Observations of carbon monoxide (CO) and ozone (O3) at the surface have been made at Rishiri, a northern remote island in Japan. O3 seasonal variation shows a spring maximum and summer minimum, which are typically observed at remote mid-latitude regions in the Northern Hemisphere. The seasonal cycle of CO shows a baseline enhancement and episodic high concentrations during the period from summer to early fall 1998, indicating a strong source of CO nearby. Both Advanced Very High Resolution Radiometer and Earth Probe Total Ozone Mapping Spectrometer satellite images during the same period produce clear pictures illustrating severe forest fire events and widespread smoke plumes in far eastern Siberia. Back trajectory analyses suggest that boreal forest fires in far eastern Siberia had a significant impact on CO observed at the site from summer to early fall 1998. ¿ 2000 American Geophysical Union