Assessing parsimonious hydrological model structures with distributed adjoint-based calibration in SMASH Python-Fortran platform on large sample of French catchments and flash floods
Authors: Colleoni François , Garambois Pierre-André , Jay-Allemand Maxime , Javelle Pierre , Arnaud Patrick , Fouchier Catherine , Gejadze Igor 
Published: March 2022

&lt;p&gt;&lt;span&gt;This&lt;/span&gt; &lt;span&gt;contribution&lt;/span&gt; &lt;span&gt;presents&lt;/span&gt; &lt;span&gt;improvements&lt;/span&gt; &lt;span&gt;of&lt;/span&gt; &lt;span&gt;conceptual&lt;/span&gt; &lt;span&gt;models&lt;/span&gt; &lt;span&gt;in &lt;/span&gt;&lt;span&gt;SMASH (Spatially distributed Modelling and ASsimilation for Hydrology) plat&lt;/span&gt;&lt;span&gt;form,&lt;/span&gt; &lt;span&gt;underlying&lt;/span&gt; &lt;span&gt;the&lt;/span&gt; &lt;span&gt;French&lt;/span&gt; &lt;span&gt;national&lt;/span&gt; &lt;span&gt;flash&lt;/span&gt; &lt;span&gt;flood&lt;/span&gt; &lt;span&gt;forecasting&lt;/span&gt; &lt;span&gt;system&lt;/span&gt; &lt;span&gt;Vigicrues &lt;/span&gt;&lt;span&gt;Flash&lt;/span&gt; &lt;span&gt;[1],&lt;/span&gt; &lt;span&gt;based&lt;/span&gt; &lt;span&gt;on:&lt;/span&gt; &lt;span&gt;(i)&lt;/span&gt; &lt;span&gt;the&lt;/span&gt; &lt;span&gt;3-parameters&lt;/span&gt; &lt;span&gt;model&lt;/span&gt; &lt;span&gt;formulation&lt;/span&gt; &lt;span&gt;and&lt;/span&gt; &lt;span&gt;variational &lt;/span&gt;&lt;span&gt;data assimilation algorithm of [2] that showed promising results (i) hypothesis &lt;/span&gt;&lt;span&gt;testing on a large sample of catchments and flash floods; (ii) comparison of &lt;/span&gt;&lt;span&gt;the SMASH model performances in uniform and distributed calibration to GR &lt;/span&gt;&lt;span&gt;models;&lt;/span&gt; &lt;span&gt;(iii)&lt;/span&gt; &lt;span&gt;a&lt;/span&gt; &lt;span&gt;new&lt;/span&gt; &lt;span&gt;wrapped&lt;/span&gt; &lt;span&gt;Python&lt;/span&gt; &lt;span&gt;interface&lt;/span&gt; &lt;span&gt;automatically&lt;/span&gt; &lt;span&gt;generated&lt;/span&gt; &lt;span&gt;by&lt;/span&gt; &lt;span&gt;the &lt;/span&gt;&lt;span&gt;f90wrap library [3]. &lt;/span&gt;&lt;span&gt;Multiple tests have allowed us to converge on two parsimonious distributed &lt;/span&gt;&lt;span&gt;model structures that have comparable performances to the GR models in spa&lt;/span&gt;&lt;span&gt;tially uniform calibration.&lt;/span&gt; &lt;span&gt;These two structures, mainly based on GR operators &lt;/span&gt;&lt;span&gt;at&lt;/span&gt; &lt;span&gt;the&lt;/span&gt; &lt;span&gt;pixel&lt;/span&gt; &lt;span&gt;scale,&lt;/span&gt; &lt;span&gt;differ&lt;/span&gt; &lt;span&gt;in&lt;/span&gt; &lt;span&gt;the&lt;/span&gt; &lt;span&gt;production&lt;/span&gt; &lt;span&gt;operator,&lt;/span&gt; &lt;span&gt;with&lt;/span&gt; &lt;span&gt;the&lt;/span&gt; &lt;span&gt;6-parameters&lt;/span&gt; &lt;span&gt;structure being GR production and the 7-parameters structure being VIC pro&lt;/span&gt;&lt;span&gt;duction.&lt;/span&gt; &lt;span&gt;Furthermore, the use of distributed calibration applied to these formu&lt;/span&gt;&lt;span&gt;lations&lt;/span&gt; &lt;span&gt;via&lt;/span&gt; &lt;span&gt;adjoint&lt;/span&gt; &lt;span&gt;model&lt;/span&gt; &lt;span&gt;resolution&lt;/span&gt; &lt;span&gt;shows&lt;/span&gt; &lt;span&gt;significantly&lt;/span&gt; &lt;span&gt;better&lt;/span&gt; &lt;span&gt;calibration&lt;/span&gt; &lt;span&gt;per&lt;/span&gt;&lt;span&gt;formances&lt;/span&gt; &lt;span&gt;without&lt;/span&gt; &lt;span&gt;being&lt;/span&gt; &lt;span&gt;less&lt;/span&gt; &lt;span&gt;robust&lt;/span&gt; &lt;span&gt;in&lt;/span&gt; spatio-&lt;span&gt;temporal&lt;/span&gt; &lt;span&gt;validation.&lt;/span&gt; &lt;span&gt;Immediate&lt;/span&gt; &lt;span&gt;work &lt;/span&gt;&lt;span&gt;deals&lt;/span&gt; &lt;span&gt;with&lt;/span&gt; &lt;span&gt;improving&lt;/span&gt; &lt;span&gt;the&lt;/span&gt; &lt;span&gt;regional&lt;/span&gt; &lt;span&gt;calibration&lt;/span&gt; &lt;span&gt;scheme&lt;/span&gt; &lt;span&gt;by&lt;/span&gt; &lt;span&gt;tayloring&lt;/span&gt; &lt;span&gt;the&lt;/span&gt; &lt;span&gt;global&lt;/span&gt; &lt;span&gt;search&lt;/span&gt; &lt;span&gt;of&lt;/span&gt; &lt;span&gt;semi-distributed&lt;/span&gt; &lt;span&gt;prior&lt;/span&gt; &lt;span&gt;parameter&lt;/span&gt; &lt;span&gt;sets,&lt;/span&gt; &lt;span&gt;with&lt;/span&gt; &lt;span&gt;multi-gauge&lt;/span&gt; &lt;span&gt;constrains, &lt;/span&gt;&lt;span&gt;improving physiographic regularizations in the forward-inverse SMASH assimilation&lt;/span&gt; &lt;span&gt;chain, using Python librairies. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;&lt;span&gt;References&lt;/span&gt;&lt;/strong&gt;&lt;br&gt;&lt;span&gt;[1]&lt;/span&gt; &lt;span&gt;P. Javelle, et al.&lt;/span&gt; &lt;span&gt;Flash flood warn&lt;/span&gt;&lt;span&gt;ings:&lt;/span&gt; &lt;span&gt;Recent achievements in france with the national vigicrues flash system UNDRR GAR, 2019.&lt;br&gt;[2] M. Jay-Allemand, et al.. On the potential of variational calibration for a fully distributed hydrological model: application on a mediterranean catchment. HESS, 2020, https://doi.org/10.5194/hess-24-5519-2020&lt;br&gt;[3] J. R. Kermode. f90wrap: an automated tool for constructing deep python interfaces to modern fortran codes. 2020. https://doi.org/10.1088/1361-648X/ab82d2&lt;br&gt;&lt;/span&gt;&lt;/p&gt;