Biogenic Emissions over Europe and VOC Oxidation Gabriele Curci http://pumpkin.aquila.infn.it/gabri With contribution from: Paul Palmer, May Fu, Kelly Chance 3rd GEOS-Chem Users’ Meeting, Harvard University, April 11-13 2007

Motivation Biogenic emission inventories are very uncertain, e.g. even more than a factor of 5 for isoprene emissions Effect on atmospheric chemistry is significant! Palmer et al. developed the idea of using satellite formaldehyde (HCHO) observations to constrain North American isoprene emissions In this work we focus on Europe 3rd GEOS-Chem meeting 10 April 2019 Gabriele Curci

VOC oxidation and HCHO production WIND CITY FOREST HCHO WIND HCHO VOC NOx NOx HCHO VOC VOC THIS HCHO IS WELL CORRELATED TO ITS PARENT VOC! 3rd GEOS-Chem meeting 10 April 2019 Gabriele Curci

GOME HCHO Seasonal Cycle in Europe Formaldehyde column abundances in phase with vegetation growing season August maximum and winter below detection limit (4x1015 molec cm-2) 3rd GEOS-Chem meeting 10 April 2019 Gabriele Curci

GOME HCHO in August on a 0.5°x0.5° grid GOME HCHO 1996-2000 average column 2.4 Enhanced HCHO near urban/industrial areas 2.0 1.5 Moderate HCHO columns near forested areas 1.0 Elevated HCHO offshore of the continent 0.5 [1016 molec cm-2] 3rd GEOS-Chem meeting 10 April 2019 Gabriele Curci

GEOS-Chem vs GOME HCHO column GOME HCHO 2°x2.5° August 1996-2000 GEOS-Chem HCHO (v736) August 2000 GEIA [Guenther 95] MEGAN [Guenther 06] GEOS-Chem HCHO columns with MEGAN are <50% than GEIA GC HCHO vs GOME: GEIA: bias -17% and r2 = 0.48 MEGAN: bias -38% and r2 = 0.61 3rd GEOS-Chem meeting 10 April 2019 Gabriele Curci

GEOS-Chem vs EMEP ground VOC obs Routine measurement of VOCs since ’90s twice a week at EMEP background sites August 2000: 4 stations in Germany, 1 CZ, 1 France Result: there is a light advantage in using MEGAN, but data are really limited! MEGAN better MEGAN worse 3rd GEOS-Chem meeting 10 April 2019 Gabriele Curci

HCHO Production over Europe in August (1) On continental scale methanol, methane and acetone provide ~60% of HCHO Isoprene with its short lifetime (<1 h) is expected to drive HCHO variability Monoterpene and AVOC ~10% each, but delayed HCHO production 3rd GEOS-Chem meeting 10 April 2019 Gabriele Curci

HCHO Production over Europe in August (2) GEOS-Chem model calculations for August 2000 ISOPRENE AVOCs Isoprene contributes up to 40% locally to HCHO column AVOC contribute only 5%, but reactive VOC (xylenes, ethene, …) are missing AVOC signal in GOME HCHO was not detectable in China during summer [Fu et al., 2007] 3rd GEOS-Chem meeting 10 April 2019 Gabriele Curci

NOx-dependent inversion of HCHO column for Isoprene emissions Yield of isoprene oxidation product non-linearly depend on ambient NOx [e.g. Barket et al., 2004] (1) GEOS-Chem NO2 column HCHO = S * EISOP + B (2) Divide domain’s grid cells in two categories according to NO2 column content (LOW and HIGH) Use GEOS-Chem to relate HCHO column to isoprene emissions for two NOx categories 3rd GEOS-Chem meeting 10 April 2019 Gabriele Curci

GEOS-Chem vs GOME Isoprene emissions GOME Isoprene Emissions August 1996-2000 GEOS-Chem Isoprene Emissions August 2000 GEIA GOME-derived isoprene emissions high in Spain, France, Italy, Eastern and South-Eastern Europe (total C in August 2.3 Tg) GEIA (2.1 Tg): -20% and r2 = 0.31 MEGAN (0.8 Tg): -67% and r2 = 0.47 AVOC emissions are about 1.2 Tg MEGAN 3rd GEOS-Chem meeting 10 April 2019 Gabriele Curci

Thanks for your attention!