1. Time Variability of Chemical Species in Mt. Lemmon Aerosol using Principal Component Analysis Anna Wonaschütz ATMO 529 Class Project Dec. 3rd, 2007

2. Description of the Data (I)‏ 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

3. 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

5. 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

6. Description of the Data (II)‏ Aerosol (PM2.0): sulfate (SO 4 2- ), nitrate (NO 3 - ), chloride (Cl - ), sodium (Na + ), ammonium (NH 4 + ), calcium (Ca 2+ ), elemental carbon (EC), organic carbon (OC)‏ precursor gases: ammonia (NH 3 ), nitric acid (HNO 3 ), sulfuric acid (H 2 SO 4, proxy for SO 2 ), hydrochloric acid (HCl)‏

7. Description of the Data (III)‏ Summary of results from Matichuk et al., 2006: 1. all species show a strong seasonal dependence 2. trends: - OC, Cl - and Na + : insignificant - NH 3, SO 4 2-, NH 4 +, SO 2 : negative - all other species: positive

8. Analysis Method PCA using SVD: U...principal components (derived variables)‏ S...singular values (square root of eigenvalues)‏ V...EOF's (eigenvectors of the correlation matrix)‏ 1 st 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 data = USV

9. Data Preparation units: mg/m 3 (aerosol), ppb v (gases) standardize gaps: gap in one chemical species – eliminate those months for all other species

11. 53 % variance explained

13. 15.5 % variance explained

16. References 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”, 2 nd 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”, 2 nd edition, 2006, Elsevier