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Ozone, UV and Aerosol studies

AEROCLOUD - Instrumentation

General

The Belgian Antarctic research station Princess Elisabeth, inaugurated in February 2009, is situated north of the Sor Rondane Mountains in Dronning Maud Land, East Antarctica, on the small, granite Utsteinen ridge (71.9°S, 23.3°E, 1390 m asl). The station is designed as a zero-emission station with power supplied by wind turbines, solar panels and batteries. Two diesel-generators serve only as back-up. The station is manned only during austral summer. In winter, station and instruments operate in automatic mode with remote control. The station is located around 180 km inland. In order to address the scientific tasks within AEROCLOUD, the atmospheric aerosol composition is measured using an aethalometer, a sunphotometer, a Tapered Element Oscillating Microbalance, an ultrafine condensation particle counter, an aerosol sizing spectrometer, and a nephelometer. The aerosol instruments (except the sunphotometer) are installed in a container-size special shelter 60m south of the station on the Utsteinen ridge. As the main wind direction is from East, Southeast, the measurements are most of the time not contaminated by the station's operation. Any contamination can easily be detected by the signals of the aethalometer and the condensation particle counter. During summer seasons 2013/14, 2014/15 and 2015/16, a cloud condensation nuclei counter has been additionally installed in the aerosol shelter (see also under 'collaborations').

Data of an automatic weather station (HYDRANT project, KU Leuven), installed about 300 m away from the station are used to relate the measured ambient aerosol data to the meteorological conditions. During austral summer season 2013/14, a programme to launch radiosondes via weather balloons has been started (see collaboration sub page). It has been continued during 2014/15 season and is also scheduled for summer season 2015/16. In addition, a Brewer ozone spectrophotometer, a pyranometer, and two sensors for UV-A and UV-B are installed.   The sunphotometer, the Brewer ozone spectrophotometer, pyranometer, UV-A and UV-B sensors are installed on the northern roof of Princess Elisabeth station.

Magee Sci. Aethalometer AE31:
With this multi-wavelength aethalometer, the aerosol absorption coefficient (m-1) at seven wavelengths (370, 450, 520, 590, 660, 880, 950 nm), and the mass concentration (nanogram/m-3) of light-absorbing aerosol (at the 7 wavelengths) can be measured. The aethalometer technique uses light-transmission through a quartz fibre filter to derive the attenuation caused by the aerosol particles which then is transferred to absorption by the particles. The instrument was first installed during February 2009. Data is available for the following periods: Feb 2009 / Jan, Feb, Dec 2010 / Jan-Apr, Nov, Dec 2011 / Jan-Aug, Nov, Dec 2012 / Jan-Apr, Nov, Dec 2013 / Jan-Aug, Nov, Dec 2014 / complete Jan-Dec 2015 / Jan, Feb, Mar, Apr 2016.

Tapered Element Oscillating Microbalance with Filter Dynamic Measurement System (Thermo Electron Corp):
With a TEOM-FDMS, the total aerosol mass concentration (microgram/m-3) is measured. It employs a filter on a microbalance, oscillating with a specific frequency. Any mass change on the filter causes a change of the oscillating frequency which can be converted to a mass concentration. The instrument was first installed in December 2010. Data is available for the following periods:  Dec 2010 / Jan-Apr, Dec 2011 / Jan-Aug, Nov, Dec 2012 / Jan-May, Nov, Dec 2013 / Jan-Aug, Nov, Dec 2014 / complete Jan-Dec 2015 / Jan, Feb, Mar, Apr 2016.

Ecotech Aurora 3000 3-wavelength Nephelometer:
The nephelometer measures the intensity of light scattered by aerosol particles at 450, 525, 635 nm. The instrument uses light emitting diodes as light sources. The measured variables are the total scattering coefficients (m-1) and the backscatter coefficients (m-1). Calibrations with a pure reference gas (CO2) are done during summer season. During winter,  only zero checks are regularly done, as for security reasons, no open gas bottles can be left unattended. The instrument was first installed in February 2012. Data is available for the following periods: Feb, Nov, Dec 2012 / Jan-Apr 2013. Unfortunately, the nephelometer was damaged during a storm in April 2013 and had to be shipped back during season 2013/14. It has been repaired and has been re-installed in November 2014. Data is again available for Nov, Dec 2014 / complete Jan-Dec 2015 / Jan, Feb, Mar, Apr 2016.

