htdma: Humidified Tandem Differential Mobility Analyzer

The humidified tandem differential mobility analyzer (HTDMA) is part of the aerosol observing system (AOS).

It measures how aerosol particles of different initial dry sizes grow or shrink when exposed to changing relative humidity (RH). It uses two different mobility analyzers (DMA) and a humidification system to make the measurements.

One DMA selects a narrow size range of dry aerosol particles, which are exposed to varying RH conditions in the humidification system. The second (humidified) DMA scans the particle size distribution output from the humidification system.

Scanning a wide range of particle sizes enables the second DMA to measure changes in size or growth factor (growth factor = humidified size/dry size) due to water uptake by the particles. A condensation particle counter (CPC) downstream of the second DMA counts particles as a function of selected size in order to obtain the number size distribution of particles exposed to different RH conditions.

Measurements

Locations

  • Fixed
  • AMF1
  • AMF2
  • AMF3

Active Instrument Locations

Facility Name Instrument Start Date
Graciosa Island, Azores, Portugal 2015-04-24
Lamont, OK (Extended and Co-located with C1) 2017-08-29
Andenes, Norway; AMF1 (main site for COMBLE) 2019-09-10

Related Publications

2019

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.

2018

Liu J, J Dedrick, L Russell, G Senum, J Uin, C Kuang, S Springston, W Leaitch, A Aiken, and D Lubin. 2018. "High summertime aerosol organic functional group concentrations from marine and seabird sources at Ross Island, Antarctica, during AWARE." Atmospheric Chemistry and Physics, 18(12), 10.5194/acp-18-8571-2018.

PZ, M Alvarado, C Chiu, S DeSzoeke, C Fairall, G Feingold, A Freedman, S Ghan, J Haywood, P Kollias, E Lewis, G McFarquhar, A McComiskey, D Mechem, T Onasch, J Redemann, D Romps, D Turner, H Wang, R Wood, S Yuter, and P Zhu. 2018. Layered Atlantic Smoke Interactions with Clouds (LASIC) Field Campaign Report. Ed. by Robert Stafford, ARM Climate Research Facility. DOE/SC-ARM-18-018.

Mahish M, A Jefferson, and D Collins. 2018. "Influence of Common Assumptions Regarding Aerosol Composition and Mixing State on Predicted CCN Concentration." Atmospheric Chemistry and Physics, 9(2), 10.3390/atmos9020054.

2017

Chen H, A Hodshire, J Ortega, J Greenberg, P McMurry, A Carlton, J Pierce, D Hanson, and J Smith. 2017. "Vertically resolved concentration and liquid water content of atmospheric nanoparticles at the US DOE Southern Great Plains site." Atmospheric Chemistry and Physics, 18(1), doi:10.5194/acp-18-311-2018.
Research Highlight

Fridlind A, X Li, D Wu, M van Lier-Walqui, A Ackerman, W Tao, G McFarquhar, W Wu, X Dong, J Wang, A Ryzhkov, P Zhang, M Poellot, A Neumann, and J Tomlinson. 2017. "Derivation of aerosol profiles for MC3E convection studies and use in simulations of the 20 May squall line case." Atmospheric Chemistry and Physics, 17(9), 10.5194/acp-17-5947-2017.
Research Highlight

2016

Lewis ER. 2016. Marine ARM GPCI Investigation of Clouds (MAGIC) Field Campaign Report. Ed. by Robert Stafford, DOE ARM Climate Research Facility. DOE/SC-ARM-16-057.

Mahish M, DR Collins, A Jefferson, PJ Marinescu, EJ Levin, PJ DeMott, and SM Kreidenweis. 2016. Seasonal and Interannual Variations in Aerosol Characteristics at the ARM Southern Great Plains Site. Presented at Annual American Meteorological Society (AMS) Meeting. Seattle, WA.

Kourtchev I, C Giorio, A Manninen, E Wilson, B Mahon, J Aalto, M Kajos, D Venables, T Ruuskanen, J Levula, M Loponen, S Connors, N Harris, D Zhao, A Kiendler-Scharr, T Mentel, Y Rudich, M Hallquist, J Doussin, W Maenhaut, J Bäck, T Petäjä, J Wenger, M Kulmala, and M Kalberer. 2016. "Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols." Scientific Reports, 6(1), 10.1038/srep35038.

Pajunoja A, W Hu, Y Leong, N Taylor, P Miettinen, B Palm, S Mikkonen, D Collins, J Jimenez, and A Virtanen. 2016. "Phase state of ambient aerosol linked with water uptake and chemical aging in the southeastern US." Atmospheric Chemistry and Physics, 16(17), 10.5194/acp-16-11163-2016.


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