Stable isotopic composition of precipitation in a tropical rainforest region of the Niger Delta, Nigeria

The isotopic compositions of oxygen (δ ¹⁸O) and hydrogen (δ ²H) of precipitation were determined from three different locations in the western Niger Delta (Warri, Ughelli and Abraka) between 2014 and 2015. ¹⁸O and ²H in wet season precipitation were more depleted compared to the dry season. Similarly, d-excess computed for wet season precipitation is lower than that for the dry season. The δ ¹⁸O and δ ²H variations in precipitation suggest the effect of the convective system and north-easterly and south-westerly trade winds. The decrease in δ ¹⁸O and δ ²H was also observed in precipitation data of a continuous rain event of two successive days. The local meteoric water lines estimated for Warri, Ughelli and Abraka were δ ²H = 8.8 δ ¹⁸O + 9.1 ‰ (R ² = 0.93), δ ²H = 6.9 δ ¹⁸O + 10.7 ‰ (R ² = 0.98) and δ ²H = 7.9 δ ¹⁸O + 11.3 ‰ (R ² = 0.87), respectively. The Niger Delta regional meteoric water line of δ ²H = 7.7 δ ¹⁸O + 10.2 ‰ (R ² = 0.91) was derived from the monthly average from the three locations. The provided local meteoric water line for the Niger Delta from unweighted stable isotopic data represents a baseline for regional water resources studies.

GRIP Deuterium Excess Reveals Rapid and Orbital-Scale Changes in Greenland Moisture Origin

The Northern Hemisphere hydrological cycle is a key factor coupling ice sheets, ocean circulation, and polar amplification of climate change. Here we present a Northern Hemisphere deuterium excess profile covering one climatic cycle, constructed with the use of delta18O and deltaD Greenland Ice Core Project (GRIP) records. Past changes in Greenland source and site temperatures are quantified with precipitation seasonality taken into account. The imprint of obliquity is evidenced in the site-to-source temperature gradient at orbital scale. At the millennial time scale, GRIP source temperature changes reflect southward shifts of the geographical locations of moisture sources during cold events, and these rapid shifts are associated with large-scale changes in atmospheric circulation.

Glacial surface temperatures of the southeast Atlantic Ocean

A detailed record of sea surface temperature from sediments of the Cape Basin in the subtropical South Atlantic indicates a previously undocumented progression of marine climate change between 41 and 18 thousand years before the present (ky B.P.), during the last glacial period. Whereas marine records typically indicate a long-term cooling into the Last Glacial Maximum (around 21 ky B.P.) consistent with gradually increasing global ice volume, the Cape Basin record documents an interval of substantial temperate ocean warming from 41 to 25 ky B.P. The pattern is similar to that expected in response to changes in insolation owing to variations in Earth's tilt.