Table 1: Summary of OMEGA observations and inferred CO mixing ratios over Hellas.

Orbit	Ls	Ps (mbar)	Airmass	CO (ppm, +/- )
30-1	335.7	10.0	1.17	970 +/- 370
41-3	337.9	10.0	1.20	810 +/- 360
47-1	339.0	10.0	1.20	760 +/- 360
284-0	16.6	11.5	1.15	1000 +/- 400
422-1	36.1	12.0	1.75	1220 +/- 370
521-1	48.5	13.5	2.25	1220 +/- 520
554-1	52.6	13.5	2.70	1550 +/- 500
1186-4	132.0	11.5	1.52	2770 +/- 770
1241-5	139.5	10.5	1.52	1890 +/- 590
1935-4	251.7	10.0	1.55	1640 +/- 640
1946-4	253.6	10.0	1.47	1290 +/- 690
2177-4	295.9	9.7	1.55	1020 +/- 570