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Table D.2
Input parameters used for the carbon cycle model presented in Sect. 2.2 and Appendix B.
| Parameter | Name | Value | Unit |
|---|---|---|---|
| a | Saturation vapor pressure scaling law exponent | 0.3 | – |
| a1 | Plate speed coefficient 1 | 8.0592 | cm yr−1 |
| a2 | Plate speed coefficient 2 | 0.0107 | cm yr−1 K−1 |
| A | Average planetary albedo | 0.31 | – |
| Am | Mantle surface area | 5.1 × 1014 | m2 |
| α | Partial CO2 pressure Fsfw scaling law exponent | 0.25 | – |
| b | Partial CO2 pressure Fweather scaling law exponent | 0.55 | – |
| dmelt | Mid-ocean ridge melting depth | 70 | km |
| Ea | Weathering reaction activation energy | 42 × 103 | J mol−1 |
| Emax | Upper bound on erosion rate | 10−3 | m yr−1 |
| f | Subduction zone CO2 degassing fraction | 0.5 | – |
| fd | Mantle CO2 degassing fraction at mid ocean ridges | 0.32 | – |
| fland⊕ | Present-day Earth land fraction | 0.3 | – |
| Fsfw⊕ | Present-day Earth seafloor weathering flux | 1.75 × 1018 | mol Myr−1 |
| Fw⊕ | Present-day Earth continental weathering flux | 12 × 1018 | mol Myr−1 |
| kc | Solubility of CO2 in seawater | 107 | Pa |
| L | Total length of subduction zones and mid ocean ridges | 6 × 104 | km |
| Lw | Latent heat of water | 2469 × 103 | J kg |
 |
Mean molar mass of elements participating in weathering | 32 | g mol−1 |
 |
Molar mas of CO2 | 44 | g mol−1 |
| mw | Molar mass of water | 18 | g mol−1 |
 |
Moles of water per ocean mass | 7.6 × 1022 | mol |
 |
Present-day Earth partial CO2 pressure | 33 | Pa |
| Psat0 | Reference saturation vapor pressure | 610 | Pa |
| Psat ⊕ | Present-day Earth saturation vapor pressure | 1391 | Pa |
| Rg | Gas constant | 8.314 | J K−1 mol−1 |
| ρr | Surface regolith density | 2500 | kg m3 |
| S⊙ | Solar constant | 1360 | W m2 |
| σ | Stefan-Boltzmann constant | 5.67 × 10−8 | W m−2 K−4 |
| t⊙ | Age of the Sun | 4.5 | Gyr |
| Te ⊕ | Present-day Earth effective temperature | 254 | K |
| Ts ⊕ | Present-day Earth average surface temperature | 285 | K |
| Tsat 0 | Saturation pressure reference temperature | 273 | K |
| vp ⊕ | Present-day Earth average plate speed | 5 | cm yr−1 |
| χcc | Average fraction of cations participating in weathering | 0.08 | – |
References.Parameters values are taken from Foley (2015) and Foley, (priv. comm.) (a1 and a2 parameters).
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