Climate Data: National Climate Centre, Bureau of Meteorology

Brief description

Three datasets containing climate data, compiled in April 2011, have been purchased from the Bureau of Meteorology. These datasets include observations from stations in all Australian States and Territories. Each dataset includes a file which gives details of the stations where observations were made and a file describing the data. AWS Hourly Data contains hourly records of precipitation, air temperature, wet bulb temperature, dew point temperature, relative humidity, vapour pressure, saturated vapour pressure, wind speed, wind direction, maximum wind gust, mean sea level pressure, station level pressure. Each record for each parameter is also flagged to indicate the quality of the value.Synoptic Data contains records of air temperature, dew point temperature, wet bulb temperature, relative humidity, wind speed, wind direction, mean sea level pressure, station level pressure, QNH pressure, vapour pressure and saturated vapour pressure. Each record for each parameter is also flagged to indicate the quality of the value.Daily Rainfall Data contains records precipitation in the 24 hours before 9 am, number of days of rain within the days of accumulation and the accumulated number of days over which the precipitation was measured. Each precipitation record is flagged to indicate the quality of the value.

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Maintenance and Update Frequency: notPlanned

Statement: Statement: Completeness of record:Many sites have gaps in observations and/or particular elements. Not all sites send reports in each day. Some sites, especially "rainfall only" sites, only report on a monthly basis. By the time the data are received and quality controlled, it could be several months before they are available: The Bureau of Meteorology will make its best efforts to estimate data availability but cannot guarantee completeness of record.Quality Control:Quality control flags and explanations are generally supplied with climate data. The majority of data provided by the Bureau of Meteorology have passed through a quality control process. However, in some instances (such as for recent data) the data may not have been quality controlled. A quality control flag may also indicate that a value is erroneous, suspect or has been derived. It is the responsibility of the user to understand what these flags mean in relation to the intended use of the climate data.Site History:There may have been changes in site location, instrumentation and/or observing practices over the period included in a dataset, which may have an effect on the long-term record. In recent years many sites have had observers replaced by Automatic Weather Stations, either completely or at certain times of the day. Site numbers may also have changed. Any station move is generally accompanied by a number change.Climate change and trends:When using weather data be aware that non-climatic factors may affect the results of your analysis, particularly examination of long-term trends. Any change in site location, exposure, instrumentation or observation practice has the potential to result in a signficant artificial discontinuity in the climate record of an observing site. These "inhomogeneities" can be as large as natural climate variations and make it difficult to detect real long term trends. For example, prior to about 1910 thermometers in many Australian states were housed in instrument screens different to the current standard. These shelters produce a warm bias in the temperature record compared to today's standard and can result in artificial trends in the data if this bias is not corrected. It is preferable to use data that have been adjusted for such inhomogeneities when investigating long-term climate trends. To do this properly the station history information or "metadata" needs to be examined to identify potential times of discontinuity. This has been done during the development of a number of Australian "high-quality" climate datasets. For further information please contact webclim@bom.gov.au or phone 0396694082.

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Credit
Climate Information Services, National Climate Centre (Owner)