Launch with Larry

 
Published: 7 September 2012

(Far right with bow tie) Principal investigator Larry Berg watches a sonde launch at TCAP while giving a tour to the opening ceremony visitors.The Two-Column Aerosol Project (TCAP) is now underway, and the instrumentation at the ARM Mobile Facility (AMF) is up and running at the Cape Cod National Seashore’s Highlands Center. The site is an excellent place for observing both clouds and aerosol (small particles ranging in size from nanometers to micrometers that are suspended in the air). This location was selected by a team of individuals working for both the National Park Service and ARM.

The AMF site was also the location of the TCAP Opening Ceremony that was held on July 25. This event was attended by a number of scientists associated with the National Seashore, members of various advisory boards and state and local governments, representatives from the U.S. Department of Energy, and the ARM Facility, as well as myself. As the principal investigator of TCAP, it was a great chance for me to thank everyone for their hard work. I also described how it is exciting to see it all come together and watch the data start to flow from all of the instruments. As part of the opening there was a weather balloon launch. From the reaction of the crowd (check out the photo), you can tell this was one of the highlights. Even with all of the high-tech gear associated with the AMF, weather balloons still provide critical data. More details about the Opening Ceremony can be found here.

TCAP was designed to focus on two vertical columns of the atmosphere. These columns are analogous to the vertical columns applied by computer models that simulate weather and climate. The first column is located directly above the AMF site on Cape Cod. The second column is located several hundred kilometers out over the Atlantic Ocean. There is no fixed site associated with the second column; rather, it is only sampled during the two aircraft intensive operations periods (IOPs).

The first aircraft IOP was conducted during July 2012. In this part of the study, the surface-based instruments were augmented by equipment on the DOE Gulfstream-1 (G-1) and NASA B-200 King Air. During the IOP, a large number of scientists and support personnel (including myself) lived and worked in Hyannis, Mass. The G-1 was configured to make measurements near the surface, in the layers of the atmosphere with the largest number of particles. The G-1 is also equipped with a special instrument (called the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research—4STAR) to measure the amount of sunlight scattered by particles between the G-1 and the top of the atmosphere.

Other instrumentation on the G-1 provides detailed measurements of the chemical composition of the particles, their optical properties (how much light they scatter or absorb), and the their number and size along the flight path of the plane. In contrast, the King Air flies much higher (around 22,000 feet) and is equipped with downward-looking remote sensing instruments to provide data about the particles between the King Air and the surface. The lidar provides detailed measurement of the amount of laser light scattered by the particles and can be used to determine if the particles are spherical or not. All of these data collected during TCAP will be used to develop and test climate models and how they treat particles and interactions between the particles and the clouds.

My future postings will describe the AMF and aircraft instrumentation in more detail.