Abstract
Using principal component (PC) analysis of 16 years of monthly series of
nitrogen dioxide (NO2) from the Ozone Monitoring Instrument on the Aura
satellite, we show that it is the third PC (PC3) from the deseasonalized
hierarchy of principal modes that is best coupled with the economic
indicators. This coupling is positive, i.e. PC3 and economic indicators
manifest positive covariance. However, the economic variability can
explain only 40% of the information in PC3. Furthermore, this mode by
itself explains only 3% of the total deseasonalized NO2 variability. We
thus conclude that, while having an unambiguous impact, the economy can
be awarded at best third order of importance in the NO2 departures from
the seasonal averages. Once we identified PC3 as the NO2 mode that is
coupled with the economic variability, we use this mode as an indicator
and look for rapid climate adjustments to that part of NO2 variability
that we are confident is coupled with the economic variability. We focus
on observational data from the Atmospheric Infrared Sounder (AIRS) on
board of NASA Aqua satellite, decompose series of surface skin
temperature and clear-sky outgoing longwave radiances (OLR) into
principal components, and identify potential impacts of NO2 PC3 on these
climate variables.