Influence of seasonality, canopy light extinction, and terrain on potential isoprenoid emission from a Mediterranean‐type ecosystem in France

Schaab, Gertrud; Steinbrecher, R.; Lacaze, Bernard

doi:10.1029/2002jd002899

Cited by 18 publications

(10 citation statements)

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“…The length of this lag phase depends on the growth temperature and may exceed ten days (Wiberley et al, 2005). For senescing leaves, a decline in emission capacity has been found (Monson et al, 1994;Schaab et al, 2003). Some global models account for this effect, either by assigning younger and older leaves lower emission capacities Lathière et al, 2006), or modelling emission capacity in deciduous trees as a function of growing degree day temperature sums (Arneth et al, 2007b).…”

Section: Leaf Developmental Stagementioning

confidence: 99%

“…A number of previous studies have shown that clear-sky space-borne formaldehyde (HCHO) columns can be used to quantitatively test current understanding of isoprene emissions on regional to continental spatial scales (e.g., Chance et al, 2000;Palmer et al, 2001;Palmer et al, 2003;Shim et al, 2005;Abbot et al, 2003). Most of these studies have used HCHO column data from GOME or -more recently-from the newer Ozone Monitoring Instrument (OMI) space-borne sensor aboard the NASA Aura satellite (Millet et al, 2006).…”

Section: Top-down Constraints For Emission Modelsmentioning

confidence: 99%

“…V) While all the above estimates rely on bottom-up approaches to estimate global totals, one analysis presented a top-down view constrained by satellite remote sensing (Shim et al, 2005). This approach is based on providing emission constraints from the short-term variations of the high-yield isoprene oxidation product formaldehyde (HCHO, derived from the Global Ozone Monitoring Experiment (GOME) satellite instrument aboard the European ERS-2 satellite) that depend on the isoprene source on the one hand, and the removal of HCHO oxidation by OH and photolysis on the other.…”

Section: Iii)mentioning

confidence: 99%

“…The study by Shim et al (2005) currently represents the only global estimation of isoprene emissions using HCHO columns, in which they used an inversion approach to fit model estimates for biogenic and pyrogenic emissions to GOME observations of HCHO. This study used global a priori isoprene emissions of 375 Tg C a −1 and calculated global annual a posteriori isoprene emissions of 566 Tg C a −1 , an increase of 50%.…”

Section: Top-down Constraints For Emission Modelsmentioning

confidence: 99%

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Why are estimates of global terrestrial isoprene emissions so similar (and why is this not so for monoterpenes)?

et al. 2008

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Abstract. Emissions of biogenic volatile organic compounds (BVOC) are a chief uncertainty in calculating the burdens of important atmospheric compounds like tropospheric ozone or secondary organic aerosol, reflecting either imperfect chemical oxidation mechanisms or unreliable emission estimates, or both. To provide a starting point for a more systematic discussion we review here global isoprene and monoterpene emission estimates to-date. We note a surprisingly small variation in the predictions of global isoprene emission rate that is in stark contrast with our lack of process understanding and the small number of observations for model parameterisation and evaluation. Most of the models are based on similar emission algorithms, using fixed values for the emission capacity of various plant functional types. In some cases, these values are very similar but differ substantially in other models. The similarities with regard to the global isoprene emission rate would suggest that the dominant parameters driving the ultimate global estimate, and thus the dominant determinant of model sensitivity, are the specific emission algorithm and isoprene emission capacity. But the models also differ broadly with regard to their representation of net primary productivity, method of biome coverage determination and climate data. Contrary to isoprene, monoterpene estimates show significantly larger model-tomodel variation although variation in terms of leaf algorithm, emission capacities, the way of model upscaling, vegetation cover or climatology used in terpene models are comparable to those used for isoprene. From our summary of published studies there appears to be no evidence that the terrestrial modelling community has been any more successful in Correspondence to: A. Arneth (almut.arneth@nateko.lu.se) "resolving unknowns" in the mechanisms that control global isoprene emissions, compared to global monoterpene emissions. Rather, the proliferation of common parameterization schemes within a large variety of model platforms lends the illusion of convergence towards a common estimate of global isoprene emissions. This convergence might be used to provide optimism that the community has reached the "relief phase", the phase when sufficient process understanding and data for evaluation allows models' projections to converge, when applying a recently proposed concept. We argue that there is no basis for this apparent relief phase. Rather, we urge modellers to be bolder in their analysis, and to draw attention to the fact that terrestrial emissions, particularly in the area of biome-specific emission capacities, are unknown rather than uncertain.

