The role of vegetation-climate interaction on Africa under climate change - literature review seminar Minchao Wu Supervisor: Markku Rummukainen, Guy Schurgers

Main drivers of climate and climate change Source. IPCC 2013

The development of Earth System Models (ESMs) Source. IPCC 2013

Vegetation feedback on climate A Source. Bonan et al. 2008

Challenge to quantify due to various sensitivity in different process Adapted from Zhang et al Positive or negative depends on process sensitivity (contribution)

Effects of large-scale deforestation Source. Bala et al Borael : Deforst.  Albedo (+)  shortwave net rad. (-)  temp. (-) Tropics : Deforst.  Albedo (+)  shortwave net rad. (-)  evap. (-) & sensible heat flux (-)  temp. (+)

Effects of vegetation carbon-cycle feedback CO2 (+)  Stomata cond. (-)  Evap. (-)  Precp. (-)Veg. (-) Temp. + Source. Bett et al. 2004

RCMs : essential for policymaking for regional climate change

Coupled Regional climate model – dynamic global vegetation model (coupled RCM-DGVM) Feedback Variables Study region Models (RCM/DGVM) Finding PapersComments/outlook Vegetation structure Central United States RAMS/CENTURY (weekly) Seasonal vegetation phenological variation strongly influences regional climate patterns through its control over land surface water and energy exchange. (Lu et al., 2001)Lu et al., 2001 The inadequate and unrealistic description of vegetation evolution in its current land surface models is considered a major deficiency Vegetation structure West Africa RegCM3/CLM- DGVM (asynchronously, yearly) Precipitation increase by 23% over the Sahel in summer compared 5% decrease without vegetation feedback (Alo and Wang, 2010), (Wang and Alo, 2012)Alo and Wang, 2010Wang and Alo, 2012 Should use synchronously (fully) coupling approach in future study; Land use should be consider; model consistency: soil moisture; Vegetation structure, fraction Europe RCA/LPJ-GUESS, (fully coupled, daily) Feedback effects are rather modest: feedback contribute degree C increase for southern Europe and decrease for northern and central Europe. (Smith et al., 2011, Wramneby et al., 2010)Smith et al., 2011 Wramneby et al., 2010 Smaller than assumed, such as in other studies Betts et al., 2000, Bala et al., 2007; Land use should be consider; model consistency: such as land surface process, stomatal regulation and soil hydrology. Land use Unite State WRF3/CLM3.5 Strong soil moisture-precipitation feedback in Midwest irrigated area (Lu and Kueppers, 2012)Lu and Kueppers, 2012 Need to improve LAI simulation, and irrigation scheme. Crop, Vegetation structure, vegetation fraction East Asian monsoon area RegCM3/CERES (fully coupled, daily, land-surface scheme derived from BATS) Reduced RMSE of the simulated precipitation by 2.2–10.7% over north China (Chen and Xie, 2012)Chen and Xie, 2012 Uncertainties in modeling how monsoon dynamics responds in RCMs. Uncertainties also lie in the lack of description of natural vegetation growth and develop and the simplification of cropping system over the region. Vegetation structure EuropeREMO/iMOVE (vegetation part originates from JSBACH) Dynamics of vegetation cover and density contribute to difference from REMO2009 (Wilhelm et al., 2013)Wilhelm et al., 2013Soil hydrological dynamics is not capture for some regions that influence vegetation growth, e.g. LAI Further development effort should put to multi-layer scheme Uncertainties in vegetation dynamics Or coupling approach

RCA-GUESS application (Europe) Normalized phenology index summer Temp. summer Latent Heat flux Change in future Feedback contribution Wramneby et al., 2010 Northern & central E.: cooler & wetter Southern E: warmer & drier

RCA-GUESS application (Arctic) Normalized phenology index Change in future Feedback contribution Zhang et al., 2014 Spring: warming Summer: cooling

Reflection of previous RCA-GUESS studies Europe - Small feedback effects:  Climate is controlled by general circulation and effects of the Atlantic sea.  Feedback is merely locally significant? Artic – More processes should be included?  SST feedback, Permafrost C feedbacks, land use, nutrient feedbacks

Attractive research domain - Africa Carbon stock: 20% of global (NPP) Landscape change: Deforestation: ca. 10% of the total forest area of Africa annually ( ) Greening: 10%-50% increase in NDVI in over Sahel. 20% of global land use CO 2 emission Wildfire: > 68% of the global wildfire, 40% fire emission

Research Questions General research question: What is the role of regional vegetation-climate feedback for African climate change studies? Sub-research questions:  Can vegetation-climate feedbacks help to better understand regional climate and vegetation conditions for present-day Africa?  If vegetation feedback is still limited to local or regional effects, it remote effect is possible to identify?  If integrating more processes would help better under vegetation- climate feedback and if so if how to better constrain uncertainty?

Papers plan

Some results for the current project plan

Thanks!