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Data from: Terrestrial evaporation and global climate: lessons from Northland, a planet with a hemispheric continent

Citation

Lague, Marysa M. et al. (2022), Data from: Terrestrial evaporation and global climate: lessons from Northland, a planet with a hemispheric continent, Dryad, Dataset, https://doi.org/10.6078/D1399Q

Abstract

Motivated by the hemispheric asymmetry of land distribution on Earth, we explore the climate of Northland, a highly idealized planet with a Northern Hemisphere continent and a Southern Hemisphere ocean. The climate of Northland can be separated into four distinct regions: the Southern Hemisphere ocean, the seasonally wet tropics, the mid-latitude desert, and the Great Northern Swamp. We evaluate how modifying land surface properties on Northland drives changes in temperatures, precipitation patterns, the global energy budget, and atmospheric dynamics. We observe a surprising response to changes in land-surface evaporation, where suppressing terrestrial evaporation in Northland cools both land and ocean. In previous studies, suppressing terrestrial evaporation has been found to lead to local warming by reducing latent cooling of the land surface. However, reduced evaporation can also decrease atmospheric water vapor, reducing the strength of the greenhouse effect and leading to large-scale cooling. We use a set of idealized climate model simulations to show that suppressing terrestrial evaporation over Northern Hemisphere continents of varying size can lead to either warming or cooling of the land surface, depending on which of these competing effects dominate. We find that a combination of total land area and contiguous continent size controls the balance between local warming from reduced latent heat flux and large-scale cooling from reduced atmospheric water vapor. Finally, we demonstrate how terrestrial heat capacity, albedo, and evaporation all modulate the location of the ITCZ both over the continent and over the ocean.

Methods

Isca climate model output for the experiments described in the paper "Terrestrial evaporation and global climate: lessons from Northland, a planet with a hemispheric continent" published in Journal of Climate.

Usage Notes

Each netcdf file contains the monthly mean output of each field for the duration of the simulation. Variables are as described in the Isca documentation (and noted below), except for:

flux_lw is the downard flux of longwave radiation at the surface.

mml_lwup is the upward flux of longwave radiation at  the surface.

Full time series variable list:

bucket_depth   -  time-varying soil moisture
olr                    - top of atmosphere outgoing longwave radiation (positive up) [W/m2]
t_surf               - surface temperature (radiative skin temperature) [K]
flux_lhe           - surface evaporation (positive up) [W/m2]
precipitation    - rain/snow (positive down)
temp                 - temperature (vertically resolved through atmosphere) [K]
flux_lw            - Downwards LW radiation at the surface. Positive down. [W/m2]. NOT net surface LW.
ps                     - surface pressure
toa_sw              - top of atmosphere incoming shortwave radiation, positive down [W/m2]
flux_sw            - net surface flux of shortwave radiation, positive down [W/m2]
rh                      - relative humidity
vcomp_height  - poleward transport of potential energy
flux_t               - surface sensible heat flux, positive up [W/m2]
sphum              - specific humidity [kg/kg]
vcomp_temp    - poleward transport of heat (dry)
mml_flus          - surface upwards (emitted) longwave radiation [W/m2]
sphum_v          - poleward transport of moisture

Funding

James S. McDonnell Foundation