Role of equatorial waves in regulating equatorial cold-point tropopause temperature

Vertical velocities at the 100-hPa-level range up to 3 mm per second during January in the region of planetary-scale ascent over the equatorial western Pacific warm pool In the ERA-40 reanalyses. Vertical velocities of this magnitude, if they are real, imply the existence of radiative heating rates of several degrees C per day, about an order of magnitude larger than estimated clear-sky radiative heating rates. Thin cirrus cloud layers could conceivably provide an in situ heat source that could enable the planetary-scale "plume" of ascending air over the warm pool to penetrate much deeper into the tropopause transition layer than it could in the absence of the waves. The strength of this plume is strongly modulated by the annual cycle and by the ENSO cycle, and there is evidence that it exhibits a response to wave-driving from the extratropics. The degree of equatorial symmetry of the equatorial stationary waves and the zonal flow upon which they are superimposed is quite remarkable.