noaa-lake-13686 East African 675 Year MCEOF Hydroclimatic Lake Proxy Data Synthesis Tierney, J.E.; Smerdon, J.E.; Anchukaitis, K.J.; Seager, R. East African 675 Year MCEOF Hydroclimatic Lake Proxy Data Synthesis 2013-01-28 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/13686 Investigator J.E. Tierney Investigator J.E. Smerdon Investigator K.J. Anchukaitis Investigator R. Seager earth science paleoclimate paleolimnology empirical orthogonal function,null,68% confidence interval lower bound,dimensionless,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology age,null,null,year Common Era,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology empirical orthogonal function,null,null,dimensionless,null,paleolimnology,null,null,N,median earth science paleoclimate paleolimnology empirical orthogonal function,null,68% confidence interval upper bound,dimensionless,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology empirical orthogonal function,null,95% confidence interval lower bound,dimensionless,null,paleolimnology,null,null,N,null earth science paleoclimate paleolimnology reconstruction geoscientificInformation hydrology 1275 AD 1950 AD 675 cal yr BP 0 cal yr BP Complete -10 -.25 29.5 37.7 Continent Africa Eastern Africa East Africa>LATITUDE >LONGITUDE 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 Jessica E. Tierney, Jason E. Smerdon, Kevin J. Anchukaitis, and Richard Seager. 2013. Multidecadal variability in East African hydroclimate controlled by the Indian Ocean. Nature, Vol. 493, No. 7432, pp. 389-392. DOI: 10.1038/nature11785 Kevin J. Anchukaitis and Jessica E. Tierney. 2012. Identifying coherent spatiotemporal modes in time-uncertain proxy paleoclimate records. Climate Dynamics, DOI: 10.1007/s00382-012-1483-0

The recent decades-long decline in East African rainfall suggests that multidecadal variability is an important component of the climate of this vulnerable region. Prior work based on analysing the instrumental record implicates both Indian and Pacific ocean sea surface temperatures (SSTs) as possible drivers of East African multidecadal climate variability, but the short length of the instrumental record precludes a full elucidation of the underlying physical mechanisms. Here we show that on timescales beyond the decadal, the Indian Ocean drives East African rainfall variability by altering the local Walker circulation, whereas the influence of the Pacific Ocean is minimal. Our results, based on proxy indicators of relative moisture balance for the past millennium paired with long control simulations from coupled climate models, reveal that moist conditions in coastal East Africa are associated with cool SSTs (and related descending circulation) in the eastern Indian Ocean and ascending circulation over East Africa. The most prominent event identified in the proxy record - a coastal pluvial from 1680 to 1765 - occurred when Indo-Pacific warm pool SSTs reached their minimum values of the past millennium. Taken together, the proxy and model evidence suggests that Indian Ocean SSTs are the primary influence on East African rainfall over multidecadal and perhaps longer timescales. STUDY NOTES: Synthesis of lacustrine hydroclimatic proxy records from East Africa using a Monte Carlo empirical orthogonal function (MCEOF) approach. MCEOF1 timeseries and spatial loadings plus 68% and 95% uncertainty bounds are reported. Site information for Lake proxy records utilized Lake Latitude Longitude Proxy Average DT References Challa -3.32 37.70 "BIT, dDwax, varve thickness" 33 "Verschuren et al. (2009), Nature; Tierney et al., (2011) QSR; Wolff et al. (2011) Science" Naivasha -0.77 36.35 Lake level reconstruction 3 "Verschuren et al. (2000), Nature" Victoria -1.00 33.00 % shallow water diatoms 5 "Stager et al. (2005), J. Paleolimnol." Edward -0.25 29.50 % Mg in authigenic calcite 4 "Russell and Johnson (2007), Geology" Tanganyika -6.70 30.00 Charcoal 10 "Tierney et al. (2010), Nature Geosci." Masoko -9.33 33.76 Magnetic susceptibility 10 "Garcin et al. (2006), Palaeo3; Garcin et al. (2007), J. Paleolimnol." Malawi -10.00 34.22 Terrigenous mass accumulation rate 6 "Brown and Johnson (2005), G3; Johnson and McCave (2008), Limnol. Oceanogr."

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/eastafrica/tierney2013nature11785-s2.xls GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/eastafrica/tierney2013mceof.txt USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11