"Oxygen isotope analyses were performed at the Isotope Laboratory, Institute of Karst Geology, Guilin, China, using a VG MM-903 gas mass spectrometer (for Dongge Cave D3 and D4 analyses, except for D4 between 15.81 ky and 9.98 ky); at the State Key Laboratory of Loess and Quaternary Geology, Insti- tute of Earth Environment, Xi?an, China, using a Finni- gan MAT 252 Kiel Device III (Dongge Cave D4 be- tween 15.81 and 9.98 ky); and on a Finnigan MAT 251 at the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (Hulu Cave H82 be- tween 15.34 and 16.30 ky before the present)."

ZK (07/01/2019): Pre-Holocene part of the D4 stal. No data from the past 2000yrs

ZK (07/01/2019): Pre-Holocene part of the D4 stal.

sample D4 and H82 from Hulu Cave (Wang, et al., 2001) replicate, however "In detail, D3 and D4 do not replicate perfectly, with some times characterized by differences in  18O that are large as compared to analytical error but small compared to the amplitude of the record (Fig. 2). These discrepancies are likely due to kinetic effects, water/rock interactions, and/or differential evapora- tion of water at the land surface."

Interpretations of changes in precipitation d18O have focused on (i) the correlation be- tween mean annual temperature and  18O of modern meteoric precipitation [for temperatures  10i¿½C (15)] and (ii) the anticorrelation between rainfall amount and precipitation d18O [the ?amount effect? (15)]. However, modern precipitation d18O trends basically result from the progressive removal of water vapor from air masses as they move from moisture source regions, resulting in decreasing water vapor and precipitation d18O, which explains the first-order observation of lower precipitation d18O values at higher lat- itudes. Precipitation d18O at Hulu/Dongge is therefore largely a measure of the fraction of water vapor removed from air masses be- tween the tropical Indo-Pacific and southeastern China.

To estimate absolute amounts of rainfall integrated from sources to southeast China, we must make assumptions about absolute humidity in tropical source regions. Even assuming a glacial relative humidity as high as today?s and only a modest tropical temper- ature depression (2.5i¿½C), we calculate an ab- solute tropical glacial vapor pressure that is 85% of today?s and 79% of mid-Holocene/ Last Interglacial values (at a mid-Holocene temperature 1i¿½C greater than today and con- stant relative humidity). Coupled with the Rayleigh calculations, the amount of precip- itation integrated between tropical sources and southeast China is today  87% of mid- Holocene/Last Interglacial values and was  65% of mid-Holocene/Last Interglacial val- ues at glacial times corresponding to the heaviest Hulu/Dongge calcite  18O values, indicating that this region was significantly drier during glacial times.