My research interests include validating and analyzing data from satellite-based instruments and developing reference global aerosol and trace-gas climatologies and time series analysis with a special emphasis on trend detection and climate change. My doctoral thesis involved the retrieval of microphysical properties such as size distribution, surface area concentrations, volume concentrations and effective radius from the Stratospheric Aerosol and Gas Experiment (SAGE) II measurements with a special emphasis on Mt. Pinatubo aerosol properties. I joined the Center for Atmospheric Sciences (CAS) staff as a post-doctoral research fellow in May of 1998.
I have previously merged trace-gas records measured by the SAGE II, Aura Microwave Limb Sounder (MLS), Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS), and the Halogen Occultation Experiment (HALOE) instruments as part of the NASA MEaSUREs Global OZone Chemistry And Related trace gas Data records for the Stratosphere (GOZCARDS) project [see Froidevaux et. al (2016) for details]. The purpose of the project was to create composite data records of trace gases important in stratospheric ozone chemistry. Composite data records are useful in principle due to the fact that they are sufficiently long enough to exhibit changes (such as ozone recovery) over decadal time scales, provide boundary conditions for Global Climate Model (GCM) simulations, and they are a vital tool in validating Chemistry Climate Model (CCM) simulations. The GOZCARDS project spanning from 1978 through the present created one such composite ozone record. The GOZCARDS composite ozone record is constructed of measurements from SAGE I, SAGE II, HALogen Occultation Experiment (HALOE), ACE-FTS, MLS on the Upper Atmosphere Research Satellite (UARS) and Aura. The GOZCARDS team also developed a Hydrogen Chloride (HCl) composite data record constructed from HALOE, ACE-FTS, and Aura MLS measurements. This record has proven to be useful in corroborating northern hemisphere HCl increases due to atmospheric circulation changes as measured by column-based Fourier Transform Thermal Infrared Spectroscopy (FTIR) measurements made at various NDACC locations and SLIMCAT model results (Mahieu et al., 2014). Furthermore, GOZCARDS ozone data were used in a study by Ball et. Al (2018) that showed surprising decreases in lower stratospheric ozone since 1998.
I have participated in the SPARC Data Initiative where trace-gas and aerosol climatologies from HALOE were constructed for comparison with other satellite data sets. I am also the Deputy Campus PI on the NOAA EPP Cooperative Science Center for Earth System Science Remote Sensing Technology (CREST).