Reply to L. Kutzbach     

By D. V. KHVOROSTYANOV  G. KRINNER  P. CIAIS  M. HEIMANN  S. A. ZIMOV 《Tellus. Series B, Chemical and physical meteorology》2009,61(3):579-580

  相似文献   

Role of a simplified hydrological cycle and clouds in regulating the climate–biota system of Daisyworld     

By JUAN FERNANDO SALAZAR  GERMÁN POVEDA 《Tellus. Series B, Chemical and physical meteorology》2009,61(2):483-497

The role of a simplified hydrological cycle and a physical representation of clouds is investigated in the Daisyworld model, subject to constant and variable solar forcing and varying cloud albedo and height. Under constant forcing, properties of the cloudy hydrologic cycle control the long-term system dynamics to non-oscillatory, oscillatory, abiotic or biotic states. In case of oscillatory solutions, their amplitude and periodicity are controlled by the net cooling or warming effects from clouds. Two conditions are considered under variable forcing—active or neutral—depending on the existence or not of biota–environment feedbacks. Temperature, cloudiness and hydrological variables are self-regulated in the active condition, whereas non-regulated in the neutral condition. Self-regulation is quantified through two measurements (luminosity range and total life), both of which can be larger in our model than in several other variants of Daisyworld, depending on cloud characteristics. The hydrological cycle and clouds can make the planet more habitable for life, independent of the capacity of the system for biological adaptation. Two hypotheses are put forward: (1) beneficial effects for life emerge from biota–clouds interactions, enhancing the global amount of life and extending the life span; and (ii) the existence of a maximum self-regulation capacity principle.  相似文献   

Transport of ²²²Rn using the regional model REMO: a detailed comparison with measurements over Europe     

ANNE CHEVILLARD  PHILIPPE CIAIS  UTE KARSTENS  MARTIN HEIMANN  MARTINA SCHMIDT  INGEBORG LEVIN  DANIELA JACOB  RALF PODZUN  VICTOR KAZAN  HARTMUT SARTORIUS  ERNEST WEINGARTNER 《Tellus. Series B, Chemical and physical meteorology》2002,54(5):850-871

  相似文献   

Modelling of biospheric CO₂ gross fluxes via oxygen isotopes in a spruce forest canopy: a ²²²Rn calibrated box model approach     

UWE LANGENDÖRFER  MATTHIAS CUNTZ  PHILIPPE CIAIS  PHILIPPE PEYLIN  THIERRY BARIAC  IRENA MILYUKOVA  OLAF KOLLE  TOBIAS NAEGLER  INGEBORG LEVIN 《Tellus. Series B, Chemical and physical meteorology》2002,54(5):476-496

  相似文献   

Vertical profiles of biospheric and fossil fuel-derived CO₂ and fossil fuel CO₂ : CO ratios from airborne measurements of Δ¹⁴C, CO₂ and CO above Colorado, USA     

By HEATHER D. GRAVEN †  BRITTON B. STEPHENS  THOMAS P. GUILDERSON  TERESA L. CAMPOS  DAVID S. SCHIMEL  J. ELLIOTT CAMPBELL  RALPH F. KEELING 《Tellus. Series B, Chemical and physical meteorology》2009,61(3):536-546

Measurements of  Δ¹⁴C  in atmospheric CO₂ are an effective method of separating CO₂ additions from fossil fuel and biospheric sources or sinks of CO₂. We illustrate this technique with vertical profiles of CO₂ and  Δ¹⁴C  analysed in whole air flask samples collected above Colorado, USA in May and July 2004. Comparison of lower tropospheric composition to cleaner air at higher altitudes (>5 km) revealed considerable additions from respiration in the morning in both urban and rural locations. Afternoon concentrations were mainly governed by fossil fuel emissions and boundary layer depth, also showing net biospheric CO₂ uptake in some cases. We estimate local industrial CO₂:CO emission ratios using in situ measurements of CO concentration. Ratios are found to vary by 100% and average 57 mole CO₂:1 mole CO, higher than expected from emissions inventories. Uncertainty in CO₂ from different sources was ±1.1 to ±4.1 ppm for addition or uptake of −4.6 to 55.8 ppm, limited by  Δ¹⁴C  measurement precision and uncertainty in background  Δ¹⁴C  and CO₂ levels.  相似文献   

Contributions of carbon cycle uncertainty to future climate projection spread   总被引：2，自引：0，他引：2  

By C. HUNTINGFORD  J. A. LOWE  B. B. B. BOOTH  C. D. JONES  G. R. HARRIS  L. K. GOHAR  P. MEIR 《Tellus. Series B, Chemical and physical meteorology》2009,61(2):355-360

