Australian Region Cyclone Intensity and Frequency Index - CAMRIS

Brief description

This database presents an index of the intensity, frequency and density of cyclone occurrence in the Australian region. It has been derived from data held in CSIRO CAMRIS database and originally collected by the Bureau of Meteorology from 1958 - 1990. The cyclone_density code in the coverage represents: 1 Australia, 2-23 the nominal index of cyclone density/intensity, as per the Bureau of Meteorology cyclones database.

Format: shapefile.

Quality -
Scope: Dataset.
Absolute External Positional Accuracy Check: +/- one degree.
Non Quantitative accuracy: The attribute called nominal_index holds values 0-23, which represent the intensity and density of cyclone occurrence. The attribute called cyclone_density provides a subjective definition of the density of cyclone occurrence:

Nominal_Index : Cyclone_Density
----------------------------
0 : No cyclone occurrence.
1 : Australian Continent.
2 : Low.
3-8 : Medium
9-16 : High.
17-23 : Very high.

Conceptual consistency: Coverages are topologically consistent. No particular tests conducted by ERIN.
Completeness omission: Complete for the Australian continent and oceans.
Lineage: The database shows an index of cyclone intensity and frequency from 1958-1990. The map was created from raw data provided by the Bureau of Meterology:
1. Data points represented each 6 hourly location of every cyclone.
2. Modelled the density of points to create a contour map by counting points which fell within a certain radius of each point. Weighted by distance as 1 to all points within 25 km of a cyclone eye, and a linearly decaying weight (with distance) of between 1 and 0 to all points between 25 and 50km away. This assumed that cyclones significantly affect areas less than 25km from the eye, and have a decreasing effect with distance away from the eye.
3. Values on the contour map were multiplied by an index derived from intensity (barometric depression) at cyclone eye.
4. Reclassed intensity - density distribution using a linear scale.

CAMRIS data were stored in VAX files, MS-DOS R-base files and as a microcomputer dataset accessible under the LUPIS (Land Use Planning Information System) land allocation package. A summary follows of data processing by the CSIRO:
1. r-BASE: Information imported into r-BASE from a number of different sources.
2. BASE Table was generated incorporating specific fields.
3. SPANS environment: creating a geographic projection - Equidistant Conic (Simple Conic) and Lambert Conformal Conic, Spheroid: International Astronomical Union 1965 (Australia/Sth America).
4. BASE Table imported into SPANS and a BASE Map generated.
5. Categorise Maps - selecting out specified fields, a desired window size (ie continental or continent and oceans) and resolution level (ie the quad tree level).
6. Rasterise maps specifying key parameters.
7. Gifs produced using categorised maps with a title, legend, scale and long/lat grid, and supplied to ERIN.
9. The reference coastline for CAMRIS was the mean high water mark (AUSLIG 1:100 000 topographic map series).