scholarly journals Ground-based lidar measurements from Ny-Ålesund during ASTAR 2007: a statistical overview

2009 ◽  
Vol 9 (4) ◽  
pp. 15453-15510 ◽  
Author(s):  
A. Hoffmann ◽  
C. Ritter ◽  
M. Stock ◽  
M. Shiobara ◽  
A. Lampert ◽  
...  
Keyword(s):  
Optical Properties ◽  
Weather Conditions ◽  
The Arctic ◽  
Research Station ◽  
Marine Research ◽  
Air Mass ◽  
Tropospheric Aerosol ◽  
Ground Based Lidar ◽  
Micro Pulse Lidar ◽  
Mixed Phase Clouds

Abstract. During the Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) in March and April 2007, measurements obtained at the AWIPEV Research station in Ny-Ålesund, Spitsbergen (operated by the Alfred-Wegener-Institute for Polar and Marine Research and the Institut polaire français Paul-Emile Victor), supported the airborne campaign. This included Lidar data from the Koldewey Aerosol Raman Lidar (KARL) and the Micro Pulse Lidar (MPL), located in the atmospheric observatory as well as photometer data and the daily launched radiosonde. The MPL features nearly continuous measurements; the KARL was switched on whenever weather conditions allowed observations (145 h in 61 days). From 1 March to 30 April, 71 meteorological balloon soundings were performed and compared with the corresponding MPL measurements; photometer measurements are available from 18 March. For the KARL data, a statistical overview based on the optical properties backscatter ratio and volume depolarization can be given. The altitudes of the occurrence of the named features (subvisible and visible ice and water as well as mixed-phase clouds, aerosol layers) as well as their dependence on different air mass origins are analyzed. Although the spring 2007 was characterized by rather clean conditions, diverse case studies of cloud and aerosol occurrence during March and April 2007 are presented in more detail, including temporal development and main optical properties as backscatter, depolarization and extinction coefficients. Links between air mass origins and optical properties can be presumed but need further evidence.

scholarly journals Ground-based lidar measurements from Ny-Ålesund during ASTAR 2007

2009 ◽  
Vol 9 (22) ◽  
pp. 9059-9081 ◽  
Author(s):  
A. Hoffmann ◽  
C. Ritter ◽  
M. Stock ◽  
M. Shiobara ◽  
A. Lampert ◽  
...  
Keyword(s):  
Optical Properties ◽  
Weather Conditions ◽  
The Arctic ◽  
Particle Detection ◽  
Marine Research ◽  
Air Mass ◽  
Tropospheric Aerosol ◽  
Ground Based Lidar ◽  
Micro Pulse Lidar ◽  
Mixed Phase Clouds

Abstract. During the Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) in March and April 2007, measurements obtained at the AWIPEV Arctic Research Base in Ny-Ålesund, Spitsbergen at 78.9° N, 11.9° E (operated by the Alfred Wegener Institute for Polar and Marine Research – AWI and the Institut polaire français Paul-Emile Victor – IPEV), supported the airborne campaign. This included lidar data from the Koldewey Aerosol Raman Lidar (KARL) and the Micro Pulse Lidar (MPL), located in the atmospheric observatory as well as photometer data and the daily launched radiosonde. The MPL features nearly continuous measurements; the KARL was switched on whenever weather conditions allowed observations (145 h in 61 days). From 1 March to 30 April, 71 meteorological balloon soundings were performed and compared with the concurrent MPL measurements; photometer measurements are available from 18 March. For the KARL data, a statistical overview of particle detection based on their optical properties backscatter ratio and volume depolarization can be given. The altitudes of the occurrence of the named features (subvisible and visible ice and water as well as mixed-phase clouds, aerosol layers) as well as their dependence on different air mass origins are analyzed. Although the spring 2007 was characterized by rather clean conditions, diverse case studies of cloud and aerosol occurrence during March and April 2007 are presented in more detail, including temporal development and main optical properties as depolarization, backscatter and extinction coefficients. Links between air mass origins and optical properties can be presumed but need further evidence.

