Making the case for coupled chemistry, climate, biogeochemistry simulations E.A. (Beth) Holland Chemistry-Climate Workshop Santa Fe, NM, Feb Thank you!

Roadmap Carbon cycle Carbon/Nitrogen Cycle CN Chemistry CN Chemistry Climate CN Chemistry Climate Biogeochemistry

Summary for Policymakers, IPCC 2001

Table 3.1: Global CO2 budgets (in Pg C/yr) based on intra-decadal trends in atmospheric CO 2 and O 2. IPCC 2001, Prentice et al, Chapter s1990s Atmospheric increase3.3 ± ± 0.1 Emissions (fossil fuel, cement) 5.4 ± ± 0.4 Ocean-atmosphere flux-1.9 ± ± 0.5 Land atmosphere flux*-0.2± ±0.7 Land use change1.7 (0.6 to 2.5)NA Residual terrestrial sink-1.9 (-3.8 to 0.3)NA Positive values are fluxes to the atmosphere; negative values represent uptake from the atmosphere. The fossil fuel emissions term for the 1980s (Marland et al., 2000) has been slightly revised downward since the SAR. Error bars denote uncertainty (± 1s), not interannual variability, which is substantially greater.

Atmosphere photosynthesis & respiration plants etc. soil ( microbes, roots ) Biosphere (C, H 2 O, N…) O2O2 CO 2 O2O2 O2O2 Pedosphere H2OH2O NO y NO x N org NO 3 - N2N2 NH 4 + N org NO, N 2 O NO 2

Coupling C and N Vegetation Type Fraction wood C:N microbes C:N leaves C:N wood Tropical rainforest Temperate Evergreen forest Shrubland Grassland

What are the implications of N deposition for the global carbon cycle?

Wet deposition of NH 4 + Wet deposition of NO 3 - Dry deposition of particulate NH 4 + Dry deposition of HNO 3 (g) Dry deposition of particulate NO 3 - Holland, Braswell, Sulzman, Lamarque submitted All units kg N ha -1 y -1

How does N retention vary with N deposition? Holland, Braswell and Bossdorf How does N deposition impact C storage across a range of vegetation types?

Do these simulations provide any evidence of N saturation characterized by a non-linear increase in outputs relative to inputs? Holland, Braswell and Bossdorf, in prep. NO! N losses=gaseous losses (NO + NH 3 +N 2 O+ nitrate leaching, kg N ha -1 y -1

Figure 4: The correlation between NOy deposition and surface ozone concentrations predicted by IMAGES, a 3-D chemical transport model. The correlation occurs because both depend on the same sets of chemical reactions, precursors. (from Holland et al 1997, JGR Atmospheres 102:15,849-15,866). What’s missing?

Vegetation Dynamics Temperature (  C)  g CO 2  g -1  s -1 Root Heterotrophic Respiration Ecosystem Carbon Balance Growth Respiration  g CO 2  g -1  s Foliage Nitrogen (%) Temperature (  C)  g CO 2  g -1  s Ambient CO 2 (ppm) Photosynthesis 0-2 Foliage Water Potential (MPa)  g CO 2  g -1  s Vapor Pressure Deficit (Pa) PPFD (  mol  m -2  s -1 ) Sapwood Temperature (  C)  g CO 2  g -1  s -1 Foliage Temperature (  C)  g CO 2  g -1  s Temperature (  C) Relative Rate 1 8 Soil Water (% saturation) Relative Rate Autotrophic Respiration Litterfall Nutrient Uptake Community Land Model Dynamic Vegetation Bonan 2002

Vegetation Dynamics Species composition Ecosystem structure Nutrient availability Minutes-To-Hours Days-To-Weeks Years-To-Centuries Heat Moisture Momentum Climate Temperature, Precipitation, Radiation, Humidity, Wind Chemistry CO 2, CH 4, N 2 O Ozone, Aerosols CO 2, CH 4 N 2 O, Dust, Volatile organic compounds PhysiologyPhenology Ecosystems Carbon uptake Carbon loss Nutrient uptake Allocation Bud break Leaf drop Litterfall Decomposition Mineralization Soil chemistry Watersheds Evapotranspiration Interception Infiltration Runoff Snowmelt Aero- dynamics Biogeophysics Energy Water Ecosystem Processes Plant Demography Old-Growth Forest Disturbance Fires Hurricanes Land use Invasive species Open Site Surface Fluxes Element Cycles Biogeochemistry Canopy Physiology Soil Processes Soil water, snowpack Leaf area, leaf nutrition Integrator Of Processes And Time-Scales Bonan (2002) Ecological Climatology. Cambridge Univ. Press Community Land Model

