scholarly journals On measurements of aerosol-gas composition of the atmosphere during two expeditions in 2013 along the Northern Sea Route

2015 ◽  
Vol 15 (21) ◽  
pp. 12413-12443 ◽  
Author(s):  
S. M. Sakerin ◽  
A. A. Bobrikov ◽  
O. A. Bukin ◽  
L. P. Golobokova ◽  
Vas. V. Pol'kin ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Black Carbon ◽  
Far East ◽  
Japan Sea ◽  
Water Soluble ◽  
The Arctic ◽  
Layer Height ◽  
Boundary Layer Height ◽  
The Japan Sea ◽  
Carbon Mass

Abstract. We presented the results of expedition measurements of the set of physical-chemical characteristics of atmospheric aerosol in areas of the Arctic and Far East seas, performed onboard RV Akademik Fedorov (17 August–22 September 2013) and RV Professor Khljustin (24 July–7 September 2013). The specific features of spatial distribution and time variations of aerosol optical depth (AOD) of the atmosphere in the wavelength range of 0.34–2.14 μm and boundary layer height, aerosol and black carbon mass concentrations, and disperse and chemical composition of aerosol are discussed. Over the Arctic Ocean (on the route of RV Akademik Fedorov) there is a decrease in aerosol and black carbon concentrations in a northeastern direction: higher values were observed in the region of Spitsbergen and near the Kola Peninsula; and minimum values were observed at northern margins of the Laptev Sea. Average AOD (0.5 μm) values in this remote region were 0.03; the aerosol and black carbon mass concentrations were 875 and 22 ng m−3, respectively. The spatial distributions of most aerosol characteristics over Far East seas show their latitudinal decrease in the northern direction. On transit of RV Professor Khljustin from the Japan Sea to the Chukchi Sea, the aerosol number concentration decreased on average from 23.7 to 2.5 cm−3, the black carbon mass concentration decreased from 150 to 50 ng m−3, and AOD decreased from 0.19 to 0.03. We analyzed the variations in the boundary layer height, measured by ship-based lidar: the average value was 520 m, and the maximal value was 1200 m. In latitudinal distribution of the boundary layer height, there is a characteristic minimum at a latitude of ~ 55° N. For water basins of eight seas, we present the chemical compositions of the water-soluble aerosol fraction (ions, elements) and small gas-phase species, as well as estimates of their vertical fluxes. It is shown that substances are mainly (75–89 %) supplied from the atmosphere to the sea surface together with gas-phase species. The deposited ions account for from 11 to 24.5 %, and trace elements account for 0.2–0.4 % of the total sum of water-soluble components. The average vertical fluxes of aerosol substance are a factor of 4–7 larger in the Japan Sea than in the water basins of Arctic seas.

scholarly journals On measurements of aerosol–gas composition of the atmosphere during two expeditions in 2013 along Northern Sea Route

2015 ◽  
Vol 15 (12) ◽  
pp. 16775-16859
Author(s):  
S. M. Sakerin ◽  
A. A. Bobrikov ◽  
O. A. Bukin ◽  
L. P. Golobokova ◽  
Vas. V. Pol'kin ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Black Carbon ◽  
Far East ◽  
Water Soluble ◽  
The Arctic ◽  
Layer Height ◽  
Boundary Layer Height ◽  
Vertical Fluxes ◽  
Carbon Mass ◽  
Mass Concentrations

Abstract. We presented the results of expedition measurements of the set of physical-chemical characteristics of atmospheric aerosol in water basins of Arctic and Far East seas, performed onboard RV Akademik Fedorov (17 August–22 September 2013) and RV Professor Khljustin (24 July–7 September 2013). The specific features of spatial distribution and time variations of aerosol optical depth (AOD) of the atmosphere in the wavelength range of 0.34–2.14 μm and boundary layer height, aerosol and black carbon mass concentrations, and disperse and chemical composition of aerosol are discussed. Over the Arctic Ocean (on the route of RV Akademik Fedorov) there is a decrease in aerosol and black carbon concentrations in northeastern direction: higher values were observed in the region of Spitsbergen and near the Kola Peninsula; and minimum values were observed at northern margins of the Laptev Sea. Average AOD (0.5 μm) values in this remote region were 0.03; the aerosol and black carbon mass concentrations were 875 and 22 ng m-3, respectively. The spatial distributions of most aerosol characteristics over Far East seas show their latitudinal decrease in the northern direction. On transit of RV Professor Khljustin from Japan to Chukchi Sea, the aerosol number concentration decreased, on the average, from 23.7 to 2.5 cm-3, the black carbon mass concentration decreased from 150 to 50 ng m-3, and AOD decreased from 0.19 to 0.03. We analyzed the variations in the boundary layer height, measured by ship-based lidar: the average value was 520 m, and the maximal value was 1200 m. In latitudinal distribution of the boundary layer height, there is a characteristic minimum at latitude of ∼ 55° N. For water basins of eight seas, we present the chemical compositions of water-soluble aerosol fraction (ions, elements) and small gaseous impurities, as well as estimates of their vertical fluxes. It is shown that substances are mainly (75–89 %) supplied from the atmosphere to the sea surface together with small gaseous impurities. The deposited ions account for from 11 to 24.5 %, and trace elements account for 0.2–0.4 %. The average vertical fluxes of aerosol substance are a factor of 4–7 larger in the Japan Sea than in the water basins of Arctic seas.

