000902254 001__ 902254 000902254 005__ 20240507205536.0 000902254 0247_ $$2doi$$a10.3389/frwa.2021.723548 000902254 0247_ $$2Handle$$a2128/28941 000902254 0247_ $$2altmetric$$aaltmetric:116527111 000902254 0247_ $$2WOS$$aWOS:000720866900001 000902254 037__ $$aFZJ-2021-04124 000902254 082__ $$a333.7 000902254 1001_ $$0P:(DE-Juel1)176840$$aMa, Yueling$$b0$$eCorresponding author 000902254 245__ $$aAn Indirect Approach Based on Long Short-Term Memory Networks to Estimate Groundwater Table Depth Anomalies Across Europe With an Application for Drought Analysis 000902254 260__ $$aLausanne$$bFrontiers Media$$c2021 000902254 3367_ $$2DRIVER$$aarticle 000902254 3367_ $$2DataCite$$aOutput Types/Journal article 000902254 3367_ $$0PUB:(DE-HGF)16$$2PUB:(DE-HGF)$$aJournal Article$$bjournal$$mjournal$$s1715083469_818 000902254 3367_ $$2BibTeX$$aARTICLE 000902254 3367_ $$2ORCID$$aJOURNAL_ARTICLE 000902254 3367_ $$00$$2EndNote$$aJournal Article 000902254 520__ $$aThe lack of high-quality continental-scale groundwater table depth observations necessitates developing an indirect method to produce reliable estimation for water table depth anomalies (wtda) over Europe to facilitate European groundwater management under drought conditions. Long Short-Term Memory (LSTM) networks are a deep learning technology to exploit long-short-term dependencies in the input-output relationship, which have been observed in the response of groundwater dynamics to atmospheric and land surface processes. Here, we introduced different input variables including precipitation anomalies (pra), which is the most common proxy of wtda, for the networks to arrive at improved wtda estimates at individual pixels over Europe in various experiments. All input and target data involved in this study were obtained from the simulated TSMP-G2A data set. We performed wavelet coherence analysis to gain a comprehensive understanding of the contributions of different input variable combinations to wtda estimates. Based on the different experiments, we derived an indirect method utilizing LSTM networks with pra and soil moisture anomaly (θa) as input, which achieved the optimal network performance. The regional medians of test R2 scores and RMSEs obtained by the method in the areas with wtd ≤ 3.0 m were 76%-95% and 0.17-0.30, respectively, constituting a 20%-66% increase in median R2 and a 0.19-0.30 decrease in median RMSEs compared to the LSTM networks only with pra as input. Our results show that introducing θa significantly improved the performance of the trained networks to predict wtda, indicating the substantial contribution of θa to explain groundwater anomalies. Also, the European wtda map reproduced by the method had good agreement with that derived from the TSMP-G2A data set with respect to drought severity, successfully detecting ~41% of strong drought events (wtda ≥ 1.5) and ~29% of extreme drought events (wtda ≥ 2) in August 2015. The study emphasizes the importance to combine soil moisture information with precipitation information in quantifying or predicting groundwater anomalies. In the future, the indirect method derived in this study can be transferred to real-time monitoring of groundwater drought at the continental scale using remotely sensed soil moisture and precipitation observations or respective information from weather prediction models. 