altitude range and most drifts are not significant at the 2σ level. We also discuss the possibilities of extending the SAGE II and HALOE data with the GOMOS and Aura MLS data in consideration with relative offsets and drifts since the combination of such data sets are likely to be used for the study of stratospheric ozone recovery in the future.

scholarly journals Coherence of long-term stratospheric ozone vertical distribution time series used for the study of ozone recovery at a northern mid-latitude station

2010 ◽  
Vol 10 (11) ◽  
pp. 28519-28564
Author(s):  
P. J. Nair ◽  
S. Godin-Beekmann ◽  
A. Pazmiño ◽  
A. Hauchecorne ◽  
G. Ancellet ◽  
...  
Keyword(s):  
Time Series ◽  
Stratospheric Ozone ◽  
Stratospheric Aerosol ◽  
Data Sets ◽  
Zero Bias ◽  
Lidar Measurements ◽  
Relative Differences ◽  
Difference Time

Abstract. The coherence of stratospheric ozone time series retrieved from various observational records is investigated at Haute–Provence Observatory (OHP–43.93° N, 5.71° E). The analysis is accomplished through the intercomparison of collocated ozone measurements of Light Detection and Ranging (lidar) with Solar Backscatter UltraViolet(/2) (SBUV(/2)), Stratospheric Aerosol and Gas Experiment II (SAGE II), Halogen Occultation Experiment (HALOE), Microwave Limb Sounder (MLS) on Upper Atmosphere Research Satellite (UARS) and Aura and Global Ozone Monitoring by Occultation of Stars (GOMOS) satellite observations as well as with in-situ ozonesondes and ground-based Umkehr measurements performed at OHP. A detailed statistical study of the relative differences of ozone observations is performed to detect any specific drifts in the data. On average, all instruments show their best agreement with lidar at 20–40 km, where deviations are within ±5%. Discrepancies are somewhat higher below 20 and above 40 km. The agreement with SAGE II data is remarkable since average differences are within ±1% at 17–41 km. In contrast, Umkehr data underestimate systematically the lidar measurements in the whole stratosphere albeit a near zero bias is observed at 16–8 hPa (~30 km). Drifts are estimated using simple linear regression for the long-term (more than 10 years long) data sets analysed in this study, from the monthly averaged difference time series. The derived values are less than ±0.5% yr−1 in the 20–40 km altitude range and most drifts are not significant at the 2σ level.

The prevalence of meteoric-sulphuric particles within the stratospheric aerosol layer

2021 ◽  
Author(s):  
Graham Mann ◽  
James Brooke ◽  
Kamalika Sengupta ◽  
Lauren Marshall ◽  
Sandip Dhomse ◽  
...  
Keyword(s):  
High Latitude ◽  
Climate Model ◽  
Polar Vortex ◽  
Stratospheric Aerosol ◽  
Light Extinction ◽  
The Arctic ◽  
Aerosol Layer ◽  
Aerosol Composition ◽  
Particle Layer

