Japan Geoscience Union Meeting 2019

Presentation information

[J] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS09] dust

Thu. May 30, 2019 1:45 PM - 3:15 PM 102 (1F)

convener:Ishizuka Masahide(Kagawa University), Yasunori Kurosaki(Arid Land Research Center, Tottori University), Thomas Sekiyama(Meteorological Research Institute), Kana Nagashima(Japan Agency for Marine-Earth Science and Technology, Research and Development Center for Global Change), Chairperson:Tsuyoshi Sekiyama

1:55 PM - 2:15 PM

[MIS09-01] Global modeling study of atmospheric supply of lithogenic and pyrogenic Fe-containing aerosols to the ocean

★Invited Papers

*Akinori Ito1, Akitomo Yamamoto1, Michio Watanabe1, Maki Noguchi Aita1, Ying Ye2 (1.Japan Agency for Marine-Earth Science and Technology, 2.Alfred Wegener Institute for Polar and Marine Research)

Keywords:Mineral dust, Combustion aerosols, Iron deposition

Atmospheric supply of iron (Fe) to the ocean has been suggested to increase the marine primary productivity in large parts of the ocean. However, there are still large uncertainties regarding the effects of atmospheric aerosols on Fe dissolved in the surface ocean and marine productivity. Here, we use an atmospheric chemistry model and two ocean biogeochemistry models to explore the sensitivity to the atmospheric input of dissolved Fe.

The atmospheric model considered the deposition of both lithogenic and pyrogenic Fe-containing aerosols and their chemical transformation due to reactions with gaseous species. Sensitivity simulations are carried out with the deposition of lithogenic Fe only, and both Fe content in mineral dust of 3.5% and solubility of 2% are prescribed in the ocean models.

The results from the sensitivity simulations show that additional sources of dust and combustion aerosols increased the marine phytoplankton biomass in the subarctic north Pacific. The two ocean biogeochemistry models show similar spatial patterns but substantially different magnitude of responses to the atmospheric input of dissolved Fe. Moreover, the atmospheric model underestimated dissolved Fe concentration in aerosols over the North Pacific, although more observations are needed before drawing any firm conclusions on the model performance over the Pacific. Thus, further investigations of processes in emission of Fe from East Asia and transformation of dissolved Fe in the atmosphere and the ocean are needed.