Evapotranspiration Response to Climate Change in Semi-Arid Areas: Using Random Forest as Multi-Model Ensemble Method

Large ensembles of climate models are increasingly available either as ensembles of opportunity or perturbed physics ensembles, providing a wealth of additional data that is potentially useful for improving adaptation strategies to climate change. In this work, we propose a framework to evaluate the...

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Main Authors: Marcos Ruiz-Aĺvarez, Francisco Gomariz-Castillo, Francisco Alonso-Sarría
Format: Article
Language:English
Published: MDPI AG 2021-01-01
Series:Water
Subjects:
Online Access:https://www.mdpi.com/2073-4441/13/2/222
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author Marcos Ruiz-Aĺvarez
Francisco Gomariz-Castillo
Francisco Alonso-Sarría
author_facet Marcos Ruiz-Aĺvarez
Francisco Gomariz-Castillo
Francisco Alonso-Sarría
author_sort Marcos Ruiz-Aĺvarez
collection DOAJ
description Large ensembles of climate models are increasingly available either as ensembles of opportunity or perturbed physics ensembles, providing a wealth of additional data that is potentially useful for improving adaptation strategies to climate change. In this work, we propose a framework to evaluate the predictive capacity of 11 multi-model ensemble methods (MMEs), including random forest (RF), to estimate reference evapotranspiration (ET<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>0</mn></msub></semantics></math></inline-formula>) using 10 AR5 models for the scenarios RCP4.5 and RCP8.5. The study was carried out in the Segura Hydrographic Demarcation (SE of Spain), a typical Mediterranean semiarid area. ET<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>0</mn></msub></semantics></math></inline-formula> was estimated in the historical scenario (1970–2000) using a spatially calibrated Hargreaves model. MMEs obtained better results than any individual model for reproducing daily ET<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>0</mn></msub></semantics></math></inline-formula>. In validation, RF resulted more accurate than other MMEs (Kling–Gupta efficiency (KGE) <inline-formula><math display="inline"><semantics><mrow><mi>M</mi><mo>=</mo><mn>0.903</mn></mrow></semantics></math></inline-formula>, <inline-formula><math display="inline"><semantics><mrow><mi>S</mi><mi>D</mi><mo>=</mo><mn>0.034</mn></mrow></semantics></math></inline-formula> for KGE and <inline-formula><math display="inline"><semantics><mrow><mi>M</mi><mo>=</mo><mn>3.17</mn></mrow></semantics></math></inline-formula>, <inline-formula><math display="inline"><semantics><mrow><mi>S</mi><mi>D</mi><mo>=</mo><mn>2.97</mn></mrow></semantics></math></inline-formula> for absolute percent bias). A statistically significant positive trend was observed along the 21st century for RCP8.5, but this trend stabilizes in the middle of the century for RCP4.5. The observed spatial pattern shows a larger ET<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>0</mn></msub></semantics></math></inline-formula> increase in headwaters and a smaller increase in the coast.
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spelling doaj.art-7abe62eda5044a7baf64d2e2e7157dd42023-12-03T13:41:38ZengMDPI AGWater2073-44412021-01-0113222210.3390/w13020222Evapotranspiration Response to Climate Change in Semi-Arid Areas: Using Random Forest as Multi-Model Ensemble MethodMarcos Ruiz-Aĺvarez0Francisco Gomariz-Castillo1Francisco Alonso-Sarría2University Institute for Water and Environment, University of Murcia, 30100 Murcia, SpainUniversity Institute for Water and Environment, University of Murcia, 30100 Murcia, SpainUniversity Institute for Water and Environment, University of Murcia, 30100 Murcia, SpainLarge ensembles of climate models are increasingly available either as ensembles of opportunity or perturbed physics ensembles, providing a wealth of additional data that is potentially useful for improving adaptation strategies to climate change. In this work, we propose a framework to evaluate the predictive capacity of 11 multi-model ensemble methods (MMEs), including random forest (RF), to estimate reference evapotranspiration (ET<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>0</mn></msub></semantics></math></inline-formula>) using 10 AR5 models for the scenarios RCP4.5 and RCP8.5. The study was carried out in the Segura Hydrographic Demarcation (SE of Spain), a typical Mediterranean semiarid area. ET<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>0</mn></msub></semantics></math></inline-formula> was estimated in the historical scenario (1970–2000) using a spatially calibrated Hargreaves model. MMEs obtained better results than any individual model for reproducing daily ET<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>0</mn></msub></semantics></math></inline-formula>. In validation, RF resulted more accurate than other MMEs (Kling–Gupta efficiency (KGE) <inline-formula><math display="inline"><semantics><mrow><mi>M</mi><mo>=</mo><mn>0.903</mn></mrow></semantics></math></inline-formula>, <inline-formula><math display="inline"><semantics><mrow><mi>S</mi><mi>D</mi><mo>=</mo><mn>0.034</mn></mrow></semantics></math></inline-formula> for KGE and <inline-formula><math display="inline"><semantics><mrow><mi>M</mi><mo>=</mo><mn>3.17</mn></mrow></semantics></math></inline-formula>, <inline-formula><math display="inline"><semantics><mrow><mi>S</mi><mi>D</mi><mo>=</mo><mn>2.97</mn></mrow></semantics></math></inline-formula> for absolute percent bias). A statistically significant positive trend was observed along the 21st century for RCP8.5, but this trend stabilizes in the middle of the century for RCP4.5. The observed spatial pattern shows a larger ET<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>0</mn></msub></semantics></math></inline-formula> increase in headwaters and a smaller increase in the coast.https://www.mdpi.com/2073-4441/13/2/222random forest regressionreference evapotranspirationmulti-model ensemblesClimate Changefifth assessment reportrandom forest regression kriging
spellingShingle Marcos Ruiz-Aĺvarez
Francisco Gomariz-Castillo
Francisco Alonso-Sarría
Evapotranspiration Response to Climate Change in Semi-Arid Areas: Using Random Forest as Multi-Model Ensemble Method
Water
random forest regression
reference evapotranspiration
multi-model ensembles
Climate Change
fifth assessment report
random forest regression kriging
title Evapotranspiration Response to Climate Change in Semi-Arid Areas: Using Random Forest as Multi-Model Ensemble Method
title_full Evapotranspiration Response to Climate Change in Semi-Arid Areas: Using Random Forest as Multi-Model Ensemble Method
title_fullStr Evapotranspiration Response to Climate Change in Semi-Arid Areas: Using Random Forest as Multi-Model Ensemble Method
title_full_unstemmed Evapotranspiration Response to Climate Change in Semi-Arid Areas: Using Random Forest as Multi-Model Ensemble Method
title_short Evapotranspiration Response to Climate Change in Semi-Arid Areas: Using Random Forest as Multi-Model Ensemble Method
title_sort evapotranspiration response to climate change in semi arid areas using random forest as multi model ensemble method
topic random forest regression
reference evapotranspiration
multi-model ensembles
Climate Change
fifth assessment report
random forest regression kriging
url https://www.mdpi.com/2073-4441/13/2/222
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AT franciscogomarizcastillo evapotranspirationresponsetoclimatechangeinsemiaridareasusingrandomforestasmultimodelensemblemethod
AT franciscoalonsosarria evapotranspirationresponsetoclimatechangeinsemiaridareasusingrandomforestasmultimodelensemblemethod