We have developed numerical codes that can be used to calculate aerosol extinction from CMAQ aerosol, parameters for each height layer. Once the extinction / backscatter for the correct wavelength is calculated, we can compare CMAQ backscatter directly to lidar as well as integrated aerosol extinction to total optical depth defined as Gary Bouton, Department of ESE, CCNY Crae Sosa, Bard High School Early College Dr. Barry Gross, Department of Electrical Engineering, CCNY INTRODUCTION PRODCEDURE CONCLUSIONS / FUTURE WORK REFERENCES ACKNOWLEDGEMENTS Aerosols are liquid or solid substances suspended in the atmosphere. Aerosols come from content under high amounts of pressure that are released as fine particles usually pollutants… –Paint –Detergent –Insecticide –Aerosols have dramatic effect on air quality and climate EPA is mandated in the coming years to provide predictions of Air Quality just like the National Weather Service is Mandated to provide weather forecasts. CMAQ (Community Multiscale and Air Quality) predicts microphysical properties of aerosols retrieved at different heights due to emission inventories and meteorological transport. However, validation is mainly confined to surface measurements and does not address the vertical information. Therefore, we wish to validate CMAQ retrievals using optical remote sensing measurements suited for vertical retrieval of optical coefficients such as backscatter, and extinction of aerosol species Including Sky radiometer which gives total column optical depth at different wavelengths. Lidar which gives backscatter vertical profiles directly The main purpose of this project is to learn enough about modeling the optical properties of aerosols that can be used in future to connect output from the CMAQ Model to optical measurements above. Christopher J. Paciorek, Yang Liu, Hortensia Moreno-Macias, and Shobha Kondragunta, "Spatio-temporal Associations Between GOES Aerosol Optical Depth Retrievals and Ground-Level PM2.5" (December 2007). Harvard University Biostatistics Working Paper Series. Working Paper Article: An empirical relationship between PM2.5 and aerosol optical depth in Delhi Metropolitan (Naresh Kumara,Allen Chub, Andrew Foster - Department of Geography, 316 Jessup Hall, University of Iowa, Iowa City, IA 52242, USA) P1.7 ANALYZING AEROSOLS OVER THE U. S. IN NEAR REAL-TIME WITH MODIS Anthony Wimmers*, A. Scott Bachmeier, Scott Lindstrom, Jerrold Robaidek, William Bellon, Kathleen Strabala, Nikhil Kumar University of Wisconsin – Cooperative Institute for Meteorological Satellite Studies Dr. Barry Gross Dr Viviana Vladutescu Dr. Frank Scalzo Dr. Reginald Blake Dr. Shakila Merchant AtmosphereLidar Principle Lidar acts like Radar sending pulses into the air and measuring range by time of flight echo. Lidar can give range dependant backscatter which provides an incredibly good test for CMAQ However, aerosol sizes are modeled as continuous distributions so we used Matlab to simulate CMAQ data with the following formula To calculate extinction we then would need to sum the distribution of particles(Nv) multiplied by extinction coefficient (a function of refractive index(m) and q() Instead of summing all particulate distributions over special radial ranges, Matlab has built in integration tools that allow this to be done more efficiently. Transforming the prior formula to Where dN/dr is change in size distribution over change in particulate radii PRELIMINARY OPTICAL COEFFICIENTS CALCULATIONS Wavelength with respect to extinction compared to CMAQ data. (SUSO00) Mie Scattering Less sensitivity to wavelength Very big particles like clouds have No sensitivity to wavelength Therefore, they are white. With Gaussian distribution (radii) there would be a small but finite probability that a particle radius is negative (nonsense) A common distribution used that eliminates this problem is the log-normal distribution sigma(width) Rmod(Dry) Aerosol density from radial distribution of Sea Salt (acc mode) Rayleigh Scattering Regime Extinction Behavior as function of wavelength (ref index = 1.5) Comparisons of sulfate aerosols at 0% humidity from our modeled extinction and backscatter coefficients (blue) with those obtained by CMAQ (green) Note that after Normalizations that there is good correlation with our model and their data. Normalizations require detailed information on density and units and is still being worked out Wavelength with respect to backscatter compared to CMAQ data. (SUSO00) The total Optical depth from CMAQ is calculated as and can then be compared to our Sky Radiometer measurements. Underestimated PBL consistent With overestimate Of CMAQ PM2.5 WHY IS VERTICAL PBL INFORMATION SO IMPORTANT Incorrect underestimation of PBL height leads to the overestimation of PM2.5, since these same emissions are forced into smaller volume. Never understand error without Lidar data LIDAR PRINCIPLES Radiometer for Optical Depth Lidar for vertical Backscatter Modeling Optical Properties of Aerosols Using Microphysical Retrievals from Air Quality Models