1. AERONET DRAGON Campaign, Summer 2011 Christina Justice College Park Scholars – Science & Global Change Program Environmental Science and Policy christinaj.justice@gmail.com College Park Scholars Academic Showcase, May 4, 2012 Introduction: During the summer of 2011 I worked as an intern at NASA Goddard Space Flight Center for the AERONET calibrating the AERONET (Aerosol Robotic Network) - a network DRAGON campaign, deploying, of ground based sun photometers – instruments that measure the amount of aerosols in the atmosphere. Acknowledgments: I would like to thank Brent Holben and the AERONET team at NASA GSFC for their support and mentoring on this project as well as Drs. Holtz & Merck. Site Information: Location: NASA Goddard Space Flight Center, Greenbelt Maryland 20771 Site Director: Brent Holben Program Description: The campaign, implemented under the NASA funded mission Discover AQ employed NASA aircrafts with scientific instruments on board to collect aerosol measurements of gaseous and particulate pollution. These measurements were collected in a coordinated grid of 42 ground based sun-photomers at different locations around Maryland and the Metropolitan area. Activities: During my time at AERONET I worked on the DRAGON campaign, implemented under the NASA funded mission Discover AQ (Air Quality) helping with the set up take down, calibration and organization of the campaign and its instruments. During this mission I would drive out to the chosen sites around Maryland and be involved in the complete process of the data collection and site analysis necessary for the success of the campaign. Future Work: During the upcoming Summer 2012 the campaign is being expanded to Japan and South Korea. This campaign will be measuring aerosol pollution using the same AERONET method, enabling a comparison of data from a dense network of daily measurements in three international Metropolitan settings.. Background A sunphotometer is an instrument which measures the intensity of the Sun's light when pointed directly at the Sun. Any aerosols and gases (haze) between the Sun and the photometer decrease the Sun's intensity. A hazy sky would read a lower intensity of sunlight and give a lower voltage reading on the photometer. The automatic Sun – and sky- scanning radiometers make direct Sun measurements with a 1.2 degree full field of view every 15 minutes at wavelengths of 340, 440, 500, 675, 870, 940, and 1020 nm. Aerosols of different sizes respond differently at different wavelengths. The direct measurements of the Sun take 8 seconds to scan through all eight of these spectral bands with a motor driven wheel positioning each of seven filters in front of a detector pointed at the Sun. A sequence of three measurements is taken 30 seconds apart resulting in 3 measurements for each wavelength. These solar measurements are then used to compute aerosol optical thickness at each level except for the 940 nm channel which is used to retrieve the precipitable water. The measurements are transmitted to communication satellites which then beam them down to NASA GSFC. The instruments which are well calibrated to a reference site at Mauna Loa, Hawaii, provide a signal at each wavelength which is used to calculate the aerosol optical thickness. Conclusion: The campaign ran for 6 weeks in the middle of summer – a peak season for aerosol production. The results and goals of this campaign will be to better inform policymakers on the current status of air pollution in the tested area – aiding in decisions and regulatory law as well as leading to new scientific studies on the nature of aerosols, which still remains a largely unexplored field within atmospheric sciences. Image 1: Sunphotometer at NASA Goddard Figure 1: Aerosol Optical Thickness for NASA Goddard site for the year 2011 Figure 2: This figure shows the sites and flyover path for the 2011 Dragon Campaign focused on the Maryland and metropolitan areas