Resumen
In this paper, we test if any statistically significant periodicities are detectable in carbon monoxide emissions over China, the European Union, and the United States of America. To do this, we performed a period analysis using 10 years of daily-averaged data, from the Measurements Of Pollution In The Troposphere (MOPITT) instrument. Besides a seasonal period, we found no clearly detectable periods at any timescale with the exception of a strong signal at 2.28 days. This period was observed over all tested regions and persisted when larger (hemisphere-wide) regions were considered. However, rather than resulting from a physical variation in carbon monoxide, it resulted from day-to-day changes in the area covered by MOPITT on-board its polar-orbiting satellite platform. We also examined linear trends over the dataset, and found that MOPITT identifies several centers of increasing carbon monoxide concentration?the largest being over China?although globally MOPITT reports a significant decrease in carbon monoxide has occurred over the past decade.