nomadssThe Selin group is part of the NOMADSS (Nitrogen, Oxidants and Aerosol Distribution, Sources and Sinks) study, a field campaign using the NCAR C-130 in summer 2013 out of Smyrna, Tennessee. The NOMADSS study merges three major experiments, focusing on understanding major atmospheric constituents and their behavior in the eastern U.S. The Selin group’s work as part of this campaign focuses on mercury, with goals to constrain emissions of mercury from major source regions in the United States, and quantify the distribution and chemical transformations of spectated mercury in the troposphere. The Selin group runs forecasting and near-real-time monitoring in the field using the GEOS-Chem model.


AIDA Schematic. Figure courtesy of AIDA/KIT

AIDA Schematic. Figure courtesy of AIDA/KIT

During Spring, 2011 Dan Cziczo participated in NASA’s The Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) with Dr. Karl Froyd from NOAA’s Earth Systems Research Laboratory. They deployed a novel counterflow virtual impactor inlet and the Particle Analysis by Laser Mass Spectrometry (PALMS) instrument which determined the size and composition of cirrus cloud forming aerosol in situ and in real time. Samples were also acquired for off line electron microscopy at MIT. MACPEX was an airborne field campaign which investigated cirrus cloud properties and the processes that affect their impact on radiation. Utilizing the NASA WB-57 based at Ellington Field, TX, the campaign took place in March and April 2011. Science flights focused on south and central North America with an emphasis over the Department of Energy’s Atmospheric Radiation Measurement site in Oklahoma.

The major science questions addressed by MACPEX include:

NASA WB-57F. Photo courtesy of E. Jensen

NASA WB-57F. Photo courtesy of E. Jensen

• How prevalent are smaller crystals in cirrus clouds, and how important are these for extinction, radiative forcing, and radiative heating?

• How are cirrus microphysical properties (particle size distribution, ice crystal habit, extinction, ice water content) related to the dynamical forcing driving cloud formation?

• How are cirrus microphysical properties related to aerosol loading and composition, including the abundance of heterogeneous ice nuclei?

• How do cirrus microphysical properties evolve through the lifecycles of the clouds, and what role do radiatively driven dynamical motions play?

In addition to the in situ measurements, flights were coordinated with the NASA EOS / A-Train satellite observations for validation and evaluation of new remote-sensing retrievals for future Earth Science Decadal satellites. The detailed measurements acquired by MACPEX will also be used to improve cloud model parameterizations in Global Climate Models (GCMs).
Watch Video of takeoff and landings here!

In summer 2011, members of Jesse Kroll’s group took part in the BEACHON-RoMBAS (“Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen – Rocky Mountain Biogenic Aerosol Study”) field campaign, in Manitou Forest, CO.  This multigroup, international effort was focused in part on better understanding the chemistry of biogenic  secondary organic aerosol.  Kroll Group members brought a new instrument for the detection and characterization of intermediate-volatility and semivolatile organic compounds.  Measurements were highly complementary to the VOC and PM measurements made by other groups; together these instruments provided the fullest description to date of the volatiliy distribution of organic compounds in the atmosphere.