TY - JOUR
T1 - Climatology of aerosol radiative properties in the free troposphere
AU - Andrews, E.
AU - Ogren, J. A.
AU - Bonasoni, P.
AU - Marinoni, A.
AU - Cuevas, E.
AU - Rodríguez, S.
AU - Sun, J. Y.
AU - Jaffe, D. A.
AU - Fischer, E. V.
AU - Baltensperger, U.
AU - Weingartner, E.
AU - Coen, M. Collaud
AU - Sharma, S.
AU - Macdonald, A. M.
AU - Leaitch, W. R.
AU - Lin, N. H.
AU - Laj, P.
AU - Arsov, T.
AU - Kalapov, I.
AU - Jefferson, A.
AU - Sheridan, P.
N1 - Funding Information:
Support for the Mount Bachelor Observatory was provided by the National Science Foundation under grant ATM-0724327 . Emily V. Fischer was supported by a Department of Energy Graduate Research Environmental Fellowship.
Funding Information:
Co-operation and support from the Environmental Management group of Whistler–Blackcomb is gratefully acknowledged. We thank the site operators, Juniper Buller and Anton Horvath, the maintenance staff, lift operators and members of ski patrol. We also thank Dave Halpin for technical support.
Funding Information:
We thank the International Foundation High Altitude Research Stations Jungfraujoch and Gornergrat (HFSJG), which made it possible to carry out the experiments at the High Altitude Research Station at the Jungfraujoch. This work was supported by MeteoSwiss within the Swiss program of the Global Atmosphere Watch (GAW) of the World Meteorological Organization as well as the EU FP6 project EUSAAR.
Funding Information:
The Basic Environment Observatory (BEO) is supported by the Institute for Nuclear Research and Nuclear Energy within the Bulgarian Academy of Sciences. Measurements of meteorological parameters began in 2003, measurements of greenhouse gasses (ozone, CO 2 , NO x ), and trace gasses concentrations (CO, SO 2 ) began in 2006 ( Angelov et al., 2011 ). Light scattering measurements began in 2007. Nojarov et al. (2009) studied ozone concentrations at BEO and saw differences in concentration depending on wind direction and time of day. They suggested the site had little boundary layer influence in the winter but transport from lower elevations was common in the summer.
Funding Information:
Monte Cimone data presented here benefited from measurements performed within the European Commission funded FP6-EUSAAR Integrated Infrastructure Initiative.
PY - 2011/12
Y1 - 2011/12
N2 - High altitude mountaintop observatories provide the opportunity to study aerosol properties in the free troposphere without the added expense and difficulty of making airborne measurements. Climatologies for free tropospheric aerosol radiative properties in cloud-free air, including light scattering, light absorption, light extinction, single scattering albedo, Ångström exponent, hemispheric backscatter fraction and radiative forcing efficiency, from twelve high altitude (2.2-5.1km) measurement platforms are presented at low relative humidity and at standard temperature and pressure. These climatologies utilize data from ten mountaintop observatories in the 20-50-0N latitude band: Mauna Loa, USA; Lulin Mountain, Taiwan; Nepal Climate Observatory - Pyramid; Izaña, Spain; Mount Waliguan, China; Beo Moussala, Bulgaria; Mount Bachelor, USA; Monte Cimone, Italy; Jungfraujoch, Switzerland; Whistler Mountain, Canada. Results are also included from two multi-year, in-situ aerosol vertical profiling programs: Southern Great Plains, USA and Bondville, USA. The amount of light absorption and scattering observed at these high altitude sites either peaks in the spring or it has a broad spring to summer enhancement. The seasonal variation of the aerosol single scattering albedo, backscatter fraction and Ångström exponent changes from site to site but the timing can be related to aerosol sources and transport processes known to impact the individual sites. The seasonal variation of in-situ aerosol light extinction from these high altitude measurements is in excellent agreement with extinction values derived from CALIPSO lidar measurements. Analysis of the systematic variability among in-situ aerosol properties shows that these relationships can be used to infer aerosol types. In particular, the relationship between single scattering albedo and Ångström exponent can indicate the presence of dust aerosol. Radiative forcing efficiency (RFE=aerosol forcing/aerosol optical depth) is used to assess the importance of single scattering albedo and backscatter fraction on aerosol forcing by eliminating aerosol amount (i.e., aerosol optical depth) from the calculation. Variability in monthly cycles of RFE corresponds with changes in single scattering albedo and hemispheric backscatter fraction. Utilizing site-specific, climatological values of single scattering albedo and backscatter fraction to calculate RFE results in departures from the monthly median values of RFE typically in the range 10-30%. The greatest discrepancy occurs for months with low aerosol loading where the observed variability of single scattering albedo and backscatter fraction is the greatest. At most sites the radiative forcing efficiency at low aerosol loading (light scattering<10Mm-1) is slightly less negative (more warming) than at higher aerosol loading.
