Research

d18o

Precip d18O isoscape for China


  • Isotope hydroclimatology  This includes the use of stable isotope tracers to study hydrological process and lake water balance, atmospheric dynamics, climatology and terrestrial hydrology.

Fig. 5Precip d18O  gradient (slope and aspect) in the USA and circulation pattern


  • PNA pattern and isotopic expression  For these studies, I am trying to identify where the isotopic expression of the PNA  is strongest and how the PNA controls the isotopic patterns.

PNA_patternPNA+ and PNA- from 500-mb geopotential height anomalies

isodiffIsotopic expression of the PNA patterns

Fig_7

Dipolar pattern in  winter precipitation isotope anomaly and PNA


  • External forcings on the PNA   We explore the influence of major external forcings such solar activites and explosive valcanic eruption on the PNA pattern

hgt

Changes in PNA response to solar variability: HGT difference for LS-HS at lags 0, 1 and 2 years

Fig_4

Changes in PNA response to volcanic eruptions: HGT anomalies in two post-eruption winters

Fig_5

Superposed epoch analysis of the winter surface temperature anomaly  and PNA index for the eruptions


  • Contrasting climate extremes linked to PNA  Recent intensification of positive PNA events is associated with amplified planetary waves over North America, driving cold-air outbreaks into the southeast and warm tropical/subtropical air into the northwest. This not only results in a strengthened winter mean temperature contrast, but increases the occurrence of the opposite-signed extremes in these two regions

Fig_1

Recent contrasting in winter temperature changes linked to enhanced positivePNA


  • Paleoclimate reconstruction   I am always trying to develop isotopic proxies for past climatological and environmental  trait, andseeking to fully interpret climate signals recorded in natural isotopic archives such as ice cores, tree rings, lake sediments and speleothems.

Fig_3

 Isotope and climate field differences: PPNA-NPNA vs. LH-MH

Fig_4

PNA-like climate oscillations and possible solar forcing during the mid- an late Holocene