Process-based modelling of biogenic monoterpene emissions combining production and release from storage

Abstract

Abstract. Monoterpenes, primarily emitted by terrestrial vegetation, can influence atmospheric ozone chemistry, and can form precursors for secondary organic aerosol. The short-term emissions of monoterpenes have been well studied and understood, but their long-term variability, which is particularly important for atmospheric chemistry, has not. This understanding is crucial for the understanding of future changes.In this study, two algorithms of terrestrial biogenic monoterpene emissions, the first one based on the shortterm volatilization of monoterpenes, as commonly used for temperature-dependent emissions, and the second one based on long-term production of monoterpenes (linked to photosynthesis) combined with emissions from storage, were compared and evaluated with measurements from a Ponderosa pine plantation (Blodgett Forest, California). The measurements were used to parameterize the long-term storage of monoterpenes, which takes place in specific storage organs and which determines the temporal distribution of the emissions over the year. The difference in assumptions between the first (emission-based) method and the second (production-based) method, which causes a difference in upscaling from instantaneous to daily emissions, requires roughly a doubling of emission capacities to bridge the gap to production capacities. The sensitivities to changes in temperature and light were tested for the new methods, the temperature sensitivity was slightly higher than that of the short-term temperature dependent algorithm.Correspondence to: G. Schurgers (guy.schurgers@nateko.lu.se) Applied on a global scale, the first algorithm resulted in annual total emissions of 29.6 Tg C a −1 , the second algorithm resulted in 31.8 Tg C a −1 when applying the correction factor 2 between emission capacities and production capacities. However, the exact magnitude of such a correction is spatially varying and hard to determine as a global average.

Global data set of biogenic VOC emissions calculated by the MEGAN model over the last 30 years

“…They are lower then those reported by Guenther et al (2012) and significantly higher than those of Schurgers et al (2009), which are the lowest among the values published in the literature. MEGAN-MACC monoterpene emissions were compared to regional estimates in China and Europe (Table 5) and are within 30 % of regional totals, except for comparison with Curci et al (2009) whose estimate is about a factor of 2 higher than that of MEGAN-MACC.…”

Long-term chemical analysis and organic aerosol source apportionment at nine sites in central Europe: source identification and uncertainty assessment

“…Indeed, the aforementioned parameters may contribute, together with model and measurement uncertainties, to the observed scatter in the data. Biogenic volatile organic compound emissions might even be nonnegligible in winter (Oderbolz et al, 2013;Schurgers et al, 2009;Holzke et al, 2006). Therefore, significant wintertime SOOA concentrations are not in disagreement with the hypothesized biogenic origin.…”

A review of natural aerosol interactions and feedbacks within the Earth system

“…There is considerable uncertainty in estimates of the global flux of BVOCs. For example, the global flux of isoprene has been estimated at 412-601 Tg C a −1 and monoterpenes at 30-128 Tg C a −1 with the range due to different emission algorithms, vegetation distributions, climatologies, basal emission rates, and spatial and temporal resolutions (Arneth et al, 2008;Schurgers et al, 2009). Once in the atmosphere, some BVOCs react to produce compounds that can partition into the particulate phase, forming SOA.…”