# Southern African Precipitation Reconstructions From Ships' Logbooks 1796-1854 #----------------------------------------------------------------------- # World Data Center for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program #----------------------------------------------------------------------- # NOTE: Please cite original publication, online resource and date accessed when using this data. # If there is no publication information, please cite Investigator, title, online resource and date accessed. # # Description/Documentation lines begin with # # Data lines have no # # # Online_Resource: http://ncdc.noaa.gov/paleo/study/18655 # # Original_Source_URL: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/historical/africa/mthatha2015precip.txt # # Archive: Climate Reconstructions #--------------------------------------- # Contribution_Date # Date: 2015-05-18 #--------------------------------------- # Title # Study_Name: Southern African Precipitation Reconstructions From Ships' Logbooks 1796-1854 #--------------------------------------- # Investigators # Investigators: Hannaford, M.J.; Jones, J.M; Bigg, G.R. #--------------------------------------- # Description and Notes # Description: 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. # Provided Keywords: Climate change, El Nino, ships' logbooks, 19th century, precipitation reconstruction, southern Africa #--------------------------------------- # Publication # Authors: Matthew J. Hannaford, Julie M. Jones, and Grant R. Bigg # Published_Date_or_Year: 2015-02-01 # Published_Title: Early-nineteenth-century southern African precipitation reconstructions from ships' logbooks # Journal_Name: The Holocene # Volume: 25 # Issue: 2 # Pages: 379-390 # DOI: 10.1177/0959683614557573 # Online_Resource: # Abstract: 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 Nino 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. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: University of Sheffield # Grant: Energy and Environment PhD fellowship #--------------------------------------- # Site Information # Site_Name: Mthatha # Location: Africa>Southern Africa>South Africa # Country: South Africa # Northernmost_Latitude: -31.53 # Southernmost_Latitude: -31.53 # Easternmost_Longitude: 28.67 # Westernmost_Longitude: 28.67 # Elevation: 742 #--------------------------------------- # Data_Collection # Collection_Name: Mthatha2015precip # First_Year: 1796 # Last_Year: 1854 # Time_Unit: AD # Core_Length: # Notes: #--------------------------------------- # Chronology: #--------------------------------------- # Variables # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-longname components (9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) ## Age_AD Age,,,years AD,,,Dated by Nov,,N ## precipanom-NDJFM Precipitation anomaly November-March,,+/-147.6,mm,Nov-Mar,,Reconstructed precipitation relative to 1979-2008 mean, Principal Component Regression,N #------------------------ # Data # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Value: N/A Age_AD precipanom-NDJFM 1796 -199.81 1797 -115.23 1798 -15.89 1799 46.32 1800 90.63 1801 -96.18 1802 101.67 1803 70.79 1804 -69.22 1805 -151.77 1806 -54.60 1807 90.57 1808 -2.85 1809 4.44 1810 13.19 1811 53.58 1812 244.53 1813 -27.85 1814 N/A 1815 108.08 1816 67.48 1817 -51.60 1818 167.42 1819 205.00 1820 -154.00 1821 -11.84 1822 106.17 1823 114.31 1824 -65.93 1825 -102.93 1826 -206.66 1827 -189.09 1828 12.79 1829 -207.48 1830 141.10 1831 -153.49 1832 42.48 1833 119.89 1834 12.66 1835 131.15 1836 -39.73 1837 -12.02 1838 -35.47 1839 21.32 1840 -41.45 1841 -129.80 1842 -69.85 1843 65.83 1844 33.73 1845 174.73 1846 99.50 1847 35.82 1848 -71.04 1849 14.17 1850 52.12 1851 -114.02 1852 -90.40 1853 -13.48