Worth waiting for, hardly worth waiting: data latency and the timing of regional landslide warnings in China
Year: 2026
Type: preprint
Abstract: . Landslide warning services must weigh the better evidence that later data bring against the lead time lost while waiting for them. We studied this trade-off for 280 rainfall-induced landslides in China (2015–2024) with minute-, hour- or period-level occurrence times reported in the news, using the Global Precipitation Measurement (GPM) mission's Integrated Multi-satellitE Retrievals for GPM (IMERG) precipitation and as-issued Global Forecast System (GFS) forecasts in a latency-aware retrospective replay. In a case-crossover design, observed rainfall replacing forecasts added substantial information (matched area under the receiver operating characteristic curve +0.058 [0.034, 0.081]), whereas later satellite runs and newer forecast cycles added little or none. In a rolling replay of 24 h warnings, waiting one 6 h step before issuing gave no stable gain in detection at warning loads of 0.5–10 % of cell-time. In a cost–loss analysis, issuing at once with satellite rainfall plus forecast reached a relative economic value (REV, dimensionless) of 0.55, close to a latency-free benchmark (0.57) and above a rainfall threshold (0.34) and, on matched 2015–2020 decisions, the archived version 2.0.0 Landslide Hazard Assessment for Situational Awareness (LHASA) nowcast (0.34). A value-of-information waiting rule added +0.002 [−0.005, +0.007] over the best fixed policy, averaged across the exploratory cost–loss range. The pre-specified cost–loss test could not discriminate, because almost no rule warns at its cost–loss ratios, but a second test, fixed before an independent 2008–2014 sample was assembled, detected a value of waiting when no forecast was available (+0.03 [0.01, 0.05] in REV). Brackets give 95 % confidence intervals. With both satellite rainfall and forecasts available, waiting rarely repaid its lead-time cost.
Language: English
Subfield: Management, Monitoring, Policy and Law
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7225622464
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