We have characterized the relative contributions to uncertainty in predictions of global warming amount by year 2100 in the C4MIP model ensemble ( Friedlingstein et al., 2006 ) due to both carbon cycle process uncertainty and uncertainty in the physical climate properties of the Earth system. We find carbon cycle uncertainty to be important. On average the spread in transient climate response is around 40% of that due to the more frequently debated uncertainties in equilibrium climate sensitivity and global heat capacity.
This result is derived by characterizing the influence of different parameters in a global climate-carbon cycle 'box' model that has been calibrated against the 11 General Circulation models (GCMs) and Earth system Models of Intermediate Complexity (EMICs) in the C4MIP ensemble; a collection of current state-of-the-art climate models that include an explicit representation of the global carbon cycle.  相似文献   

Is the recent build-up of atmospheric CO₂ over Europe reproduced by models. Part 2: an overview with the atmospheric mesoscale transport model CHIMERE     

By C. AULAGNIER  P. RAYNER  P. CIAIS  R. VAUTARD  L. RIVIER  M. RAMONET 《Tellus. Series B, Chemical and physical meteorology》2010,62(1):14-25

In this issue, Ramonet et al. revealed a positive trend in European, atmospheric CO₂ concentrations relative to a marine, North Atlantic reference baseline, for the years 2001–2006. The observed build up mainly occurred during the cold season where it reaches a 0.8 ppm yr⁻¹ at low-altitude stations to a 0.3 ppm yr⁻¹ at mid-altitude stations. We explore the cause of this build-up using the mesoscale model CHIMERE. We first model the observed trends, using interannually varying fluxes and transport, then suppress the interannual variability in fluxes or aspects of transport to elucidate the cause. The run with no interannual variability in fluxes still matches observed trends suggesting that transport is the major cause. Separate runs varying either boundary layer height or winds show that changes in boundary layer height explain the trends at low-altitude stations within the continents while changes in wind regimes drive changes elsewhere.  相似文献   

Assessment of the soil CO₂ gradient method for soil CO₂ efflux measurements: comparison of six models in the calculation of the relative gas diffusion coefficient     

By NATCHAYA PINGINTHA  MONIQUE Y. LECLERC  JOHN P. BEASLEY Jr.  GENGSHENG ZHANG  CHUCKREE SENTHONG 《Tellus. Series B, Chemical and physical meteorology》2010,62(1):47-58

This paper uses a refined soil gradient method to estimate soil CO₂ efflux. Six different models are used to determine the relative gas diffusion coefficient (ξ). A weighted harmonic averaging is used to estimate the soil CO₂ diffusion coefficient, yielding a better estimate of soil CO₂ efflux. The resulting soil CO₂ efflux results are then compared to the soil CO₂ efflux measured with a soil chamber. Depending on the choice of ξ model used, the estimated soil CO₂ efflux using the gradient method reasonably approximates the efflux obtained using the soil chamber method. In addition, the estimated soil CO₂ efflux obtained by this improved method is well described by an exponential function of soil temperature at a depth of 0.05 m with the temperature sensitivity ( Q ₁₀) of 1.81 and a linear function of soil moisture at a depth of 0.12 m, in general agreement with previous findings. These results suggest that the gradient method is a practical cost-effective means to measure soil CO₂ emissions. Results from the present study suggest that the gradient method can be used successfully to measure soil CO₂ efflux provided that proper attention is paid to the judicious use of the proper diffusion coefficient.  相似文献   

Carbon dioxide and methane in continental Europe: a climatology, and ²²²Radon-based emission estimates     

MARTINA SCHMIDT  ROLF. GRAUL  HARTMUT SARTORIUS  INGEBORG LEVIN 《Tellus. Series B, Chemical and physical meteorology》1996,48(4):457-473

  相似文献   

The eigenvalue equations of equatorial waves on a sphere     

By YAIR DE-LEON  CARYNELISA ERLICK  NATHAN PALDOR 《地球，A辑:动力气象学与海洋学》2010,62(1):62-70

Zonally propagating wave solutions of the linearized shallow water equations (LSWE) in a zonal channel on the rotating spherical earth are constructed from numerical solutions of eigenvalue equations that yield the meridional variation of the waves' amplitudes and the phase speeds of these waves. An approximate Schrödinger equation, whose potential depends on one parameter only, is derived, and this equation yields analytic expressions for the dispersion relations and for the meridional structure of the waves' amplitudes in two asymptotic cases. These analytic solutions validate the accuracy of the numerical solutions of the exact eigenvalue equation. Our results show the existence of Kelvin, Poincaré and Rossby waves that are harmonic for large radius of deformation. For small radius of deformation, the latter two waves vary as Hermite functions. In addition, our results show that the mixed mode of the planar theory (a meridional wavenumber zero mode that behaves as a Rossby wave for large zonal wavenumbers and as a Poincaré wave for small ones) does not exist on a sphere; instead, the first Rossby mode and the first westward propagating Poincaré mode are separated by the anti-Kelvin mode for all values of the zonal wavenumber.  相似文献