Regional reconstruction of water availability to extend instrumental hydroclimatic records into the Late Holocene – a high-resolution investigation of natural archives dated in calendar-years from maar-lake sediments in the Newer Volcanic Province, south-

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We will develop a regional hydroclimatic record from a climatic center-of-action in the Southern Hemisphere. Based on calendar-year timescales, site-specific and ultra-high resolution environmental parameters will be obtained with novel non-destructive sediment scanning-techniques. Together with standard yet high-resolution multiproxy analyses, data will be merged to yield regional records of precipitation/evaporation ratios, lake level fluctuations, changes in trophic state, soil erosion and mixing regimes that will tap unprecedented and sensitive information about hydroclimatic variability. Understanding of decadal to centennial climate variability is significantly lacking for the Southern Hemisphere, from where no precisely dated hydroclimate records extend beyond the last centuries. This is particularly the case for severe hydroclimatic extremes, such as droughts and floods with their environmental consequences, which are closely tied to key modes of large-scale atmospheric circulation patterns with many socio-economic and environmental implications. To overcome this lack of data, annually laminated (varved) lake sediments provide excellent natural archives for obtaining high-resolution hydroclimate records covering many millennia. Based on underutilized lacustrine sediment archives in SE Australia and their strategic position in a center-of-action of the global climate system, we propose to investigate sediment records from crater lakes of the Newer Volcanic Province (NVP), where two sites archived varved sediments while for two additional lakes annual laminations are expected. With recent advances in computed tomography (µCT) scanning, a technology became available for decoding sediment matrices with ultra-high resolution providing sub-seasonally resolved radiographic images suitable for cost and time efficient varve recognition, characterization and measurement. We will explore this technology and develop innovative ways for establishing calendar-year chronologies. These precise timescales we will put in value innovative micro X-ray fluorescence (µXRF) and hyperspectral image (HSI) scanning as well as lower resolution standard sedimentological, geochemical, geophysical and biological analyses. Thus, unprecedented insights into past environmental and climatic variability will be provided tapping new information that will add to our understanding of linkages between local environmental conditions and hemispheric climate modes to better comprehend contemporary and future climate change.