The modern configuration of the South East Asian Islands (SEAI) evolved over the last fifteen million years, as a result of subduction, arc magmatism, and arc-continent collisions, contributing to both increased land area and high topography.  The presence of the additional land area has been postulated to enhance convective rainfall, facilitating both increased silicate weathering and the development of the modern-day Walker circulation.  Using an Earth System Model in conjunction with a climate-silicate weathering model, we argue instead for a significant role of SEAI topography for both effects.  This dataset archives model output used in this investigation, including simulations using the Community Earth System Model version 1.2, and the climate-silicate weathering model GEOCLIM.

The dataset contains model output from:

Chiang, JCH, P Maffre, NL Swanson-Hysell, and FA Macdonald, 2023: The role of Southeast Asian Island  topography on Indo-Pacific climate and silicate weathering.  Revised for Paleoceanography and Paleoclimate, Nov 2023.

All data are in Netcdf format, and were generated either by the Community Earth System Model 1.2 (Hurrell et al. 2013) or the climate-silicate weathering model GEOCLIM (Park et al. 2020).

Model output is organized into 6 tar files:

1) B1850C5.tar

Contains model output for the fully coupled CESM1.2 runs.  Monthly mean data for years 41-110 of the simulations.  

a) Atmosphere model output for 2D fields and for 3D pressure vertical velocity (W) between 10S-10N.

Filename description is

0% SEAI topography (aka flat SEAI): B1850C5_noSEAItopo_y41-110.nc and B1850C5_noSEAItopo_W_y41-110.nc

50% SEAI topography: B1850C5_0.5SEAItopo_y41-110.nc and B1850C5_0.5SEAItopo_W_y41-110.nc

100% SEAI topography (aka modern SEAI): B1850C5_y41-110.nc and B1850C5_W_y41-110.nc

150% SEAI topogaphy: B1850C5_1.5SEAItopo_y41-110.nc and B1850C5_1.5SEAItopo_W_y41-110.nc

0% SEAI topogaphy and 394.1ppm: B1850C5_noSEAItopo_394CO2_y41-110.nc and B1850C5_noSEAItopo_394CO2_W_y41-110.nc

b) Ocean model output for subsurface temperature (bilinearly interpolated from the gx1v6 ocean grid).  

Filename description is

0% SEAI topography (aka flat SEAI): B1850C5_noSEAItopo_ocn_y41-110.nc

100% SEAI topography (aka modern SEAI): B1850C5_ocn_y41-110.nc 

2) E1850C5.tar

Contains model output for the slab ocean CESM1.2 runs, for 2D fields and for 3D pressure vertical velocity (W) between 10S-10N.  Monthly mean data for years 41-70 of the simulations.  

Filename description is

No SEAI: E1850C5_noSEAI_y21-50.nc and E1850C5_noSEAI_W_y41-70.nc

0% SEAI topography (aka flat SEAI): E1850C5_noSEAItopo_y41-70.nc and E1850C5_noSEAItopo_W_y41-70.nc

50% SEAI topography: E1850C5_0.5SEAItopo_y41-70.nc and E1850C5_0.5SEAItopo_W_y41-70.nc

100% SEAI topography (aka modern SEAI): E1850C5_y41-70.nc and E1850C5_W_y41-70.nc

150% SEAI topogaphy:  E1850C5_1.5SEAItopo_y41-70.nc and E1850C5_1.5SEAItopo_W_y41-70.nc

3) GEOCLIM.tar

Contains model output from the climate-silicate weathering model GEOCLIM.  Data is provided for all 573 parameter combinations.  There is one file for each year of the CESM1.2 simulation input denoted on the filename as 'yXX' where XX is from year 41 through 70.

There are two subdirectories: 'Global-integrated' and 'Spatial-fields'

a) Files in the 'Global-integrated' folder contain these variables:

GMST: global mean surface temperature (in K)

atm_CO2_level: atmospheric pCO2 (in ppm)

degassing: globally-integrated CO2 flux (in mol/yr)

Filename description is

E1850C5_yXX_PIctrl.nc - GEOCLIM output using the CESM1.2 slab ocean modern SEAI simulation as input, GEOCLIM topography set to modern, and GEOCLIM pCO2 fixed to 284.7ppm. 

E1850C5_yXX_noSEAI_1xCO2.nc - GEOCLIM output using the CESM1.2 slab ocean no SEAI simulation as input, GEOCLIM SEAI removed, and GEOCLIM pCO2 fixed to 284.7ppm. 

E1850C5_yXX_noSEAI_equil.nc - GEOCLIM output using the CESM1.2 slab ocean no SEAI simulation as input, GEOCLIM SEAI removed, and GEOCLIM pCO2 set so that system is in carbon flux equilibrium.  

E1850C5_yXX_noSEAItopo_1SEAIslope_1xCO2.nc - GEOCLIM output using the CESM1.2 slab ocean flat SEAI simulation as input, GEOCLIM topography set to modern, and pCO2 fixed to 284.7ppm. 

E1850C5_yXX_noSEAItopo_flatSEAIslope_1xCO2.nc - GEOCLIM output using the CESM1.2 slab ocean flat SEAI simulation as input, GEOCLIM SEAI topography set to flat, and GEOCLIM pCO2 fixed to 284.7ppm. 

E1850C5_yXX_noSEAItopo_flatSEAIslope_equil.nc - GEOCLIM output using the CESM1.2 slab ocean flat SEAI simulation as input, GEOCLIM SEAI topography set to flat, and GEOCLIM pCO2 adjusted so that system is in carbon flux equilibrium.  

b) Files in the 'Spatial-fields' folder contain these variables:

weathering_lithmean: Ca-Mg weathering rate for all lithology classes (mol/m^2/yr)

Filename description is

E1850C5_yXX_PIctrl_wthmap.nc - GEOCLIM output using the CESM1.2 slab ocean modern SEAI simulation as input, GEOCLIM topography set to modern, and GEOCLIM pCO2 fixed to 284.7ppm. 

