  This paper reveals a large and all-season ozone hole in the lower
stratosphere over the tropics (30degN-30degS) since the 1980s, where an O3 hole
is defined as an area of O3 loss larger than 25% compared with the undisturbed
atmosphere. The depth of this tropical O3 hole is comparable to that of the
well-known springtime Antarctic O3 hole, whereas its area is about seven times
that of the latter. Similar to the Antarctic O3 hole, approximately 80% of the
normal O3 value is depleted at the center of the tropical O3 hole. The results
strongly indicate that both Antarctic and tropical O3 holes must arise from an
identical physical mechanism, for which the cosmic-ray-driven electron reaction
(CRE) model shows good agreements with observations. The whole-year large
tropical O3 hole could cause a serious global concern as it can lead to
increases in ground-level ultraviolet radiation and affect 50% of Earth's
surface area, home to approximately 50% of the world's population. Moreover,
the presence of the tropical and polar O3 holes is equivalent to the formation
of three 'temperature holes' observed in the stratosphere. These findings will
have significances in understanding planetary physics, ozone depletion, climate
change, and human health.
