Southern African Precipitation Reconstructions From Ships' Logbooks 1796-1854 Hannaford, M.J.; Jones, J.M.; Bigg, G.R. Hannaford, M.J. Jones, J.M. Bigg, G.R. Precipitation Reconstruction earth science/paleoclimate/climate reconstructions|historical (precipitation,null,null,millimeter,Apr-Sep,climate reconstructions|historical,anomalized,principal component analysis|regression analysis,N,Reconstructed precipitation relative to 1979-2008 mean; error = +/-119.9; principal components regression) earth science/paleoclimate/climate reconstructions|historical (age,null,null,year Common Era,null,climate reconstructions|historical,null,null,N,dated by Nov) earth science/paleoclimate/climate reconstructions|historical (precipitation,null,null,millimeter,Nov-Mar,climate reconstructions|historical,anomalized,principal component analysis|regression analysis,N,Reconstructed precipitation relative to 1979-2008 mean; error = +/-343.67; principal components regression) earth science/paleoclimate/climate reconstructions|historical (precipitation,null,null,millimeter,Nov-Mar,climate reconstructions|historical,anomalized,principal component analysis|regression analysis,N,Reconstructed precipitation relative to 1979-2008 mean; error = +/-147.6; principal components regression) earth science/paleoclimate/reconstructions (Mthatha>LATITUDE -31.53>LONGITUDE 28.67) (Royal National Park>LATITUDE -28.6858>LONGITUDE 28.9542) (Cape Town>LATITUDE -33.97>LONGITUDE 18.6) Atmospheric circulation in the oceans surrounding southern Africa plays an important role in determining its precipitation. This study uses wind information recorded in ships' logbooks in order to statistically reconstruct summer and winter season precipitation at four southern African weather stations from 1796 to 1854. The reconstruction was obtained by first relating gridded 8 x 8 degree NCEP-DOE reanalysis seasonal mean wind vectors in the adjacent oceans to station precipitation. Over a 30-year calibration period (1979-2008), significant correlations between wind and precipitation at Cape Town, Mthatha and Royal National Park showed particular correspondence with those areas with the greatest concentration of logbook observations. Principal component regression was used to assess the potential of the dominant patterns of variability in the wind vectors as predictors to reconstruct precipitation. Cross-validation in the calibration period gave confidence that precipitation could be reconstructed at several stations across South Africa, meaning the regression relationships derived in the calibration period could be applied to the gridded seasonal mean logbook data to produce reconstructions of precipitation from 1796 to 1854. The reconstructions show a degree of correspondence with other regional data sets. For instance, the decade beginning in 1810 was the wettest of the period at Mthatha and Royal National Park, while the 1820s were the driest. At Cape Town, the 1820s were the wettest decade, with drier conditions observed in the 1830s. An index of west-east circulation in the summer season revealed correspondence with two documentary reconstructions of El Niño events and increased westerliness, although this did not always result in drier conditions. Attention is also drawn to the remaining 3000 yet to be digitised English East India Company logbooks which would provide a high-resolution picture of atmospheric circulation back to 1700 in the region under consideration. STUDY NOTES: Wind data from ships' logbooks are used to reconstruct precipitation at southern African rainfall stations, including Mthatha, Royal National Park and Cape Town, between 1796-1854. The reconstructions are based on relationships derived between NCEP-DOE 2 reanalysis u-wind data and station precipitation data over a calibration period of 1979-2008. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Hannaford, M.J. Investigator : Jones, J.M. Investigator : Bigg, G.R. 2015-05-18 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/18655 https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/mthatha2015precip.txt https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/royal2015precip.txt https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/capetown2015precip.txt https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/mthatha2015precip.txt https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/royal2015precip.txt https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/capetown2015precip.txt English https://www.ncdc.noaa.gov/paleo/study/18655 https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/mthatha2015precip.txt https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/royal2015precip.txt https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/capetown2015precip.txt Matthew J. Hannaford, Julie M. Jones, and Grant R. Bigg 2015Early-nineteenth-century southern African precipitation reconstructions from ships' logbooksThe Holocene252379-39010.1177/0959683614557573 START YEAR: 1796 AD * END YEAR: 1854 AD 18.6 -33.97 28.9542 -28.6858