Pan‐Arctic sunphotometry during the ARCTAS‐A campaign of April 2008

Saha, A.; O’Neill, Norman T.; Eloranta, E. W.; Stone, R. S.; Eck, T. F.; Zidane, S.; Daou, David; Lupu, A.; Lesins, Glen; Shiobara, Masataka; McArthur, L. J. B.

doi:10.1029/2009gl041375

Cited by 38 publications

(41 citation statements)

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“…This method (whose output is also an AERONET (Aerosol Robotic Network) product) was employed, for example, by O'Neill et al (2008a) and Saha et al (2010) to analyze co-located sunphotometer and lidar data at Eureka and other Arctic stations. Its basic premise, that aerosol (and cloud) optics are largely driven by independent fine and coarse mode particle size distributions, permits a more fundamental understanding of both optical depths, lidar backscatter profiles and the link between the two.…”

Section: Spectral Deconvolution Algorithm (Sda) Processingmentioning

confidence: 99%

“…As a consequence, there are fewer than a dozen permanent Arctic stations with a continuous track of aerosol measurements. This record is augmented by intensive field campaigns with particular objectives concerning aerosols and aerosol-cloud interactions such as SHEBA/FIRE-ACE (October 1997-October 1998, Curry et al, 2000Uttal et al, 2002), ASTAR (March-April 2000, Yamanouchi et al, 2005), ARCTAS (April, June-July 2008, Jacob et al, 2010), ISDAC (April 2008, McFarquhar et al, 2011, ARCPAC (April 2008, Brock et al, 2011 and PO-LARCAT (June-July 2008, Schmale et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Synchronous polar winter starphotometry and lidar measurements at a High Arctic station

Baibakov¹,

O’Neill²,

Ivanescu³

et al. 2015

Atmos. Meas. Tech.

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Abstract. We present recent progress on nighttime retrievals of aerosol and cloud optical properties over the PEARL (Polar Environmental Atmospheric Research Laboratory) station at Eureka (Nunavut, Canada) in the High Arctic (80 • N, 86 • W). In the spring of 2011 and 2012, a star photometer was employed to acquire aerosol optical depth (AOD) data, while vertical aerosol and cloud backscatter profiles were measured using the CANDAC Raman Lidar (CRL). We used a simple backscatter coefficient threshold (β thr ) to distinguish aerosols from clouds and, assuming that aerosols were largely fine mode (FM)/sub-micron, to distinguish FM aerosols from coarse mode (CM)/super-micron cloud or crystal particles. Using prescribed lidar ratios, we computed FM and CM AODs that were compared with analogous AODs estimated from spectral star photometry. We found (β thr dependent) coherences between the lidar and star photometer for both FM events and CM cloud and crystal events with averaged, FM absolute differences being <∼ 0.03 when associated R 2 values were between 0.2 and 0.8. A β thr sensitivity study demonstrated that zero crossing absolute differences and R 2 peaks were in comparable regions of the β thr range (or physical reasons were given for their disparity). The utility of spectral vs. temporal cloud screening of star photometer AODs was also illustrated. In general our results are critical to building confidence in the physical fidelity of derived, weak amplitude, star photometry AODs and, in turn, towards the development of AOD climatologies and validation databases for polar winter models and satellite sensors.

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Section: Spectral Deconvolution Algorithm (Sda) Processingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synchronous polar winter starphotometry and lidar measurements at a High Arctic station

Baibakov¹,

O’Neill²,

Ivanescu³

et al. 2015

Atmos. Meas. Tech.

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“…Footprints from the different levels were combined as a weighted mean to create a single footprint that is representative of a column measurement. Weights were derived as the product of the pressure at the receptor In addition, we use AERONET aerosol optical depth (AOD) data measured at Eureka Saha et al, 2010; http://aeronet.gsfc.nasa.gov/), when available, to detect simultaneous increases in fine-mode AOD and trace gas total columns, which is an additional fire event indicator. If these data all agree on a common origin for a plume, and the back-trajectories intersect that region during the same time, then the source of a biomass burning event has been successfully detected.…”

Section: Detection Of Biomass Burning Events With Ftir Observations Imentioning

confidence: 99%

Identifying fire plumes in the Arctic with tropospheric FTIR measurements and transport models

