iTRACE: an isotope-enabled Transient Climate Experiment for the last deglaciation

The iTRACE project is a publicly available set of climate model simulations that explicitly simulates the water isotope and climate change during the last deglaciation. It aims to understand the deglacial climate change by comparing the modeled water isotope against the observations. It is also useful for addressing the individual roles of ice sheets, greenhouse gases, orbital insolation and meltwater fluxes in the pat climate change. The iTRACE simulations are performed in the iCESM1.3, with realistic forcings applied. The full dataset contains 4 simulations: (ice_ghg_orb_wtr, all forcing runs), (ice_ghg_orb, factorized-forcing runs with ice sheet, greenhouse gas and orbital forcing),  (ice_orb, factorized-forcing runs) and (itrace.0x, factorized runs with only ice sheet forcng). Further details are found in the paper and dissertation below.

The corresponding preindustrial and LGM control simulations are available here.

We kindly ask that you acknowledge CESM project support from NSF and NCAR CISL supercomputing resources (doi:10.5065/D6RX99HX) and reference He et al. (2021) when presenting results based on the iTRACE in either oral or written form.

• He, C., Liu, Z., Otto-Bliesner, B. L., Brady, E. C., Zhu, C., Tomas, R., Clark, P. U., Zhu, J., Jahn, A., &Gu, S. (2021), Hydroclimate footprint of pan-Asian monsoon water isotope during the last deglaciation, Science Advances, 7(4), eabe2611.
• He, C. (2021), Deciphering the deglacial evolution of water isotope and climate in the Northern Hemisphere, The Ohio State University, 2021.

Project Details

• Simulation Protocols: Details of experimental design is found in papers listed above.
• Simulation Names: [replace "xx" with ka year at start of simulation; see RoadMap below for details]
  • [all-forcing run]
    • b.e13.Bi1850C5.f19_g16.xxka.itrace.ice_ghg_orb_wtr.0x.cam.h0.variable.model-year.nc
  • [ice+ghg+orb run] 
    • b.e13.Bi1850C5.f19_g16.xxka.itrace.ice_ghg_orb.0x.cam.h0.variable.model-year.n
  • [ice+orb run]
    • b.e13.Bi1850C5.f19_g16.xxka.itrace.ice_orb.0x.cam.h0.variable.model-year.nc
  • [ice run]
    • b.e13.Bi1850C5.f19_g16.xxka.itrace.0x.cam.h0.variable.model-year.nc
  • [NOTE] Some runs named in ice_ghg_orb_mwtr available at Climate Data Gateway, are extra runs not part of the main simulation roadmap. These are failed test runs, so please neglect them. Contact Chengfei He to get the case roadmap (cxh1079@earth.miami.edu). 
• Model Version: iCESM1.3
• Resolution: f19_g16
• Period: 20,000-11,000 years before present
• Time frequencies saved: monthly
• Machine: Cheyenne
• Compset: Bi1850C5

Data Acquisition 

The data is available on the NWSC computing storage at /glade/campaign/cesm/collections/iTRACE and via the web from the NCAR Climate Data Gateway here. 

Follow these steps to obtain output from the Climate Data Gateway:

• Register/login to the Climate Data Gateway.
• Navigate to experiment landing page: https://www.earthsystemgrid.org/dataset/ucar.cgd.ccsm4.iTRACE.html
• Scroll down to Child Datasets, click chosen component and time frequency.
• Click a Child Dataset organized by variable.
• Login to CDG to access download options (if not done so before.) 
• Choose a set of files to download from the list. 

Contacts:

Zhengyu Liu [liu.7022@osu.edu]

Bette Otto-Bliesner [ottobli@ucar.edu]

Chengfei He [he.1519@osu.edu; cxh1079@earth.miami.edu]