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Section: Leaf Developmental Stagementioning

confidence: 99%

Section: Top-down Constraints For Emission Modelsmentioning

confidence: 99%

Section: Iii)mentioning

confidence: 99%

Section: Top-down Constraints For Emission Modelsmentioning

confidence: 99%

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Why are estimates of global terrestrial isoprene emissions so similar (and why is this not so for monoterpenes)?

et al. 2008

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“…This requires the coupling of an emission model with a process-based SVAT (soil-vegetation-atmosphere transfer) model. Such models describe leaf scale processes, set the micrometeorological canopy conditions which drive these processes, and describe the biomass and foliage distribution throughout the canopy (Baldocchi et al, 1999;Grote, 2006;Lamb et al, 1993;Lenz et al, 1997;Schaab et al, 2003). Such an approach also requires reliable information of emission potentials of each individual species.…”

Section: Introductionmentioning

confidence: 99%

Process based inventory of isoprenoid emissions from European forests: model comparisons, current knowledge and uncertainties

et al. 2009

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Abstract. Large uncertainties exist in our knowledge of regional emissions of non-methane biogenic volatile organic compounds (BVOC). We address these uncertainties through a two-pronged approach by compiling a state of the art database of the emissions potentials for 80 European forest species, and by a model assessment and inter-comparison, both at the local and regional scale, under present and projected future climatic conditions. We coupled three contrasting isoprenoid models with the ecophysiological forest model GOTILWA+ to evaluate leaf and ecosystem isoprenoid emissions, build an emissions inventory for European forests, and to consider model behaviour in present climate and under projected future climate change conditions. Hourly, daily and annual isoprene emissions as simulated by the models were evaluated against flux measurements. The validation highlighted a general model capacity to capture gross fluxes but inefficiencies in capturing short term variability. A regional inventory of isoprenoid emissions for European forests was created using each of the three modelling approaches. The models agreed on an average European emissions budget of 1.03 TgC a −1 for isoprene and 0.97 TgC a −1 for monoterpenes for the period 1960-1990, which was dominated by a few species with largest aerial coverage. Species contribution to total emissions depended both on species emission potential and geographical distribution. For projected future climate conditions, however, emissions budgets proved highly model dependent, illustrating the current uncertainty associated with isoprenoid emissions responses to potential future conditions.Correspondence to: T. Keenan (t.keenan@creaf.uab.es) These results suggest that current model estimates of isoprenoid emissions concur well, but future estimates are highly uncertain. We conclude that development of reliable models is highly urgent, but for the time being, future BVOC emission scenario estimates should consider results from an ensemble of available emission models.

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Improvement of emission factors

Theloke¹,

Steinbrecher²,

Smiatek³

et al. 2004

Emissions of Air Pollutants

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Influence of seasonality, canopy light extinction, and terrain on potential isoprenoid emission from a Mediterranean‐type ecosystem in France

Cited by 18 publications

References 50 publications

Why are estimates of global terrestrial isoprene emissions so similar (and why is this not so for monoterpenes)?

Why are estimates of global terrestrial isoprene emissions so similar (and why is this not so for monoterpenes)?

Process based inventory of isoprenoid emissions from European forests: model comparisons, current knowledge and uncertainties

Improvement of emission factors

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