Tree-ring stable carbon isotope-based June–September maximum temperature reconstruction since AD 1788, north-west Thailand

Figures & data

Fig. 1. The sampling site: Mae Surin arboretum, Mae Hong Son province, northwestern Thailand.

Fig. 2. Monthly mean temperature, precipitation and relative humidity data since 1951 in Mae Hong Son.

Table 1. The correlation between the original series (δ¹³C) and detrended series (∆¹³C) from Mae Hong Son (1788–2013 AD).

		δ^13C				∆^13C
		PM1b	PM2a	PM4b	PM5a	PM1b	PM2a	PM4b	PM5a
δ^13C	PM1b	1
	PM2a	0.83	1
	PM4b	0.79	0.84	1
	PM5a	0.66	0.83	0.80	1
	Average	0.89	0.94	0.93	0.89
∆^13C	PM1b					1
	PM2a					0.65	1
	PM4b					0.62	0.65	1
	PM5a					0.53	0.66	0.65	1
	Average					0.86	0.86	0.85	0.83

Note: Correlation is significant at the 0.01 level.

Fig. 3. (a) Average δ¹³C (black) values from 4 trees (grey) and δ¹³C values in the atmosphere (blue); (b) ∆¹³C series after removing the long-term decreasing trend of δ¹³C in the atmosphere; (c) the EPS and Rbar statistics of ∆¹³C.

Fig. 4. Correlations between tree-ring ∆¹³C chronology and climatic factors obtained from the MHS station (mean temperature, rainy days and relative humidity) and the CRU TS3.24 (diurnal temperature and maximum temperature) at the 95% significance confidence level. The grey area is the 95% confidence limit after the Bonferroni adjustment.

Fig. 5. Comparison of the reconstructed and actual June–September maximum temperature from 1901–2013.

Table 2. The split-cross calibration of the June–September maximum temperature reconstruction.

Calibration	r	Sign test	Verification	r	RE	CE	Sign test
1901–1957	0.70**	38+/19–*	1957–2013	0.64**	0.272	0.229	40+/16–**
1957–2013	0.64**	42+/15–**	1901–1957	0.70**	0.132	0.042	36+/20–*
1901–2013	0.62**	80+/33–**

* p < 0.05.

** p < 0.01.

Fig. 6. The June–September maximum temperature reconstruction (grey line) with a 0.1-Hz low-pass filter (red line). (a) The standard deviation (σ) was ±0.29. (b) Four shifting segments calculated using the Bernaola-Galvan Segmentation Algorithm.

Fig. 7. (a) 21-year running correlation between June–September T_max reconstruction and May–June Nino 3 and Nino 4; (b) May–June sea surface temperature of the PDO index.