16 May 1997
Vol 276, Issue 5315

About The Cover

Simulated mixing ratio of atmospheric nitrous oxide on the Southern Hemisphere 320 K potential temperature surface. Continental boundaries are indicated in white. The sharp gradient on nitrous oxide (blue edge) marks the meandering jet stream and the boundary between the stratosphere (blue) and the troposphere (red and yellow). See 1079 and the special section on tropospheric processes beginning on 1039. [Image: J. D. Mahlman]