High Indian Native Moustafa

Core/Site name:

Ras Um Sidd RUS-93a

Country/Region:

Sinai Penninsula, Red Sea

Elevation:

-3

Archive:

corals

Species:

Porites sp.

Proxy measurement:

O18

Sampling resolution:

seasonal

Climate sensitivity:

temperature, salinity

Dating resolution:

1/year

Dating information:

annual cycle count

Startyear:

1993 AD

Endyear:

1897 AD

All uncertainties:

Analytical precision is 0.07 permil for replicate analyses.

Description:

High-resolution d18O records of the two coral colonies Porites spp. (RUS-93a and RUS-93b) reveal ages of the last 96 (1897-1993) and 50 (1943-1993) years, respectively. The colonies grew about 250 m apart at Ras Umm Sidd off the southern Sinai coast, in the northern Red Sea proper. The two d18O records show the same average seasol1al amplitude (0.70%0) and the same annual growth rate (1 cm/yr). Therefore, they respond similarly to the same environmental signals. They correlate well with each other on a seasonal time scale (r=0.69; at the 99.5% level) but on the annual time scale correlation is only moderate (r=0.40; at the 99.5% level). To assess the colony oxygen isotope variability in Porites spp. during the twentieth century, two previous d18O records; RUS-95 from Felis (1999), RUS-l from Pätzold and Klein (unpublished data) from the same region were correlated with our d18O records (RUS-93a and b). The correlation coefficients between the four coral d18O records vary on the annual time scale. These deviations are most likely due to different microenvironments causing variations in the "vital effect"" of the respective coral colonies. Annual means of the different coral d18O records were compared with instrumentally measured sea-surface temperatures (in four time intervals, 1907-1916, 1919-1939, 1946-1966 and 1976-1992 as a result of data gaps in the instrumental record). Apart from the gaps in the data, the correlation coefficients varied from -0.45 (RUS-95) to -0.60 (RUS-93a). The highest correlation (r=-0.68) is obtained by averaging the three longest d18O. Therefore, it is required to analyze more than one coral from a locality to reduce the local variability in coral d18O, and to use averaged data sets which are more representative for paleoclimate studies as is the case in tree-ring paleoclimate studies. The d18O/SST gradient varies between 0.15 to 0.18 ‰, with a mean value of 0.165‰, as is shown in a previous study (Felis 1999). The longest record of coral d18O (RUS-93a) indicates a warming of about 1.1°C in the twentieth-century. Pronounced coherent cyclicities of 10 and 3.6 years are evident in the coral d18O time series by cross-spectral analysis between RUS-93a and RUS-93b. Also, a highly coherent 5.8-year cyc1icity is also evident. This period is evident in the coral d18O of RUS-95 2 core, which is also the most prominent coherent period in the co-spectrum of the North Atlantic Oscillation Index (NAO) and the EI-Niño Oscillation Index (ENSO) (Felis 1999). The 3.6-year period is coherent with a similar cyclicity in the Southern Oscillation Index (SOI)."

Data entered by name:

Hali Kilbourne

Data entered by email:

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Main reference(s):

Moustafa, Yaser Ahmed (2000): Paleoclimatic reconstructions of the northern Red Sea during the Holocene inferred from stable isotope records of modern and fossil corals and molluscs. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 153, 102 pp,

Link to reference 1:

http://nbn-resolving.de/urn:nbn:de:gbv:46-ep000102745

Data storage link 1:

http://doi.pangaea.de/10.1594/PANGAEA.388665

Comments:

Reference is dissertation, not full peer-review article. These data may be used in papers by T. Felis as well.

Current dating method:

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Annual snow acc rate:

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Category: Ocean2k