BAMOS Vol 30 No. 4 2017 - Page 33

BAMOS Dec 2017 Figure 3. Bureau of Meteorology weather station locations, measured decadal percentage changes in wind speeds (Positive percentage change - increasing wind speeds, Negative percentage change - decreasing wind speeds), and tornado sightings (Data source: Bureau of Meteorology, 2016a; Bureau of Meteorology, 2016b) (Background source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community). 3. Results and discussions 3.1 Wind speeds Obtaining high quality surface wind speed measurements can be fraught with numerous challenges and issues (Jakob 2010). Potentially affecting the quality of the data obtained, issues may include; wind speed monitoring equipment and standards being modified or upgraded over time, missing data sets due to equipment malfunction, changes in the surrounding environment, and altered measurement times due to inconsistent day light savings procedures. Detailed information regarding each weather station’s wind speed monitoring equipment maintenance and replacement history can be found in corresponding ‘Basic Climatological Station Metadata’ reports, available from the Bureau of Meteorology website (Bureau of Meteorology, 2016a). While the Bureau of Meteorology had addressed some data quality control issues by utilising a range of quality control measures (Bureau of Meteorology, 2017), current methods for accurately resolving issues pertaining to monitoring equipment upgrades are generally considered unsatisfactory (Jakob 2010). The changes in wind speed monitoring equipment from one type to another have mostly occurred around 1995 (Bureau of Meteorology, 2016a; Jakob, 2010), which may have caused some of the most recent thirty-year mean annual wind speed data-points to have additionally varied. While the Larapuna (Eddystone Point), Swansea Post Office, and Bushy Park (Bushy Park Estate) sites all had similar equipment upgrades to many of the other stations used in this study, their long-term (four to five decades of ) thirty-year mean annual 33