ENSO 기간 전 지구 해수면 변화 특징
Characteristics of Global Sea Level Changes during ENSO periods
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Natural climate variability, such as El Niño and La Niña, can result global sea levels rise or fall over several months, which leads to rapid sea level changes in coastal areas. Thus, it is very important to identify the causes of sea level fluctuations during the El Niño-Southern Oscillation (ENSO). In this study, Gravity Recovery and Climate Experiment (GRACE) satellites and reanalysis data based on Array for Real-time Geostrophic Oceano graphy (Argo) from April 2002 to December 2022 were used to identify the characteristics of land mass and ocean density and examine the contribution of each process to Global Mean Sea Level (GMSL) changes during the ENSO period. The results show that the interannual variability of GMSL is highly correlated with ocean mass changes caused by Land Water Storage (LWS), which contributes a larger amount to GMSL than ocean density driven Steric Sea Level (SSL) changes. SSL exhibits significant regional variations, representing the distinct dipole pattern of the tropical Pacific sea levels during the ENSO period. During El Niño period, SSL decreased by about -11 cm in the western tropical Pacific and increased by about 7 cm in the eastern Pacific. In contrast, during La Niña, SSL increased by approximately 10 cm in the tropical western Pacific and decreased by approximately -7 cm in the eastern Pacific. LWS pattern indicated negative anomalies of more than -5 cm in India, eastern China, and northern South America, and positive anomalies of more than ~5 cm in southern China and southeastern South America during El Niño period. During La Niña period, the opposite pattern was observed in these regions. The global LWS and total precipitation showed a high correlation of 0.61 with a lag of 6 months and the land precipitation during the ENSO period exhibited a similar spatial pattern to the LWS. Additionally, we quantified the contribution of LWS to GMSL over the continents. The results showed that Asia has the largest contribution to GMSL rise (39 ± 1.63%) during El Niño, while Africa is the largest contribution to GMSL decrease (53.67 ± 6.13%).
Abstract
Natural climate variability, such as El Niño and La Niña, can result global sea levels rise or fall over several months, which leads to rapid sea level changes in coastal areas. Thus, it is very important to identify the causes of sea level fluctuations during the El Niño-Southern Oscillation (ENSO). In this study, Gravity Recovery and Climate Experiment (GRACE) satellites and reanalysis data based on Array for Real-time Geostrophic Oceano graphy (Argo) from April 2002 to December 2022 were used to identify the characteristics of land mass and ocean density and examine the contribution of each process to Global Mean Sea Level (GMSL) changes during the ENSO period. The results show that the interannual variability of GMSL is highly correlated with ocean mass changes caused by Land Water Storage (LWS), which contributes a larger amount to GMSL than ocean density driven Steric Sea Level (SSL) changes. SSL exhibits significant regional variations, representing the distinct dipole pattern of the tropical Pacific sea levels during the ENSO period. During El Niño period, SSL decreased by about -11 cm in the western tropical Pacific and increased by about 7 cm in the eastern Pacific. In contrast, during La Niña, SSL increased by approximately 10 cm in the tropical western Pacific and decreased by approximately -7 cm in the eastern Pacific. LWS pattern indicated negative anomalies of more than -5 cm in India, eastern China, and northern South America, and positive anomalies of more than ~5 cm in southern China and southeastern South America during El Niño period. During La Niña period, the opposite pattern was observed in these regions. The global LWS and total precipitation showed a high correlation of 0.61 with a lag of 6 months and the land precipitation during the ENSO period exhibited a similar spatial pattern to the LWS. Additionally, we quantified the contribution of LWS to GMSL over the continents. The results showed that Asia has the largest contribution to GMSL rise (39 ± 1.63%) during El Niño, while Africa is the largest contribution to GMSL decrease (53.67 ± 6.13%).