Global multiple tropopause features derived from COSMIC radio occultation data during 2007 to 2012

The spatiotemporal structure of the climatology of multiple tropopauses (MTs) is presented in this paper by using the temperature profiles from the Global Positioning System radio occultation measurements from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission between January 2007 and December 2012. Various climatological characteristics about MTs are studied, including the relationship between the occurrence of double tropopauses (DTs) and jet streams, the interannual variation and the trends of the occurrence of DTs, the seasonal and geographical variations of the occurrence of MTs, and the meridional distributions of the features of MTs in different seasons. Our results agree well with those of earlier studies based on other data sets. In addition, we find some new MT features. A global increase of the occurrence of DTs of about 0.15% +/- 0.09% yr(-1) (0.13% +/- 0.09% yr(-1)) is found between 2007 and 2012 including (excluding) the sampling errors, respectively. There is an increasing trend of the occurrence of DTs in the extratropics, especially in the subtropics in both hemispheres, and a decreasing trend in the tropics. We also find that the maximum seasonal variation of the occurrence of DTs is located between 30 degrees N and 40 degrees N, which is much stronger than that in the Southern Hemisphere. The occurrence of DTs is much lower from the winter of 2009 to the spring of 2010 than during the same time period of other years.