Lorraine Lisiecki

Lorraine Lisiecki is an American paleoclimatologist. She is a professor in the Department of Earth Sciences at the University of California, Santa Barbara.[1] She has proposed a new analysis of the 100,000-year problem in the Milankovitch theory of climate change.[2] She also created the analytical software behind the LR04,[3] a "standard representation of the climate history of the last five million years".[4]

Education

Lisiecki graduated in 1995 from the South Carolina Governor’s School for Science and Mathematics.[5][6] Lisiecki received her B.Sc. in Earth, Atmospheric, and Planetary Science in 1999 and also obtained an M.Sc. in Geosystems in 2000 from the Massachusetts Institute of Technology. She earned a M.Sc. and Ph.D. in Geological Sciences, both from Brown University in 2003 and 2005. Lisiecki's Ph.D. thesis was titled “Paleoclimate time series: New alignment and compositing techniques, a 5.3-Myr benthic δ18O stack, and analysis of Pliocene-Pleistocene climate transitions”.[7]

Current research

Lisiecki's current research focuses on paleoclimatology. Lisiecki's research interest in paleoclimatology arose from the lack of research and current understanding of the glacial cycles. Lisiecki uses various computational and mathematical methods to interpret and compare different paleoclimate records.[5] In specific, she focuses on the evolution of the Plio-Pleistocene climate due to its relation to the Milankovitch forcing, 100-kyr glacial cycles, the carbon cycle, and deep-ocean circulation. Currently, Lisiecki designs and develops software for rendering age models and stratigraphy.[7][8] As well, Lisiecki is creating 3D models of ocean circulation to determine the relationship between orbital forcing and ocean circulation patterns and account for time-variant uncertainties.[9]

Contributions

HMM-Match (Lin et al, 2014)

Software designed using a Hidden Markov Model (HMM) for probabilistic sequence alignment of stratigraphic records.[10][11]

Match & Autocomp Software (Lisiecki and Lisiecki, 2002)

Paleoceanography software designed to find the optimal alignment of two paleoclimate signals using penalty functions to constrain the rate of accumulation for sediments.[12]

LR04 Benthic Stack (Lisiecki and Raymo, 2005)

A Pliocene-Pleistocene stack, spanning 5.3-Myr, demonstrating an average of 57 globally distributed Benthic δ18O records collected from scientific literature, which measure ice volume and deep ocean temperature. The records were placed on a common age model, represented by a graphic correlation algorithm.[13] Lisiecki and Raymo's LR04 Stack contains significantly more variance in benthic δ18O, in comparison to former published stacks of the late Pleistocene epoch. In the LR04, there are higher resolution records, an improved alignment technique, and a higher percentage of records from the Atlantic.[14]

The LR04 Stack is one of the most heavily cited Pliocene-entitled papers for δ18O due to the intensive mathematical meticulousness incorporated into the record, the level of objectivity involved, its use of global distribution and duration. The existence of the LR04 Stack serves as a very important tool in paleoceanography.[5]

Earth's climate history

In an effort to find patterns in Earth's climate history, Lisiecki researches ocean sediment cores.[15] The history of Earth's climate lies in the composition of ocean sediments as scientists are able to derive millions of years worth of information through the alignment of these sedimentary layers.[16] Through these layers, Lisiecki found a connection between earth’s climate cycle and earth’s orbital cycle; assuming glaciation and orbital eccentricity are both on 100,000-year cycles, she found that stronger changes in Earth’s orbit correlated with weaker changes in glaciation.[15] The correlation between the two consists of complicated relations as 3 different elements of Earth's orbit; eccentricity, tilt and precession, must be taken into consideration alongside Earth's convoluted climate system.[15]

100,000-year problem

One previous hypothesis held that the 100,000-year glacial cycles in the past 800,000 years were a result of cyclic changes in the Earth's orbital eccentricity. In 2010, Lisiecki discovered a negative correlation between the strength of glacial cycles and the eccentricity of the earth’s orbit over the past 1.2 million years, suggesting the possibility of internal instability of the earth’s climate in conjunction with its orbital cycles.[15] Lisiecki proposed that this negative correlation is caused by the inhibition of internal climate feedbacks by periods of strong precession forcing. Lisiecki also suggested that long-term internal factors might be responsible, such as the carbon cycle or the ice sheets, though more research is required.[17]

Awards

References
  1. USCB faculty page
  2. Lorraine E. Lisiecki (2010). "Links between eccentricity forcing and the 100,000-year glacial cycle". Nature Geoscience. 3 (5): 349–352. Bibcode:2010NatGe...3..349L. doi:10.1038/ngeo828. S2CID 19077579.
  3. Paleoceangraphy, 2004 Archived 2011-06-16 at the Wayback Machine
  4. Geological Society of America, 2008 Subaru Outstanding Woman in Science Award
  5. "Into the deep ocean with Lorraine Lisiecki". Forecast: a podcast about climate science and climate scientists. 2016-02-12. Retrieved 2016-11-03.
  6. "About". SC Governor's School for Science & Mathematics. 2012-09-18. Retrieved 2016-11-03.
  7. "Lorraine Lisiecki's CV" (PDF).
  8. "Lorraine Lisiecki". lorraine-lisiecki.com. Retrieved 2016-10-29.
  9. "Into the deep ocean with Lorraine Lisiecki - Forecast". l.facebook.com. Retrieved 2016-11-01.
  10. "Bayesian Geociences". ccmbweb.ccv.brown.edu. Retrieved 2016-11-01.
  11. Lin Luan, Khider Deborah, Lisiecki Lorraine E., Lawrence Charles E. (2014). "Probabilistic sequence alignment of stratigraphic records" (PDF). Paleoceanography. 29 (10): 976–989. Bibcode:2014PalOc..29..976L. doi:10.1002/2014pa002713.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. "Match Software". lorraine-lisiecki.com. Retrieved 2016-11-01.
  13. "LR04 Benthic Stack". www.lorraine-lisiecki.com. Retrieved 2016-11-03.
  14. "LR04 Global Pliocene-Pleistocene Benthic d180 Stack".
  15. "UCSB geologist discovers pattern in Earth's long-term climate record". EurekAlert. AAAS. Retrieved October 29, 2016.
  16. "Paleoceanography" (PDF). lorraine-lisiecki.com. American Geophysical Union. 2014. Retrieved November 4, 2016.
  17. Lisiecki, Lorraine E. (2010). "Links between eccentricity forcing and the 100,000-year glacial cycle". Nature Geoscience. 3 (5): 349–352. Bibcode:2010NatGe...3..349L. doi:10.1038/ngeo828. S2CID 19077579.
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