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

2019 ◽  
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 sub-micron 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 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 Aircraft measurements of gravity waves in the upper troposphere and lower stratosphere during the START08 field experiment

2015 ◽  
Vol 15 (13) ◽  
pp. 7667-7684 ◽  
Author(s):  
Fuqing Zhang ◽  
Junhong Wei ◽  
Meng Zhang ◽  
K. P. Bowman ◽  
L. L. Pan ◽  
...  
Keyword(s):  
Power Law ◽  
Gravity Waves ◽  
Lower Stratosphere ◽  
Potential Temperature ◽  
Shear Instability ◽  
Aircraft Measurements ◽  
Upper Troposphere ◽  
Airborne Measurements ◽  
Wide Range

Abstract. This study analyzes in situ airborne measurements from the 2008 Stratosphere–Troposphere Analyses of Regional Transport (START08) experiment to characterize gravity waves in the extratropical upper troposphere and lower stratosphere (ExUTLS). The focus is on the second research flight (RF02), which took place on 21–22 April 2008. This was the first airborne mission dedicated to probing gravity waves associated with strong upper-tropospheric jet–front systems. Based on spectral and wavelet analyses of the in situ observations, along with a diagnosis of the polarization relationships, clear signals of mesoscale variations with wavelengths ~ 50–500 km are found in almost every segment of the 8 h flight, which took place mostly in the lower stratosphere. The aircraft sampled a wide range of background conditions including the region near the jet core, the jet exit and over the Rocky Mountains with clear evidence of vertically propagating gravity waves of along-track wavelength between 100 and 120 km. The power spectra of the horizontal velocity components and potential temperature for the scale approximately between ~ 8 and ~ 256 km display an approximate −5/3 power law in agreement with past studies on aircraft measurements, while the fluctuations roll over to a −3 power law for the scale approximately between ~ 0.5 and ~ 8 km (except when this part of the spectrum is activated, as recorded clearly by one of the flight segments). However, at least part of the high-frequency signals with sampled periods of ~ 20–~ 60 s and wavelengths of ~ 5–~ 15 km might be due to intrinsic observational errors in the aircraft measurements, even though the possibilities that these fluctuations may be due to other physical phenomena (e.g., nonlinear dynamics, shear instability and/or turbulence) cannot be completely ruled out.

scholarly journals The aerosol-climate model ECHAM5-HAM

2005 ◽  
Vol 5 (4) ◽  
pp. 1125-1156 ◽  
Author(s):  
P. Stier ◽  
J. Feichter ◽  
S. Kinne ◽  
S. Kloster ◽  
E. Vignati ◽  
...  
Keyword(s):  
Size Distribution ◽  
Climate Model ◽  
Normal Modes ◽  
Anthropogenic Activity ◽  
Climate Modelling ◽  
Extensive Evaluation ◽  
Wide Range ◽  
Log Normal ◽  
Year 2000

Abstract. The aerosol-climate modelling system ECHAM5-HAM is introduced. It is based on a flexible microphysical approach and, as the number of externally imposed parameters is minimised, allows the application in a wide range of climate regimes. ECHAM5-HAM predicts the evolution of an ensemble of microphysically interacting internally- and externally-mixed aerosol populations as well as their size-distribution and composition. The size-distribution is represented by a superposition of log-normal modes. In the current setup, the major global aerosol compounds sulfate (SU), black carbon (BC), particulate organic matter (POM), sea salt (SS), and mineral dust (DU) are included. The simulated global annual mean aerosol burdens (lifetimes) for the year 2000 are for SU: 0.80 Tg(S) (3.9 days), for BC: 0.11 Tg (5.4 days), for POM: 0.99 Tg (5.4 days), for SS: 10.5 Tg (0.8 days), and for DU: 8.28 Tg (4.6 days). An extensive evaluation with in-situ and remote sensing measurements underscores that the model results are generally in good agreement with observations of the global aerosol system. The simulated global annual mean aerosol optical depth (AOD) is with 0.14 in excellent agreement with an estimate derived from AERONET measurements (0.14) and a composite derived from MODIS-MISR satellite retrievals (0.16). Regionally, the deviations are not negligible. However, the main patterns of AOD attributable to anthropogenic activity are reproduced.

