2007 Cumulus Humilis Aerosol Process Study (CHAPS)

4 June 2007 - 25 June 2007

Lead Scientist: Carl Berkowitz

Observatory: osc, osc

The primary goal of this campaign was to characterize and contrast freshly emitted aerosols above, within and below fields of cumulus humilis (or fair-weather cumulus, FWC) and to use these observations to address how below-cloud and above-cloud aerosol optical and cloud nucleating properties differ downwind of a mid-size city relative to similar aerosols in air less affected by emissions. The observations from this campaign can also be used to aid in the development and evaluation of parameterizations of the transformation and transport of these aerosols by FWC for use in regional-scale and Global Climate Models. This final product has the potential to reduce the uncertainties associated with the treatment of aerosols by these models.

During CHAPS, the DOE Gulfstream-1 (G-1) aircraft carried two broad categories of instruments to measure climate-relevant properties of aerosols. One set of instruments measured the properties of aerosols found within individual cloud droplets. The other set of instruments measured these same properties both for aerosols not incorporated into cloud droplets as well as aerosols found outside of the larger cloudy environment. Joining the G-1 was the NASA Langley Research Center’s King Air Be-200. This aircraft had a High Spectral Resolution Lidar (HSRL) onboard to obtain profiles of aerosol backscatter and extinction in the vicinity of these clouds. Measurements were also made of the composition of aerosols inside and outside of the urban plume in order to characterize both activated and interstitial aerosols. Due to the transient nature and the small spatial scale of the individual FWC, this study looked at the aerosol properties in aggregate, rather than data from individual transects through a cloud. Surface measurements made just north of Oklahoma City can be used to continuously characterize aerosol and chemical features within the boundary layer.


Larry Berg
Richard Ferrare
Chris Hostetler
John Ogren



Mei F, D Dexheimer, J Fast, M Diao, B Geerts, A Bucholtz, L Riihimaki, C Flynn, T Thornberry, T Campos, S Springston, C Kuang, J Tomlinson, and B Schmid. 2020. ARM Aerial Instrument Workshop Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-20-010.


Berg L and P Lamb. 2016. "Surface Properties and Interactions: Coupling the Land and Atmosphere within the ARM Program." Meteorological Monographs, 57, 10.1175/AMSMONOGRAPHS-D-15-0044.1.


Berg LK, M Shrivastava, RC Easter, JD Fast, EG Chapman, Y Liu, and RA Ferrare. 2015. "A new WRF-Chem treatment for studying regional-scale impacts of cloud processes on aerosol and trace gases in parameterized cumuli." Geoscientific Model Development, 8(2), 10.5194/gmd-8-409-2015.
Research Highlight


Rogers R, M Vaughan, C Hostetler, S Burton, R Ferrare, S Young, J Hair, M Obland, D Harper, A Cook, and D Winker. 2014. "Looking through the haze: evaluating the CALIPSO level 2 aerosol optical depth using airborne high spectral resolution lidar data." Atmospheric Measurement Techniques, 7(12), 10.5194/amt-7-4317-2014.


Shrivastava M, L Berg, J Fast, D Easter, A Laskin, E Chapman, W Gustafson, Y Liu, and C Berkowitz. 2013. Modeling Aerosols and their Interactions with Shallow Cumuli. Presented at 4th Atmospheric System Research (ASR) Science Team Meeting. Potomac, MD.

Shrivastava M, LK Berg, J Fast, R Easter, A Laskin, WI Gustafson, Y Liu, and CM Berkowitz. 2013. "Modeling aerosols and their interactions with shallow cumuli during the 2007 CHAPS field study." Journal of Geophysical Research: Atmospheres, 118(3), 10.1029/2012jd018218.
Research Highlight


Burton SP, RA Ferrare, CA Hostetler, JW Hair, RR Rogers, RR Obland, CF Butler, AL Cook, DB Harper, and KD Froyd. 2012. "Aerosol classification using airborne High Spectral Resolution Lidar measurements – methodology and examples." Atmospheric Measurement Techniques, 5(1), 10.5194/amt-5-73-2012.


Berg LK, CM Berkowitz, JC Barnard, G Senum, and SR Springston. 2011. "Observations of the first aerosol indirect effect in shallow cumuli." Geophysical Research Letters, 38(3), L03809, 10.1029/2010gl046047.
Research Highlight

Fast J, M Shrivastava, E Champman, R Ferrare, C Hostetler, and L Berg. 2011. Simulating Aerosols Entrained Into Fair Weather Cumulus During CHAPS. Presented at 2nd Atmospheric System Research (ASR) Science Team Meeting. San Antonio, TX.

Farrare R, M Clayton, D Turner, C Hostetler, J Hair, M Obland, R Rogers, A Swanson, A Jefferson, and H Jonsson. 2011. Raman Lidar and HSRL Measurements of Aerosol and Water Vapor Variability. Presented at 2nd Atmospheric System Research (ASR) Science Team Meeting. San Antonio, TX.

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Campaign Data Sets

IOP Participant Data Source Name Final Data
Larry Berg Total Sky Imager- Ground Order Data
Manvendra Dubey Photoacoustic Spectroscopy- T0 Site Order Data
Richard Ferrare HSR Lidar Order Data
John Hubbe Passive Cavity Aerosol Spectrometer Order Data
Alexander Laskin Cloud Condensation Nuclei Counter Order Data
Alexander Laskin Time Resolved Aerosol Collectors (CVI inlet) Order Data
Alexander Laskin Time Resolved Aerosol Collectors (ISO inlet) Order Data
Yin-Nan Lee Time of Flight Aerosol Mass Spectrometer Order Data
John Ogren Condensation Particle Counter Order Data
John Ogren Nephelometer Order Data
John Ogren Particle Soot Absorption Photometer - G-1 Aircraft Order Data
John Ogren Tunable Diode Laser (CVI) Order Data
Jason Olfert Fast Integrated Mobility Spectrometer Order Data
Mikhail Pekour Aerosol Monitoring System- Ground Order Data
Mikhail Pekour Radiosonde Data Order Data
Gunnar Senum Cloud Aerosol Precip Spectrometer(CAPS)/Cloud Imaging Probe (CIP) Order Data
Gunnar Senum Cloud and Aerosol Spectrometer Order Data
Jian Wang Scanning mobility particle sizer Order Data