Rebecca Lagoon, Tasmania 3,700 Year Sediment Reflectance and Precipitation Reconstruction Saunders, K.M.; Kamenik, C.; Hodgson, D.A.; Hunziker, S.; Siffert, L.; Fischer, D.; Fujak, M.; Gibson, J.A.E.; Grosjean, M. Saunders, K.M. Kamenik, C. Hodgson, D.A. Hunziker, S. Siffert, L. Fischer, D. Fujak, M. Gibson, J.A.E. Grosjean, M. Precipitation Reconstruction earth science/paleoclimate/climate reconstructions|paleolimnology (precipitation,null,null,millimeter per year,annual,climate reconstructions|paleolimnology,filtered,null,N,Relationship based on correlation of sediment reflectance with Instrumental records 1911-2000; 51 year filter; R= -0.56 P auto < 0.001 RMSEP = 43.0 mm/year) earth science/paleoclimate/paleolimnology (reflectance,sediment,null,dimensionless,null,paleolimnology,null,spectrophotometry,N,Ratio between reflectance at 660 and 670 nm wavelength - degree of diagenesis; Relationship based on correlation with Instrumental records 1911-2000) earth science/paleoclimate/paleolimnology (reflectance,sediment,null,dimensionless,null,paleolimnology,null,spectrophotometry,N,Ratio between reflectance at 660 and 670 nm wavelength - degree of diagenesis) earth science/paleoclimate/climate reconstructions|paleoceanography (precipitation,null,null,millimeter per year,annual,climate reconstructions|paleoceanography,filtered,null,N,based on sediment reflectance; R= -0.56 P auto < 0.001 RMSEP = 43.0 mm/year; Relationship based on correlation with Instrumental records 1911-2000; 51 year filter) earth science/paleoclimate/paleolimnology (depth,null,null,centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|paleolimnology (age,null,null,year Common Era,null,climate reconstructions|paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|paleolimnology (age,null,null,calendar year before present,null,climate reconstructions|paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|paleoceanography (depth,null,null,centimeter,null,climate reconstructions|paleoceanography,null,null,N,null) earth science/paleoclimate/paleolimnology (age,null,null,year Common Era,null,paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|paleolimnology (precipitation,null,null,millimeter per year,annual,climate reconstructions|paleolimnology,filtered,null,N,Relationship based on correlation of sediment reflectance with Instrumental records 1911-2000; 5 year filter; R= -0.56 P auto < 0.001 RMSEP = 43.0 mm/year) earth science/paleoclimate/climate reconstructions|paleoceanography (age,null,null,year Common Era,null,climate reconstructions|paleoceanography,null,null,N,null) earth science/paleoclimate/climate reconstructions|paleoceanography (precipitation,null,null,millimeter per year,annual,climate reconstructions|paleoceanography,filtered,null,N,based on sediment reflectance; R= -0.56 P auto < 0.001 RMSEP = 43.0 mm/year; 5 year filter) earth science/paleoclimate/climate reconstructions|paleoceanography (age,null,null,calendar year before present,null,climate reconstructions|paleoceanography,null,null,N,null) earth science/paleoclimate/paleolimnology (age,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology (Rebecca Lagoon>LATITUDE -41.183>LONGITUDE 144.683) Accurate projections of future climate changes in regions susceptible to drought depend on a good understanding of past climate changes and the processes driving them. In the absence of longer term instrumental data, paleoclimate data are needed. In this study we develop a precipitation reconstruction for Rebecca Lagoon (41 11'S, 144 41'E), northwest Tasmania. First, the relationship between scanning reflectance spectroscopy measurements of sediment cores in the visible spectrum (380-730 nm) and instrumental precipitation record (1912-2009) was used to develop a model to reconstruct precipitation back in time. Results showed that the ratio of reflectance between 660 and 670 nm (i.e., reflectance at 660 nm/reflectance at 670 nm; a measure of pigment diagenesis) was significantly related to annual precipitation. A calibration model was developed (R = -0.56, pauto < 0.001, RMSEP = 43.0 mm yr- 1, 5 year triangular filtered data, calibration period 1912-2009). Second, this calibration-in-time model was used to reconstruct late Holocene precipitation changes over the last ~ 3000 years. This showed relatively dry conditions from ca. 3100-2800 cal yr BP, wet conditions from ca. 2800-2400 cal yr BP, dry conditions from ca. 2400-2000 calyr BP, and variable conditions after this. Relatively wet conditions occurred from ca. 500 cal yr BP to the late AD 1800 s (ca. 50 cal. yr BP). The precipitation reconstruction indicates that conditions were relatively dry for the 20th century compared to the last ~ 3000 years. In particular, the dry period measured in recent decades is one of the most intense in at least the last 500 years. As precipitation in this region is primarily driven by the Southern Hemisphere westerly winds, these changes are discussed in terms of shifts in westerly wind strength and/or position. STUDY NOTES: Sediment reflectance data from Rebecca Lagoon, Tasmania, plus precipitation reconstructions spanning the past 3,700 years. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Saunders, K.M. Investigator : Kamenik, C. Investigator : Hodgson, D.A. Investigator : Hunziker, S. Investigator : Siffert, L. Investigator : Fischer, D. Investigator : Fujak, M. Investigator : Gibson, J.A.E. Investigator : Grosjean, M. 2017-07-10 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/22416 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/australia/rebecca2012refl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/australia/rebecca2012precip.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/australia/rebecca2012refl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/australia/rebecca2012precip.txt English https://www.ncdc.noaa.gov/paleo/study/22416 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/australia/rebecca2012refl.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/australia/rebecca2012precip.txt Saunders, K.M.; Kamenik, C.; Hodgson, D.A.; Hunziker, S.; Siffert, L.; Fischer, D.; Fujak, M.; Gibson, J.A.E.; Grosjean, M.2012Late Holocene changes in precipitation in northwest Tasmania and their potential links to shifts in the Southern Hemisphere westerly windsGlobal and Planetary Change92-9382-9110.1016/j.gloplacha.2012.04.005http://www.sciencedirect.com/science/article/pii/S0921818112000616 START YEAR: 3654 cal yr BP * END YEAR: -58 cal yr BP 144.683 -41.183 144.683 -41.183