uhsas: Ultra-High Sensitivity Aerosol Spectrometer

The ultra-high-sensitivity aerosol spectrometer (UHSAS) is an optical-scattering, laser-based, aerosol particle spectrometer system for sizing particles in the 60 to 1000 nanometer (nm) range [1–3].

The instrument counts particles in up to 100 user-specified sizing bins. The instrument’s laser illuminates particles, which scatter light. The system captures the peak light signals that are generated. These signals are used for particle sizing, since the amount of light scattered correlates strongly with particle size.

The UHSAS is part of the aerosol observing system (AOS).



  • Fixed
  • AMF1
  • AMF2
  • AMF3

Active Instrument Locations

Facility Name Instrument Start Date
Oliktok Point, Alaska; AMF3 2016-08-05
Graciosa Island, Azores, Portugal 2014-02-17
Lamont, OK (Extended and Co-located with C1) 2016-11-15


Levin E, P DeMott, K Suski, Y Boose, T Hill, C McCluskey, G Schill, K Rocci, H Al‐Mashat, L Kristensen, G Cornwell, K Prather, J Tomlinson, F Mei, J Hubbe, M Pekour, R Sullivan, L Leung, and S Kreidenweis. 2019. "Characteristics of Ice Nucleating Particles in and Around California Winter Storms." Journal of Geophysical Research: Atmospheres, , 10.1029/2019JD030831. ONLINE.
Research Highlight

Varble A, S Nesbitt, P Salio, E Avila, P Borque, P DeMott, G McFarquhar, S van den Heever, E Zipser, D Gochis, R Houze, M Jensen, P Kollias, S Kreidenweis, R Leung, K Rasmussen, D Romps, and C Williams. 2019. Cloud, Aerosol, and Complex Terrain Interactions (CACTI) Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-19-028.

Williamson C, A Kupc, D Axisa, K Bilsback, T Bui, P Campuzano-Jost, M Dollner, K Froyd, A Hodshire, J Jimenez, J Kodros, G Luo, D Murphy, B Nault, E Ray, B Weinzierl, J Wilson, F Yu, P Yu, J Pierce, and C Brock. 2019. "A large source of cloud condensation nuclei from new particle formation in the tropics." Nature, 574(7778), 10.1038/s41586-019-1638-9.

Yeom J, S Yum, F Mei, B Schmid, J Comstock, L Machado, and M Cecchini. 2019. "Impact of secondary droplet activation on the contrasting cloud microphysical relationships during the wet and dry seasons in the Amazon." Atmospheric Research, , 10.1016/j.atmosres.2019.104648. ONLINE.

Jensen M, E Bruning, D Collins, A Fridlind, P Kollias, C Kuang, D Rosenfeld, A Ryzhkov, A Varble, SD Brooks, S Collis, E Defer, J Fan, J Flynn, S Giangrande, R Griffin, J Hu, R Jackson, M Kumjian, T Logan, T Matsui, G McFarquhar, C Nowotarski, J Quaas, M Oue, R Sheesley, J Snyder, P Stier, S Usenko, S van den Heever, M van Lier Walqui, Y Wang, Y Xu, and G Zhang. 2019. Tracking Aerosol Convection Interactions ExpeRiment (TRACER) Science Plan. Ed. by Robert Stafford, DOE/SC-ARM-19-017.

Wang J, R Wood, M Jensen, E Azevedo, C Bretherton, D Chand, C Chiu, X Dong, J Fast, A Gettelman, S Ghan, S Giangrande, M Gilles, A Jefferson, P Kollias, C Kuang, A Laskin, E Lewis, X Liu, Y Liu, E Luke, A McComiskey, F Mei, M Miller, A Sedlacek, and R Shaw. 2019. Aerosol and Cloud Experiments in Eastern North Atlantic (ACE-ENA) Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-19-012.

McFarquhar G, R Marchand, C Bretherton, S Alexander, A Protat, S Siems, R Wood, and P DeMott. 2019. Measurements of Aerosols, Radiation, and Clouds over the Southern Ocean (MARCUS) Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-19-008.

Bretherton C, I Mccoy, J Mohrmann, R Wood, V Ghate, A Gettelman, C Bardeen, B Albrecht, and P Zuidema. 2019. "Cloud, Aerosol and Boundary Layer Structure across the Northeast Pacific Stratocumulus-Cumulus Transition as observed during CSET." Monthly Weather Review, 147(6), 10.1175/MWR-D-18-0281.1.


Zheng G, Y Wang, A Aiken, F Gallo, M Jensen, P Kollias, C Kuang, E Luke, S Springston, J Uin, R Wood, and J Wang. 2018. "Marine boundary layer aerosol in the eastern North Atlantic: seasonal variations and key controlling processes." Atmospheric Chemistry and Physics, 18(23), doi:10.5194/acp-18-17615-2018.
Research Highlight

Ahlgrimm M, R Forbes, R Hogan, and I Sandu. 2018. "Understanding Global Model Systematic Shortwave Radiation Errors in Subtropical Marine Boundary Layer Cloud Regimes." Journal of Advances in Modeling Earth Systems, 10(8), 10.1029/2018MS001346.
Research Highlight

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