000902254 536__ $$0G:(DE-HGF)POF4-2173$$a2173 - Agro-biogeosystems: controls, feedbacks and impact (POF4-217)$$cPOF4-217$$fPOF IV$$x0 000902254 536__ $$0G:(EU-Grant)689443$$aERA-PLANET - The European network for observing our changing planet (689443)$$c689443$$fH2020-SC5-2015-one-stage$$x1 000902254 588__ $$aDataset connected to CrossRef, Journals: juser.fz-juelich.de 000902254 7001_ $$0P:(DE-Juel1)129506$$aMontzka, Carsten$$b1$$ufzj 000902254 7001_ $$0P:(DE-Juel1)177038$$aBayat, Bagher$$b2$$ufzj 000902254 7001_ $$0P:(DE-Juel1)151405$$aKollet, Stefan$$b3$$ufzj 000902254 773__ $$0PERI:(DE-600)2986721-6$$a10.3389/frwa.2021.723548$$gVol. 3, p. 723548$$p723548$$tFrontiers in water$$v3$$x2624-9375$$y2021 000902254 8564_ $$uhttps://juser.fz-juelich.de/record/902254/files/frwa-03-723548.pdf$$yOpenAccess 000902254 909CO $$ooai:juser.fz-juelich.de:902254$$pVDB$$pdriver$$popen_access$$pdnbdelivery$$pec_fundedresources$$popenaire 000902254 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)176840$$aForschungszentrum Jülich$$b0$$kFZJ 000902254 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)129506$$aForschungszentrum Jülich$$b1$$kFZJ 000902254 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)177038$$aForschungszentrum Jülich$$b2$$kFZJ 000902254 9101_ $$0I:(DE-588b)5008462-8$$6P:(DE-Juel1)151405$$aForschungszentrum Jülich$$b3$$kFZJ 000902254 9131_ $$0G:(DE-HGF)POF4-217$$1G:(DE-HGF)POF4-210$$2G:(DE-HGF)POF4-200$$3G:(DE-HGF)POF4$$4G:(DE-HGF)POF$$9G:(DE-HGF)POF4-2173$$aDE-HGF$$bForschungsbereich Erde und Umwelt$$lErde im Wandel – Unsere Zukunft nachhaltig gestalten$$vFür eine nachhaltige Bio-Ökonomie – von Ressourcen zu Produkten$$x0 000902254 9141_ $$y2021 000902254 915__ $$0LIC:(DE-HGF)CCBY4$$2HGFVOC$$aCreative Commons Attribution CC BY 4.0 000902254 915__ $$0StatID:(DE-HGF)0501$$2StatID$$aDBCoverage$$bDOAJ Seal$$d2020-09-06 000902254 915__ $$0StatID:(DE-HGF)0500$$2StatID$$aDBCoverage$$bDOAJ$$d2020-09-06 000902254 915__ $$0StatID:(DE-HGF)0510$$2StatID$$aOpenAccess 000902254 915__ $$0StatID:(DE-HGF)0030$$2StatID$$aPeer Review$$bDOAJ : Blind peer review$$d2020-09-06 000902254 915__ $$0StatID:(DE-HGF)0561$$2StatID$$aArticle Processing Charges$$d2020-09-06 000902254 915__ $$0StatID:(DE-HGF)0700$$2StatID$$aFees$$d2020-09-06 000902254 915__ $$0StatID:(DE-HGF)0100$$2StatID$$aJCR$$bFRONT WATER : 2022$$d2023-10-27 000902254 915__ $$0StatID:(DE-HGF)0200$$2StatID$$aDBCoverage$$bSCOPUS$$d2023-10-27 000902254 915__ $$0StatID:(DE-HGF)0300$$2StatID$$aDBCoverage$$bMedline$$d2023-10-27 000902254 915__ $$0StatID:(DE-HGF)0501$$2StatID$$aDBCoverage$$bDOAJ Seal$$d2021-05-03T10:51:43Z 000902254 915__ $$0StatID:(DE-HGF)0500$$2StatID$$aDBCoverage$$bDOAJ$$d2021-05-03T10:51:43Z 000902254 915__ $$0StatID:(DE-HGF)0030$$2StatID$$aPeer Review$$bDOAJ : Anonymous peer review$$d2021-05-03T10:51:43Z 000902254 915__ $$0LIC:(DE-HGF)CCBYNV$$2V:(DE-HGF)$$aCreative Commons Attribution CC BY (No Version)$$bDOAJ$$d2021-05-03T10:51:43Z 000902254 915__ $$0StatID:(DE-HGF)0199$$2StatID$$aDBCoverage$$bClarivate Analytics Master Journal List$$d2023-10-27 000902254 915__ $$0StatID:(DE-HGF)1050$$2StatID$$aDBCoverage$$bBIOSIS Previews$$d2023-10-27 000902254 915__ $$0StatID:(DE-HGF)1190$$2StatID$$aDBCoverage$$bBiological Abstracts$$d2023-10-27 000902254 915__ $$0StatID:(DE-HGF)0112$$2StatID$$aWoS$$bEmerging Sources Citation Index$$d2023-10-27 000902254 915__ $$0StatID:(DE-HGF)0150$$2StatID$$aDBCoverage$$bWeb of Science Core Collection$$d2023-10-27 000902254 915__ $$0StatID:(DE-HGF)1040$$2StatID$$aDBCoverage$$bZoological Record$$d2023-10-27 000902254 915__ $$0StatID:(DE-HGF)9900$$2StatID$$aIF < 5$$d2023-10-27 000902254 915__ $$0StatID:(DE-HGF)0561$$2StatID$$aArticle Processing Charges$$d2023-10-27 000902254 915__ $$0StatID:(DE-HGF)0700$$2StatID$$aFees$$d2023-10-27 000902254 920__ $$lyes 000902254 9201_ $$0I:(DE-Juel1)IBG-3-20101118$$kIBG-3$$lAgrosphäre$$x0 000902254 980__ $$ajournal 000902254 980__ $$aVDB 000902254 980__ $$aI:(DE-Juel1)IBG-3-20101118 000902254 980__ $$aUNRESTRICTED 000902254 9801_ $$aFullTexts