noaa-recon-18655 Southern African Precipitation Reconstructions From Ships' Logbooks 1796-1854 Hannaford, M.J.; Jones, J.M.; Bigg, G.R. Southern African Precipitation Reconstructions From Ships' Logbooks 1796-1854 2015-05-18 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/18655 Investigator M.J. Hannaford Investigator J.M. Jones Investigator G.R. Bigg 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 precipitation geoscientificInformation Precipitation Reconstruction 1796 AD 1854 AD 154 cal yr BP 96 cal yr BP Complete -33.97 -28.6858 18.6 28.9542 42 1392 Continent Africa Southern Africa South Africa Mthatha>LATITUDE -31.53>LONGITUDE 28.67 Continent Africa Southern Africa South Africa Royal National Park>LATITUDE -28.6858>LONGITUDE 28.9542 Continent Africa Southern Africa South Africa Cape Town>LATITUDE -33.97>LONGITUDE 18.6 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Matthew J. Hannaford, Julie M. Jones, and Grant R. Bigg 2015 The Holocene 25 2 379-390 10.1177/0959683614557573

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.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/mthatha2015precip.txt Data File; Mthatha Precipitation Reconstruction GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/royal2015precip.txt Data File; Royal National Park Precipitation Reconstruction GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/historical/africa/capetown2015precip.txt Data File; Cape Town Precipitation Reconstruction USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11