scholarly journals Tropospheric aerosol scattering and absorption over Central Europe: a closure study for the dry particle state

2013 ◽  
Vol 13 (10) ◽  
pp. 27811-27854 ◽  
Author(s):  
N. Ma ◽  
W. Birmili ◽  
T. Müller ◽  
T. Tuch ◽  
Y. F. Cheng ◽  
...  
Keyword(s):  
Optical Properties ◽  
Direct Measurement ◽  
Radiative Forcing ◽  
Control Measure ◽  
Atmospheric Stability ◽  
Scattering Coefficient ◽  
Particle State ◽  
Air Mass ◽  
Aerosol Scattering ◽  
Tropospheric Aerosol

Abstract. This work analyses optical properties of the dry tropospheric aerosol measured at the regional GAW observation site Melpitz in East Germany. For a continuous observation period between 2007 and 2010, we provide representative values of the dry-state scattering coefficient, the hemispheric backscattering coefficient, the absorption coefficient, single scattering albedo, and the Ångström exponent. Besides the direct measurement, the aerosol scattering coefficient was alternatively computed from experimental particle number size distributions using a Mie code. Within pre-defined limits, a closure could be achieved with the direct measurement. The achievement of closure implies that such calculations can be used as a high-level quality control measure for data sets involving multiple instrumentation. All dry optical properties showed significant annual variations, which were attributed to corresponding variations in the regional emission fluxes, the intensity of secondary particle formation, and the mixed layer height. Air mass classification showed that atmospheric stability is a major factor influencing the dry aerosol properties at the GAW station. In the cold season, temperature inversions limit the volume available for atmospheric mixing, so that the aerosol optical properties near the ground proved quite sensitive to the geographical origin of the air mass. In the warm season, when the atmosphere is usually well-mixed during day-time, considerably less variability was observed for the optical properties between different air masses. This work provides, on the basis of quality-checked in-situ measurements, a first step towards a climatological assessment of direct aerosol radiative forcing in the region under study.

scholarly journals AMALi – the Airborne Mobile Aerosol Lidar for Arctic research

2010 ◽  
Vol 10 (6) ◽  
pp. 2947-2963 ◽  
Author(s):  
I. S. Stachlewska ◽  
R. Neuber ◽  
A. Lampert ◽  
C. Ritter ◽  
G. Wehrle
Keyword(s):  
Weather Conditions ◽  
The Arctic ◽  
Unknown Boundary ◽  
Polar Regions ◽  
Raman Lidar ◽  
Reliable Operation ◽  
Marine Research ◽  
Cloud Properties ◽  
Iterative Inversion ◽  
532 Nm

Abstract. The Airborne Mobile Aerosol Lidar (AMALi) is an instrument developed at the Alfred Wegener Institute for Polar and Marine Research for reliable operation under the challenging weather conditions at the Earth's polar regions. Since 2003 the AMALi has been successfully deployed for measurements in ground-based installation and zenith- or nadir-pointing airborne configurations during several scientific campaigns in the Arctic. The lidar provides backscatter profiles at two wavelengths (355/532 nm or 1064/532 nm) together with the linear depolarization at 532 nm, from which aerosol and cloud properties can be derived. This paper presents the characteristics and capabilities of the AMALi system and gives examples of its usage for airborne and ground-based operations in the Arctic. As this backscatter lidar normally does not operate in aerosol-free layers special evaluation schemes are discussed, the nadir-pointing iterative inversion for the case of an unknown boundary condition and the two-stream approach for the extinction profile calculation if a second lidar system probes the same air mass. Also an intercomparison of the AMALi system with an established ground-based Koldewey Aerosol Raman Lidar (KARL) is given.

scholarly journals In situ measurements of aerosols optical properties and number size distributions in a subarctic coastal region of Norway