scholarly journals Weaker cooling by aerosols due to dust–pollution interactions

2020 ◽  
Vol 20 (23) ◽  
pp. 15285-15295
Author(s):  
Klaus Klingmüller ◽  
Vlassis A. Karydis ◽  
Sara Bacer ◽  
Georgiy L. Stenchikov ◽  
Jos Lelieveld
Keyword(s):  
Atmospheric Chemistry ◽  
Climate Model ◽  
Cloud Condensation Nuclei ◽  
Radiative Effect ◽  
Dust Pollution ◽  
Aerosol Composition ◽  
Anthropogenic Aerosol ◽  
Aerosol Forcing ◽  
Condensed Water ◽  
Chemical Ageing

Abstract. The interactions between aeolian dust and anthropogenic air pollution, notably chemical ageing of mineral dust and coagulation of dust and pollution particles, modify the atmospheric aerosol composition and burden. Since the aerosol particles can act as cloud condensation nuclei, this affects the radiative transfer not only directly via aerosol–radiation interactions, but also indirectly through cloud adjustments. We study both radiative effects using the global ECHAM/MESSy atmospheric chemistry-climate model (EMAC) which combines the Modular Earth Submodel System (MESSy) with the European Centre/Hamburg (ECHAM) climate model. Our simulations show that dust–pollution–cloud interactions reduce the condensed water path and hence the reflection of solar radiation. The associated climate warming outweighs the cooling that the dust–pollution interactions exert through the direct radiative effect. In total, this results in a net warming by dust–pollution interactions which moderates the negative global anthropogenic aerosol forcing at the top of the atmosphere by (0.2 ± 0.1) W m−2.

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 Linking Meteorology, Turbulence, and Air Chemistry in the Amazon Rain Forest

2016 ◽  
Vol 97 (12) ◽  
pp. 2329-2342 ◽  
Author(s):  
Jose D. Fuentes ◽  
Marcelo Chamecki ◽  
Rosa Maria Nascimento dos Santos ◽  
Celso Von Randow ◽  
Paul C. Stoy ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Surface Layer ◽  
Vertical Distribution ◽  
Rain Forest ◽  
Forest Canopy ◽  
Cloud Condensation Nuclei ◽  
Chemical Species ◽  
Chemical Transformations ◽  
Condensation Nuclei ◽  
The Vertical Distribution

Abstract We describe the salient features of a field study whose goals are to quantify the vertical distribution of plant-emitted hydrocarbons and their contribution to aerosol and cloud condensation nuclei production above a central Amazonian rain forest. Using observing systems deployed on a 50-m meteorological tower, complemented with tethered balloon deployments, the vertical distribution of hydrocarbons and aerosols was determined under different boundary layer thermodynamic states. The rain forest emits sufficient reactive hydrocarbons, such as isoprene and monoterpenes, to provide precursors of secondary organic aerosols and cloud condensation nuclei. Mesoscale convective systems transport ozone from the middle troposphere, enriching the atmospheric boundary layer as well as the forest canopy and surface layer. Through multiple chemical transformations, the ozone-enriched atmospheric surface layer can oxidize rain forest–emitted hydrocarbons. One conclusion derived from the field studies is that the rain forest produces the necessary chemical species and in sufficient amounts to undergo oxidation and generate aerosols that subsequently activate into cloud condensation nuclei.

scholarly journals Vertical movements of “escaped” farmed Atlantic salmon (Salmo salar L.)—a simulation study in a western Norwegian fjord

