Extended Data Table 1 Physical constants and parameters used for equations (3)–(6)

From: Permafrost slows Arctic riverbank erosion

  1. Note that the parameters A, M and τcrit are poorly constrained from the existing literature. In Extended Data Fig. 4i–k, we perform an optimization, allowing A, M and τcrit to adopt the values such that the estimated annual erosion over the period 2017–2021 best matches the observations for the Koyukuk River (Extended Data Fig. 4l). The thaw-limited model has the free parameter {A}, the entrainment-limited model has the free parameters {M, τcrit} and the combined model has all three free parameters {A, M and τcrit}. Note that the improvement in the goodness of fit (quantified through R2) from Extended Data Fig. 4i to Extended Data Fig. 4k could simply represent the increase in the number of tunable parameters from one (thaw-only) to two (entrainment-only) to three (combined thaw and entrainment). To try to address this effect arising from the change in the number of model parameters, we also compute the adjusted R2 value (see equation (15)), which includes a penalty for models with more parameters. Sources: refs. 9,15,27,37,38,74,75.
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