<p>The widespread presence of meteoric smoke particles (MSPs) within a distinct class of stratospheric aerosol particles has become clear from in-situ measurements in the Arctic, Antarctic and at mid-latitudes.<br> <br>We apply an adapted version of the interactive stratosphere aerosol configuration of the composition-climate model UM-UKCA, to predict the global distribution of meteoric-sulphuric particles nucleated heterogeneously on MSP cores. We compare the UM-UKCA results to new MSP-sulphuric simulations with the European stratosphere-troposphere chemistry-aerosol modelling system IFS-CB05-BASCOE-GLOMAP.</p><p><br>The simulations show a strong seasonal cycle in meteoric-sulphuric particle abundance results from the winter-time source of MSPs transported down into the stratosphere in the polar vortex. Coagulation during downward transport sees high latitude MSP concentrations reduce from ~500 per cm3 at 40km to ~20 per cm3 at 25km, the uppermost extent of the stratospheric aerosol particle layer (the Junge layer).<br> <br>Once within the Junge layer's supersaturated environment, meteoric-sulphuric particles form readily on the MSP cores, growing to 50-70nm dry-diameter (Dp) at 20-25km. Further inter-particle coagulation between these non-volatile particles reduces their number to 1-5 per cc at 15-20km, particle sizes there larger, at Dp ~100nm.</p><p><br>The model predicts meteoric-sulphurics in high-latitude winter comprise >90% of Dp>10nm particles above 25km, reducing to ~40% at 20km, and ~10% at 15km.<br> <br>These non-volatile particle fractions are slightly less than measured from high-altitude aircraft in the lowermost Arctic stratosphere (Curtius et al., 2005; Weigel et al., 2014), and consistent with mid-latitude aircraft measurements of lower stratospheric aerosol composition (Murphy et al., 1998), total particle concentrations  also matching in-situ balloon measurements from Wyoming (Campbell and Deshler, 2014).<br> <br>The MSP-sulphuric interactions also improve agreement with SAGE-II observed stratospheric aerosol extinction in the quiescent 1998-2002 period. <br> <br>Simulations with a factor-8-elevated MSP input form more Dp>10nm meteoric-sulphurics, but the increased number sees fewer growing to Dp ~100nm, the increased MSPs reducing the stratospheric aerosol layer’s light extinction.</p>

Operation and regulation of the lutein epoxide cycle in seedlings of Ocotea foetens

2010 ◽  
Vol 37 (9) ◽  
pp. 859 ◽  
Author(s):  
Raquel Esteban ◽  
Shizue Matsubara ◽  
María Soledad Jiménez ◽  
Domingo Morales ◽  
Patricia Brito ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Higher Plants ◽  
Daily Basis ◽  
Field Conditions ◽  
Photochemical Quenching ◽  
Complete Restoration ◽  
Non Photochemical Quenching ◽  
First Time

Two xanthophyll cycles are present in higher plants: the ubiquitous violaxanthin (V) cycle and the taxonomically restricted lutein epoxide (Lx) cycle. Conversions of V to zeaxanthin (Z) in the first and Lx to lutein (L) in the second happen in parallel under illumination. Unlike the V cycle, in which full epoxidation is completed overnight, in the Lx cycle, this reaction has been described as irreversible on a daily basis in most species (the ‘truncated’ Lx cycle). However, there are some species that display complete restoration of Lx overnight (‘true’ Lx cycle). So far, little is known about the physiological meaning of these two versions of the Lx cycle. Therefore, in the present work, the ‘true’ Lx cycle operation was studied in seedlings of Ocotea foetens (Aiton) Benth. under controlled and field conditions. Complete overnight recovery of the Lx pool in the presence of norfluorazon suggested that the inter-conversions between Lx and L represent a true cycle in this species. Furthermore, Lx responded dynamically to environmental conditions during long-term acclimation. Our data demonstrate the operation of a ‘true’ Lx cycle and, for the first time, its potential involvement in the regulation of non-photochemical quenching in situ. We propose dual regulation of Lx cycle in O. foetens, in which the extent of Lx restoration depends on the intensity and duration of illumination.

scholarly journals Upper tropospheric water vapour and its interaction with cirrus clouds as seen from IAGOS long-term routine in situ observations

2017 ◽  
Vol 200 ◽  
pp. 229-249 ◽  
Author(s):  
Andreas Petzold ◽  
Martina Krämer ◽  
Patrick Neis ◽  
Christian Rolf ◽  
Susanne Rohs ◽  
...  
Keyword(s):  
Water Vapour ◽  
Dynamic Equilibrium ◽  
North Atlantic Ocean ◽  
Global Scale ◽  
Data Set ◽  
Geographical Regions ◽  
Tropopause Region ◽  
Passenger Aircraft