2009 ◽  
Vol 66 (2) ◽  
pp. 278-288 ◽  
Author(s):  
Ove T. Skilbrei ◽  
Jens Christian Holst ◽  
Lars Asplin ◽  
Marianne Holm
Keyword(s):  
Atlantic Salmon ◽  
Vertical Distribution ◽  
Salmo Salar ◽  
Simulation Study ◽  
Vertical Movements ◽  
Atlantic Salmon Salmo Salar ◽  
Wide Range ◽  
Norwegian Fjord ◽  
Farmed Atlantic Salmon ◽  
The Vertical Distribution

Abstract Skilbrei, O. T., Holst, J. C., Asplin, L., and Holm, M. 2009. Vertical movements of “escaped” farmed Atlantic salmon (Salmo salar L.)—a simulation study in a western Norwegian fjord. – ICES Journal of Marine Science, 66: 278–288. To study the vertical distribution of fish that had been allowed to escape, farmed Atlantic salmon were tagged with acoustic tags equipped with depth sensors, and then released on five different dates in the course of a year from two fish farms in the Hardanger Fjord in western Norway. Release stimulated the fish to dive to deeper than 15 m during the first hours or days post-release, often down to 50–80 m. However, during the following 4 weeks, most of the escapees spent most of their time above the pycnocline at depths of 0–4 m. The fish were more widely distributed in the water column after release during winter, but still spent most of the time in the cold surface layers. There was a wide range in the vertical distribution of individual fish, and the proportion of detections below 14-m depth ranged from 0 to 90%. There was a significant diurnal cycle in all seasons except midsummer, when the fish were less abundant in the upper layer during daylight, especially on brighter days. The results suggest that salmon diving activity following escape may complicate the recapture of escaped fish at the farm site but that the subsequent tendency of most fish to stay near the surface, virtually irrespective of the time of year, may facilitate recapture.

scholarly journals Influence of the Arctic Oscillation on the Vertical Distribution of Wintertime Ozone in the Stratosphere and Upper Troposphere over the Northern Hemisphere

2017 ◽  
Vol 30 (8) ◽  
pp. 2905-2919 ◽  
Author(s):  
Jiankai Zhang ◽  
Fei Xie ◽  
Wenshou Tian ◽  
Yuanyuan Han ◽  
Kequan Zhang ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Northern Hemisphere ◽  
Arctic Oscillation ◽  
Stratospheric Ozone ◽  
The Arctic ◽  
Upper Troposphere ◽  
Eddy Transport ◽  
The Arctic Oscillation ◽  
The Vertical Distribution ◽  
Middle Stratosphere

The influence of the Arctic Oscillation (AO) on the vertical distribution of stratospheric ozone in the Northern Hemisphere in winter is analyzed using observations and an offline chemical transport model. Positive ozone anomalies are found at low latitudes (0°–30°N) and there are three negative anomaly centers in the northern mid- and high latitudes during positive AO phases. The negative anomalies are located in the Arctic middle stratosphere (~30 hPa; 70°–90°N), Arctic upper troposphere–lower stratosphere (UTLS; 150–300 hPa, 70°–90°N), and midlatitude UTLS (70–300 hPa, 30°–60°N). Further analysis shows that anomalous dynamical transport related to AO variability primarily controls these ozone changes. During positive AO events, positive ozone anomalies between 0° and 30°N at 50–150 hPa are related to the weakened meridional transport of the Brewer–Dobson circulation (BDC) and enhanced eddy transport. The negative ozone anomalies in the Arctic middle stratosphere are also caused by the weakened BDC, while the negative ozone anomalies in the Arctic UTLS are caused by the increased tropopause height, weakened BDC vertical transport, weaker exchange between the midlatitudes and the Arctic, and enhanced ozone depletion via heterogeneous chemistry. The negative ozone anomalies in the midlatitude UTLS are mainly due to enhanced eddy transport from the midlatitudes to the latitudes equatorward of 30°N, while the transport of ozone-poor air from the Arctic to the midlatitudes makes a minor contribution. Interpreting AO-related variability of stratospheric ozone, especially in the UTLS, would be helpful for the prediction of tropospheric ozone variability caused by the AO.

