As we celebrate International Women’s Day, Weather & Radar pays tribute to a woman who paved the way for modern forecasting.

Dr. Joanne Simpson was born in Boston, Mass., on March 23, 1923. As a child, she was always fascinated by clouds but didn’t really get excited about science until she took a course in astrophysics at the University of Chicago.

In fact, had it not been for World War II, Dr. Simpson may have been lost to the world of weather entirely. As a student pilot, she had to take a course in meteorology. She became fascinated by the subject and sought out more knowledge in the field.

When the war ended, women were supposed to resume their duties in the home, but Simpson was more interested in the weather than housework. She completed her master’s degree and wanted to go into a Ph.D. program, something that was unheard of at the time.

Her Ph.D. work focussed on tropical cumulous clouds, then regarded as not a particularly important part of the subject. Subsequently, she went on to show how tropical “hot tower” clouds drive the tropical circulation, and to propose a new process by which hurricanes maintain their “warm core”. She became the first woman to hold a Ph.D. in Meteorology.

Following stints at UCLA, NOAA, and the University of Virginia, Joanne ended up at NASA Goddard Space Flight Centre. It was here that she made what she described as the single biggest accomplishment in her career. She was asked to lead the research team for the Tropical Rainfall Measuring Mission (TRMM) – a satellite carrying the first space-based rain radar.

TRMM has led to many discoveries about tropical rainfall, including the ability to estimate latent heat in the tropics. This work linked directly back to Joanne’s early work on tropical cloud processes.