Coastal groundwater response to climate variability coupling in California and Portugal
Aquifers are a fundamental source of freshwater, yet they are particularly vulnerable in coastal Mediterranean regions due to climate and anthropogenic pressures. This comparative study examines the interrelationships between ocean-atmosphere teleconnections, groundwater levels and precipitation in...
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ftunivalgarve:oai:sapientia.ualg.pt:10400.1/15209 2023-05-15T17:36:25+02:00 Coastal groundwater response to climate variability coupling in California and Portugal Malmgren, Katherine Allise Neves, Maria C. Gurdak, Jason 2020-12-10 http://hdl.handle.net/10400.1/15209 eng eng http://hdl.handle.net/10400.1/15209 202652114 openAccess http://creativecommons.org/licenses/by/4.0/ CC-BY Água subterrânea Variabilidade climática Aquíferos costeiros Mediterrâneo Sustentabilidade Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais masterThesis 2020 ftunivalgarve 2022-05-30T08:49:33Z Aquifers are a fundamental source of freshwater, yet they are particularly vulnerable in coastal Mediterranean regions due to climate and anthropogenic pressures. This comparative study examines the interrelationships between ocean-atmosphere teleconnections, groundwater levels and precipitation in coastal aquifers of California and Portugal, deepening the understanding of climate variability coupling behaviors across mirrored Mediterranean climates. Piezometric and precipitation records (1982-2019) are analyzed using singular spectral analysis, wavelet transform and lag correlation methods. Additionally, the development of a groundwater sustainability index (GSI) exposes vulnerability to drought and provides useful insights for future groundwater management and security. Singular spectral analysis identify signals consistent with the six dominant climate patterns, the Pacific Decadal Oscillation (PDO), the El Niño-Southern Oscillation (ENSO), and the Pacific/North American Oscillation (PNA) in California, and the North Atlantic Oscillation (NAO), the Eastern Atlantic Oscillation (EA) and the Scandinavian Pattern (SCAND) in Portugal. Lower frequency oscillations have a greater influence on hydrologic patterns, with PDO (52.75%) and NAO (46.25%) accounting for the largest amount of groundwater level variability. Wavelet coherences show non-stationary covariability between climate patterns and groundwater levels in distinct period bands; 4-8 years for PDO, 2-4 years for ENSO, 1-2 years for PNA, 5-8 years for NAO, 2-4 years for EA and 2-8 years for SCAND, presenting some dispersion of the low frequency signals. Wavelet coherence patterns also show that coupled climate patterns (NAO+ EA- and paired PDO and ENSO phases) are associated with major drought periods in both regions. Finally, the GSI classify highly vulnerable and low sustainability aquifers in southern California and in northern Portugal, warranting further policy and mitigation measures in these at-risk areas. The current work shows how pairing ... Master Thesis North Atlantic North Atlantic oscillation Universidade do Algarve: Sapienta Pacific |
institution |
Open Polar |
collection |
Universidade do Algarve: Sapienta |
op_collection_id |
ftunivalgarve |
language |
English |
topic |
Água subterrânea Variabilidade climática Aquíferos costeiros Mediterrâneo Sustentabilidade Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais |
spellingShingle |
Água subterrânea Variabilidade climática Aquíferos costeiros Mediterrâneo Sustentabilidade Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais Malmgren, Katherine Allise Coastal groundwater response to climate variability coupling in California and Portugal |
topic_facet |
Água subterrânea Variabilidade climática Aquíferos costeiros Mediterrâneo Sustentabilidade Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais |
description |
Aquifers are a fundamental source of freshwater, yet they are particularly vulnerable in coastal Mediterranean regions due to climate and anthropogenic pressures. This comparative study examines the interrelationships between ocean-atmosphere teleconnections, groundwater levels and precipitation in coastal aquifers of California and Portugal, deepening the understanding of climate variability coupling behaviors across mirrored Mediterranean climates. Piezometric and precipitation records (1982-2019) are analyzed using singular spectral analysis, wavelet transform and lag correlation methods. Additionally, the development of a groundwater sustainability index (GSI) exposes vulnerability to drought and provides useful insights for future groundwater management and security. Singular spectral analysis identify signals consistent with the six dominant climate patterns, the Pacific Decadal Oscillation (PDO), the El Niño-Southern Oscillation (ENSO), and the Pacific/North American Oscillation (PNA) in California, and the North Atlantic Oscillation (NAO), the Eastern Atlantic Oscillation (EA) and the Scandinavian Pattern (SCAND) in Portugal. Lower frequency oscillations have a greater influence on hydrologic patterns, with PDO (52.75%) and NAO (46.25%) accounting for the largest amount of groundwater level variability. Wavelet coherences show non-stationary covariability between climate patterns and groundwater levels in distinct period bands; 4-8 years for PDO, 2-4 years for ENSO, 1-2 years for PNA, 5-8 years for NAO, 2-4 years for EA and 2-8 years for SCAND, presenting some dispersion of the low frequency signals. Wavelet coherence patterns also show that coupled climate patterns (NAO+ EA- and paired PDO and ENSO phases) are associated with major drought periods in both regions. Finally, the GSI classify highly vulnerable and low sustainability aquifers in southern California and in northern Portugal, warranting further policy and mitigation measures in these at-risk areas. The current work shows how pairing ... |
author2 |
Neves, Maria C. Gurdak, Jason |
format |
Master Thesis |
author |
Malmgren, Katherine Allise |
author_facet |
Malmgren, Katherine Allise |
author_sort |
Malmgren, Katherine Allise |
title |
Coastal groundwater response to climate variability coupling in California and Portugal |
title_short |
Coastal groundwater response to climate variability coupling in California and Portugal |
title_full |
Coastal groundwater response to climate variability coupling in California and Portugal |
title_fullStr |
Coastal groundwater response to climate variability coupling in California and Portugal |
title_full_unstemmed |
Coastal groundwater response to climate variability coupling in California and Portugal |
title_sort |
coastal groundwater response to climate variability coupling in california and portugal |
publishDate |
2020 |
url |
http://hdl.handle.net/10400.1/15209 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
http://hdl.handle.net/10400.1/15209 202652114 |
op_rights |
openAccess http://creativecommons.org/licenses/by/4.0/ |
op_rightsnorm |
CC-BY |
_version_ |
1766135897173000192 |