Table 2 Soil moisture anomalies during high-temperature case (highest 5 years) and low-precipitation case (lowest 5 years) events depending on permafrost types.

* indicates significance at the 95% confidence level based on the bootstrap method. In the bootstrap method, to get probabilistic density function, random resampling is repeated 10,000 times from the observed data.

April soil moisture anomaly
(m2 m−2)
Continuous and
discontinuous permafrost
(>50%)
Sporadic permafrost
(10–50%)
Isolated permafrost
(0–10%)
Nonpermafrost
Composite of February to
March high-temperature
case
−6.83 × 10−3 (P = 0.05*)−8.25 × 10−3 (P = 0.04*)−8.54 × 10−3 (P = 0.06)−3.27 × 10−3 (P = 0.19)
Composite of February to
March low-precipitation
case
−0.38 × 10−3 (P = 0.49)−4.53 × 10−3 (P = 0.16)−1.19 × 10−3 (P = 0.37)−0.39 × 10−3 (P = 0.45)