River flow reconstruction using stalagmite oxygen isotope δ18O: An example of the Jialingjiang River, China

The instrument-based hydrometric data from most rivers in China and in the world are only 50-60 years and there is an urgent need for reconstruction of river flow using various proxy data. We have found that the stalagmite oxygen isotope delta O-18 record can be used for this purpose. Zhang et al. (2008) established a 1800-year high-resolution cave delta O-18 record from the Wanxiang Cave located in the drainage basin of the Jialingjiang River, a major tributary of the Changjiang River. These data were used in the present study to reconstruct the precipitation and river flow. We found that the 5-year averages of annual precipitation over the Jialingjiang River basin (P-m,P-J,P-5m) and the annual river flow at Beibei hydrometric station (Q(w,B,5m)) are closely correlated with the 5-year average of the Wanxiang cave delta O-18 (delta O-18(5m)). The regression equations between P-m,P-J,P-5m and delta O-18(5m) were established, with R-2 = 0.4852, F(1,46) = 43.360, p = 3.83 x 10(-8), standard error of estimate SE = 0.04335. The regression equations between Q(w,B,5m) and delta O-18(5m) was also established, with R-2 = 0.6177, F(1,42) = 67.869, p = 2.6 x 10(-10), SE = 0.09732. The delta O-18(5m) variation can explains 48.5% and 61.8% of the variations in P-m,P-J,P-5m and Q(w,B,5m), respectively. Based on the two equations and using the delta O-18(5m) data from 192 to 1951, P-m,P-J,P-5m and Q(w,B,5m) over the past 1800 years have been reconstructed, which show a decreasing first-order trend between ca. 600 and 1600 AD followed by an increasing trend. At shorter timescales, II sub-periods were divided. The eleven sub-periods may be classified as two types: slowly changing over long timescales (Type I) and rapidly changing over short timescales (Type II). (C) 2014 Elsevier B.V. All rights reserved.