2011 ◽  
Vol 11 (12) ◽  
pp. 32921-32964
Author(s):  
S. Mogo ◽  
V. E. Cachorro ◽  
J. F. Lopez ◽  
E. Montilla ◽  
B. Torres ◽  
...  
Keyword(s):  
Optical Properties ◽  
Single Scattering ◽  
Mean Value ◽  
The Arctic ◽  
Optical Parameters ◽  
Size Distributions ◽  
Air Mass ◽  
Air Masses ◽  
Particle Sizer

Abstract. In situ measurements of aerosol optical properties were made in the summer of 2008 at the ALOMAR station facility (69°16 N, 16°00 E), located at a rural site in the north of the island of Andøya (Vesterålen archipelago), approximately 300 km north of the Arctic Circle. The extended three-month campaign was part of the POLARCAT Project (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) of the International Polar Year (IPY-2007-2008). Its goal was to characterize the aerosols of this sub-Arctic area, which are frequently transported to the Arctic region. The ambient light-scattering coefficient, σs (550 nm), at ALOMAR had a measured hourly mean value of 5.41 Mm−1 (StD = 3.55 Mm−1), and the light-absorption coefficient, σa (550 nm), had a measured hourly mean value of 0.40 Mm−1 (StD = 0.27 Mm−1). The scattering/absorption Ångström exponents, αs,a, are used for a detailed analysis of the variations of the spectral shape of σs,a. Whereas αs demonstrates the presence of two particle sizes corresponding to two types of aerosols, the αa demonstrates only one type of absorbing aerosol particles. Values of αa above 1 were not observed. The single-scattering albedo, ω0, ranged from 0.62 to 0.99 (mean = 0.91, StD = 0.05), and the relationships of this property to the absorption/scattering coefficients and the Ångström exponents are presented. The concentration of the particles was monitored using a scanning mobility particle sizer (SMPS), an aerodynamic particle sizer (APS) and an ultrafine condensation particle counter (UCPC). The shape of the median size distribution of the particles in the submicrometer fraction was bimodal, and the submicrometer, micrometer and total concentrations presented hourly mean values of 1277 cm3 (StD = 1563 cm3), 1 cm3 (StD = 1 cm3) and 2463 cm3 (StD = 4251 cm3), respectively. The modal correlations were investigated, and the concentration of particles sized between 30 and 100 nm (Aitken mode) are presented as a function of the concentration of the particles sized between 100 and 390 nm (accumulation mode). The optical and the microphysical parameters are related to each other, and the results are presented. The origins and pathways of air masses were examined by computing the back-trajectories in a trajectory model (HYSPLIT). Six geographical sectors were defined to classify the air masses, and, based on the sector classification, the linkage between the air mass origin and the optical parameters was established. Aerosol size distributions were also evaluated in relation to the air masses. The relationships between the air mass origins and other parameters, especially those related to the single scattering albedo, allow us to describe two characteristic situations: northern and western air masses, which had predominantly marine aerosols, presented lower optical parameter values, indicating predominantly coarser and non-absorbent particles; and eastern and southern air masses, in which continental aerosols were predominant, presented higher values for all optical parameters, indicating the presence of smaller absorbent particles.

scholarly journals Statistics on clouds and their relation to thermodynamic conditions at Ny-Ålesund using ground-based sensor synergy

2019 ◽  
Vol 19 (6) ◽  
pp. 4105-4126 ◽  
Author(s):  
Tatiana Nomokonova ◽  
Kerstin Ebell ◽  
Ulrich Löhnert ◽  
Marion Maturilli ◽  
Christoph Ritter ◽  
...  
Keyword(s):  
Microwave Radiometer ◽  
Single Layer ◽  
Mixed Phase ◽  
The Arctic ◽  
Time Data ◽  
Liquid Water Path ◽  
Marine Research ◽  
Mean Values ◽  
Water Path ◽  
Mixed Phase Clouds

