Climate Effects of Land Use Change in CESM Dr. Peter … · Climate Effects of Land Use Change in...
Transcript of Climate Effects of Land Use Change in CESM Dr. Peter … · Climate Effects of Land Use Change in...
Climate Effects of Land Use Change in CESM
Dr. Peter Lawrence
Project Scientist
Terrestrial Science SectionClimate and Global Dynamics Division
(With thanks to the TSS group for their many contributions)
Slide 1 - Title
Understanding the Land Surface in the Climate System: Investigations with an Earth System Model (NCAR CESM)
The land is a critical interface through which:
1. Climate and climate change impactshumans and ecosystems
and
2. Humans and ecosystems can force global environmental and climate change
Gridcell
Glacier Wetland Lake
Landunit
Columns
PFTs
UrbanVegetated
Soil Type 1
Community Land Model (CLM) subgrid tiling structure
1. Direct Biogeophysical Impacts:- Albedo – Radiation (Snow Interactions)- Surface Hydrology (Irrigation)- Surface Roughness
2. Direct Biogeochemical Impacts:- Vegetation and Soil Carbon Fluxesfrom Conversion Natural -> Human systems
- Harvesting from Forestry and Agriculture
3. Indirect Impacts:- Increased Photosynthesis through higherCO2, Nitrogen, Phosphorus and Potassium
- Atmospheric Responses in Temperature, Cloud,Precipitation and Larger Scale Circulation
- Fire, Methane, Dust, Volatile Organics, AerosolsLawrence et al., [2011], Lawrence and Chase, [2010], Feddema, et al., [2005], Findell, et al., [2007], IPCC, [2007], Bonan, [2008], and Canadell, et al., [2007]
Slide 4 – Land Cover Change
Human Land Cover Change
AgricultureAfforestation
Growth Growth
Urban
Forestry
1. Direct Biogeophysical Impacts:- Albedo – Radiation (Snow Interactions)- Surface Hydrology (Irrigation)- Surface Roughness
2. Direct Biogeochemical Impacts:- Vegetation and Soil Carbon Fluxesfrom Conversion Natural -> Human systems
- Harvesting from Forestry and Agriculture
3. Indirect Impacts:- Increased Photosynthesis through higherCO2, Nitrogen, Phosphorus and Potassium
- Atmospheric Responses in Temperature, Cloud,Precipitation and Larger Scale Circulation
- Fire, Methane, Dust, Volatile Organics, AerosolsLawrence et al., [2011], Lawrence and Chase, [2010], Feddema, et al., [2005], Findell, et al., [2007], IPCC, [2007], Bonan, [2008], and Canadell, et al., [2007]
Slide 4 – Land Cover Change
Human Land Cover Change
AgricultureAfforestation
Growth Growth
Urban
Forestry
1. Direct Biogeophysical Impacts:- Albedo – Radiation (Snow Interactions)- Surface Hydrology (Irrigation)- Surface Roughness
2. Direct Biogeochemical Impacts:- Vegetation and Soil Carbon Fluxesfrom Conversion Natural -> Human systems
- Harvesting from Forestry and Agriculture
3. Indirect Impacts:- Increased Photosynthesis through higherCO2, Nitrogen, Phosphorus and Potassium
- Atmospheric Responses in Temperature, Cloud,Precipitation and Larger Scale Circulation
- Fire, Methane, Dust, Volatile Organics, AerosolsLawrence et al., [2011], Lawrence and Chase, [2010], Feddema, et al., [2005], Findell, et al., [2007], IPCC, [2007], Bonan, [2008], and Canadell, et al., [2007]
Slide 4 – Land Cover Change
Human Land Cover Change
AgricultureAfforestation
Growth Growth
Urban
Forestry
1. The biogeophysical climate impacts of changing land cover from precleared vegetation to current day vegetation were investigated with the CCSM 3.0 model in Lawrence and Chase (2010)
2. The investigation compared six ensemble members of 30 years of current day equilibrium climate simulated in the fully coupled CCSM 3.0 model with Precleared Vegetation land surface parameters, against the same climate simulated with Current Day land surface parameters
3. The Land Surface Hydrology representation in CLM 3.0 was modified as described in Lawrence and Chase (2009) to address modeling biases.
