Fig. 1. The statistical relationships between the LSSD and February-April mean temperature in Hangzhou during 1951-2010 ( ·: Annual samples; —: Linear fit line; DOY: Day of the year, also called Ordinal date (e.g., 2 represents January 2))

Fig. 2. The climatic significances of Hangzhou’s quantifiable-amount LSSD during different time spans

Fig. 3. The relationships between the 10-year mean LSSD and 6 statistic indexes in Hangzhou. The dots are samples; the red solid lines are nonlinear trend lines fitted by the Boltzmann function; the blue dotted lines are prediction bands at the 95% confidence level; the green beelines refer to the six corresponding statistic values for the LSSDs in the decade when the 10-year mean LSSD is March 6.

Fig. 4. Comparison of reconstructed climatic series for 1131-1270. (a) The inter-annual variations in the LSSD in Hangzhou and its abrupt change detection result of probability anomaly, ´ refer to 57 samples later than the perennial mean of the LSSDs, black line refers to the curve of probability distribution, and Southern Song Dynasty is taken as the reference period; (b) Reconstructed series of the LSSDs in Hangzhou with different temporal resolutions, the red step line refers to a 10-year temporal resolution, the sand-yellow step line refers to a 30-year temporal resolution, and the black Zero Anomaly line is the mean LSSD (March 6) during the reference period 1951-1980. (c) Decadal-scale variations in temperature at two other regions in 1131-1270, the orange line refers to the result revealed by historical documents in Central China (Wang et al., 2007), the green line refers to the result revealed by tree rings in Animaqin Mountains (Chen et al., 2016), the black Zero Anomaly line refers to the corresponding means in different reference periods (the past millennia for the former, and the past two millennia for the latter), the blue area indicates relatively cold periods, and the red area relatively warm periods. (d) Variations in the PDO index (Macdonald and Case, 2005) in 1131-1270, the yellow line refers to annual values, and the rose line refers to 11-point running averages.