Abstract. The French–German Arctic research base AWIPEV (the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research – AWI – and the French Polar Institute Paul Emile Victor – PEV) at Ny-Ålesund, Svalbard, is a unique station for monitoring cloud-related processes in the Arctic. For the first time, data from a set of ground-based instruments at the AWIPEV observatory are analyzed to characterize the vertical structure of clouds. For this study, a 14-month dataset from Cloudnet combining observations from a ceilometer, a 94 GHz cloud radar, and a microwave radiometer is used. A total cloud occurrence of ∼81 %, with 44.8 % multilayer and 36 % single-layer clouds, was found. Among single-layer clouds the occurrence of liquid, ice, and mixed-phase clouds was 6.4 %, 9 %, and 20.6 %, respectively. It was found that more than 90 % of single-layer liquid and mixed-phase clouds have liquid water path (LWP) values lower than 100 and 200 g m−2, respectively. Mean values of ice water path (IWP) for ice and mixed-phase clouds were found to be 273 and 164 g m−2, respectively. The different types of single-layer clouds are also related to in-cloud temperature and the relative humidity under which they occur. Statistics based on observations are compared to ICOsahedral Non-hydrostatic (ICON) model output. Distinct differences in liquid-phase occurrence in observations and the model at different environmental temperatures lead to higher occurrence of pure ice clouds. A lower occurrence of mixed-phase clouds in the model at temperatures between −20 and −5 ∘C becomes evident. The analyzed dataset is useful for satellite validation and model evaluation.

scholarly journals Dynamics of gaseous oxidized mercury at Villum Research Station during the High Arctic summer

2021 ◽  
Author(s):  
Jakob Boyd Pernov ◽  
Bjarne Jensen ◽  
Andreas Massling ◽  
Daniel Charles Thomas ◽  
Henrik Skov
Keyword(s):  
Meteorological Data ◽  
High Arctic ◽  
Atmospheric Mercury ◽  
The Arctic ◽  
Research Station ◽  
Cold Temperatures ◽  
Air Mass ◽  
Back Trajectories ◽  
Arctic Summer ◽  
Gaseous Oxidized Mercury

Abstract. While much research has been devoted to the subject of gaseous elemental mercury (GEM) and gaseous oxidized mercury (GOM) in the Arctic spring, during atmospheric mercury depletion events, few studies have examined the behavior of GOM in the High Arctic summer. GOM, once introduced into the ecosystem, can pose a threat to human and wildlife health, though there remain large uncertainties regarding the transformation, deposition, and assimilation of mercury into the ecosystem. Therefore, to further our understanding of the dynamics of gaseous oxidized mercury in the High Arctic during the late summer, we performed measurements of GEM and GOM along with meteorological parameters, atmospheric constituents, and air mass history during two summer campaigns in 2019 and 2020 at Villum Research Station (Villum) in Northeastern Greenland. Five events of enhanced GOM concentrations were identified and investigated in greater detail. The origin of these events was identified, through analysis of air mass back-trajectories, associated meteorological data, and other atmospheric constituents, to be the cold, dry free troposphere. These events were associated with low RH, limited precipitation, cold temperatures, and intense sunlight along the trajectory path. Events were positively correlated with ozone, aerosol particle number, and black carbon mass concentration, which were interpreted as an indication of tropospheric air masses. This work aims to provide a better understanding of the dynamics of GOM during the High Arctic summer.

scholarly journals AMALi – the Airborne Mobile Aerosol Lidar for Arctic research

2009 ◽  
Vol 9 (5) ◽  
pp. 18745-18792 ◽  
Author(s):  
I. S. Stachlewska ◽  
R. Neuber ◽  
A. Lampert ◽  
C. Ritter ◽  
G. Wehrle
Keyword(s):  
Present State ◽  
Aerosol Particles ◽  
Weather Conditions ◽  
The Arctic ◽  
Polar Regions ◽  
Marine Research ◽  
The Past ◽  
Cloud Properties ◽  
And Performance