BASE CASE EMISSIONS from MOZART 2 (JULY) Isoprene Flux NO flux Weidenmyer, C, XX Tie, S. Levis, A. Guenther, and EA Holland

What is the impact of land use change on global O 3 concentrations? Change in Concentration (ppbv) % Change For 25% of each grid cell in the Amazon basic, isoprene flux is increased by a factor of 8, replacement with oil palm plantations For 25% of each grid cell in the northwest U.S., isoprene flux is increased by a factor of 30, replacement with Poplar plantations Weidenmyer, C, XX Tie, S. Levis, A. Guenther, and EA Holland

The GLOBAL N CYCLE Putting the pieces together

Sellers et al 1997, Science Stomatal conductance

N interactions Dickinson, R.E., J. A. Berry, G. B.Bonan, G. J. Collatz, C. B. Field, I. Y. Fung, M. Goulden, W. A. Hoffman, R. B. Jackson, R. Myneni, P. J. Sellers and M. Shaikh, 2001: Nitrogen Controls on Climate Model Evapotranspiration. J Clim., 15, No. 3, RESULT: Improvements in models ability to capture the seasonal cycle of temperature.

What if? We included N, CO 2 and O 3 feedbacks on stomatal conductance and the influence of stomatal conductance on dry deposition?

Deposition Velocity Calculation Fc = Vd * C Fc- flux, Vd- deposition velocity, C- concentration Vd =(Ra + Rb + Rs) –1 Ra-aerodyamic resistance, from CLM Rb-quasi-boundary layer resistance, from CLM Rs-surface resistance approach of Ganzeveld (1995, 1999) + Wesley and Hicks 2000

HNO 3 dry deposition (kg N ha -1 y -1) Holland, EA, JF Lamarque, J Sulzman, R. Braswell, submitted, Global Biogeochemical Cycles

N deposition partitioning for two measurement compilations (Holland et al. submitted) and one model compilation (Neff et al. 2002)

Wet deposition of NH 4 + Wet deposition of NO 3 - Dry deposition of particulate NH 4 + Dry deposition of HNO 3 (g) Dry deposition of particulate NO 3 - Holland, Braswell, Sulzman, Lamarque submitted All units kg N ha -1 y -1

Atmosphere photosynthesis & respiration plants etc. soil ( microbes, roots ) Biosphere (C, H 2 O, N…) O2O2 CO 2 O2O2 O2O2 Pedosphere H2OH2O NO y NO x N org NO 3 - N2N2 NH 4 + N org NO, N 2 O NO 2

Coupling C and N Vegetation Type Fraction wood C:N microbes C:N leaves C:N wood Tropical rainforest Temperate Evergreen forest Shrubland Grassland

P. Thornton, NCAR/CGD, Sept. 2002

Soil NO flux Yienger and Levy

Soil N gas model Model measurement comparison Parton, 1, W.J., E.A. Holland, 2 S.J. Del Grosso, 1 M.D. Hartman, 1 R.E. Martin, 3 A.R. Mosier, 4 D.S. Ojima, 1 and D.S. Schimel 2. Generalized Model for NO x and N 2 O Emissions from Soils. J. Geophys. Res. 106:17,403-17,419.

What is the acceleration of the N cycle?

How has the quantity and pattern of N deposition changed over the last 100 years?

N forcing Summary for Policymakers, IPCC 2001

What does the future hold ? IPCC SRES scenario emissions: % increases projected for 2100, relative to 2000

The NCAR Biogeosciences Initiative: Elisabeth Holland (Program Leader) Gordon Bonan Alex Guenther Natalie Mahowald David Schimel Britton Stephens Jielun Sun Peter Thornton

yr 4.1 million yr NO 3 -N ug/g yr4.1 million yr Net Nitrification/Net Mineralization % yr4.1 million yr N2O-N and NO-N ng cm-2 h-1 NO N2O Nitrate Concentration Net Nitrification (% Net Mineralization) N Trace Gases

Abiotic controls on nitrification

Regulation of NO:N2O ratio