TY - JOUR
T1 - Unraveling Glacial Hydroclimate in the Indo-Pacific Warm Pool
T2 - Perspectives From Water Isotopes
AU - Windler, Grace
AU - Tierney, Jessica E.
AU - Zhu, Jiang
AU - Poulsen, Christopher J.
N1 - Funding Information:
Funding for this study was provided by the David and Lucile Packard Foundation Fellowship in Science and Engineering to J. E. Tierney, by the National Science Foundation Graduate Research Fellowship Program to G. Windler (grant no. DGE-1746060), and by the Heising-Simons Foundation to J. E. Tierney and C. J. Poulsen (grant no. 2016-015). We thank P. Murphy for technical support and J. B. Wurtzel for guidance using HYSPLIT4.
Funding Information:
Funding for this study was provided by the David and Lucile Packard Foundation Fellowship in Science and Engineering to J. E. Tierney, by the National Science Foundation Graduate Research Fellowship Program to G. Windler (grant no. DGE‐1746060), and by the Heising‐Simons Foundation to J. E. Tierney and C. J. Poulsen (grant no. 2016‐015). We thank P. Murphy for technical support and J. B. Wurtzel for guidance using HYSPLIT4.
Publisher Copyright:
©2020. American Geophysical Union. All Rights Reserved.
PY - 2020/12
Y1 - 2020/12
N2 - The Indo-Pacific Warm Pool (IPWP) is home to the warmest sea surface temperatures in the world oceans, favoring strong tropospheric convection and heavy rainfall. The mechanisms controlling long-term change in the region's hydroclimate are still uncertain. Here, we present a 450,000-year record of precipitation δD from southern Sumatra that records a consistent pattern of glacial isotopic enrichment and interglacial depletion. We synthesize existing paleo-indicators of precipitation δD and δ18O in the IPWP and compare results with water isotope-enabled climate simulations of the Last Glacial Maximum (LGM). The simulations show glacial isotopic enrichment over the eastern Indian Ocean extending into the southern IPWP and isotopic depletion over Southeast Asia, the west Pacific, and Australia. The pattern of simulated LGM isotopic change agrees generally well with our proxy synthesis. We conclude that reorganization of regional circulation under glacial conditions controls precipitation isotope variability in the IPWP: Low-level tropospheric convergence dominates the signal in the north/east, whereas divergence controls the response in the south/west. Additional sensitivity simulations suggest that the LGM ice sheets and the associated lowering in sea level, rather than decreased greenhouse gases, are responsible for the distinctive spatial pattern in glacial changes of precipitation isotopes and hydroclimate across the IPWP.
AB - The Indo-Pacific Warm Pool (IPWP) is home to the warmest sea surface temperatures in the world oceans, favoring strong tropospheric convection and heavy rainfall. The mechanisms controlling long-term change in the region's hydroclimate are still uncertain. Here, we present a 450,000-year record of precipitation δD from southern Sumatra that records a consistent pattern of glacial isotopic enrichment and interglacial depletion. We synthesize existing paleo-indicators of precipitation δD and δ18O in the IPWP and compare results with water isotope-enabled climate simulations of the Last Glacial Maximum (LGM). The simulations show glacial isotopic enrichment over the eastern Indian Ocean extending into the southern IPWP and isotopic depletion over Southeast Asia, the west Pacific, and Australia. The pattern of simulated LGM isotopic change agrees generally well with our proxy synthesis. We conclude that reorganization of regional circulation under glacial conditions controls precipitation isotope variability in the IPWP: Low-level tropospheric convergence dominates the signal in the north/east, whereas divergence controls the response in the south/west. Additional sensitivity simulations suggest that the LGM ice sheets and the associated lowering in sea level, rather than decreased greenhouse gases, are responsible for the distinctive spatial pattern in glacial changes of precipitation isotopes and hydroclimate across the IPWP.
KW - Indo-Pacific Warm Pool
KW - leaf wax
KW - Pleistocene
KW - proxy-model comparison
KW - water isotopes
UR - http://www.scopus.com/inward/record.url?scp=85098183821&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85098183821&partnerID=8YFLogxK
U2 - 10.1029/2020PA003985
DO - 10.1029/2020PA003985
M3 - Article
AN - SCOPUS:85098183821
VL - 35
JO - Paleoceanography and Paleoclimatology
JF - Paleoceanography and Paleoclimatology
SN - 2572-4517
IS - 12
M1 - e2020PA003985
ER -