IAGOS (In-service Aircraft for a Global Observing System) performs long-term routinein situobservations of atmospheric chemical composition (O3, CO, NOx, NOy, CO2, CH4), water vapour, aerosols, clouds, and temperature on a global scale by operating compact instruments on board of passenger aircraft. The unique characteristics of the IAGOS data set originate from the global scale sampling on air traffic routes with similar instrumentation such that the observations are truly comparable and well suited for atmospheric research on a statistical basis. Here, we present the analysis of 15 months of simultaneous observations of relative humidity with respect to ice (RHice) and ice crystal number concentration in cirrus (Nice) from July 2014 to October 2015. The joint data set of 360 hours of RHice–Niceobservations in the global upper troposphere and tropopause region is analysed with respect to the in-cloud distribution of RHiceand related cirrus properties. The majority of the observed cirrus is thin withNice< 0.1 cm−3. The respective fractions of all cloud observations range from 90% over the mid-latitude North Atlantic Ocean and the Eurasian Continent to 67% over the subtropical and tropical Pacific Ocean. The in-cloud RHicedistributions do not depend on the geographical region of sampling. Types of cirrus origin (in situorigin, liquid origin) are inferred for differentNiceregimes and geographical regions. Most importantly, we found that in-cloud RHiceshows a strong correlation toNicewith slightly supersaturated dynamic equilibrium RHiceassociated with higherNicevalues in stronger updrafts.

scholarly journals Temporary pause in the growth of atmospheric ethane and propane in 2015–2018

2021 ◽  
Vol 21 (19) ◽  
pp. 15153-15170
Author(s):  
Hélène Angot ◽  
Connor Davel ◽  
Christine Wiedinmyer ◽  
Gabrielle Pétron ◽  
Jashan Chopra ◽  
...  
Keyword(s):  
Organic Aerosols ◽  
Ambient Air ◽  
Potential Contribution ◽  
Emission Inventories ◽  
Sampling Network ◽  
Oil And Natural Gas ◽  
Northern Hemispheric ◽  
Similar Decrease

Abstract. Atmospheric non-methane hydrocarbons (NMHCs) play an important role in the formation of secondary organic aerosols and ozone. After a multidecadal global decline in atmospheric mole fractions of ethane and propane – the most abundant atmospheric NMHCs – previous work has shown a reversal of this trend with increasing atmospheric abundances from 2009 to 2015 in the Northern Hemisphere. These concentration increases were attributed to the unprecedented growth in oil and natural gas (O&amp;NG) production in North America. Here, we supplement this trend analysis building on the long-term (2008–2010; 2012–2020) high-resolution (∼3 h) record of ambient air C2–C7 NMHCs from in situ measurements at the Greenland Environmental Observatory at Summit station (GEOSummit, 72.58 ∘ N, 38.48 ∘ W; 3210 m above sea level). We confirm previous findings that the ethane mole fraction significantly increased by +69.0 [+47.4, +73.2; 95 % confidence interval] ppt yr−1 from January 2010 to December 2014. Subsequent measurements, however, reveal a significant decrease by −58.4 [−64.1, −48.9] ppt yr−1 from January 2015 to December 2018. A similar reversal is found for propane. The upturn observed after 2019 suggests, however, that the pause in the growth of atmospheric ethane and propane might only have been temporary. Discrete samples collected at other northern hemispheric baseline sites under the umbrella of the NOAA cooperative global air sampling network show a similar decrease in 2015–2018 and suggest a hemispheric pattern. Here, we further discuss the potential contribution of biomass burning and O&amp;NG emissions (the main sources of ethane and propane) and conclude that O&amp;NG activities likely played a role in these recent changes. This study highlights the crucial need for better constrained emission inventories.

