A breeze from the past: Maritime wind and rainfall patterns from historical New England whaling ship voyages in the 19th century

Maritime weather data from historical ship logbooks are used to assess 19^th century surface wind and precipitation conditions across the world oceans. Housed across several New England archives (e.g., Providence Public Library, New Bedford Whaling Museum, Nantucket Historical Association, and Martha’s Vineyard Museum), logbooks of U.S. whaling voyages contain systematic weather observations (e.g., wind strength/direction, sea state, precipitation) at (sub-)daily temporal resolution. As part of the eWHALES (extracting Weather data: Historical Analysis of Logbooks from Early Ships) project, qualitative wind descriptions by the whalers from >200 ship logbooks are quantified to generate a dataset with >80,000 daily records of wind strength and direction en route and covering key whaling grounds in the Atlantic, Pacific, Indian, and Southern Ocean during the period 1820-1900 CE.

Following extensive quality control, we find overall good agreement in wind strength and direction for the whaling logbook wind records with reanalysis products for mean and seasonal climatologies around the world. For the North Atlantic with the densest coverage of whaling records, interannual variations in the basin-wide wind field associated with variations in the Azores High subtropical pressure system are also reflected in the whaling ship recordings. Predominant precipitation patterns around the world oceans can be captured and variations across a range of timescales are assessed.

Our results demonstrate that the historical records provide an important long-term context for changing maritime wind and rainfall patterns in remote ocean regions lacking observational records during the 19^th century. Challenges and opportunities for data rescue and digitisation of maritime weather records in these under-utilised historical ship logbooks for climate purposes will be discussed.