Improving the Australian Tropical Cyclone Database: Extension of the GMS Satellite Digital Image Archive

Abstract

Japan’s GMS series of satellites were, and MTSAT-1R currently is, located at a nominal sub-satellite of 0°S, 140°E in geostationary orbit to retrieve imagery for meteorological purposes. This suite of satellites has been active since 14 July 1977 when the first of five GMS satellites was launched. The Bureau did not start receiving imagery from GMS until late 1977 and it was not until early in 1978 that imagery was received regularly. The Bureau now has an archive of meteorological satellite data extending over 30 years. The best use of this data can be achieved by converting it all to a single format, which can be utilised within computer-based analysis systems. As the Bureau uses McIDAS as its primary visualisation and image-processing tool it was decided that all historical data should be converted to a format that would allow it to be utilised within McIDAS. The image data format within McIDAS is called AREA format, so all of the historical imagery needed to be converted to AREA file format. A search of relevant literature was undertaken to ascertain if others had attempted to resurrect scanned imagery in this manner. While no evidence of this was apparent it did reveal that the Japanese Meteorological Agency’s (JMA) Meteorological Satellite Centre (MSC) had a significant part of their archive in a digital format (JMA,1980). This format is known as archived Visible Infrared Spin Scan Radiometer (VISSR) and will be referred to herein as VISSR format. These archive data comprise much of the IR imagery that the Bureau only has as scanned tiff files. Converting the VISSR data to AREA format is far more desirable as the quality of digital data does not degrade over time. This chapter concentrates on the processes involved in converting scanned imagery to AREA format as it will be needed to fill in the data gap and the conversion of VISSR to AREA in comparison is a trivial matter.