E1850C5_yXX_noSEAI_1xCO2_wthmap.nc - GEOCLIM output using the CESM1.2 slab ocean no SEAI simulation as input, GEOCLIM SEAI removed, and GEOCLIM pCO2 fixed to 284.7ppm. 

E1850C5_yXX_noSEAItopo_flatSEAIslope_1xCO2_wthmap.nc - GEOCLIM output using the CESM1.2 slab ocean flat SEAI simulation as input, GEOCLIM SEAI topography set to flat, and GEOCLIM pCO2 fixed to 284.7ppm. 

4) Surface.tar

Contains land fraction and surface geopotential fields for the modern SEAI (Landfrac.nc) and no SEAI (Landfrac_noSEAI.nc) simulations

5) CESM_input.tar 

Contains initialization and boundary condition files for running the various SEAI cases on CESM1.2.  There are 3 subdirectories: E1850C5_noSEAI, E1850C5_qflux, and Topography 

a) E1850C5_noSEAI 

Contains initialization and boundary condition files for the CESM1.2 slab ocean no SEAI case.  See the README.txt in that subdirectory for use information

b) E1850C5_qflux

Contains q-flux files for CESM1.2 slab ocean run for various case:

pop_frc.b.e11.B1850C5CN.f09_g16.005.150217.nc - used for modern SEAI and flat SEAI cases

pop_frc.b.e11.B1850C5CN.f09_g16.005.150217_noSEAI.nc - used for no SEAI case where mixed layer depth set to 16m and ocean heat flux convergence set to 0 W/m^2 over SEAI gridpoints

pop_frc.b.e11.B1850C5CN.f09_g16.005.150217_noSEAI_HBLT32.nc - used for no SEAI case with mixed layer depth over SEAI gridpoints doubled to 32m

pop_frc.b.e11.B1850C5CN.f09_g16.005.150217_noSEAI_QDP20.nc - used for no SEAI case with ocean heat flux convergence over SEAI gridpoints set to 20W/m^2

c) Topography

Contains topography files for CESM1.2 slab ocean and fully coupled runs:

USGS-gtopo30_0.9x1.25_remap_c051027.nc - used for modern SEAI case

USGS-gtopo30_0.9x1.25_remap_c051027_noSEAItopo.nc - used for flat SEAI case

USGS-gtopo30_0.9x1.25_remap_c051027_noSEAI.nc - - used for no SEAI case (slab ocean only)

USGS-gtopo30_0.9x1.25_remap_c051027_0.5SEAItopo.nc - used for 50% SEAI case (slab ocean only)

USGS-gtopo30_0.9x1.25_remap_c051027_1.5SEAItopo.nc - used for 150% SEAI case (slab ocean only)

6) GEOCLIM_input.tar

Contains CESM1.2 slab ocean simulation annual mean output used as input for the GEOCLIM simulations.  

Data is organized in folders by year from 41 to year 70.  

Filename description is as follows:

E1850C5_2xCO2_lnd_ANN_y41.nc - Land surface data, modern SEAI simulation and with CO2 set to 569.4ppm

E1850C5_lnd_ANN_y41.nc - Land surface data, modern SEAI simulation and with CO2 set to 284.7ppm

E1850C5_noSEAI_2xCO2_lnd_ANN_y41.nc - Land surface data, no SEAI simulation and with CO2 set to 569.4ppm

E1850C5_noSEAI_2xCO2_TS_ANN_y41.nc - Surface temperature data, no SEAI simulation and with CO2 set to 569.4ppm

E1850C5_noSEAI_lnd_ANN_y41.nc - Land surface data, no SEAI simulation and with CO2 set to 284.7ppm

E1850C5_noSEAI_TS_ANN_y41.nc -  Surface temperature data, no SEAI simulation and with CO2 set to 284.7ppm

E1850C5_noSEAItopo_2xCO2_lnd_ANN_y41.nc - Land surface data, flat SEAI simulation and with CO2 set to 569.4ppm

E1850C5_noSEAItopo_2xCO2_TS_ANN_y41.nc - Surface temperature data, flat SEAI simulation and with CO2 set to 569.4ppm

E1850C5_noSEAItopo_lnd_ANN_y41.nc - Land surface data, flat SEAI simulation and with CO2 set to 284.7ppm

E1850C5_noSEAItopo_TS_ANN_y41.nc - Surface temperature data, flat SEAI simulation and with CO2 set to 284.7ppm

E1850C5_TS_2xCO2_ANN_y41.nc - Surface temperature data, modern SEAI simulation and with CO2 set to 569.4ppm

E1850C5_TS_ANN_y41.nc - Surface temperature data, modern SEAI simulation and with CO2 set to 284.7ppm

 

References

Hurrell, J.W., Holland, M.M., Gent, P.R., Ghan, S., Kay, J.E., Kushner, P.J., Lamarque, J.F., Large, W.G., Lawrence, D., Lindsay, K. and Lipscomb, W.H., 2013. The community earth system model: a framework for collaborative research. Bulletin of the American Meteorological Society, 94(9), pp.1339-1360.

Park, Y., Maffre, P., Goddéris, Y., Macdonald, F.A., Anttila, E.S. and Swanson-Hysell, N.L., 2020. Emergence of the Southeast Asian islands as a driver for Neogene cooling. Proceedings of the National Academy of Sciences, 117(41), pp.25319-25326.