Determining the cascade of passive scalar variance in the lower stratosphere

Using aircraft data from 7630 commercial flights, we determine the flux of temperature and ozone variance from large to small scales in the lower stra tosphere. The relation that we use for this purpose is a form of the classi cal Yaglom relation [A. M. Yaglom, Dokl. Akad. Nauk SSSR 69, 743 (1949)] fo r the third-order scalar-velocity structure function. We find that this fun ction is negative and that it depends linearly on separation distance in th e mesoscale range for temperature as well as ozone.