Fig. 1.
Map showing the location of the sampling site in the Yulong Snowy Mountains.
Fig. 2.
(a) Monthly mean temperature, precipitation, and relative humidity values from 1951 to 2004 at the Lijiang meteorological station. The inter-annual variations of (b) temperature and (c) total precipitation during the early growing season (May to July) and the late growing season (August to October).
Fig. 3.
Standard ring-width index series of fir from the Yulong Snowy Mountains since 1827 (a); values of tree-ring cellulose δ18O from 1902 to 2005 for (b) earlywood, (c) latewood and (d) the sample size.
Table 1. Correlation coefficients between ring-width series and climate data of fir from Yulong Snowy Mountains (*p<0.05; **p<0.01)
Table 2. Statistical characteristics of the tree-ring earlywood (EW) and latewood (LW) δ18O values for Lijiang fir (*p<0.1; **p<0.001). ‘Current’ and ‘previous’ refer to the current and previous growing seasons
Fig. 4.
Correlation coefficients between monthly temperature, precipitation, relative humidity, and total cloud cover and (a) earlywood δ18O, (b) latewood δ18O. Dotted lines indicate the 95% confidence interval. Months with a ‘p” prefix indicate values from the previous year.
Table 3. Correlations between earlywood and latewood δ18O and the four climate variables for the May to July and August to October parts of the growing season. Climatic data are from the nearest meteorological station (at Lijiang) from 1951 to 2004 (*p<0.01; **p<0.001)
Fig. 5.
Inter-annual variations in the observed precipitation δ18O at the GNIP station closest to the study site (in Kunming) and the reconstructed precipitation δ18O based on (a) earlywood δ18O and (b) latewood δ18O. EWG and LWG represent the earlywood and LWG periods.
Table 4. The coefficients of the linear regression for source water δ18O during EWG and LWG and the Indian summer monsoon (ISM) index, Eastern Asian summer monsoon (EASM) index during different periods (*p<0.05; **p<0.01)
[i] Note: The r is the correlation coefficient of the investigated series against the time series and p is the p-value. The ISM and EASM index have been detrended by linear regression.
Fig. 6.
(a) Comparison of inter-annual variations in earlywood (EW) δ18O and the Indian Ocean SST (HadlSST, from 50°E to 100°E, and from 10°S to 15°N) from the previous December to the current July, and smoothed values using a 10-year running average (black solid line for SST, and black dotted line for EW-δ18O). (b) Comparison of inter-annual variations in latewood (LW) δ18O and the Indian Ocean SST (from 50°E to 100°E, and from 10°S to 15°N) from current May to current October, and smoothed values using a 10-year running average (black solid line for SST, and black dotted line for LW-δ18O). The y-axis for each parameter has been standardized to be dimensionless.
Fig. 7.
Spatial distribution of the correlations between earlywood δ18O (December to July), latewood δ18O (May to October), and the HadlSST grid data (http://climexp.knmi.nl) from 1902 to 1979 for (a) earlywood δ18O and (c) latewood δ18O, and from 1980 to 2004 for (b) earlywood δ18O and (d) latewood δ18O. Values significant at p<0.10 are shown.
Fig. 8.
Inter-annual variations in the source water δ18O reconstructed from the (a) earlywood and (c) latewood δ18O values from 1950 to 2005. (b) The ISM index and (d) the EASM index during the same period. EWG and LWG represent the earlywood and LWG periods, respectively. Dashed lines indicate linear increasing and decreasing trend at decadal scale during different periods.
Fig. 9.
Spatial distributions of correlations between the source water δ18O and precipitable water vapour (http://www.esrl.noaa.gov/) from 1948 to 2005 for earlywood and from 1948 to 2004 for latewood. (a) current May to July for earlywood δ18O; (b) current May to October for latewood δ18O.
Fig. 10.
(a) Comparison of inter-annual variations in source water δ18O for EWG and the SOI from 1951 to 2005 and from 1902 to 2004. Months with a ‘p’ prefix indicate values from the previous year. (b) Comparison of inter-annual variations in source water δ18O for LWG and the SOI from 1951 to 2004 and from 1902 to 2004. Months with a ‘p’ prefix indicate values from the previous year.