MORPHODYNAMICS OF THE SHORES OF THE VISTULA SPIT (THE BALTIC SEA) IN A PERIOD OF 2002-2015 BY RESULTS OF IN-SITU MEASUREMENTS

2017 ◽  
Author(s):  
Valentina Bobykina ◽  
Valentina Bobykina ◽  
Boris Chubarenko ◽  
Boris Chubarenko ◽  
Konstantin Karmanov ◽  
...  
Keyword(s):  
Erosion Rate ◽  
The South ◽  
The Baltic Sea ◽  
The North ◽  
Quantitative Characteristics ◽  
The Subject ◽  
The Baltic ◽  
First Time

For the first time, the quantitative characteristics of the Vistula Spit shore dynamics based on the ground-based monitoring data for 2002-2015 were presented. On the sea shore, 3 sections can be distinguished by the direction of coastal processes, i.e. the stable section to the north of the Strait of Baltiysk, the eroded 4-km section to the south of the Strait of Baltiysk, with maximum erosion rate up to 2 m/year; in the remaining area of the Spit (21 km) to the Polish border there is an alternation of stable, eroded and accumulative areas. Since 2011, a steady erosion (in the stable segments of the third section) and general weakening of the erosion rate (in the second section) have been recorded. 50% of the length of the lagoon shore was the subject to annual active erosion (0.2 - 1.4 m/year). The beaches of the sea and lagoon shores of the Vistula Spit were mainly composed of medium sands. The alongshore variability in particle size distribution on the sea and lagoon shores (according to the 2015 survey data) actually fail to correlate with long-term dynamic processes, with the exception of the steadily eroded 4-kilometer area on the sea coast to the south of the Strait of Baltiysk. Variations in the composition of sediment along the shore on the shoreline are most likely associated with the results of the latest wave processing (or storm processing and eolian transport in the case of an average beach sample).

Abandonment Solution for Wells With Gauge Cables: An Engineered Self-Sealing Cement System

2021 ◽  
Author(s):  
Anton Rublevskyi ◽  
Carl Johnson ◽  
Chuang Hwee Tay ◽  
Darren Main ◽  
Axle Herrera
Keyword(s):  
Simulation Software ◽  
Fluid Simulation ◽  
Cost Cutting ◽  
Ability To Regenerate ◽  
Well Abandonment ◽  
First Time ◽  
Safety And Environment ◽  
Production Tubing

Abstract With an increasing number of wells transitioning to their abandonment stages, associated operational efficiency and cost cutting have become a major focus in the industry. An operator had an objective to permanently abandon an offshore well that was suspended in 2016. The key challenge was to develop a long-term well abandonment solution leaving the completion tubing and gauge cables in the well. All the associated operations had to be completed utilizing a lightweight well intervention vessel. Traditionally, retrieving the entire 5 ½-in. production tubing during plug and abandonment operations has added operational complexity and costs, which increases the risk of exposure to health, safety, and environment (HSE) hazards. Alternatively, a sealant technique placing cement through and around the completion tubing with gauge cables in situ exists. However, this technique is associated with a heightened risk of leak path development over time. Ongoing experimental work suggested that enhancements to the conventional cement sealant systems are beneficial to improve long-term sealing; thus, an active self-sealing cement (SSC) system that would seal microannuli or small fissures around the tubing and gauge cables was designed. The set cement sealant characteristics include low Young’s modulus to resist failure from wellbore stresses and the ability to regenerate the original seal upon contact with any hydrocarbons that may seep through any isolation defects through the life of the abandoned well. To achieve proper cement placement, advanced fluid simulation software and carefully tailored fluid density and rheology profiles were used. During the operation, a plug of the SSC sealant was pumped through the production tubing and squeezed into the perforations to create a permanent barrier across the reservoir section. Next, a mechanical plug was set inside the production tubing to isolate the lower section, and the tubing was perforated to provide access to the A-annulus above; subsequently, a balanced plug of SSC system was spotted above. After 30 hours, the plug passed a 3.4-MPa [500-psi] verification pressure test. The operator estimated the operation saved 2 to 3 days of rig time, valued at approximately GBP 400,000 to 600,000. The operator also avoided the risk of leaving the well on long-term suspension with mechanical plugs while waiting for a rig to complete the isolation, and the operation minimized the number of intervention steps required for abandonment, thereby limiting scope growth. Operators are constantly looking for ways to increase reliability, improve efficiency, and minimize risks; and therefore, abandonment techniques are evolving. The developed solution is a novel and robust alternative to conventional well abandonment using an advanced cement sealant technology for the first time and an innovative placement technique.

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