This a very interesting and well-structured paper. It shows the transport pathways of CO from Indonesia to sub-tropical high-altitude locations during two extreme fire pollution events (2006 and 2015) using in-situ and satellite measurements along with MERRA-2 reanalysis products. The topic of this study is interesting and the authors have presented the results with sufficient analyses. The manuscript could be considered to be published in ACP after the following revision.

I have two major suggestions/comments for the authors

1. Before Figure 2, in the manuscript, the authors could provide a vertical cross-section of CO over the maritime continent from satellite measurements. This will give a better understanding of CO inter-annual variability and the high CO enhancement in two events, particularly in October 2006 and 2015 compare to other years.
2. As mentioned in the introduction by the authors, the 1997 fire event was one of Indonesia’s worst fire events. Are there any similarities between 1997 and 2006 and 2015, particularly in large-scale circulations? It would be great if the authors add the large-scale circulations in October 1997, before the conclusions section.

Pleas find the attched comments