et al. 2015

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Abstract. We investigate Arctic tropospheric composition using ground-based Fourier transform infrared (FTIR) solar absorption spectra, recorded at the Polar Environment Atmospheric Research Laboratory (PEARL, Eureka, Nunavut, Canada, 80 • 05 N, 86 • 42 W) and at Thule (Greenland, 76 • 53 N, −68 • 74 W) from 2008 to 2012. The target species, carbon monoxide (CO), hydrogen cyanide (HCN), ethane (C 2 H 6 ), acetylene (C 2 H 2 ), formic acid (HCOOH), and formaldehyde (H 2 CO) are emitted by biomass burning and can be transported from mid-latitudes to the Arctic.By detecting simultaneous enhancements of three biomass burning tracers (HCN, CO, and C 2 H 6 ), ten and eight fire events are identified at Eureka and Thule, respectively, within the 5-year FTIR time series. Analyses of Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model back-trajectories coupled with Moderate Resolution Imaging Spectroradiometer (MODIS) fire hotspot data, Stochastic Time-Inverted Lagrangian Transport (STILT) model footprints, and Ozone Monitoring Instrument (OMI) UV aerosol index maps, are used to attribute burning source regions and travel time durations of the plumes. By taking into account the effect of aging of the smoke plumes, measured FTIR enhancement ratios were corrected to obtain emission ratios and equivalent emission factors. The means of emission factors for extratropical forest estimated with the two FTIR data sets are 0.40 ± 0.21 g kg −1 for HCN, 1.24 ± 0.71 g kg −1 for C 2 H 6 , 0.34 ± 0.21 g kg −1 for C 2 H 2 , and 2.92 ± 1.30 g kg −1 for HCOOH. The emission factor for CH 3 OH estimated at Eureka is 3.44 ± 1.68 g kg −1 .To improve our knowledge concerning the dynamical and chemical processes associated with Arctic pollution from fires, the two sets of FTIR measurements were compared to the Model for OZone And Related chemical Tracers, version 4 (MOZART-4). Seasonal cycles and day-to-day variabilities were compared to assess the ability of the model to reproduce emissions from fires and their transport. Good agreement in winter confirms that transport is well implemented in the model. For C 2 H 6 , however, the lower wintertime concentration estimated by the model as compared to the FTIR observations highlights an underestimation of its emission. Results show that modeled and measured total columns are correlated (linear correlation coefficient r>0.6 for all gases except for H 2 CO at Eureka and HCOOH at Thule), but suggest a general underestimation of the concentrations in the model for all seven tropospheric species in the high Arctic.

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“…Some modeling studies suggest anthropogenic sources from Europe and Asia maintain the enhanced level of pollution at northern high latitudes often referred to as Arctic haze (Quinn et al, 2007;Koch and Hansen, 2005). A number of other works have shown how transport of biomass-burning plumes from agricultural and forest fires at midlatitudes contribute to Arctic haze particularly in spring (Saha et al, 2010;Warneke et al, 2009;Generoso et al, 2007). The partitioning of anthropogenic and biomass-burning influenced air masses in the springtime Arctic largely depends on interannual variability in biomass burning at northern midlatitudes .…”

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confidence: 99%

Aircraft observations of enhancement and depletion of black carbon mass in the springtime Arctic

et al. 2010

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Abstract. Understanding the processes controlling black carbon (BC) in the Arctic is crucial for evaluating the impact of anthropogenic and natural sources of BC on Arctic climate. Vertical profiles of BC mass loadings were observed from the surface to near 7-km altitude in April 2008 using a Single-Particle Soot Photometer (SP2) during flights on the NOAA WP-3D research aircraft from Fairbanks, Alaska. These measurements were conducted during the NOAAsponsored Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) project. In the free troposphere, the Arctic air mass was influenced by long-range transport from biomass-burning and anthropogenic source regions at lower latitudes especially during the latter part of the campaign. Average BC mass mixing ratios peaked at about 150 ng BC (kg dry air ) −1 near 5.5 km altitude in the aged Arctic air mass and 250 ng kg −1 at 4.5 km in biomassburning influenced air. BC mass loadings were enhanced by up to a factor of 5 in biomass-burning influenced air compared to the aged Arctic air mass. At the bottom of some of the profiles, positive vertical gradients in BC were observed over the sea-ice. The vertical profiles generally occurred in the vicinity of open leads in the sea-ice. In the aged ArcticCorrespondence to: J. R. Spackman (ryan.spackman@noaa.gov) air mass, BC mass loadings more than doubled with increasing altitude within the ABL and across the boundary layer transition while carbon monoxide (CO) remained constant. This is evidence for depletion of BC mass in the ABL. BC mass loadings were positively correlated with O 3 in ozone depletion events (ODEs) for all the observations in the ABL. Since bromine catalytically destroys ozone in the ABL after being released as molecular bromine in regions of new seaice formation at the surface, the BC-O 3 correlation suggests that BC particles were removed by a surface process such as dry deposition. We develop a box model to estimate the dry deposition flux of BC mass to the snow constrained by the vertical profiles of BC mass in the ABL. Open leads in the sea-ice may increase vertical mixing and entrainment of pollution from the free troposphere possibly enhancing the deposition of BC aerosol to the snow.

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Pan‐Arctic sunphotometry during the ARCTAS‐A campaign of April 2008

Cited by 38 publications

References 10 publications

Synchronous polar winter starphotometry and lidar measurements at a High Arctic station

Synchronous polar winter starphotometry and lidar measurements at a High Arctic station

Identifying fire plumes in the Arctic with tropospheric FTIR measurements and transport models

Aircraft observations of enhancement and depletion of black carbon mass in the springtime Arctic

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