An Eyewitness Account of Cross-tropopause Transport of Water Substance by Storms in East Asian Summer Monsoon and Its Implication on UT/LS Exchange

It is usually accepted that deep convective storms should play an important role in the vertical transport of energy, momentum and chemical species across the tropopause into the stratosphere. Previous satellite observational studies also suggested that monsoons may play an important role in the cross-tropopause transport of water substance. However, so far the evidence is largely indirect and cross-validation of the transport process by evidence from different sources is difficult because data are often collected at different times and locations. A rare opportunity occurred on July 19 2016 when the lead author (PKW) was onboard of an aircraft flying from Beijing to Taipei and passing by a series of coastal thunderstorms developed in the East Asian summer monsoonal flow. This afforded a real time observation of the storm transport in action. Virtually all these thunderstorms exhibited characteristics of gravity wave breaking at the storm top which is known to irreversibly transport materials into the lower stratosphere. Photographs of these storm tops were taken. We also obtained Himawari 8 satellite images of storms in coastal China in the same period so that a one-to-one correspondence of storm photos and satellite images can be achieved. This correspondence can be used for future retrieval of cross-tropopause transport by storms using satellite data. We have recently performed new analysis on the possible quantitative transport and its implication on the global climate.

In addition to aircraft observational photos and satellite images, we will also show results from cloud resolving model to demonstrate that the storm top wave breaking can indeed cause water substance to be injected into the lower stratosphere.