AB - High altitude mountaintop observatories provide the opportunity to study aerosol properties in the free troposphere without the added expense and difficulty of making airborne measurements. Climatologies for free tropospheric aerosol radiative properties in cloud-free air, including light scattering, light absorption, light extinction, single scattering albedo, Ångström exponent, hemispheric backscatter fraction and radiative forcing efficiency, from twelve high altitude (2.2-5.1km) measurement platforms are presented at low relative humidity and at standard temperature and pressure. These climatologies utilize data from ten mountaintop observatories in the 20-50-0N latitude band: Mauna Loa, USA; Lulin Mountain, Taiwan; Nepal Climate Observatory - Pyramid; Izaña, Spain; Mount Waliguan, China; Beo Moussala, Bulgaria; Mount Bachelor, USA; Monte Cimone, Italy; Jungfraujoch, Switzerland; Whistler Mountain, Canada. Results are also included from two multi-year, in-situ aerosol vertical profiling programs: Southern Great Plains, USA and Bondville, USA. The amount of light absorption and scattering observed at these high altitude sites either peaks in the spring or it has a broad spring to summer enhancement. The seasonal variation of the aerosol single scattering albedo, backscatter fraction and Ångström exponent changes from site to site but the timing can be related to aerosol sources and transport processes known to impact the individual sites. The seasonal variation of in-situ aerosol light extinction from these high altitude measurements is in excellent agreement with extinction values derived from CALIPSO lidar measurements. Analysis of the systematic variability among in-situ aerosol properties shows that these relationships can be used to infer aerosol types. In particular, the relationship between single scattering albedo and Ångström exponent can indicate the presence of dust aerosol. Radiative forcing efficiency (RFE=aerosol forcing/aerosol optical depth) is used to assess the importance of single scattering albedo and backscatter fraction on aerosol forcing by eliminating aerosol amount (i.e., aerosol optical depth) from the calculation. Variability in monthly cycles of RFE corresponds with changes in single scattering albedo and hemispheric backscatter fraction. Utilizing site-specific, climatological values of single scattering albedo and backscatter fraction to calculate RFE results in departures from the monthly median values of RFE typically in the range 10-30%. The greatest discrepancy occurs for months with low aerosol loading where the observed variability of single scattering albedo and backscatter fraction is the greatest. At most sites the radiative forcing efficiency at low aerosol loading (light scattering<10Mm-1) is slightly less negative (more warming) than at higher aerosol loading.
KW - Aerosol radiative properties
KW - Climatology
KW - Free troposphere
UR - http://www.scopus.com/inward/record.url?scp=79960220943&partnerID=8YFLogxK
U2 - 10.1016/j.atmosres.2011.08.017
DO - 10.1016/j.atmosres.2011.08.017
M3 - 回顧評介論文
AN - SCOPUS:79960220943
SN - 0169-8095
VL - 102
SP - 365
EP - 393
JO - Atmospheric Research
JF - Atmospheric Research
IS - 4
ER -