Long-term midlatitude mesopause region temperature trend deduced from quarter century (1990ndash;2014) Na lidar observations

摘要

The long-term midlatitude temperature trend between 85 and 105 km is deducedfrom 25 years (March 1990–December 2014) of Na Lidar observations. With astrong warming episode in the 1990s, the time series was least-square fittedto an 11-parameter nonlinear function. This yields a cooling trend startingfrom an insignificant value of 0.64 ± 0.99 K decade at 85 km,increasing to a maximum of 2.8 ± 0.58 K decade between 91 and93 km, and then decreasing to a warming trend above 103 km. The geographicaltitude dependence of the trend is in general agreement with modelpredictions. To shed light on the nature of the warming episode, we show thatthe recently reported prolonged global surface temperature cooling after theMt Pinatubo eruption can also be very well represented by the same responsefunction.