Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 3 5 2003 10.5194/acp-3-1293-2003 http://www.atmos-chem-phys.net/3/1293/2003/ http://www.atmos-chem-phys.net/3/1293/2003/acp-3-1293-2003.html http://www.atmos-chem-phys.net/3/1293/2003/acp-3-1293-2003.pdf 1293 1300 2003-09-04 Sensitivity studies of the recent new data on O(¹<i>D</i>) quantum yields in O₃ Hartley band photolysis in the stratosphere N. Taniguchi S. Hayashida K. Takahashi Y. Matsumi Faculty of Science, Nara Women’s University, Kitauoya - Nishimachi, Nara, 630 - 8506, Japan Solar - Terrestrial Environment Laboratory, Nagoya University, Honohara 3 - 13, Toyokawa, 442 - 8507, Japan The production yields of excited oxygen O(¹<i>D</i>) atoms from the near ultraviolet O₃ photolysis are essential quantities for atmospheric chemistry calculations because of its importance as major sources of hydroxyl (OH) radicals and nitric oxide (NO). Recently, new O(¹<i>D</i>) quantum yields from O₃ photolysis between 230 and 305 nm in the Hartley band region were reported, which are almost independent of the photolysis wavelength (0.88-0.93) and smaller than NASA/JPL-2000 recommendations (0.95 between 240 and 300 nm). In order to assess consequences of the new data of O(¹<i>D</i>) quantum yields on the stratospheric chemistry, the changes in stratospheric chemical partitioning and O₃ concentration are examined using a one-dimensional atmospheric model. Our steady state model simulations for 40° N in March indicate that the smaller O(¹<i>D</i>) quantum yields result in increases of stratospheric O₃ (up to ~2% in the upper stratosphere), which are attributed to the changes in HO_x, NO_x, and ClO_x abundance and their catalyzed O₃ loss rates.