HOLOCENE CLIMATE VARIATIONS IN THE CORE AREA OF CENTRAL ASIA DRY LANDS

There exist large discrepancies accounting for the wetting trend since ~8.0 cal. kyr BP in the Altai Mountains and the surrounding areas. In order to validate or invalidate the widely-reported wetting trend, Zhang et al. (2017) presented a Holocene warm-season moisture history at Narenxia (NRX) peat core in the southern Altai Mountains (or Chinese Altai) within northern Xinjiang of China using the carbon isotope signature of cellulose (δ¹³C_celluose) as a proxy for peat land-surface moisture. The δ¹³C_celluose-based warm-season moisture variation at NRX peat core does lend a strong support to the widely-reported proposition that the climate was generally dry before ~8.0 cal. kyr BP and experienced a wetting trend during the past ~8000 years. This wetting trend since ~8.0 cal. kyr BP in the Altai Mountains and the surrounding areas well resembles the declining trend of the reconnaissance drought index (RDI) that was calculated on the basis of pollen-inferred climate parameters at NRX peat core (Feng et al., 2017). The resemblance implies that the wetting trend was resulted from a combined effect of temperature and precipitation. It should be irritated here that the reconstructed variations both in temperatures and in precipitation were proposed to have been modulated by a combination of North Atlantic Oscillations (NAO) and El Nino-Southern Oscillations (ENSO) (Feng et al., 2017).