Project at a Glance

Title: Determination of the spatial distribution of ozone precursor and greenhouse gas concentrations and emissions on the LA-Basin

Principal Investigator / Author(s): Stutz, Jochen and Qinlin Li, Stan Sander

Contractor: UC Los Angeles

Contract Number: 09-318

Research Program Area: Atmospheric Processes, Climate Change

Topic Areas: Area Sources, Field Studies, Greenhouse Gas Emissions


The monitoring of pollutants and greenhouse gases is crucial to support efforts by the State of California to improve air quality and combat climate change. Two remote sensing methods, a multi-axis Differential Optical Absorption Spectroscopy (MAX-DOAS) instrument and a Fourier Transform Spectrometer (CLARS-FTS) to monitor pollutants and greenhouse gases, were developed and deployed at JPL's California Laboratory for Atmospheric Remote Sensing (CLARS) on Mt. Wilson (1673 meters asl) to scan the Los Angeles Basin. A version of the regional air quality model WRF-Chem for the LA basin was developed and validated for the 2010 CalNex Study.

Vertical profiles of NO2 concentrations and aerosol extinction were retrieved from the MAX-DOAS observations. MAX-DOAS HCHO/NO2 ratios show a decreased VOC sensitivity during the weekends compared to weekdays due to lower NO2 levels on the weekends, in agreement with WRF-Chem results. Elevated CH4:CO2 ratios were observed in west Pasadena and in the eastern LA basin by the CLARS-FTS. The annual basin total top-down CH4 emissions was derived to be 0.39±0.06 Tg CH4 per year, significantly larger than the bottom-up emissions. The preliminary annual top-down CO2 emissions of 211±12 Tg CO2/year in 2011, 230±12 Tg CO2/year in 2012, 212±11 Tg CO2/year in 2013, and 204±10 Tg CO2/year in 2014, were about 10-15% greater than the CARB bottom-up CO2 emissions in 2012.

For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

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