Old Weather Forum

Old Weather - WW2

There is a new Old Weather project now available on the Zooniverse. The aim of this project is to recover hidden marine weather data recorded in U.S. Navy ships’ logbooks during World War II, and we need your help. Like all Old Weather projects, these data will be used to drive sophisticated computer models that help us understand and reconstruct weather and climate in extraordinary detail. But there is another goal that is just as vital – to uncover the source of a mysterious distortion in sea-surface temperature data collected during the war. This distortion, known as the World War II Warm Anomaly, is large enough to affect the long-term global mean sea-surface temperature record, and hence our understanding of how the Earth’s climate has changed over time.

Because of the work we’ve been doing with the U.S. National Archives over the past eight years or so we are in a unique position to help investigate this question – we have digital images of many of the original U.S. Navy logbooks, a resource unavailable to earlier investigators. The small sample of logbooks we are transcribing in this project were selected because they are representative of different ship types deployed by the U.S. Navy, from destroyers and cruisers to cargo ships. More importantly, they were at times in the same place, occasionally even moored alongside each other in port. All but two survived the entire war, 1941-1945. Twelve were based at Pearl Harbor in 1941, eighteen were in the Aleutian Islands in 1942-1943, and ten were caught in Typhoon Cobra in December 1944. This opens up many opportunities to investigate sources of bias in the data, from factors associated with different ship types, the weather instruments in use at different times, or changes in methods required by wartime operations (such as blackout for example). It will also be possible to investigate how tropical and sub-polar environments may have influenced the data in different ways.

At the end of this project we should be able to verify whether or not the warm anomaly during the 1940s is real or an artefact, and, if it’s the latter, describe what factors explain the bias in the data. If the bias hypothesis turns out to be true, the corrected ocean temperature record would appear to evolve upward more smoothly through the 20th century.

The project is led by an international team of scientists from the University of Washington (CICOES), University of Colorado (CIRES), NOAA, the UK Met Office, and the University of Reading. For more information see our blog post and join the project at https://www.zooniverse.org/projects/krw ... eather-ww2 to lend a hand.