Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 9 6 2009 10.5194/acpd-9-23547-2009 http://www.atmos-chem-phys-discuss.net/9/23547/2009/ http://www.atmos-chem-phys-discuss.net/9/23547/2009/acpd-9-23547-2009.html http://www.atmos-chem-phys-discuss.net/9/23547/2009/acpd-9-23547-2009.pdf 23547 23563 2009-11-05 Sensitivity of isoprene emission estimates to the time resolution of input climate data K. Ashworth k.ashworth1@lancaster.ac.uk O. Wild C. N. Hewitt Lancaster Environment Centre, Lancaster University, LA1 4YQ, Lancaster, UK We evaluate the effect of varying the temporal resolution of the input climate data on isoprene emission estimates generated by the community emissions model MEGAN (Model of Emissions of Gases and Aerosols from Nature). The estimated total global annual emissions of isoprene is reduced from 766 Tg y^−1 for hourly input data to 746 Tg y^−1 (a reduction of 3%) for daily average input data and 711 Tg y^−1 (down 7%) for monthly average input data. The impact on a local scale can be more significant with reductions of up to 65% for some locations when using monthly average data. If the daily and monthly average temperature data are used without the imposition of a diurnal cycle the global emissions estimates fall by 27–32%, and local annual emissions by up to 77%. A similar pattern emerges if hourly isoprene fluxes are considered. Given the importance of land-atmosphere interactions in the Earth system and the low computational cost of the MEGAN algorithms, we recommend that chemistry-climate models and the new generation of Earth system models input biogenic emissions at the highest temporal resolution possible. Arneth, A., Monson, R. K., Schurgers, G., Niinemets, Ü., and Palmer, P. 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