Unravelling relations between ENSO-related sea-level anomalies and Terrestrial Hydroclimatic Conditions over China

Pengfei Yang, Hok Sum Fok, Bastien Dieppois, Qing He, Zhongtian Ma

Research output: Contribution to journalArticlepeer-review

Abstract

As a key driver of global climate variability, El Niño–Southern Oscillation (ENSO)
significantly impacts the regional hydrological cycle. Similar to the recognized ENSO
monitoring index (i.e., sea surface temperature anomaly), a potential advancement in
the usage of sea level anomaly (SLA) in the equatorial Pacific is expected to enhance
our knowledge of ENSO and its influence on regional terrestrial hydroclimatic
conditions (THCs). In this study, we employed wavelet coherence and multi-channel
singular spectral analysis (MSSA) to investigate the ability of satellite altimetry-based
SLA, and its two major components (i.e., steric SLA (SSL) and non-steric SLA (NSSL))
averaged over Niño 3.4 region, to identify ENSO-related signals. Subsequently, we
explored their spatial association with THCs at interannual scales in China using a
cross-correlation method. We found that the time series of sea surface temperature
anomaly index (SSTaI), SLA index (SLAI), and SSL index (SSLI) displayed good
consistency. SSTaI was found to present higher correlations to SLAI (0.95) and SSLI
(0.94), compared to NSSL index (NSSLI; 0.42). Furthermore, the high (low) wavelet
coherence and in-phase relationship between SSTaI and SLAI/SSLI (NSSLI) was also
revealed. This indicated that SLAI and SSLI may be good complementary indices to
SSTaI in observing ENSO-related signals. Similar to the temporal association of SSTaI
and SLAI/SSLI, their spatial correlation pattern with THCs also displayed consistency.
The time lag characterizing the relationship between SSTaI/SLAI/SSLI and THCs was
also consistent, despite some regional differences. In summary, our results indicated
that the combined analyses of the time lag determined between SSTaI/SLAI/SSLI and
THCs can eventually complement the time lag analysis based solely on SSTaI. This, in
turn, provides a more comprehensive understanding of ENSO's influence on THCs in
China.
Original languageEnglish
JournalJournal of Hydrology
Publication statusSubmitted - 17 Apr 2024

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