Holocene records of effective precipitation in West Greenland

Suzanne McGowan, David B. Ryves, N. John Anderson

Publikation: Bidrag til tidsskriftArtikelForskningpeer review

68 Citationer (Scopus)

Abstrakt

Holocene changes in effective precipitation (precipitation-evaporation; P-E) were reconstructed for the Søndre Strømfjord region of southwest Greenland using the sediment records of two neighbouring closed-basin 'saline' lakes. Past lakewater conductivities (a proxy for P-E balance) were estimated using a diatom-inferred conductivity model. Broadly similar changes in both lake records corroborate the use of DI conductivity as a regional climate proxy. An increasing DI conductivity trend through the Holocene indicated net negative or balanced P-E ratios in this region, even during most of the Neoglacial period (post-4000 yr BP). This contrasts with other regions of West Greenland, where conditions became more humid in the Neoglacial period. The reconstructions presented here therefore suggest a high degree of spatial variability in the P-E balance, likely caused by region-specific orographic features. While interpretation of the mid-Holocene P-E balance was limited by dissolution of the diatom record, other sediment indicators suggest a period of extremely negative effective precipitation (∼7000-5600 yr BP), followed by a period of positive effective precipitation lasting until 4700 yr BP. This contrasts markedly with the later Holocene, after c. 4000 yr BP, when high-frequency oscillations in DI conductivity probably reflect short-term climatic variations (amplified by in-lake processes connected with meromixis) but no long-term trends in the P-E balance.

OriginalsprogEngelsk
Sider (fra-til)239-249
Antal sider11
TidsskriftHolocene
Vol/bind13
Udgave nummer2
DOI
StatusUdgivet - 1 feb. 2003

Programområde

  • Programområde 5: Natur og klima

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