Thermistor Validation and Path Radiance Effects in Ship Thermal Image Measurements
Abstract
Thermal images in the 8-12 micrometer band were taken of the research vessel R/V POINT SUR in the Monterey Bay on 7 May 1991. The images were recorded using the AGA Thermovision 780 with an IBM AT computer using CATS 2.1 software. Corrections for computed transmittance, path length, and emissivity were made to the image files utilizing the locally developed computer program AGACATS. Temperature measurement distributions made with the AGA 780 compared to thermistor Measurements of the ship temperatures were found to be extremely close (within one degree) at ranges of one half and one mile. PC-Tran in the radiance mode was than used to compute the path radiance to the ship and compared with the path radiance correction in the AGA 780 algorithm. The AGA measurements varied over the range from twenty-five to seventy-five percent while the LOWTRAN fraction ranges only from seventy-five to eighty-five percent with the biggest discrepancy occurring at the short paths. The predicted path radiance as computed using LOWTRAN 6 did not fall off as much with decreased slant range as the AGA path radiances. This differences may be attributed to problems with either the AGA algorithm or the LOWTRAN code, or with the accuracy of the inputs. A contributing factor may be the time delay of one to one and a half hours between the image data and the radiosonde balloon launch.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 05, 1991
- Accession Number
- ADA246921
Entities
People
- David S. Wood
Organizations
- Naval Postgraduate School