Dr. Joanne Simpson, the first woman to earn a Ph.D. in
meteorology, died March 4, 2010, at the age of 86. Her
groundbreaking, influential career spanned more than half a
century, beginning with her teaching meteorology to World War II
Aviation Cadets and ending with her retirement as the head of
the Severe Storms Branch in the Laboratory for Atmospheres at
NASA’s Goddard Space Flight Center. In the photo above, taken in
the 1950s, Simpson is bent over reams of images of clouds that
she filmed during long flights between islands in the tropical
Pacific. From the photos, she is drawing detailed maps of cloud
formations. These observations underpinned her first major
contribution to atmospheric science: the boat-rocking hypothesis
that tropical clouds weren’t just the passive result of
atmospheric circulation, as meteorologists of the day believed,
but were in fact the cause of it. The large-scale patterns of
air circulation in the tropics were already well-established:
fueled by solar heating, air rose over the