Laser Aerosol Spectrometer (LAS, TSI Inc, model 3340):
The LAS measures the intensity of light scattered by aerosol particles. Light source is a HeNe gas laser at 633 nm. The instrument can measure the number of particles in 100 user-selectable size bins within the diameter range 90 to 7500 nm. It is currently configured to measure aerosol number in 100 log-channels between 90 and 7000 nm. It was first installed in February 2012. Data are available for the following periods: Feb-June, Nov, Dec 2012 / Jan-May, Nov, dec 2013 / Jan-Aug, Dec 2014 / Jan, Feb 2015. The LAS has been shipped back to Belgium for calibration. It has been re-installed on 5 Dec 2015. Data are again available for Dec 2015 / Jan, Feb, Mar, Apr 2016.

Ultrafince condensation particle counter (U-CPC, TSI Inc., model 3776):
This condensation particle counter measures the total aerosol number concentration (#/cm-3) in the size range from 3 to 3000 nm. The instrument uses n-butanol as working liquid. The particles come first into a warm chamber with butanol vapour and subsequently into a cooled chamber, where supersaturation conditions prevail, the particles grow with the butanol and can then be optically detected and counted. The instrument was first installed in February 2012. Data is available for the following periods: Feb, Nov, Dec 2012 / Jan-May, Nov, Dec 2013 / Jan-Aug, Nov, Dec 2014 / complete Jan-Dec 2015/ Jan, Feb, Mar, Apr 2016.

Cimel CE318 sunphotometer:
The Cimel is a passive radiometer, measuring direct sun and diffuse sky radiances (W/m-2) at 8 wavelengths (340, 380, 440, 500, 675, 870, 936, 1020 nm). The instrument needs clear sky in front of the sun for its measurements. The primary variables derived are the total column aerosol optical depth (AOD), a proxy for the aerosol loading of the atmosphere and the integrated precipitable water vapour (mm). Derived products include i.a. the aerosol fine mode fraction, Angstrom exponent (indicative of aerosol size), and single scattering albedo. The Cimel is part of AERONET, and the data can be found in its database ('Utsteinen'). The instrument has to be calibrated in Europe yearly, and travels therefore forth and back to Antarctica (in addition, no sun or too large zenith angle during winter). It was first installed in February 2009. Data is available for the following periods: Feb 2009 / Jan, Feb, Dec 2010 / Jan, Feb, Dec 2011 / Jan, Feb, Nov, Dec 2012 / Jan, Feb, Nov, Dec 2013 / Jan, Feb, Dec 2014 / Jan, Feb, Dec 2015. Unfortunately, it encountered problems in December and is now back on its way to Europe for maintenance and calibration.

Brewer ozone spectrophotometer (Mark III #100):
The Brewer spectrophotometer provides near-simultaneous observations of the total ozone column and UV spectra. It measures the UV spectra between 283 and 363 nm. Total ozone (Dobson units) is accurately derived from the analysis of the UV spectra. From its measurements, the UV index is derived, and also the UV aerosol optical depth at 340 nm. The Brewer is installed only during summer seasons. In winter, when nobody could maintain the instrument the risk would be too high for serious damage. The data can be found on the international database on ozone and UV data (WOUDC). Data is available for the following periods: Dec 2010 / Jan, Feb, Dec 2011 / Jan, Feb, Nov, Dec 2012 / Jan, Feb 2013. Unfortunately, one of the I/O boards of the Brewer malfunctioned during setup in December 2013 and the instrument has therefore been shipped back to Brussels for repair. A calibration of the instrument has been done in April/May 2014. It has been re-installed at Princess Elisabeth in November 2014. Data is again available for Nov, Dec 2014 / Jan, Feb, Nov, Dec 2015 / Jan, Feb 2016.

Pyranometer, UV sensors (EKO) :
With a pyranometer, the total solar irradiation between 300 and 2800 nm is measured. In addition, one sensor measures the UV-A irradiation (315-380nm) and another one UV-B irradiation (280-315 nm) with high precision. The three sensors are mounted in an elevated box, which is installed on the station's northern roof. The sensors have been installed in December 2012 for permanent operation. Data is available for the following periods: Dec 2012 / Jan-May, Nov, Dec 2013 / Jan-Aug, Nov, Dec 2014 / complete Jan-Dec 2015 / Jan, Feb, Mar, Apr 2016.

 

Images of Instrumentation

View of the northern roof part of Princess Elisabeth station. The box with the pyranometer and sensors for UV-A and UV-B radiation is in the back, towards the East. In front the Brewer.

The Cimel sunphotometer mounted on the roof top of Princess Elisabeth station

View inside the aerosol measurement shelter south of the station. From left to right: TEOM-FDMS, aethalometer (first instrument on the bench), nephelometer, LAS, U-CPC.

Bulk inlets for the aerosol instruments. From left to right: TEOM-FDSM, aethalometer, nephelometer, LAS and U-CPC.

The aerosol instrument shelter on Utsteinen ridge, south of Princess Elisabeth station. Copyright of images of Princess Elisabeth station: International Polar Foundation