Diurnal cycles and seasonal variation of isoprene and its oxidation products in the tropical savanna atmosphere

Holzinger, Rupert; Sanhueza, Eugenio; Kuhlmann, R. von; Kleiss, B.; Donoso, Loreto; Crutzen, P. J.

doi:10.1029/2001gb001421

Cited by 29 publications

(24 citation statements)

References 51 publications

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“…This overestimate is consistent with findings in other 3D global model studies (Houweling et al, 1998;Granier et al, 2000). Besides too high emissions of the rainforest ecosystem as also suggested by Rinne et al (2002) other factors such as too weak vertical mixing or unknown deposition processes (Holzinger et al, 2002) could contribute to the overestimate. In fact, over Surinam the model predicts a too strong decrease of isoprene with altitude compared to the measurements by Warneke et al (2001) which indicate efficient mixing by shallow convection up to 4 km.…”

Section: Model Performancesupporting

confidence: 81%

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Sensitivities in global scale modeling of isoprene

Kuhlmann¹,

Lawrence²,

Pöschl³

et al. 2004

Atmos. Chem. Phys.

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176

139

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Abstract.A sensitivity study of the treatment of isoprene and related parameters in 3D atmospheric models was conducted using the global model of tropospheric chemistry MATCH-MPIC. A total of twelve sensitivity scenarios which can be grouped into four thematic categories were performed. These four categories consist of simulations with different chemical mechanisms, different assumptions concerning the deposition characteristics of intermediate products, assumptions concerning the nitrates from the oxidation of isoprene and variations of the source strengths. The largest differences in ozone compared to the reference simulation occured when a different isoprene oxidation scheme was used (up to 30-60% or about 10 nmol/mol). The largest differences in the abundance of peroxyacetylnitrate (PAN) were found when the isoprene emission strength was reduced by 50% and in tests with increased or decreased efficiency of the deposition of intermediates. The deposition assumptions were also found to have a significant effect on the upper tropospheric HO x production. Different implicit assumptions about the loss of intermediate products were identified as a major reason for the deviations among the tested isoprene oxidation schemes. The total tropospheric burden of O 3 calculated in the sensitivity runs is increased compared to the background methane chemistry by 26±9 Tg(O 3 ) from 273 to an average from the sensitivity runs of 299 Tg(O 3 ). Thus, there is a spread of ±35% of the overall effect of isoprene in the model among the tested scenarios. This range of uncertainty and the much larger local deviations found in the test runs suggest that the treatment of isoprene in global models can only be seen as a first order estimate at present, and points towards specific processes in need of focused future work.

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Section: Model Performancesupporting

confidence: 81%

“…Hydroxyhydroperoxides from isoprene (ISOOH and MACROOH), which are assumed to form in NO x -bereft environments are explicitly treated in the scheme. These compounds have been tentatively identified over the rainforest in Surinam Warneke et al, 2001) and over the savanna in Venezuela (Holzinger et al, 2002).…”

Section: Chemical Schemesmentioning

confidence: 99%

Sensitivities in global scale modeling of isoprene

Kuhlmann¹,

Lawrence²,

Pöschl³

et al. 2004

Atmos. Chem. Phys.

Self Cite

176

139

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“…The observed signal on m / z 61, reported as acetic acid (∼6% yield), may result from the production of glycolaldehyde, and m / z 73 and 75, likely corresponding to methylglyoxal and hydroxyacetone. Several ions were observed from isoprene photooxidation, including m / z 113, a dominant ion observed in ambient air [ Holzinger et al , 2005], and m / z 101 (Table 8), which has also been observed by PTR‐MS in ambient air above a tropical rain forest [ Warneke et al , 2001] and a tropical savanna [ Holzinger et al , 2002], and may be the C 5 hydroxycarbonyls reported by Zhao et al [2004] and Baker et al [2005].…”

Section: Resultsmentioning

confidence: 94%

Gas‐phase products and secondary aerosol yields from the photooxidation of 16 different terpenes

Lee¹,

Goldstein²,

Kroll³

et al. 2006

J. Geophys. Res.

416

494

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[1] The photooxidation of isoprene, eight monoterpenes, three oxygenated monoterpenes, and four sesquiterpenes were conducted individually at the Caltech Indoor Chamber Facility under atmospherically relevant HC:NO x ratios to monitor the time evolution and yields of SOA and gas-phase oxidation products using PTR-MS. Several oxidation products were calibrated in the PTR-MS, including formaldehyde, acetaldehyde, formic acid, acetone, acetic acid, nopinone, methacrolein + methyl vinyl ketone; other oxidation products were inferred from known fragmentation patterns, such as pinonaldehyde; and other products were identified according to their mass to charge (m/z) ratio. Numerous unidentified products were formed, and the evolution of first-and second-generation products was clearly observed. SOA yields from the different terpenes ranged from 1 to 68%, and the total gas-plus particle-phase products accounted for $50-100% of the reacted carbon. The carbon mass balance was poorest for the sesquiterpenes, suggesting that the observed products were underestimated or that additional products were formed but not detected by PTR-MS. Several second-generation products from isoprene photooxidation, including m/z 113, and ions corresponding to glycolaldehyde, hydroxyacetone, methylglyoxal, and hydroxycarbonyls, were detected. The detailed time series and relative yields of identified and unidentified products aid in elucidating reaction pathways and structures for the unidentified products. Many of the unidentified products from these experiments were also observed within and above the canopy of a Ponderosa pine plantation, confirming that many products of terpene oxidation can be detected in ambient air using PTR-MS, and are indicative of concurrent SOA formation.

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“…For this reason both would result in a different diurnal cycle than observed. Like for isoprene, increasing mixing ratios during daytime are expected for light-triggered sources (Holzinger et al, 2002); temperaturetriggered sources would produce high concentrations in the evenings, when emissions are still strong but vertical mixing is suppressed by the developing nocturnal boundary layer. Biomass burning emissions of CH 3 CN coincide with substantial emissions of CO and a correlation between the two gases can be expected.…”

Section: Resultsmentioning

confidence: 99%

New insights in the global cycle of acetonitrile: release from theocean and dry deposition in the tropical savanna of Venezuela

Sanhueza

Holzinger

Kleiss³

et al. 2004

Atmos. Chem. Phys.

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Abstract. Using the proton transfer reaction mass spectrometry (PTR-MS) technique, acetonitrile was measured during the wet season in a Venezuelan woodland savanna. The site was located downwind of the Caribbean Sea and no biomass burning events were observed in the region. High boundary layer concentrations of 211±36 pmol/mol (median, ±standard deviation) were observed during daytime in the well mixed boundary layer, which is about 60 pmol/mol above background concentrations recently measured over the Mediterranean Sea and the Pacific Ocean. Most likely acetonitrile is released from the warm waters of the Caribbean Sea thereby enhancing mixing ratios over Venezuela. Acetonitrile concentrations will probably still be much higher in biomass burning plumes, however, the general suitability of acetonitrile as a biomass burning marker should be treated with care.During nights, acetonitrile dropped to levels typically around 120 pmol/mol, which is consistent with a dry deposition velocity of ∼0.14 cm/s when a nocturnal boundary layer height of 100m is assumed.

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Diurnal cycles and seasonal variation of isoprene and its oxidation products in the tropical savanna atmosphere

Cited by 29 publications

References 51 publications

Sensitivities in global scale modeling of isoprene

Sensitivities in global scale modeling of isoprene

Gas‐phase products and secondary aerosol yields from the photooxidation of 16 different terpenes

New insights in the global cycle of acetonitrile: release from theocean and dry deposition in the tropical savanna of Venezuela

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