Search Results (2)

Western Europe is the region with the highest density of published speleothem δ¹⁸O (δ¹⁸O_spel) records worldwide. Here, we review these records in light of the recent publication of the Speleothem Isotopes Synthesis and AnaLysis (SISAL) database. We investigate how representative the spatial and temporal distribution of the available records is for climate in Western Europe and review potential sites and strategies for future studies. We show that spatial trends in precipitation δ¹⁸O are mirrored in the speleothems, providing means to better constrain the factors influencing δ¹⁸O_spel at a specific location. Coherent regional δ¹⁸O_spel trends are found over stadial-interstadial transitions of the last glacial, especially in high altitude Alpine records, where this has been attributed to a strong temperature control of δ¹⁸O_spel. During the Holocene, regional trends are less clearly expressed, due to lower signal-to-noise ratios in δ¹⁸O_spel, but can potentially be extracted with the use of statistical methods. This first assessment highlights the potential of the European region for speleothem palaeoclimate reconstruction, while underpinning the importance of knowing local factors for a correct interpretation of δ¹⁸O_spel. Full article

As one of the most prominent seasonally recurring atmospheric circulation patterns, the Asian summer monsoon (ASM) plays a vital role for the life and livelihood of about one-third of the global population. Changes in the strength and seasonality of the ASM significantly affect the ASM region, yet the drivers of change and the varied regional responses of the ASM are not well understood. In the last two decades, there were a number of studies reconstructing the ASM using stalagmite-based proxies such as oxygen isotopes (δ¹⁸O). Such reconstructions allow examination of ASM drivers and responses, increasing monsoon predictability. In this review paper, we focus on stalagmite δ¹⁸O records from India at the proximal end of the ASM region. Indian stalagmite δ¹⁸O records show well-dated, high-amplitude changes in response to the dominant drivers of the ASM on orbital to multi-centennial timescales, and indicate the magnitude of monsoon variability in response to these drivers. We examine Indian stalagmite records collated in the Speleothem Isotope Synthesis and AnaLysis version 1 (SISAL_v1) database (http://researchdata.reading.ac.uk/139/) and support the database with a summary of record quality and regional climatic interpretations of the δ¹⁸O record during different climate states. We highlight current debates and suggest the most useful time periods (climatic events) and locations for further work using tools such as data-model comparisons, spectral analysis methods, multi-proxy investigations, and monitoring. Full article