Study of annual and long-term vertical distribution of molecular hydrogen has been done based on the data of aircraft sounding, carried out from 1997 to 2010. It is shown, that concentration of hydrogen for this period varied in the range from 391 to 597 ppb and increased with height during the observational period. The concentration maximum is observed in spring, minimum in the end of the autumn. Gradients of vertical content behave inversely: minimum falls on February, maximum - on November. There is no definite trend in the long-term variation of H2 mixing ratio. It is possible to isolate two maxima in 1998 and 2008 and one minimum in 2001.
atmosphere, vertical, hydrogen, air, gas, distribution