Sensitivity of a general circulation model to land surface parameters in African tropical deforestation experiments

2004 ◽  
Vol 22 (6-7) ◽  
pp. 555-572 ◽  
Author(s):  
K. Maynard ◽  
J.-F. Royer
Keyword(s):  
General Circulation Model ◽  
Land Surface ◽  
General Circulation ◽  
Circulation Model ◽  
Tropical Deforestation ◽  
Surface Parameters ◽  
Land Surface Parameters

scholarly journals The CSIRO Mk3L climate system model version 1.0 – Part 1: Description and evaluation

2011 ◽  
Vol 4 (2) ◽  
pp. 483-509 ◽  
Author(s):  
S. J. Phipps ◽  
L. D. Rotstayn ◽  
H. B. Gordon ◽  
J. L. Roberts ◽  
A. C. Hirst ◽  
...  
Keyword(s):  
Sea Ice ◽  
General Circulation Model ◽  
Land Surface ◽  
General Circulation ◽  
Regional Scale ◽  
Circulation Model ◽  
Climate System ◽  
System Model ◽  
Desktop Computer ◽  
Climate System Model

Abstract. The CSIRO Mk3L climate system model is a coupled general circulation model, designed primarily for millennial-scale climate simulations and palaeoclimate research. Mk3L includes components which describe the atmosphere, ocean, sea ice and land surface, and combines computational efficiency with a stable and realistic control climatology. This paper describes the model physics and software, analyses the control climatology, and evaluates the ability of the model to simulate the modern climate. Mk3L incorporates a spectral atmospheric general circulation model, a z-coordinate ocean general circulation model, a dynamic-thermodynamic sea ice model and a land surface scheme with static vegetation. The source code is highly portable, and has no dependence upon proprietary software. The model distribution is freely available to the research community. A 1000-yr climate simulation can be completed in around one-and-a-half months on a typical desktop computer, with greater throughput being possible on high-performance computing facilities. Mk3L produces realistic simulations of the larger-scale features of the modern climate, although with some biases on the regional scale. The model also produces reasonable representations of the leading modes of internal climate variability in both the tropics and extratropics. The control state of the model exhibits a high degree of stability, with only a weak cooling trend on millennial timescales. Ongoing development work aims to improve the model climatology and transform Mk3L into a comprehensive earth system model.

scholarly journals A catchment-based approach to modeling land surface processes in a general circulation model: 1. Model structure

2000 ◽  
Vol 105 (D20) ◽  
pp. 24809-24822 ◽  
Author(s):  
Randal D. Koster ◽  
Max J. Suarez ◽  
Agnès Ducharne ◽  
Marc Stieglitz ◽  
Praveen Kumar
Keyword(s):  
General Circulation Model ◽  
Land Surface ◽  
General Circulation ◽  
Circulation Model ◽  
Surface Processes ◽  
Model Structure ◽  
Land Surface Processes

scholarly journals Influence of Surface Topography on the Critical Carbon Dioxide Level Required for the Formation of a Modern Snowball Earth

2018 ◽  
Vol 31 (20) ◽  
pp. 8463-8479 ◽  
Author(s):  
Yonggang Liu ◽  
W. Richard Peltier ◽  
Jun Yang ◽  
Yongyun Hu
Keyword(s):  
Sea Ice ◽  
General Circulation Model ◽  
Land Surface ◽  
General Circulation ◽  
Coupled Model ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Ocean Model ◽  
Snowball Earth ◽  
Ice Dynamics

The influence of continental topography on the initiation of a global glaciation (i.e., snowball Earth) is studied with both a fully coupled atmosphere–ocean general circulation model (AOGCM), CCSM3, and an atmospheric general circulation model (AGCM), CAM3 coupled to a slab ocean model. It is found that when the climate is very cold, snow cover over the central region of the Eurasian continent decreases when the atmospheric CO2 concentration ( pCO2) is reduced. In the coupled model, this constitutes a negative feedback due to the reduction of land surface albedo that counteracts the positive feedback due to sea ice expansion toward the equator. When the solar insolation is 94% of the present-day value, Earth enters a snowball state when pCO2 is ~35 ppmv. On the other hand, if the continents are assumed to be flat topographically (with the global mean elevation as in the more realistic present-day case), Earth enters a snowball state more easily at pCO2 = ~60 ppmv. Therefore, the presence of topography may increase the stability of Earth against descent into a snowball state. On the contrary, a snowball Earth is found to form much more easily when complex topography is present than when it is not in CAM3. This happens despite the fact that the mid- to high-latitude climate is much warmer (by ~10°C) when topography is present than when it is not. Analyses show that neglecting sea ice dynamics in this model prevents the warming anomaly in the mid- to high latitudes from being efficiently transmitted into the tropics.

scholarly journals Effect of Human-Induced Land Disturbance on Subseasonal Predictability of Near-Surface Variables Using an Atmospheric General Circulation Model

Atmosphere ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 725
Author(s):  
Tomohito J. Yamada ◽  
Yadu Pokhrel
Keyword(s):  
General Circulation Model ◽  
Land Surface ◽  
General Circulation ◽  
Atmospheric General Circulation Model ◽  
Circulation Model ◽  
Weather Forecast ◽  
Surface Model ◽  
Near Surface ◽  
Land Disturbance ◽  
Atmospheric General Circulation

Irrigation can affect climate and weather patterns from regional to global scales through the alteration of surface water and energy balances. Here, we couple a land-surface model (LSM) that includes various human land-water management activities including irrigation with an atmospheric general circulation model (AGCM) to examine the impacts of irrigation-induced land disturbance on the subseasonal predictability of near-surface variables. Results indicate that the simulated global irrigation and groundwater withdrawals (circa 2000) are ~3600 and ~370 km3/year, respectively, which are in good agreement with previous estimates from country statistics and offline–LSMs. Subseasonal predictions for boreal summers during the 1986–1995 period suggest that the spread among ensemble simulations of air temperature can be substantially reduced by using realistic land initializations considering irrigation-induced changes in soil moisture. Additionally, it is found that the subseasonal forecast skill for near-surface temperature and sea level pressure significantly improves when human-induced land disturbance is accounted for in the AGCM. These results underscore the need to incorporate irrigation into weather forecast models, such as the global forecast system.

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