High speed size distribution measurements of aerosol particles

Time: Wednesday, November 8, 2017 - 2:30pm - 3:30pm
Type: Seminar Series
Presenter: Jian Wang; Environmental and Climate Sciences Department, Brookhaven National Laboratory
Room/Office: Room 107
Mason Lab
9 Hillhouse Avenue
New Haven, CT 06511
United States

Department of Mechanical Engineering & Materials Science Seminar

Professor Jian Wang
Environmental and Climate Sciences Department
Brookhaven National Laboratory

"High speed size distribution measurements of aerosol particles"

Aerosols strongly influence the radiative properties of clouds, and the impact of aerosols on clouds represents one of the largest uncertainties in computer simulations of climate change. The large uncertainty is in a large part due to a poor understanding of aerosol properties and processes under natural conditions, which serves as the baseline to measure the change against. The size distribution of aerosol particles is a key property required for assessing the ability of aerosol to influence clouds and climate. In this talk, I will first present a Fast Integrated Mobility Spectrometer (FIMS) developed for high speed measurements of aerosol size distribution. By combining mobility classifying, condensation growth, and optical imaging, FIMS simultaneously detects individual particles over a wide size range, allowing measurements of aerosol size distribution from 10 nm to 500 nm within a second. This represents a factor of 50 improvement in measurement speed over traditional techniques. The FIMS was deployed on board the US Department of Energy Gulfstream-1 (G-1) aircraft in the Amazon basin during Observations and Modeling of the Green Ocean Amazon campaign. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions. Cloud condensation nuclei (i.e., a subset of aerosol particles that can form cloud droplets in the atmosphere) in Amazonia are mostly produced by the growth of smaller particles in the planetary boundary layer. However, the origin of these smaller particles has remained unclear. Using the fast size distribution measurements on board the G-1 and relevant data taken at the Amazon Tall Tower Observatory (ATTO), I will examine the source of boundary layer particles that maintains the population of cloud condensation nuclei under natural conditions.

Wednesday, November 11, 2017
2:30 – 3:30 pm
Location – Mason 107
Host: Professor Juan de la Mora

Refreshments served at 2:15 pm