Spontaneous Dansgaard-Oeschger type oscillations in climate models
- Start date
- 1 January, 2020
- End date
- 1 August, 2021
Abrupt warming episodes punctuate Greenland ice core records throughout the last glacial period. These events were first identified in two Greenland stable water isotope records (Dansgaard et al., 1993), and are generally referred to as Dansgaard-Oeschger (DO) events. During an event, Greenland transitions from cold stadial (GS) to warmer Greenland Interstadial (GI) conditions within a decade (Kindler et al., 2014; Huber et al., 2006). Surface air temperatures (SATs) over Greenland increase by 10-15°C and local snow accumulation almost doubles (Andersen et al., 2006; Kindler et al., 2014; Huber et al., 2006). These events occur at the onset of an oscillation that is of millennial timescale and are rather pronounced during Marine Isotope Stage3 (MIS3; between approximately 25 – 60 thousand of years BP, hereafter ka) (Fig. 1; Johnsen et al. (2001), Voelker et al.(2002)).
There are currently few examples of spontaneous DO-type oscillations occurring in coupled climate models, under any climate conditions, glacial-state or otherwise. For example the Max-Planck Institute Earth System Model (MPI-ESM) model is able to reproduce spontaneous millennial-scale AMOC oscillations when implementing PI ice sheet distribution in combination with a CO2 concentration range of 190-217 ppm (Klockmann et al., 2018, 2020) (See figure below). Under full glacial conditions, Peltier and Vettoretti (2014) found regular cycles of DO-type oscillations with the University of Toronto version of CCSM4 (UofT CCSM4). Authors term this behaviour as a “kicked” salt oscillator.
SDOO is an ongoing model intercomparison project to study spontaneous, DO-type oscillations in climate models. SDOO is currently gathering model output for any spontaneously oscillating simulations (published or unpublished). The main goal of SDOO is to cross compare existing simulations using a common set of diagnostics so we can analyse the mechanisms and the characteristics of the oscillations.
The only condition to participate is a simulation that shows spontaneous, long time scale, oscillations. The table below shows the simulations and models currently involved in this initiative.
|Model||Time period of the simulation||Length||Atmospheric trace gases||Insolation||Ice sheets|
|MPI-ESM||Mixed forcing||12000||CO2 = 206ppm|
CH4 = 444ppb
N2O = 218ppb
|Mixed forcing||8000||CO2 = 206ppm|
CH4 = 444ppb
N2O = 218ppb
|Mixed forcing||8000||CO2 = 195ppm|
CH4 = 396ppb
N2O = 209ppb
|GISS E2-R (TCADI)||Future warming scenario||2500||CO2 = 4 x PI CO2||modern||modern|
|Future warming scenario||2500||CO2 = CO2 increases at 1%/year until 4x CO2 and then held constant||modern||modern|
|Future warming scenario||4300||RCP85 emissions||modern||modern|
|GISS E2.1-G (NINT)||Future warming scenario||650||SSP45 emissions||modern||modern|
|EC-Earth3-Veg-LR||Holocene transient from 8K||4000 (8ka-4ka)||Köhler et al (2017)||Berger (1978)||PI|
|LIG transient from 127K||3000 (127ka – 124ka)||Köhler et al (2017)||Berger (1978)||PI|
|UVIC 2.8||19 ka||10000||CO2 = 190ppm||19 ka||19 ka – ICE 4G|
|UofT CCSM4||LGM||5000||21 ka||21 ka||21 ka – ICE 6G (VM5a)|
|CLIMBER-3α||Devoninian (415 Ma & 380 Ma)||5000||CO2 = 1500ppm, a few runs with 500ppm, 800ppm, 2000ppm||Various obliquity values, eccentricities, precession angles||none|
|Mesozoic (240-145 Ma)||5000||CO2 = 500-1700 ppm depending on time slice||circular orbit, obliquity 23.5 °||none|
|HadCM3||LGM||10000||LGM||LGM||LGM – GLAC-1D|
|PlaSim v16 Transient||Deglaciation transient (21ka – 6ka)||15000||Transiently changing following PMIP4||Transient||transient following GLAC1-D|
|PLaSim v17-SEDGES||38ka||1000||CO2 = 185ppm|
CH4 = 405ppb
N2O = 207.5ppb
|38ka||38ka – GLAC1-D|
SDOO is organized by:
- Irene Malmierca-Vallet, [email protected]
- Louise C. Sime, [email protected]
- Paul J. Valdes, [email protected]
and has contributions from Marlene Klockmann (MPI-ESM), Gavin A. Schmidt (GISS E2-R and GISS E2.1-G), Qiong Zhang (EC-Earth3-Veg-LR), Olivier Arzel (UVIC 2.8), Dick Peltier and Guido Vettoretti (UofT CCSM4), Georg Feulner (CLIMBER-3α), Andres Heather (PlaSim v16 and PlaSim v17-SEDGES) and Yvan Rome (HadCM3).
Please contact the organizers for data access.
Have you seen spontaneous, long time scale, oscillations in your model (DO-type)? If so, would you be willing to share model output of these spontaneously oscillating simulations with us? We are still accepting contributions, so please get in contact if you want to participate.
The table below shows the list of variables/fields to be provided.
|Surface air temperatures||Atlantic Meridional Overturning Circulation|
|Sea surface temperatures||3D ocean temperature|
|Sea ice concentration||3D ocean salinity|
|Sea ice thickness||3D ocean velocities (u and v)|
|Surface salinity||Barotropic stream function|
|Winds – U10 V10|
|Surface Latent heat flux|
|Sensible heat flux|
|Net solar radiation at surface|
|Net longwave radiation at surface|
|Total cloud cover|