CCSM Land Cover Change Climate Experiments
Slide 2 - Outline
Current Day – Preclear Vegetation CCSM Climate-Albedo
Slide 5 – CLM Parameters - Sub-Patch PFTSLawrence and Chase (2010)
Current Day – Preclear Vegetation CCSM Climate-Latent
Slide 5 – CLM Parameters - Sub-Patch PFTSLawrence and Chase (2010)
1. High latitude winter cooling due increased albedo from current day crops and grasses which replace natural forests, savannas and shrublands. These changes were amplified by snow interactions
2. Tropical warming and summer higher latitude warming associated with reduced evapo-transpiration which left more of the surface energy budget available for sensible heating – despite higher albedo
Summary of CCSM 3.0 Land Cover Change Experiments
Slide 2 - Outline
CMIP5 CCSM Land Cover Change Emissions and Warming
Slide 2 - Outline
Time Series Landuse PgC CO2 PPM Temp OC
Historical 1850-2005 120.0 30 0.35
RCP 2.6 Image 176.9 44 0.51
RCP 4.5 GCAM 150.0 38 0.44
RCP 6.0 AIM 182.7 46 0.53
RCP 8.5 Message 259.6 65 0.75
Slide 6 – PFT Mapping
CESM Land Cover Change – Impacts of Albedo
Jones et al. 2013 (LBNL & UCB)
- Applied very large land cover change in RCP 4.5 - Found strong cooling in
northern latitudes from albedoincreases against afforestation
- These partially offset CO2warming.
Slide 6 – PFT Mapping
CESM Land Cover Change – Albedo and Hydrology
CESM Land Cover Change and Hydrology Experiments:
- Land Cover Change: Current Day to All Grass- Hydrology changes in CLM to address known Evapo-Transpiration issues (New Hydro)
- New Hydro reduces annual temperature cooling over the extra-tropics from going from trees to grasses and increases warming in tropics
22
Urban Areas in a Climate ModelGridcell
Glacier Wetland Lake
Landunits
Columns
Vegetated
(RURAL)
PerviousShaded WallRoof Sunlit Wall Impervious
Canyon Floor
Urban
,sunwall sT ,shdwall sT
,roof sT
imprvrdHprvrdH
shdwallHsunwallH
roofH
, , , ,H E L S τ↑ ↑
Impervious Road “Pervious” Road
,prvrd sT,imprvrd sT
, ,s s sT q u
Canopy Air Space
W
H
Roof
Sunlit Wall
Shaded Wall
,1prvrdT
,10prvrdT
,1imprvrdT
,10imprvrdT
,1roofT
,10roofT
,1sunwlT ,10sunwlT
roofR
imprvrdR prvrdR
,1shdwlT,10shdwlT
Atmospheric Forcing
,atm atmT q
, ,atm atm atmP S Latmu
imprvrdEprvrdE
roofE
min , maxi buildT T T< <
Community Land Model – Urban (CLMU)Oleson et al. 2008a, b, JAMC
wasteH
Present day Urban Heat Island (UHI) simulated by CLM Urban (°C)
Urban Heat Island in CCSM4
Modeled UHI ranges from near-zero up to 4°C with spatial and seasonal variability controlled by urban to rural contrasts in energy balance.
1. Changing Natural Vegetation to Agriculture and Afforestation in CESM results in three competing processes on the climate:
Albedo changes surface energy from Vegetation and Snow Evapo-Transpiration changes surface heating from latent heat Carbon fluxes impact Radiative Warming of Atmosphere
2. The representation of land cover change in CLM4 have different impacts on the surface radiation processes, evapo-transpiration partition, hydrology and the terrestrial carbon cycle which reflect these competing climate impacts.
3. The Land Surface Hydrology and Carbon Cycle representations in CLM 4 have been shown to have significant modeling biases Bonanet al. (2012). These need to be better constrained to determine robust land cover change impacts on climate in CESM.
4. The CLM Urban model has robust Urban Heat Islands with the model continuing to be improved allowing the Urban climate to be further understood in the context urban development and climate change.
CESM Land Cover Change and Climate – Summary
Slide 2 - Outline