Atmospheric Radiation Measurement Climate Research Facility US Department of Energy



Two-Column Aerosol Project (TCAP): CU GMAX-DOAS Deployment

15 July 2012 - 31 August 2012

Lead Scientist: Rainer Volkamer

Observatory: AMF, PVC

The University of Colorado has developed an innovative passive remote sensor, the CU 2D scanning ground Multi AXis Differential Optical Absorption Spectroscopy (2D-GMAX-DOAS) instrument that features an azimuth- and elevation angle scanning telescope to measure scattered and direct sun light radiance spectra. These spectra are analyzed by DOAS non-linear least square fitting to retrieve trace gas slant column densities (SCD, i.e., NO2, HONO, HCHO, CHOCHO, BrO, IO, O4 SCDs, and Raman Scattering Probability). In a second step aerosol extinction and trace gas vertical distributions are retrieved by constrained optimal estimation/regularization algorithms by inverse modeling of Radiative Transfer Modeling (RTM). 2D-GMAX-DOAS retrievals are based exclusively on relative intensity changes, i.e., do not require absolute radiance calibrations, which minimizes the need for instrument maintenance; the instrument can be remote controlled via internet, operates quasi-autonomously, and is optimized for measurements in remote locations for extended periods of time. In addition, the CU-LED-CE-DOAS instrument provides in-situ observations for NO2, CHOCHO and O4 near the surface (within the surface roughness layer).

The CU 2D-GMAX-DOAS and LED-CE-DOAS instruments were operated during the TCAP field intensive period (15 July to 31 August 2012) at Cape Cod, MA, where ground-based aerosol measurements made with the DOE Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) and Mobile Aerosol Observing System (MAOS) provide an opportunity for 1) atmospheric radiation closure studies (incl. correction of 2D-GMAX-DOAS derived NO2 vertical columns in MFRSR retrievals); 2) test retrievals of aerosol optical depth by 2D-GMAX-DOAS and compare with Cimel sunphotometer, and MFRSR in the presence and absence of clouds; and 3) study secondary organic aerosol (SOA) formation from processing of glyoxal in cloud and aerosol water by combining experimental observations of glyoxal by CU GMAX-DOAS and CU LED-CE-DOAS with numerical models. 2D-GMAX-DOAS column observations bridge between spatial scales probed by in-situ sensors, satellites and those predicted by atmospheric models. The TCAP experiment presents the first field deployment of 2D-GMAX-DOAS outside Boulder


Hilke Oetjen
Ivan Ortega

Related Publications


Fast JD, LK Berg, K Zhang, RC Easter, RA Ferrare, JW Hair, CA Hostetler, Y Liu, I Ortega, A Sedlacek III, JE Shilling, M Shrivastava, SR Springston, JM Tomlinson, R Volkamer, J Wilson, RA Zaveri, and A Zelenyuk. 2016. "Model representations of aerosol layers transported from North America over the Atlantic Ocean during the Two-Column Aerosol Project." Journal of Geophysical Research: Atmospheres, 121(16), 10.1002/2016jd025248.
Research Highlight


Ortega I, S Coburn, E Kassianov, J Barnard, LK Berg, CA Hostetler, JW Hair, RA Ferrare, and RM Volkamer. 2012. 2D-GMAX-DOAS Measurements During TCAP: Comparison with MFRSR, HSRL and Simultaneous Retrievals of Trace Gases and Aerosol Optical Properties. Presented at Fall American Geophysical Union Meeting. San Francisco, CA.


Baidar S, H Oetjen, I Ortega, C Cai, A Kaduwela, S Kim, and R Volkamer. 2011. Vertical Profiles and Column Densities of NO2 by the CU Airbone MAX-DOAS: Comparison with Model Simulations. Presented at Fall American Geophysical Union Meeting. San Francisco, CA.

View All Related Publications

PVC Data Sources

Name Full Name Browse Data
ACSM Aerosol Chemical Speciation Monitor Browse Data
AERI Atmospheric Emitted Radiance Interferometer Browse Data
AERINF AERI Noise Filtered Browse Data
AETH Aethalometer Browse Data
AIP Aerosol Intensive Properties Browse Data
AOD Aerosol Optical Depth, derived from atmospheric extinction of solar irradiance Browse Data
AOS Aerosol Observing System Browse Data
AOSCCNAVG Aerosol Observing System (AOS): cloud condensation nuclei data, averaged Browse Data
AOSMET Meteorological Measurements associated with the Aerosol Observing System Browse Data
CCN Cloud Condensation Nuclei Particle Counter Browse Data
CEIL Ceilometer Browse Data
CLAP Continuous Light Absorption Photometer Browse Data
CO-ANALYZER Carbon Monoxide Analyzer Browse Data
CPC Condensation Particle Counter Browse Data
CSPHOT Cimel Sunphotometer Browse Data
DL Doppler Lidar Browse Data
DLPROF Doppler Lidar Profiles Browse Data
ECMWFDIAG European Centre for Medium Range Weather Forecasts Diagnostic Analyses Browse Data
ECOR Eddy Correlation Flux Measurement System Browse Data
GNDRAD Ground Radiometers on Stand for Upwelling Radiation Browse Data
IRT Infrared Thermometer Browse Data
KASACR Ka-Band Scanning ARM Cloud Radar Browse Data
MET Surface Meteorological Instrumentation Browse Data
MFR Multifilter Radiometer Browse Data
MFRSR Multifilter Rotating Shadowband Radiometer Browse Data
MFRSRCLDOD Cloud Optical Properties from MFRSR Using Min Algorithm Browse Data
MPL Micropulse Lidar Browse Data
MPLCMASK Cloud mask from Micropulse Lidar Browse Data
MWR Microwave Radiometer Browse Data
MWR3C Microwave Radiometer, 3 Channel Browse Data
MWRHF Microwave Radiometer - High Frequency Browse Data
MWRP Microwave Radiometer Profiler Browse Data
MWRRET MWR Retrievals Browse Data
NEPHELOMETER Nephelometer Browse Data
NFOV Narrow Field of View Zenith Radiometer Browse Data
NOX Nitrogen Oxides Monitor Browse Data
OZONE Ozone Monitor Browse Data
PASS Photoacoustic Soot Spectrometer Browse Data
PSAP Particle Soot Absorption Photometer Browse Data
QCRAD Data Quality Assessment for ARM Radiation Data Browse Data
RWP Radar Wind Profiler Browse Data
SACRADVVAD SACR Advance Velocity Azimuth Display Browse Data
SASHE Shortwave Array Spectroradiometer-Hemispheric Browse Data
SASZE Shortwave Array Spectroradiometer-Zenith Browse Data
SEBS Surface Energy Balance System Browse Data
SKYRAD Sky Radiometers on Stand for Downwelling Radiation Browse Data
SMPS Scanning mobility particle sizer Browse Data
SO2 Sulfur Dioxide Monitor Browse Data
SODAR Mini Sound Detection and Ranging Browse Data
SONDE Balloon-Borne Sounding System Browse Data
SONDEADJUST Sonde Adjust Browse Data
TSI Total Sky Imager Browse Data
TWRCAM Tower Camera Browse Data
UHSAS Ultra-High Sensitivity Aerosol Spectrometer Browse Data
WACR W-Band (95 GHz) ARM Cloud Radar Browse Data
WACRARSCL W-band Cloud Radar Active Remote Sensing of Cloud Browse Data
WSACR W-band Scanning ARM Cloud Radar Browse Data