The effect of a dynamic soil scheme on the climate of the mid-Holocene and the Last Glacial Maximum

Abstract

Abstract. In order to account for coupled climate-soil processes, we have developed a soil scheme which is asynchronously coupled to a comprehensive climate model with dynamic vegetation. This scheme considers vegetation as the primary control of changes in physical soil characteristics. We test the scheme for a warmer (mid-Holocene) and colder (Last Glacial Maximum) climate relative to the preindustrial climate. We find that the computed changes in physical soil characteristics lead to significant amplification of global climate anomalies, representing a positive feedback. The inclusion of the soil feedback yields an extra surface warming of 0.24 • C for the mid-Holocene and an additional global cooling of 1.07 • C for the Last Glacial Maximum. Transition zones such as desert-savannah and taiga-tundra exhibit a pronounced response in the model version with dynamic soil properties. Energy balance model analyses reveal that our soil scheme amplifies the temperature anomalies in the mid-to-high northern latitudes via changes in the planetary albedo and the effective longwave emissivity. As a result of the modified soil treatment and the positive feedback to climate, part of the underestimated mid-Holocene temperature response to orbital forcing can be reconciled in the model.

Threshold in North Atlantic-Arctic Ocean circulation controlled by the subsidence of the Greenland-Scotland Ridge

“…On the basis of a Late Miocene vegetation reconstruction53, we derived physical soil characteristics, such as soil albedo and maximum water holding field capacity by adapting vegetation related parameters from Stärz et al 29…”

Impact of Weddell Sea shelf progradation on Antarctic bottom water formation during the Miocene

“…The ocean model MPIOM [Marsland et al, 2003], including thermal dynamics that is formulated using viscous-plastic rheology, has a mean resolution of GR30 (3°× 1.8°) in the horizontal, with 40 uneven vertical layers. The climate model has already been used to simulate the last millennium [Jungclaus et al, 2010], the Holocene, the Last Glacial Maximum, and the Miocene warm climate [Knorr et al, 2011;Wei and Lohmann, 2012;Lohmann et al, 2013;Gong et al, 2013;Zhang et al, 2014;Knorr and Lohmann, 2014;Stärz et al, 2016;Stein et al, 2016].…”

Late Cretaceous climate simulations with different CO2 levels and subarctic gateway configurations: A model‐data comparison

“…Parameters of Food and Agriculture Organization data flags follow Stärz et al . []. Soil wetness, which is simulated by AOGCM is initialized with values adopted from Stärz et al .…”

“…The first six parameter values for many different PFTs are described in Hagemann [2002]. Parameters of Food and Agriculture Organization data flags follow Stärz et al [2016]. Soil wetness, which is simulated by AOGCM is initialized with values adopted from Stärz et al [2016].…”