Vertical Distributions in Number of Soil Microorganism with Caragana in the Hobq of Inner Mongolia

2014 ◽  
Vol 955-959 ◽  
pp. 3581-3585
Author(s):  
Xiao Tong Wu ◽  
Ya Ting Dai ◽  
Yu Qin Shao ◽  
Jia Yin Lu ◽  
Miao Miao Hou
Keyword(s):  
Organic Matter ◽  
Vertical Distribution ◽  
Inner Mongolia ◽  
Soil Microorganisms ◽  
Soil Microorganism ◽  
Aerobic Bacteria ◽  
Vertical Distributions ◽  
The Vertical Distribution

The study investigated the vertical distribution of soil microorganism on Caragana rhizosphere at Hobq of ORDOS. The result showed that microbial vertical distribution was obvious. The order of vertical distribution in number of aerobic bacteria were 0-10cm>20-30cm>10-20cm>30-40cm, and there were significant differences between microorganisms in 0-10cm, 10-20cm and 30-40cm underground; the number of aerobic bacteria in 0-10cm underground was higher than 10-20cm, 20-30cm and 30-40cm by 1.48,1.41 and 1.86. The order of vertical distribution in number of fungi were 0-10cm>10-20cm>20-30cm>30-40cm, and there were significant differences between 0-10 cm and 20-30cm、30-40cm, and between 10-20 cm and 20-30cm、30-40cm. the number of fungi in 0-10cm underground was higher than 10-20cm, 20-30cm and 30-40cm by 1.01, 3.60 and 5.37. The order of vertical distribution in number of Actinomycetes was 0-10cm>10-20cm>20-30cm>30-40cm, and the differences between 0-10 cm and 10-20cm, 20-30cm, 30-40cm were significant; the number of Actinomycetes in 0-10cm underground was higher than 10-20cm, 20-30cm and 30-40cm by 1.54,1.66 and 2.60. The distribution and quantity of soil microorganisms might be influenced by organic matter contents.

scholarly journals Processes controlling the vertical aerosol distribution in marine stratocumulus regions – a sensitivity study using the climate model NorESM1-M

2021 ◽  
Vol 21 (1) ◽  
pp. 577-595
Author(s):  
Lena Frey ◽  
Frida A.-M. Bender ◽  
Gunilla Svensson
Keyword(s):  
Vertical Distribution ◽  
Radiative Forcing ◽  
Climate Model ◽  
Cloud Microphysics ◽  
Aerosol Extinction ◽  
Shallow Convection ◽  
Marine Stratocumulus ◽  
Aerosol Emission ◽  
Aerosol Distribution ◽  
The Vertical Distribution

Abstract. The vertical distribution of aerosols plays an important role in determining the effective radiative forcing from aerosol–radiation and aerosol–cloud interactions. Here, a number of processes controlling the vertical distribution of aerosol in five subtropical marine stratocumulus regions in the climate model NorESM1-M are investigated, with a focus on the total aerosol extinction. A comparison with satellite lidar data (CALIOP, Cloud–Aerosol Lidar with Orthogonal Polarization) shows that the model underestimates aerosol extinction throughout the troposphere, especially elevated aerosol layers in the two regions where they are seen in observations. It is found that the shape of the vertical aerosol distribution is largely determined by the aerosol emission and removal processes in the model, primarily through the injection height, emitted particle size, and wet scavenging. In addition, the representation of vertical transport related to shallow convection and entrainment is found to be important, whereas alterations in aerosol optical properties and cloud microphysics parameterizations have smaller effects on the vertical aerosol extinction distribution. However, none of the alterations made are sufficient for reproducing the observed vertical distribution of aerosol extinction, neither in magnitude nor in shape. Interpolating the vertical levels of CALIOP to the corresponding model levels leads to better agreement in the boundary layer and highlights the importance of the vertical resolution.

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