Spin-up and Tuning of the Global Carbon Cycle Model Inside the GISS ModelE2 GCM

Abstract:

Planetary carbon cycle involves multiple phenomena, acting at variety
of temporal and spacial scales. The typical times range from minutes
for leaf stomata physiology to centuries for passive soil carbon pools
and deep ocean layers. So, finding a satisfactory equilibrium state
becomes a challenging and computationally expensive task. Here we
present the spin-up processes for different configurations of the
GISS Carbon Cycle model from the model forced with MODIS observed Leaf
Area Index (LAI) and prescribed ocean to the prognostic LAI and to the
model fully coupled to the dynamic ocean and ocean biology. We
investigate the time it takes the model to reach the equilibrium and
discuss the ways to speed up this process.

NASA Goddard Institute for Space Studies General Circulation Model
(GISS ModelE2) is currently equipped with all major algorithms necessary for
the simulation of the Global Carbon Cycle. The terrestrial part is
presented by Ent Terrestrial Biosphere Model (Ent TBM), which includes
leaf biophysics, prognostic phenology and soil biogeochemistry module
(based on Carnegie-Ames-Stanford model). The ocean part is based on
the NASA Ocean Biogeochemistry Model (NOBM). The transport of
atmospheric CO2 is performed by the atmospheric part of ModelE2, which
employs quadratic upstream algorithm for this purpose.