South Asian Summer Monsoon Index 1105 Year Reconstruction Shi, F.; Fang, K.; Xu, C.; Guo, Z.; Borgaonkar, H.P. Shi, F. Fang, K. Xu, C. Guo, Z. Borgaonkar, H.P. Atmospheric and Oceanic Circulation Patterns Reconstruction Monsoon earth science/paleoclimate/climate reconstructions|tree ring (age,null,null,year Common Era,null,climate reconstructions|tree ring,null,null,N,null) earth science/paleoclimate/climate reconstructions|tree ring (South Asian Summer Monsoon Index,null,null,dimensionless,Jun-Sep,climate reconstructions|tree ring,null,null,N,optimal information extraction (OIE1.0)) earth science/paleoclimate/climate reconstructions|tree ring (South Asian Summer Monsoon Index,null,unspecified error lower bound,dimensionless,Jun-Sep,climate reconstructions|tree ring,null,null,N,optimal information extraction (OIE1.0)) earth science/paleoclimate/climate reconstructions|tree ring (number of samples,null,null,count,null,climate reconstructions|tree ring,null,null,N,number of tree-ring predictor samples) earth science/paleoclimate/climate reconstructions|tree ring (South Asian Summer Monsoon Index,null,unspecified error upper bound,dimensionless,Jun-Sep,climate reconstructions|tree ring,null,null,N,optimal information extraction (OIE1.0)) earth science/paleoclimate/instrumental (South Asian Summer Monsoon Index,null,null,dimensionless,Jun-Sep,instrumental,null,null,N,null) earth science/paleoclimate/reconstructions earth science/paleoclimate/reconstructions (South Asia>LATITUDE >LONGITUDE ) The South Asian summer monsoon (SASM) is a major atmospheric synoptic climate system affecting nearly a quarter of the human population. Climate proxy data derived from tree rings, ice cores, speleothems, and other sources can all contribute to an understanding of SASM variability prior to instrumental period. Here, we develop an optimal information extraction (OIE) method, which we use to reconstruct the SASM index (SASMI) over the last millennium using 15 tree-ring chronologies. The record generated is significantly correlated (r = 0.7, p < 0.01) with the instrumental SASMI record on annual timescales; this correlation is higher than that obtained in any previous study. The reconstructed SASMI captures 18 of 26 (69%) reordered historical famine events in India over the last millennium; notably, 11 of 16 short events with durations of 1-3 years are accurately depicted in our reconstruction. Moreover, the reconstructed SASMI is positively correlated with variations in total solar irradiance (TSI) on multi-decadal timescales implying that variations in solar activity may influence the SASM. Based on the response of SASM to 34 significant volcanic events using the superposed epoch analysis, the volcanic forcing may drive a weak SASM in the second year of an eruption. STUDY NOTES: Tree-ring based reconstruction of the South Asian Summer Monsoon Index (SASMI) for the past 1,105 years. This is an updated version of the Shi et al. 2014 SASMI reconstruction (https://www.ncdc.noaa.gov/paleo/study/17369), utilizing an expanded set of 23 tree-ring predictors (8 additional tree-ring series from India). NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Shi, F. Investigator : Fang, K. Investigator : Xu, C. Investigator : Guo, Z. Investigator : Borgaonkar, H.P. 2017-10-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/22730 https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/asia/shi2017sasmi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/asia/shi2017sasmi.txt English https://www.ncdc.noaa.gov/paleo/study/22730 https://www1.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/asia/shi2017sasmi.txt Feng Shi, Keyan Fang, Chenxi Xu, Zhengtang Guo, H.P. Borgaonkar2017Interannual to centennial variability of the South Asian summer monsoon over the past millenniumClimate Dynamics497-82803-281410.1007/s00382-016-3493-9https://link.springer.com/article/10.1007%2Fs00382-016-3493-9 Feng Shi, Jianping Li, and Rob J. S. Wilson2014A tree-ring reconstruction of the South Asian summer monsoon index over the past millenniumScientific Reports6739410.1038/srep06739http://www.nature.com/srep/2014/141023/srep06739/full/srep06739.html START YEAR: 896 AD * END YEAR: 2000 AD 35 5 97.5 22.5