Longterm Infrared Cloud Clutter Research,
Abstract
An infrared all-sky mapper Scorpio has been developed at TNO-FEL. The system has been used to obtain 10 um sky and cloud backgrounds for about one year. The data cover an area of - 18 up to + 72 in elevation and 340 in azimuth with a spatial resolution of 0.8 mrad. The system has an absolute calibration. Data recording with 12 bit resolution, and image analysis are done with a MASSCOMP computer. The image processing is done in several steps. Non-sky areas in the images are blanked. Clutter calculations are performed in cells of 4 x 12 pixels, with local RMS as a basis. The use of a moving average in the RMS calculations diminishes the content of high clutter values. Clutter and radiance distributions are studied with elevation. Lowtran 7 calculations are performed with a model based cloud structure. These are compared with real Scorpio measurements and show good agreement. The results are discussed for a measured atmospheric height profile as well as for assumed model height profiles, based on ground level data. Scorpio images of a single day have been analysed in much detail. Clutter slope calculations show that it is an important measure for the clutter content of the sky images. An algorithm for cloudiness calculations is discussed. The detection of point targets is discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1994
- Accession Number
- ADA288632
Entities
People
- A. C. Kruseman