ABSTRACT

Lakes Frome, Callabonna, Blanche and Gregory are playa lakes on the eastern and northern sides of the Flinders Ranges, South Australia. Between 2007 and 2019 we surveyed key topographic features of the lakes, including shorelines, lake floors and the alluvial sills that separate the lakes with differential GPS (DGPS). We combine these observations with the analysis of a hybrid DEM that blends data from multiple sources. The lowest elevation of the Frome-Callabonna system based on the hybrid DEM is −8.33 m Australian Height Datum (AHD) at Lake Callabonna but −5.42 m AHD based on DGPS field data. Both values are considerably lower than previous estimates based on spot heights and contours. The DGPS data for Lake Callabonna support the Shuttle Radar Terrestrial Mission (SRTM) estimates of lake-floor elevations but with a mean difference of 1.7 m in elevation. There are larger differences in elevation between the hybrid DEM and the DGPS data for the floor of Lake Frome (mean difference of 4.25 m). We also report on a newly topographically surveyed high shoreline at Lake Callabonna between 20.1 and 20.8 m AHD, the highest to date.

摘要

弗罗姆湖、卡拉博纳湖、布兰奇湖和格雷戈里湖是南澳大利亚弗林德斯山脉东部和北部的普拉亚湖。在 2007 年至 2019 年期间，我们使用差分 GPS (DGPS) 调查了湖泊的主要地形特征，包括海岸线、湖底和分隔湖泊的冲积基台。我们将这些观察结果与混合来自多个来源的数据的混合 DEM 分析相结合。基于混合 DEM 的 Frome-Callabonna 系统的最低海拔是 -8.33 m 澳大利亚高度基准 (AHD) 在卡拉博纳湖，但 -5.42 m AHD 基于 DGPS 现场数据。这两个值都大大低于先前基于点高度和轮廓的估计值。卡拉博纳湖的 DGPS 数据支持航天飞机雷达陆地任务 (SRTM) 对湖底高程的估计，但平均差为 1。海拔 7 m。混合 DEM 数据与弗洛姆湖底的 DGPS 数据之间的高程差异较大（平均差异为 4.25 m）。我们还报告了在 20.1 到 20.8 m AHD 之间的卡拉博纳湖新地形测量的高海岸线，这是迄今为止最高的。