GEOMACS (Geological and Oceanographic Model of Australias Continental Shelf) Interquartile range

Geoscience Australias GEOMACS model was utilised to produce hindcast hourly time series of continental shelf (~20 to 300 m depth) bed shear stress (unit of measure: Pascal, Pa) on a 0.1 degree grid covering the period March 1997 to February 2008 (inclusive). The hindcast data represents the combined contribution to the bed shear stress by waves, tides, wind and density-driven circulation. Included in the parameters that will be calculated to represent the magnitude of the bulk of the data are the quartiles of the distribution; Q25, Q50 and Q75 (i.e. the values for which 25, 50 and 75 percent of the observations fall below). The interquartile range, , of the GEOMACS output takes the observations from between Q25 and Q75 to provide an accurate representation of the spread of observations. The interquartile range was shown to provide a more robust representation of the observations than the standard deviation, which produced highly skewed observations (Hughes and Harris 2008). This dataset is a contribution to the CERF Marine Biodiversity Hub and is hosted temporarily by CMAR on behalf of Geoscience Australia.

澳大利亚地质调查局（Geoscience Australia）所采用的GEOMACS模型被用于生成1997年3月至2008年2月（含首尾时段）、基于0.1°网格的大陆架（水深约20至300米）区域海底剪切应力（bed shear stress）的逐小时后报时间序列，其计量单位为帕斯卡（Pascal，Pa）。该后报数据表征了波浪、潮汐、风力以及密度驱动环流对海底剪切应力的综合贡献。用于表征数据集主体分布特征的计算参数包含分布的四分位数（quartiles）：Q25、Q50与Q75（即分别有25%、50%、75%的观测值低于该数值）。GEOMACS模型输出结果的四分位距（interquartile range）选取Q25至Q75区间内的观测值，以精准表征观测数据的离散程度。研究表明，相较于会产生高度偏态观测结果的标准差，四分位距能更稳健地表征观测数据（Hughes与Harris，2008）。本数据集系CERF海洋生物多样性中心（CERF Marine Biodiversity Hub）的支撑数据集，暂由CMAR代表澳大利亚地质调查局临时托管。