Density Perturbations in the Atmosphere above the Naval Observatory Induced by Heat Transferred off Upwind Buildings
Abstract
Heat rejection by large buildings constructed adjacent to the U.S. Naval Observatory is distorting the properties of the atmosphere. The distortion refracts the incoming light in an anomalous manner, introducing uncorrectable errors into celestial observations. A building heats the atmosphere through the discharge of the heating and air conditioning systems and also by means of heat convected off hot walls and roof. As the air is heated, its physical properties are changed. This heating is heterogeneous, influenced by the geometry of the buildings and by the turbulence of the air. The perturbed atmosphere then rises due to the buoyancy of the heated air and is swept downwind toward the Observatory. The energy transferred from the buildings to the air and the resulting change in the properties of the atmosphere were examined theoretically. Building heat rejection was significant, particularly in the late afternoon and early evening, throughout the year. Heat rejection rates of 5 MW for a large building are typical. When an entire street is included, an anomalous telescope error of up to 0.3 seconds of arc is predicted. (edc)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1990
- Accession Number
- ADA221746
Entities
People
- C. A. Kodres
Organizations
- Naval Facilities Engineering Service Center