Abstract. The Airborne Mobile Aerosol Lidar (AMALi) is an instrument developed at the Alfred Wegener Institute for Polar and Marine Research for a trouble-free operation under the challenging weather conditions at the Earth's polar regions. Since 2003 the AMALi has been successfully deployed for measurements in the ground-based installation and the zenith- or nadir-aiming airborne configurations during several scientific campaigns in the Arctic. The lidar provides profiles of the total backscatter at two wavelengths, from which aerosol and cloud properties are derived. It measures also the linear depolarization of the backscattered return, allowing for the discrimination of thermodynamic cloud phase and the identification of the presence of non-spherical aerosol particles. This paper presents the capability characteristics and performance of the past and present state of the AMALi system, as well as discusses the ground-based and airborne evaluation schemes applied to invert the data.

scholarly journals Study of Persistent Foggy-Hazy Composite Pollution in Winter over Huainan Through Ground-Based and Satellite Measurements

Atmosphere ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 656
Author(s):  
Songlin Fu ◽  
Chenbo Xie ◽  
Peng Zhuang ◽  
Xiaomin Tian ◽  
Zhanye Zhang ◽  
...  
Keyword(s):  
Extinction Coefficient ◽  
Meteorological Factors ◽  
Surface Wind ◽  
Weather Conditions ◽  
Near Surface ◽  
Air Mass ◽  
Maximum Value ◽  
Lidar Ratio ◽  
Ground Based Lidar ◽  
Accumulation Of Pollutants

Through the observation of ground-based LIDAR and satellite sensors, the weather conditions of continuous foggy-hazy alternations in the Huainan region from 26 December 2016 to 5 January 2017 were analyzed and observed. In this study, the formation and influence of this event were discussed by analyzing pollutant concentrations, meteorological factors and aerosol optical characteristics. The concentrations of PM10 and PM2.5 increased significantly. The maximum value of PM10 was 412 μg/m3, and the maximum value of PM2.5 was 258 μg/m3. The transportation of pollutants and the production of man-made pollutants promote the accumulation of pollutants. In this weather process, meteorological factors such as the surface wind speed, humidity, surface temperature, and inversion also promote the accumulation of pollutants, which is the main reason for the formation of this weather process. Furthermore, the near surface air mass mainly came from the cities near the Huainan region and the heavily polluted areas in the north, while the upper air mass came from Inner Mongolia. In this paper, piecewise inversion was adopted to achieve accurate all-weather extinction coefficient profile inversion by reasonably selecting a cloud LIDAR ratio through a backscatter ratio, and the LIDAR ratio of cloud in this period was 22.57–34.14 Sr. By means of extinction coefficient inversion and correlation analysis, the correlation index of PM2.5 and the aerosol optical depth (AOD) was 0.7368, indicating that there was a positive correlation between PM2.5 and AOD, and AOD can also reflect the pollution condition of this region. The formation process of foggy-hazy weather in the Huainan region studied in this paper can provide a research basis for foggy-hazy pollution in this region.

scholarly journals Tropospheric aerosol scattering and absorption over central Europe: a closure study for the dry particle state

2014 ◽  
Vol 14 (12) ◽  
pp. 6241-6259 ◽  
Author(s):  
N. Ma ◽  
W. Birmili ◽  
T. Müller ◽  
T. Tuch ◽  
Y. F. Cheng ◽  
...  
Keyword(s):  
Optical Properties ◽  
Direct Measurement ◽  
Radiative Forcing ◽  
Control Measure ◽  
Atmospheric Stability ◽  
Scattering Coefficient ◽  
Particle State ◽  
Air Mass ◽  
Aerosol Scattering ◽  
Tropospheric Aerosol

