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Anna Wonaschütz ATMO 529 Class Project Dec. 3rd, 2007. Time Variability of Chemical Species in Mt. Lemmon Aerosol using Principal Component Analysis. Matichuk et al., 2006 mass concentration (monthly averages) of: 8 chemical species in aerosols 4 aerosol precursor gases PM2.0
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Anna Wonaschütz ATMO 529 Class Project Dec. 3rd, 2007 Time Variability of Chemical Species in Mt. LemmonAerosol using Principal Component Analysis
Matichuk et al., 2006 mass concentration (monthly averages) of: 8 chemical species in aerosols 4 aerosol precursor gases PM2.0 time range: Sept. 1992 - Apr. 2003 location: Mt. Lemmon, AZ Description of the Data (I)
Mt. Lemmon, elevation: 2791 m/9157 ft winter (NDJF): summit in free troposphere (clean, continental air masses) summer(MJJA): summit in planetary boundary layer fall (SO) and spring (MA): boundary layer depth varies Shaw, 2007, Philippin & Betterton, 1997 Location
Mt. Lemmon, elevation: 2791 m/9157 ft winter (NDJF): summit in free troposphere (clean, continental air masses) summer(MJJA): summit in planetary boundary layer fall (SO) and spring (MA): boundary layer depth varies Shaw, 2007, Philippin & Betterton, 1997 Location
Aerosol (PM2.0): sulfate (SO42-), nitrate (NO3-), chloride (Cl-), sodium (Na+), ammonium (NH4+), calcium (Ca2+), elemental carbon (EC), organic carbon (OC) precursor gases: ammonia (NH3), nitric acid (HNO3), sulfuric acid (H2SO4, proxy for SO2), hydrochloric acid (HCl) Description of the Data (II)
Summary of results from Matichuk et al., 2006: 1. all species show a strong seasonal dependence 2. trends: - OC, Cl- and Na+: insignificant - NH3, SO42-, NH4+, SO2: negative - all other species: positive Description of the Data (III)
PCA using SVD: U...principal components (derived variables) S...singular values (square root of eigenvalues) V...EOF's (eigenvectors of the correlation matrix) 1st PC: timeseries that represents most of the variability of the original dataset, i.e. the timeseries of the chemical species EOF's: contribution of the PC to each species Analysis Method data = USV
units: mg/m3 (aerosol), ppbv (gases) standardize gaps: gap in one chemical species – eliminate those months for all other species Data Preparation
Matichuk R., Barbaris B., Betterton E., Hori M., Murao N., Ohta S., Ward D.: “A Decade of Aerosol and Gas Precursor Chemical Characterization at Mt. Lemmon, Arizona (1992 to 2002)”, Journal of the Meteorological Society of Japan, Vol. 84, No.4, 2006 Philippin S., Betterton E.A.: “Cloud Condensation Nuclei Concentrations in Southern Arizona: Instrumentation and Early Observations”, Atmospheric Research 43 (3), 1997 J.H. Seinfeld & S.N. Pandis: “Atmospheric Chemistry and Physics”, 2nd edition, 2006, John Wiley & Sons, Inc. Shaw G.: “Aerosols at a mountaintop observatory in Arizona”, Journal of Geophysical Research, Vol. 112, 2007 D.S. Wilks: “Statistical Methods in the Atmospheric Sciences”, 2nd edition, 2006, Elsevier References