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Official Journal of the Asia Oceania Geosciences Society (AOGS)

Table 8 Periodicities detected in the time series of annual runoff and annual precipitation in 11 sub-basins in the Yangtze River basin (YRB, excluding Taihu Lake basin), and the gradation of their significance levels based on the correlation coefficient r

From: Correlation-aided method for identification and gradation of periodicities in hydrologic time series

No.a Runoff Precipitation
T1 Levelb (r) T2 Level (r) T1 Level (r) T2 Level (r)
1 9.2 M (0.466) 11.9 N (0.017) 11.7 M (0.410) 4.7 N (0.012)
2 29.6 M (0.353) 4.3 N (0.156) 4.3 M (0.353) 2.8 N (0.076)
3 7.5 M (0.399) 4.8 N (0.005) 4.8 M (0.393) 7.5 N (0.011)
4 9.3 M (0.405) 7.3 N (0.053) 9.4 M (0.360) 24.8 N (0.047)
5 24.6 M (0.351) 16.1 N (0.015) 4 W (0.288) 3.1 N (0.060)
6 3.1 M (0.397) 16.1 N (0.121) 16.2 M (0.373) 3.1 N (0.062)
7 24.1 M (0.420) 6.8 W (0.266) 23.2 M (0.343) 2.5 N (0.056)
8 6.8 M (0.344) 21.5 N (0.221) 3.1 W (0.314) 9 N (0.221)
9 21.8 M (0.399) 3.6 N (0.239) 21.4 M (0.365) 3.6 N (0.129)
10 6.7 M (0.392) 2.7 N (0.247) 6.7 M (0.369) 2.7 N (0.215)
11 6.7 M (0.355) 3.3 W (0.297) 6.7 W (0.324) 3.3 W (0.308)
  1. aThe numbers from top to bottom in “No.” column refer to (1) upper reaches of Jinsha River (above Shigu), (2) lower reaches of Jinsha River (below Shigu), (3) Mintuo River, (4) Jialing River, (5) Wu River, (6) reaches from Yibin to Yichang, (7) Dongting Lake system, (8) Han River, (9) Poyang Lake system, (10) reaches from Yichang to Hukou and (11) reaches below Hukou, respectively
  2. b‘N’ refers to no periodic variation; ‘W’ refers to weak periodic variation and ‘M’ refers to moderate periodic variation. For the annual time series with the length of 62 years (1956–2017), the thresholds of correlation coefficient are set as r0.05 = 0.250, r0.01 = 0.325, 0.6 and 0.8 to give five-level assessment