scholarly journals Planetary Boundary Layer Heights from Cruises in Spring to Autumn Chukchi-Beaufort Sea Compared with ERA5

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1398
Author(s):  
Mingyi Gu ◽  
G. W. K. Moore ◽  
Kevin Wood ◽  
Zhaomin Wang
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Seasonal Changes ◽  
Lower Atmosphere ◽  
The Arctic ◽  
Radiosonde Data ◽  
Planetary Boundary Layer Height ◽  
Layer Height ◽  
Surface Warming ◽  
Boundary Layer Height

The planetary boundary layer height (PBLH) is a diagnostic field related to the effective heat capacity of the lower atmosphere, both stable and convective, and it constrains motion in this layer as well as impacts surface warming. Here, we used radiosonde data from five icebreaker cruises to the Chukchi and Beaufort Seas during both spring and fall to derive PBLH using the bulk Ri method, which were then compared with results from ERA5 reanalysis. The ERA5 PBLH was similar to but slightly lower than the ship observations. Clear and consistent seasonal changes were found in both the observations and the reanalysis: PBLH decreased from mid-May to mid-June and subsequently increased after August. The comparison with ERA5 shows that, besides surface temperature, biases in PBLH are also a function of wind direction, suggesting that the availability of upwind observations is also important in representing processes active in the boundary layer over the Arctic Ocean.

scholarly journals Long term effects on regional European boreal climate due to structural vegetation changes

2014 ◽  
Vol 11 (11) ◽  
pp. 15507-15547 ◽  
Author(s):  
J. H. Rydsaa ◽  
F. Stordal ◽  
L. M. Tallaksen
Keyword(s):  
Boundary Layer ◽  
Boreal Forest ◽  
Surface Fluxes ◽  
Energy Partitioning ◽  
The Arctic ◽  
Vegetation Changes ◽  
Near Surface ◽  
Layer Height ◽  
Boundary Layer Height ◽  
Surface Atmosphere

Abstract. Amplified warming at high latitudes over the past decades has led to changes in the boreal and arctic climate system, such as structural changes in high latitude ecosystems and soil moisture properties. These changes trigger land-atmosphere feedbacks, through altered energy partitioning in response to changes in albedo and surface water fluxes. Local scale changes in the arctic and boreal zone may propagate to affect large scale climatic features. In this study, MODIS land surface data are used with the Weather Research and Forecasting model (WRF V3.5.1) and Noah LSM, in a series of experiments to simulate the influence of structural vegetation changes over a Northern European boreal ecosystem. Emphasis is placed on surface energy partitioning and near surface atmospheric variables, in order to investigate changes in atmospheric response due to observed and anticipated structural vegetation changes. We find that a northward migration of evergreen needle leaf forest into tundra regions causes an increase in latent rather than sensible heat fluxes, increased near surface temperatures and boundary layer height. Shrub expansion in tundra areas has only small effects on surface fluxes. However, it influences near surface wind speeds and boundary layer height. Northward migration of mixed forest across the present southern border of the boreal forest has largely opposite effects on surface fluxes and the near surface atmosphere, and acts to moderate the overall mean regional effects of boreal forest migration on the near surface atmosphere.

scholarly journals Technical note: Boundary layer height determination from Lidar for improving air pollution episode modelling: development of new algorithm and evaluation

2017 ◽  
Author(s):  
Ting Yang ◽  
Zifa Wang ◽  
Wei Zhang ◽  
Alex Gbaguidi ◽  
Nubuo Sugimoto ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Pollution ◽  
High Performance ◽  
Accurate Determination ◽  
Technical Note ◽  
Strong Increase ◽  
Layer Height ◽  
Boundary Layer Height ◽  
Retrieval Algorithms ◽  
The Impact

Abstract. Predicting air pollution events in low atmosphere over megacities requires thorough understanding of the tropospheric dynamic and chemical processes, involving notably, continuous and accurate determination of the boundary layer height (BLH). Through intensive observations experimented over Beijing (China), and an exhaustive evaluation existing algorithms applied to the BLH determination, persistent critical limitations are noticed, in particular over polluted episodes. Basically, under weak thermal convection with high aerosol loading, none of the retrieval algorithms is able to fully capture the diurnal cycle of the BLH due to pollutant insufficient vertical mixing in the boundary layer associated with the impact of gravity waves on the tropospheric structure. Subsequently, a new approach based on gravity wave theory (the cubic root gradient method: CRGM), is developed to overcome such weakness and accurately reproduce the fluctuations of the BLH under various atmospheric pollution conditions. Comprehensive evaluation of CRGM highlights its high performance in determining BLH from Lidar. In comparison with the existing retrieval algorithms, the CRGM potentially reduces related computational uncertainties and errors from BLH determination (strong increase of correlation coefficient from 0.44 to 0.91 and significant decrease of the root mean square error from 643 m to 142 m). Such newly developed technique is undoubtedly expected to contribute to improve the accuracy of air quality modelling and forecasting systems.

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