HR: 1340h
AN: A33B-0894    [Abstracts]
TI: Aerosol, cloud, and radiometric measurements with small autonomous unmanned aerial vehicles
AU: Ramanathan, V
EM: vram@fiji.ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr. #0239, La Jolla, CA 92093
AU: * Roberts, G
EM: greg@fiji.ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr. #0239, La Jolla, CA 92093
AU: Corrigan, C
EM: craig@fiji.ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr. #0239, La Jolla, CA 92093
AU: Ramana, M
EM: raman@fiji.ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr. #0239, La Jolla, CA 92093
AU: Nguyen, H
EM: hung@fiji.ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr. #0239, La Jolla, CA 92093
AB: The AUAV (autonomous unmanned aerial vehicle) project is a part of the Atmospheric Brown Clouds project. It has been designed to allow for routine vertical profile measurements of aerosols and clouds using AUAVs above ground-based observatories in the Indo-Pacific Ocean region. The current scientific payloads consist of optical particle counters, condensation particle counters, cloud droplet probes, aethelometers, upward and downward facing pyranometers, and temperature-relative humidity sensors. Aerosol, cloud and radiometric instruments have been miniaturized with a total payload weight and power less than 5 kg and 50 W, respectively. Demonstration flights at the Yuma Proving Grounds, AZ show the potential for small AUAVs in atmospheric studies. The flights were performed on two aircraft, which flew autonomously up to 3000 m above sea level (asl) along programmed flight tracks. The aircraft flew in stacked formation for part of the flights. Once the aircraft were stacked (550 and 2100 m asl), the projected distances were less than 50 m - which translates to less than a 1.5 sec latency between the aircraft. Vertical profiles show a constant 8 K km^-1 lapse rate and increasing relative humidity with altitude. At 2000 m asl (1600 m above ground level), an aerosol layer is evident in the total aerosol concentration profile (N_CN = 2000 cm^-3); relative humidity also increased by 10% in this layer. No such increase in 0.3 μm aerosol (N_OPC) is visible at 2000 m asl, suggesting transport from an urban center. Back trajectories indicate air masses originated from south and west across central Baja California, Mexico. Aerosol concentrations are fairly constant at 1000 cm^-3 throughout the profile indicating a well-mixed boundary layer. Spikes in aerosol concentrations are a result of sampling the aircrafts' exhaust. The vertical profiles show that spikes occurred at levels where the aircraft maintained level, repeating holding patterns. The cloud droplet probe was flown; however, due to the flight ceiling, the aircraft was not allowed to ascend into the cloud base. The pyranometers performed well during straight and level portions of the flight as the autopilot maintained a level platform (pitch and roll) to within a degree. Circular tracks (at 2 miles diameter) cause oscillations in the aircraft's pitch and constantly bank the aircraft 3 to 4 degrees. Hence, a larger radius or long straight and level legs need to be used for radiometric measurements. We will also include data from three stacked aircraft flights to be conducted in November, to sample the boundary layer, clouds and cloud top layers simultaneously.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0320 Cloud physics and chemistry
DE: 0321 Cloud/radiation interaction
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005