Using Infrared Emission Spectroscopy to Study Arctic

Using Infrared Emission
Spectroscopy to Study Arctic
Atmospheric Chemistry and
Radiation
Zen Mariani1
Kimberly Strong1, Mareile Wolff1, Mathias Palm2, Penny
Rowe3, Von Walden3, and Pierre Fogal4
1Department
of Physics, University of Toronto
of Physics, University of Bremen, Germany
3Department of Physics, University of Idaho, USA
4Environment Canada, Air Quality Research Division, Toronto, Canada
2Department
ArcticNet Conference
December 17, 2010
Climate Change in the Arctic
Climate Change in the Arctic

Evidence of rapidly changing climate in the Arctic




Annually averaged total column ozone (O3) loss of 7% since
1979 in response to enhanced chlorine (WMO, 2006)
Sea-Ice:
Melting Sea-Ice = Increased Water Vapour = Increased
Surface Temperature  Positive Feedback
Observations from ground-based instruments are crucial
to better our understanding of the changing climate.
ACIA, Arctic Climate Impact Assessment (2004), Cambridge University Press
WMO Scientic Assessment of Ozone Depletion (2006): WMO Global Ozone Research and Monitoring Project - Report No. 50, Geneva
Stratospheric O3


O3 naturally created and destroyed in stratosphere
via Chapman mechanism (Jacob, 1999):
Enhanced chlorine can
cause catalytic destruction
of O3:
Image source: http://oceanworld.tamu.edu/resources/environment-book/stratosphericozone.html
Jacob, D. (1999): Introduction to Atmospheric Chemistry. Princeton University Press
Tropospheric Trace Gases


Nitric oxide (NO) reacts to
form nitrogen dioxide (NO2),
producing tropospheric O3
in the process:
HOx (OH, HO2, and
H2O2) and NOx catalyze
O3 production in the
troposphere and O3
destruction in the
stratosphere
Image source: Jacob [1999]5
Where do we measure these Trace
Gases?
Measurement Site: Eureka

Ellesmere Island, Nunavut (80°N, 86.2°W)
PEARL
Eureka
(0PAL)


PEARL = Polar Environment Atmospheric Research Laboratory
0PAL = Zero-altitude PEARL Auxiliary Laboratory
Images from blog.norway.com, Google Maps
Photo by Paul Loewen
How do we measure these Trace
Gases above Eureka?
Photo by Paul Loewen
Photo by Paul Loewen
Photo by Paul Loewen
Photo by Paul Loewen
Photo by Paul Loewen
The (new) Instrument to Measure
these Trace Gases
The Extended-range Atmospheric Emitted
Radiance Interferometer (E-AERI)

Original AERI system selected by Atmospheric Radiation
Measurement program in 1996

E-AERI Designed by University of Wisconsin Space Science and
Engineering Centre; Manufactured by ABB Bomem (Quebec)

Infrared Fourier Transform Spectrometer with 1 cm-1 resolution

Extended wavelength range covers 400-3000 cm-1 (3-25 µm)

Measurement of accurately
calibrated downwelling infrared
thermal emission from
atmosphere
DOE (1990): Atmospheric Radiation Measurement Program plan, DOE/ER-0442 and DOE/ER-0441, U.S. Department
of Energy, Washington, DC, 135
Fourier Transform Spectroscopy


Fourier Transform-InfraRed (FT-IR)
spectrometer is based on a Michelson
Interferometer
Optical Path Difference (OPD) between two
beams creates interference pattern
Image source: http://www.cluin.org /programs/21m2/ openpath/op-ftir/
Additional E-AERI Specifications

Installed at PEARL, Eureka, NT, in October 2008

Acquired one full year of measurements

Spectra every 7 min, 24 hours a day, 365 days a year
(precipitation pending)  Polar Night
Measurements
Image credit: ABB Bomem
CANDAC Bruker 125HR
Polar Night
Rodica Lindenmaier
E-AERI at PEARL




25th October 2008 – 22nd September 2009
80.05°N, 86.42°W
Altitude: 610 m
E-AERI
Operated by Canadian Network for the Detection of
Atmospheric Change (CANDAC)
Photo by Paul Loewen
Penthouse of PEARL
April 4, 2009 Measurements at
PEARL
SFIT2 Retrieval Algorithm


Prototype version of SFIT2 to retrieve total
columns of various trace gases (Mathias
Palm, Univ. Bremen)
SFIT2 fits regions of spectrum


Well-defined spectral lines
Obtain total column concentrations of trace
gases
CO
Comparison with the PAERI




Assess initial measurements through
comparisons with a similar instrument, the
Polar-AERI (PAERI)
Installed prior to E-AERI at Eureka
Instrument mentor: Dr. Von Walden
Analysis: Dr. Penny Rowe
(University of Idaho)
Ideal Instrument for comparison purposes


Similar specs (1 cm-1 resolution) as
E-AERI
Data series overlap until June 2009
PEARL
Eureka
(0PAL)
E-AERI = PEARL
600 m
PAERI = 0PAL
Comparison with the PAERI


PAERI Spectra obtained for April 4, 2009
SFIT2 Measurements:
Retrieved total columns for five trace gases above Eureka on April 4, 2009
Error
(%)
Conclusion

E-AERI data set at PEARL from Oct 2008 – Sept
2009

Measured O3, CO, CO2, CH4, and N2O total columns
for E-AERI and PAERI


Both instruments have high
sensitivity to tropospheric
trace gases and
lower-stratospheric O3
Difference between E-AERI
and PAERI measurements <10%
Future Work




Measurements at 0PAL
Automation
Investigate of other trace gases that can be
retrieved by E-AERI (e.g. NOx)
Use extended spectral range to investigate
‘dirty window’ (400 cm-1 region) to determine
changing Arctic radiative balance
Acknowledgements





Centre for Global Change Science (CGCS)
CANDAC and PEARL are supported by:
 ARIF, AIF/NSRIT, CFCAS, CFI, CSA, EC, GOC-IPY,
NSERC, OIT, ORF, INAC, and PCSP
Logistical and operational support at Eureka:
 CANDAC operators
 Team at the EC Weather Station
 CANDAC/PEARL PI J.R. Drummond
 CANDAC data manager Yan Tsehtik
Canadian Arctic ACE Validation Campaigns supported by:
 CSA, EC, NSERC, and NSTP
Thank You! Questions?
Photo by Paul Loewen