Abstract. This work analyses optical properties of the dry tropospheric aerosol measured at the regional Global Atmosphere Watch (GAW) observation site Melpitz in East Germany. For a continuous observation period between 2007 and 2010, we provide representative values of the dry-state scattering coefficient, hemispheric backscattering coefficient, absorption coefficient, single scattering albedo, and scattering Ångström exponent. Besides the direct measurement, the aerosol scattering coefficient was alternatively computed from experimental particle number size distributions using a Mie model. Within pre-defined limits, a closure could be achieved with the direct measurement. The achievement of closure implies that such calculations can be used as a high-level quality control measure for data sets involving multiple instrumentation. All dry-state optical properties show pronounced annual and diurnal variations, which are attributed to the corresponding variations in the regional emission fluxes, the intensity of secondary particle formation, and the mixing layer height. Air mass classification shows that atmospheric stability is a major factor influencing the dry aerosol properties at the GAW station. In the cold season, temperature inversions limit the volume available for atmospheric mixing, so that the dry-state aerosol optical properties near the ground proved quite sensitive to the geographical origin of the air mass. In the warm season, when the atmosphere is usually well-mixed during daytime, considerably less variability was observed for the optical properties between different air masses. This work provides, on the basis of quality-checked in situ measurements, a first step towards a climatological assessment of direct aerosol radiative forcing in the region under study.

Knowledge of Arctic and EQQ Unmanned Aerial Vehicles for Multiple Applications

2013 ◽  
Author(s):  
Shelton G. De Silva
Keyword(s):  
Sea Ice ◽  
Unmanned Aerial Vehicles ◽  
Arctic Region ◽  
Weather Conditions ◽  
Scientific Data ◽  
The Arctic ◽  
Research Station ◽  
Remote Areas ◽  
Aerial Vehicles ◽  
The Arctic Region

The rapid change in climate conditions, and the present demand for political and commercial interest in the Arctic region will cause considerable implications on the environment, ecosystem, security, and on the social system in the region. Today, governments, scientists and researchers understand that there is a huge gap of knowledge in the Arctic region and this must be addressed prior to development of the region, or there will be devastating environmental consequences in the future. Existing studies concluded by various organizations including Lloyd’s of London, US Geological Survey and other institutes emphasize that in order to ensure sustainable development in the Arctic, it is important to close the existing gap of knowledge by obtaining accurate scientific data, and make available this data to scientists, researchers and policy makers, for them to take sound decisions on both Arctic challenges and future economic opportunities. The scientists understand that existing lack of knowledge is mainly due to insufficient information in the Arctic and the inability to obtain sufficient scientific data to understand the Arctic region in-depth. Main challenges will be, the vast area of the Arctic, inaccessibility to complex and remote areas, long cold dark winters and short summers, rapid changes of weather conditions etc. Presently, existing satellites provide extremely valuable scientific data, however scientists emphasize that this data would be further analyzed (due to inaccuracy) and collaborated with data on actual close observations, physical sea–ice samples, ice core samples, data from surface and bottom of the sea-ice, glacial ice etc. Collecting data from high altitudes using Unmanned Aerial Vehicles are not new to the Arctic region, and have been used for number of years. The AMAP, (Arctic Monitoring and Assessment Program Workshop), Oslo October, 2008, recommended that it is of great importance that scientists use unmanned aerial vehicles in the Arctic to obtain important environment measurements. Further, added to the AMAP work plan for 2011–2013, is to develop safety guidelines and cross-jurisdictional flight pilot projects, to demonstrate the use of unmanned aerial service (UAS) in the Arctic Environmental Monitoring Plan. The Canadian Government also completed the feasibility study to build a “High Arctic Research Station” in the high north to serve the entire world, for scientists to have an opportunity to share data and support the knowledge for researchers to conclude their investigations. The government is further considering purchasing, three large high-altitude Global Hawk drones for Arctic surveillance, and seeking small snowmobiles and remote control aircrafts to monitor the extreme complex landscape of the Arctic. At present, there is no method to obtain accurate surface and atmospheric data in complex and remote areas, and this requirement has become the highest priority and should be addressed urgently. In order to obtain sufficient accurate data from the Arctic surface and atmosphere, EQQUERA Inc. innovated, is designing and developing multipurpose, multifunctional SG EQQ Unmanned Aerial Vehicles that are able to access remote and complex areas in the Arctic, and operate in challengeable weather conditions such as cold long dark nights.

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