htdma > Humidified Tandem Differential Mobility AnalyzerInstrument Type(s) > Baseline • Guest

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
Houston, TX; AMF1 (main site for TRACER) 2021-04-14
Graciosa Island, Azores, Portugal 2015-04-24

2021

Geerts B, G McFarquhar, L Xue, M Jensen, P Kollias, M Ovchinnikov, M Shupe, P DeMott, Y Wang, M Tjernstrom, P Field, S Abel, T Spengler, R Neggers, S Crewell, M Wendisch, and C Lupkes. 2021. Cold-Air Outbreaks in the Marine Boundary Layer Experiment (COMBLE) Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-21-001.

Uin J and S Smith. 2021. Southern Great Plains (SGP) Aerosol Observing System (AOS) Instrument Handbook. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-267.

2020

Uin J and S Smith. 2020. Second ARM Mobile Facility (AMF2) Aerosol Observing System (AOS) Instrument Handbook. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-264.

Uin J and S Smith. 2020. Eastern North Atlantic (ENA) Aerosol Observing System (AOS) Instrument Handbook. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-266.

Uin J and S Smith. 2020. Mobile Aerosol Observing System – Aerosols (MAOS-A) Instrument Handbook. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-263.

Uin J and S Smith. 2020. Third ARM Mobile Facility (AMF3) Aerosol Observing System (AOS) Instrument Handbook. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-265.

Zheng G, C Kuang, J Uin, T Watson, and J Wang. 2020. "Large contribution of organics to condensational growth and formation of cloud condensation nuclei (CCN) in the remote marine boundary layer." Atmospheric Chemistry and Physics, 20(21), 10.5194/acp-20-12515-2020.

Zheng G, A Sedlacek, A Aiken, Y Feng, T Watson, S Raveh-Rubin, J Uin, E Lewis, and J Wang. 2020. "Long-range transported North American wildfire aerosols observed in marine boundary layer of eastern North Atlantic." Environment International, 139, 10.1016/j.envint.2020.105680.

Lubin D, D Zhang, I Silber, R Scott, P Kalogeras, A Battaglia, D Bromwich, M Cadeddu, E Eloranta, A Fridlind, A Frossard, K Hines, S Kneifel, W Leaitch, W Lin, J Nicolas, H Powers, P Quinn, P Rowe, L Russell, S Sharma, J Verlinde, and A Vogelmann. 2020. "AWARE: The Atmospheric Radiation Measurement (ARM) West Antarctic Radiation Experiment." Bulletin of the American Meteorological Society, 101(7), 10.1175/BAMS-D-18-0278.1.

Lawler M, D Draper, and J Smith. 2020. "Atmospheric fungal nanoparticle bursts." Science Advances, 6(3), 10.1126/sciadv.aax9051.
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