Spectrum and atmosphere models of irradiated transiting extrasolar giant   planets
  We show that a consistent fit to observed secondary eclipse data for several strongly irradiated transiting planets demands a temperature inversion (stratosphere) at altitude. Such a thermal inversion significantly influences the planet/star contrast ratios at the secondary eclipse,their wavelength dependences, and, importantly, the day-night flux contrast during a planetary orbit. The presence of the thermal inversion/stratosphere seems to roughly correlate with the stellar flux at the planet. Such temperature inversions might caused by an upper-atmosphere absorber whose exact nature is still uncertain 
Ivan Hubeny and Adam Burrows