The first comprehensive experiment for determining parameters of the vertical distribution of methane in the troposphere over Western Siberia from solar spectra recorded with an IFS-125M FTIR spectrometer and in situ aircraft measurements

2020 ◽  
Keyword(s):  
Vertical Distribution ◽  
Western Siberia ◽  
Aircraft Measurements ◽  
Ftir Spectrometer ◽  
The Vertical Distribution

scholarly journals The vertical distribution of biomass burning pollution over tropical South America from aircraft in situ measurements during SAMBBA

2019 ◽  
Vol 19 (9) ◽  
pp. 5771-5790 ◽  
Author(s):  
Eoghan Darbyshire ◽  
William T. Morgan ◽  
James D. Allan ◽  
Dantong Liu ◽  
Michael J. Flynn ◽  
...  
Keyword(s):  
Air Quality ◽  
South America ◽  
Vertical Distribution ◽  
Biomass Burning ◽  
Mixing Layer ◽  
Free Troposphere ◽  
The West ◽  
The Vertical Distribution ◽  
Tropical South America

Abstract. We examine processes driving the vertical distribution of biomass burning pollution following an integrated analysis of over 200 pollutant and meteorological profiles measured in situ during the South AMerican Biomass Burning Analysis (SAMBBA) field experiment. This study will aid future work examining the impact of biomass burning on weather, climate and air quality. During the dry season there were significant contrasts in the composition and vertical distribution of haze between western and eastern regions of tropical South America. Owing to an active or residual convective mixing layer, the aerosol abundance was similar from the surface to ∼1.5 km in the west and ∼3 km in the east. Black carbon mass loadings were double as much in the east (1.7 µg m−3) than the west (0.85 µg m−3), but aerosol scattering coefficients at 550 nm were similar (∼120 Mm−1), as too were CO near-surface concentrations (310–340 ppb). We attribute these contrasts to the more flaming combustion of Cerrado fires in the east and more smouldering combustion of deforestation and pasture fires in the west. Horizontal wind shear was important in inhibiting mixed layer growth and plume rise, in addition to advecting pollutants from the Cerrado regions into the remote tropical forest of central Amazonia. Thin layers above the mixing layer indicate the roles of both plume injection and shallow moist convection in delivering pollution to the lower free troposphere. However, detrainment of large smoke plumes into the upper free troposphere was very infrequently observed. Our results reiterate that thermodynamics control the pollutant vertical distribution and thus point to the need for correct model representation so that the spatial distribution and vertical structure of biomass burning smoke is captured. We observed an increase of aerosol abundance relative to CO with altitude both in the background haze and plume enhancement ratios. It is unlikely associated with thermodynamic partitioning, aerosol deposition or local non-fire sources. We speculate it may be linked to long-range transport from West Africa or fire combustion efficiency coupled to plume injection height. Further enquiry is required to explain the phenomenon and explore impacts on regional climate and air quality.

scholarly journals Vertical Distribution of Arctic Methane in 2009–2018 Using Ground-Based Remote Sensing

2020 ◽  
Vol 12 (6) ◽  
pp. 917
Author(s):  
Tomi Karppinen ◽  
Otto Lamminpää ◽  
Simo Tukiainen ◽  
Rigel Kivi ◽  
Pauli Heikkinen ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Vertical Distribution ◽  
Atmospheric Chemistry ◽  
Polar Vortex ◽  
The Arctic ◽  
Fourier Transform Spectrometer ◽  
Atmospheric Methane ◽  
The Vertical Distribution ◽  
Chemistry Experiment

We analyzed the vertical distribution of atmospheric methane (CH 4 ) retrieved from measurements by ground-based Fourier Transform Spectrometer (FTS) instrument in Sodankylä, Northern Finland. The retrieved dataset covers 2009–2018. We used a dimension reduction retrieval method to extract the profile information, since each measurement contains around three pieces of information about the profile shape between 0 and 40 km. We compared the retrieved profiles against Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) satellite measurements and AirCore balloon-borne profile measurements. Additional comparison at the lowest tropospheric layer was done against in-situ measurements from a 50-m-high mast. In general, the ground-based FTS and ACE-FTS profiles agreed within 10% below 20 km and within 30% in the stratosphere between 20 and 40 km. Our method was able to accurately capture reduced methane concentrations inside the polar vortex in the Arctic stratosphere. The method produced similar trend characteristics as the reference instruments even when a static prior profile was used. Finally, we analyzed the time series of the CH 4 profile datasets and estimated the trend using the dynamic linear model (DLM).

scholarly journals In situ constraints on the vertical distribution of global aerosol

2019 ◽  
Vol 19 (18) ◽  
pp. 11765-11790 ◽  
Author(s):  
Duncan Watson-Parris ◽  
Nick Schutgens ◽  
Carly Reddington ◽  
Kirsty J. Pringle ◽  
Dantong Liu ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Climate Model ◽  
Cloud Condensation Nuclei ◽  
Upper Troposphere ◽  
Aerosol Forcing ◽  
Wide Range ◽  
Vertical Distributions ◽  
The Vertical Distribution ◽  
Unique Dataset

Abstract. Despite ongoing efforts, the vertical distribution of aerosols globally is poorly understood. This in turn leads to large uncertainties in the contributions of the direct and indirect aerosol forcing on climate. Using the Global Aerosol Synthesis and Science Project (GASSP) database – the largest synthesised collection of in situ aircraft measurements currently available, with more than 1000 flights from 37 campaigns from around the world – we investigate the vertical structure of submicron aerosols across a wide range of regions and environments. The application of this unique dataset to assess the vertical distributions of number size distribution and cloud condensation nuclei (CCN) in the global aerosol–climate model ECHAM-HAM reveals that the model underestimates accumulation-mode particles in the upper troposphere, especially in remote regions. The processes underlying this discrepancy are explored using different aerosol microphysical schemes and a process sensitivity analysis. These show that the biases are predominantly related to aerosol ageing and removal rather than emissions.

scholarly journals Reverse engineering field-derived vertical distribution profiles to infer larval swimming behaviors

2019 ◽  
pp. 201900238 ◽  
Author(s):  
M. K. James ◽  
J. A. Polton ◽  
A. R. Brereton ◽  
K. L. Howell ◽  
W. A. M. Nimmo-Smith ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
State Of The Art ◽  
Distribution Patterns ◽  
Environmental Cues ◽  
Biophysical Models ◽  
Marine Larvae ◽  
In Situ Observations ◽  
The Vertical Distribution ◽  
Larval Swimming

Biophysical models are well-used tools for predicting the dispersal of marine larvae. Larval behavior has been shown to influence dispersal, but how to incorporate behavior effectively within dispersal models remains a challenge. Mechanisms of behavior are often derived from laboratory-based studies and therefore, may not reflect behavior in situ. Here, using state-of-the-art models, we explore the movements that larvae must undertake to achieve the vertical distribution patterns observed in nature. Results suggest that behaviors are not consistent with those described under the tidally synchronized vertical migration (TVM) hypothesis. Instead, we show (i) a need for swimming speed and direction to vary over the tidal cycle and (ii) that, in some instances, larval swimming cannot explain observed vertical patterns. We argue that current methods of behavioral parameterization are limited in their capacity to replicate in situ observations of vertical distribution, which may cause dispersal error to propagate over time, due to advective differences over depth and demonstrate an alternative to laboratory-based behavioral parameterization that encompasses the range of environmental cues that may be acting on planktic organisms.

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