Refined meteorological early warning for rainfall-induced landslide based on temporal probability model
SONG Yufei1，LI Xiang2，FAN Wen2，YU Ningyu2，CAO Yanbo2，DENG Longsheng2，TAO Hong3
(1. School of Data Science and Artificial Intelligence，Chang'an University，Xi'an，Shaanxi 710069，China；2. Department of Geological Engineering，Chang'an University，Xi'an，Shaanxi 710069，China；3. Shaanxi Institute of Geo-environment
Monitoring，Xi'an，Shaanxi 710054，China)
Abstract：The landslide meteorological early warning model based on empirical rainfall thresholds(ERT) always has a low warning accurate，and the temporal probability model(TPM) is expected to make up for this shortcoming. In order to verify this idea，this paper conducted a comparative experiment. First，we used accumulated effective rainfall-duration(EE-D) and rainfall on the day-accumulated effective rainfall in the previous 4 days(R0-AE4) as variables to construct two sets of TPM models，the receiver operating characteristic(ROC) curve and correlation coefficient were then used to evaluate the discriminative and predictive abilities of ERT/TPM. Then，the conditional probability formula was used to couple the spatiotemporal probability of landslides，and a probabilistic landslide meteorological early warning model(P-LEWM) was proposed. Finally，through the way of simulated warning，P-LEWM was compared with the matrix-based landslide early warning model(M-LEWM)，which was constructed with ERT，the results show that：(1) The ERT/TPM constructed by R0-AE4 is more accurate in judging the hazard level of rainfall to trigger landslides，the area under the ROC curve(AUC) increased by 6.8% to 12.5% compared to EE-D；(2) The TPM proposed in this paper can predict the probability of rainfall triggering landslides accurately，the correlation coefficient between the predicted amount of triggering-rainfall and the recorded amount is above 0.83，moreover，the EE-D type TPM is more accurate for heavy rainfall prediction，while the R0-AE4 is more suitable for regular rainfall events；(3) The EE-D type ERT will underestimates the hazard level of long-lasting heavy rainfall triggering landslide，which caused M-LEWM missed lots of landslides which happened in two typical rainfall events in 2018，with an missed rate of more than 50%，while P-LEWM constructed with TPM has a correct alert rate of over 90%；(4) Because of the accurate TPM and reasonable spatiotemporal model coupling method，the correct alert rate of the P-LEWM proposed in this article has been significantly improved compared to M-LEWM，the correct alert rate increased by 20.7% to 26%，the reasonable correct alert rate increased by 15.6% to 28.6%，and the missed alert rate decreased by more than 20.5%.
