The influence of albedo on Mesoarchaean climate - global tas temperature

We systematically assessed the effects of varying land distributions (diagonal, central, polar), land surface fractions (8–28 %), atmospheric CO₂-equivalent concentrations (3–30 %), and surface albedo (0.15–0.30). In addition to the expected strong dependence of global mean temperature on atmospheric greenhouse gas concentration, our results show reduced seasonality at higher atm. CO₂-equivalents.

Increasing land area generally leads to cooling, except at low CO2-equivalent concentrations (3-5 %) and low albedo (<0.2). When land exceeds ~13 % of total Earth’s surface, it starts to have a pronounced effect on global climate. Among the spatial configurations, diagonal land distribution shows the highest climate sensitivity.

The climatic shift around 2.9 Ga may be linked to emergence of extensive low-albedo (<0.2) surfaces (e.g., mafic/ultramafic rocks) and/or to the latitudinal drift of the Kaapvaal Craton into a more radiatively sensitive zone. This dataset contains global 2-meter above the ground temperature (tas) at a horizontal resolution of T21 (64 x 32 grid points). The data show the global effects of surface albedo.

In this experiment, only the diagonal land distribution with different fractions was used, while the surface albedo was systematically varied to assess its climatic impact. The prescribed albedo values were 0.15, 0.20, 0.25 and 0.30. All simulations were performed using the Planet Simulator (PlaSim; Freadrich et al. 2005), an intermediate-complexity general circulation model.

Postprocessing was conducted using PlaSim’s integrated postprocessor. The resulting data are provided in NetCDF format, representing 50-year simulations with the variable tas defined on the dimensions [long(64), lat(32), time (18263)].