Climate and terrestrial carbon cycle responses to the two types of El Niño events
The El Niño-Southern Oscillation (ENSO) is classified into Central Pacific (CP) and Eastern Pacific (EP) types based on the spatial distribution of sea surface temperature (SST) anomaly centers, which correspond to the quasi-biennial (QB) and quasi-quadrennial (QQ) modes of ENSO SST variability, res...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
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| Series: | Environmental Research Communications |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/2515-7620/ade75f |
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| Summary: | The El Niño-Southern Oscillation (ENSO) is classified into Central Pacific (CP) and Eastern Pacific (EP) types based on the spatial distribution of sea surface temperature (SST) anomaly centers, which correspond to the quasi-biennial (QB) and quasi-quadrennial (QQ) modes of ENSO SST variability, respectively. The interannual variability of the atmospheric CO _2 growth rate (CGR) is primarily influenced by terrestrial carbon flux anomalies, with ENSO-induced climate change serving as the key driver of these anomalies. In this study, we first apply the Morlet wavelet time-frequency spectrum to elucidate the time-varying characteristics of significant periodic signals in the Oceanic Niño Index (ONI) and CGR time series within the 2–7 year frequency band. Subsequently, we employ a recently proposed spectral analysis method—Hankel Spectral Analysis (HSA)—to extract the periodic and quasi-periodic signals of ONI and CGR more precisely, revealing a strong coupling between their sub-signals at multiple time scales (24–26, 28–32, 40–45, and 58–70 months). Additionally, we utilize the Climatic Research Unit gridded Time Series (CRT TS) and the process-based terrestrial carbon flux model FLUXCOM to map the spatial response patterns of temperature, precipitation, and terrestrial carbon flux anomalies to both types of El Niño. The results indicate that ENSO’s influence on terrestrial carbon flux anomalies is primarily concentrated in tropical regions, with the QQ mode exhibiting stronger spatial consistency in positive correlation with terrestrial carbon flux, particularly in South America, Africa, Australia, and Southeast Asia. In contrast, the correlation between the QB mode and interannual carbon flux anomalies aligns with the QQ mode in northern South America, southern Africa, and northern Australia but shows a negative correlation in parts of Australia and central Africa. These differences in correlation are also evident in the spatial distribution of climate responses to the two types of ENSO. |
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| ISSN: | 2515-7620 |