The tropospheric ozone (TOMS/SBUV TOR) data were obtained from the website
http://asd-www.larc.nasa.gov/TOR/data/. We used TOR data (1Â 1.25) from
January 2003 to December 2005 in the present study. Due to the data density provided
by the 1latitude by 1.25longitude pixel (TOMS grid size), the regional aspect of
both monthly and seasonal tropospheric ozone features are seen in the TOR dataset.
Fishman et al. (2003) present a summary of the global distribution of TOR using
coincident measurements from the Total Ozone Mapping Spectrometer (TOMS) and
Solar Backscattered Ultraviolet (SBUV) instruments. More details regarding the data
retrieval methods are given in Fishman et al. (2003).