BAMOS Dec 2017
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Table 1 . Australian Bureau of Meteorology weather station site information and years of wind speed data collection ( Bureau of Meteorology , 2016a ).
Site name
Bureau station number
Years of wind speed data
Latitude (° S )
Longitude (° E )
Bicheno - Council Depot 92003 1965 – 2010 41.87 148.30 Burnie - Round Hill 91009 1965 – 2010 41.07 145.94 Bushy Park - Bushy Park Estates 95003 1957 – 2010 42.71 146.90 Butlers Gorge 96003 1957 – 1993 42.28 146.28 Cape Bruny Lighthouse 94010 1957 – 2010 43.49 147.15 Dover 94020 1990 – 2010 43.33 147.00 Erriba - Craddle Mountain Road 91119 1962 – 2000 41.45 146.11 Flinders Island Airport 99005 1962 – 2010 40.09 148.00 Hobart - Ellerslie Road 94029 1893 – 2010 42.89 147.33 Hobart Airport 94008 1958 – 2010 42.83 147.50 Lake Leake - Elizabeth River 92019 1990 – 2000 42.01 147.80 Larapuna - Eddystone Point 92045 1961 – 2010 40.99 148.35 Launceston - City 91049 1884 – 1959 41.43 147.13 Launceston Airport - Comparison 91104 1939 – 2009 41.54 147.20 Low Head - Comparison 91057 1895 – 1997 41.06 146.79 Marrawah 91223 1971 – 2010 40.91 144.71 Orford - Aubin Court 92027 1968 – 2010 42.55 147.88 St Helens Post Office 92033 1957 – 2001 41.32 148.25 Strathgordon Village 97053 1971 – 2010 42.77 146.05 Swan Island Lighthouse 92037 1983 – 2001 40.73 148.13 Swansea Post Office 92038 1957 – 2008 42.12 148.07 Tarraleah Village 95018 1981 – 2010 42.30 146.45
Figure 1 consists of data from sites that had a minimum of three data-points ( three decades worth of thirty-year mean annual wind speeds ). To establish a relatively recent overview of Tasmanian wind speed trends , some data-points were removed ( pared ) ( Figure 2 ). Data lines that failed to attain the most recent thirty-year mean data-point ( ie : 1981 – 2010 ) were removed from Figure 2 . Data displaying changes in mean wind speed propensity ( from negative to positive , or visa-versa ), were pared at the inflection point . To highlight potential trends , though not commonly performed due to a potential lack of statistical significance , Figure 2 included data from sites with only two data-points ( two decades worth of thirty-year mean annual wind speeds ). All data omissions and additions can be easily seen by comparing Figures 1 and 2 .
Using data from Figure 2 , a mean decadal percentage change ( per every 10 years ) between the first and last thirty-year mean wind speed data-point , was calculated and included in Figure 3 . A zonal area of positive wind speed changes over time ( the zone ) was geographically highlighted ( Figure 3 ). Although the exact boundary position of the zone was somewhat arbitrarily determined , the region of the zone was systematically determined by including all positive decadal wind speed changes while excluding all negative decadal wind speed changes .
Historical data of recorded Tasmanian tornado sightings dating back as far as 1928 were obtained from the Bureau of Meteorology website ( Bureau of Meteorology , 2016b ). Individual tornado sightings were each geographically plotted on a map of Tasmania ( Figure 3 ). A 30-year period histogram , and trend line of tornado sightings was produced ( Figure 4 ).