Atmospheric Propagation Analysis -Gotland, Sweden Analysis of Atmospheric Transmittance and Aerosol Measurements.

摘要

Many new high resolution thermal imaging systems are being produced for the U.S. Navy which will operate primarily in the coastal warfare regions. Submarines and small coastal boat platforms present an optical imaging geometry along a horizontal path only a few meters off the surface of the ocean. It has been found that little or no spectral data exists on the atmospheric transmission which can be expected in the marine atmospheric boundary layer (MABL) for this special imaging geometry. It has been found that the atmospheric propagation models such as LOWTRAN 7 and MODTRAN do not adequately model this region of the atmosphere. As a result of this data and model deficiency, the Atmospheric Propagation Analysis (APA) program was developed at the Space and Naval Warfare Systems Center, San Diego (SPAWARSYSCEN, SD). The APA program conducts spectral measurements of atmospheric transmission in the thermal infrared region across a horizontal path over the ocean surface. The APA program has made a series of transmission measurements at several different sites which provided a variety of environmental conditions. In order to bound the problem, the first measurements were made in the cold and dry conditions of Adak, Alaska, and the hot and humid conditions of Pensacola, Florida. Measurements under intermediate conditions were made in cool and relatively humid conditions in Vindeby, Denmark. The most recent measurements were made in the Baltic Sea on the small island of Ostergarnsholm located 4 km off the east coast of the island of Gotland, Sweden. These measurements were made in conjunction with the Air Sea Exchange Process Study (ASEPS) program organized by the Ris National Laboratory, Department of Meteorology and Wind Energy, Roskilde, Denmark. This program provided detailed information on the environmental parameters of the site which can be related to the atmospheric transmission measurements and propagation model parameters.