Exploring long term climate variability in the Quaternary with icesm1.2

Transcription

1 Exploring long term climate variability in the Quaternary with icesm1.2 Clay Tabor 1, Be.e O.o-Bliesner 1, Esther Brady 1 Michael Erb 2, Jiang Zhu 3, Jesse Nusbaumer 4 1: NaDonal Center for Atmospheric Research 2: University of Southern California 3: Pennsylvania State University 4: Goddard InsDtute for Space Studies

2 CESM AGU 2016 Winter Working Group Climate Model Oxygen-18 and Deuterium tracking in all model components of the Community Earth System Model 1.2 (Nusbaumer et. al.; Wong et al.; JAMES, in review) Developed by NCAR, CU, OSU, and UW-M Fully coupled 2 atm / lnd and 1 ocn / ice Methods

3 Methods Model SimulaDons 10 runs with different orbits, CO 2, and land ice IniDalized from equilibrium climate simuladons

4 CESM AGU 2016 Winter Working Group ReconstrucDon Techniques Linear combinadons of end-member forcing experiments well replicate many aspects of long term variability (Erb et al., 2015) X D = ( X orbit *Orbit D ) + ( X GHGs *GHG D ) + ( X ice *SL D ) Can the same technique work for water isotopes? Methods

5 Example ApplicaDons China δ 18 O Records Sanbao Cave (Cheng et al., 2009) AntarcDc δd Records Fuji Dome (Kawamura et al., 2007) / Vostok (PeDt et al., 2001) / Epica Dome C (Jouzel et al., 2007) North AtlanDc Deep Water δ 18 O Records Benthic Foram Records (Lisiecki and Raymo, 2005) Methods

6 Methods Sanbao Cave ReconstrucDon δ 18 O linear combinadon: good frequency but low amplitude

7 Methods Sanbao Cave ReconstrucDon δ 18 O linear combinadon: good frequency but low amplitude

8 Sanbao Cave ReconstrucDon Model bias? Strong δ 18 O gradients in region Cave water sourced from higher aldtudes? Methods

9 Methods Sanbao Cave ReconstrucDon CirculaDon changes are important for signals (Liu et al., 2012) m/s

10 Sanbao Cave ReconstrucDon Model bias? Strong δ 18 O gradients in region Cave water sourced from higher aldtudes? Methods

11 Methods Sanbao Cave ReconstrucDon Model bias? Cave water sourced from higher aldtudes?

12 Sanbao Cave ReconstrucDon Forcings have different local temp and precip reladonships Methods

13 Methods ReconstrucDons

14 Methods ReconstrucDons HDO well captured by model simuladons without land ice forcing

15 Methods ReconstrucDons Amplitude match especially good in Winter months

16 ReconstrucDons Can model / proxy mismatch informadon AntarcDc ice volume evoludon? Response similar to AntarcDc ice volume simuladons (Pollard and DeConto, 2009) Methods

17 ReconstrucDons Can model / proxy mismatch informadon AntarcDc ice volume evoludon? Response similar to AntarcDc ice volume simuladons (Pollard and DeConto, 2009) Methods

18 ReconstrucDons Can model / proxy mismatch informadon AntarcDc ice volume evoludon? Response similar to AntarcDc ice volume simuladons (Pollard and DeConto, 2009) Methods

19 Methods Deep Water Signals Can infer future deep water signal from areas of deep water formadon PI Lo Obl Hi Obl 0 Pre 90 Pre 180 Pre 270 Pre 142 CO2 LGM Ice

20 Deep Water Signals Small δ18o variability in locadons of NADW formadon due largely to circuladon changes d18o cm/s Methods

21 Methods Deep Water Signals Linear theory unlikely a good assumpdon for NADW Signal dominated by land ice and CO 2 RelaDonship between δ 18 O and temperature depends on the forcing

22 Methods Outlook SimulaDons can help us decompose signals in the isotopic records Use model outputs in specific proxy models

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