34th Solar Physics Division Meeting, June 2003
Session 20 Instrumentation
Poster, Wednesday, June 18, 2003, 3:30-5:00pm, Mezzanine

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[20.18] Long-Term Seeing Characteristics at Big Bear Solar Observatory

C. Denker, O. D. Espinosa, J. Nenow, W. H. Marquette (NJIT/CFSR/BBSO)

We present observations of long-term seeing characteristics from June 1997 to September 2002 obtained with Seykora-type scintillometers at Big Bear Solar Observatory (BBSO). BBSO is an ideal site for ground-based campaign-style observations. Since BBSO is situated on a small island in a 2,000~m high mountain lake in the cloudless mountains of Souther California, it benefits from excellent seeing conditions all day long. The atmospheric turbulence that degrades images originates primarily from two layers near the ground and at the level of the jet stream. BBSO's dome is located at the end of a 300~m long causeway jutting into the lake. Since the lake, with its cool waters, provides a natural inversion, and the dome has three kilometers of open water to its west, the boundary layer seeing is effectively suppressed. In addition, the east-west orientation of the Big Bear Valley provides a natural channel for the prevailing winds from the west resulting in a nearly laminar flow at the observatory site. We present a comparison of scintillometer data with climate data and analyze a one year long sub-set for local seeing variations near the lake shore and at the observatory island.

We would like to thank Jacques Beckers and the National Solar Observatory for providing the scintillometer data. This work was supported by NSF under grant ATM 00-86999, ATM 00-76602, and ATM 02-36945 and by NASA under grant NAG 5-9682.

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Bulletin of the American Astronomical Society, 35 #3
© 2003. The American Astronomical Soceity.