Variability and changes in Pearl River Delta water level: oceanic and atmospheric forcing perspectives

Feng, Xiangbo; Zhang, Wei; Zhu, Zhenglei; Chevuturi, Amulya ORCID: https://orcid.org/0000-0003-2815-7221; Chen, Wenlong. 2021 Variability and changes in Pearl River Delta water level: oceanic and atmospheric forcing perspectives. Journal of Hydrometeorology, 22 (9). 2407-2422. 10.1175/JHM-D-21-0037.1

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Official URL: http://dx.doi.org/10.1175/JHM-D-21-0037.1

Abstract/Summary

Understanding water level (WL) fluctuations in river deltas is of importance for managing water resources and minimizing the impacts of floods and droughts. Here, we demonstrate the competing effects of atmospheric and oceanic forcing on multi-timescale variability and changes in the Pearl River Delta (PRD) WLs in southern China, using 52 years (1961–2012) of in-situ observations at 13 hydrological stations. PRD WL presents significant seasonal to decadal variations, with large amplitudes upstream related to strong variability of southern China rainfall, and with relatively small amplitudes at the coastal stations determined by sea level (SL) fluctuations of the northern South China Sea. We find that the strengths of atmospheric and oceanic forcing in PRD are not mutually independent, leading to a distinct contrast of WL–forcing relationships at upstream and coastal stations. In the transition zone, because of counteracts of atmospheric and oceanic forcing, no robust relationships are identified between WL and either of the forcing. We further show that in the drought season of the warm ENSO and PDO epochs, the effect of atmospheric (oceanic) forcing on PRD WL is largely enhanced (weakened), due to increased southern China rainfall and negative SL anomalies. Over the observation period, WL significantly decreased at upstream stations, by up to 28–42 mm/year for flood season, contrasting with the upward trends of <4.3 mm/year at coastal stations across all seasons. Southern China rainfall explains little of the observed WL trends, whilst SL rise is mostly responsible for the WL trends at coastal stations.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1175/JHM-D-21-0037.1
UKCEH and CEH Sections/Science Areas:	Water Resources (Science Area 2017-)
ISSN:	1525-755X
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
Additional Keywords:	rivers, climate variability, hydrologic cycle, hydrometeorology, interannual variability, interdecadal variability, seasonal cycle, trends
NORA Subject Terms:	Hydrology
Date made live:	10 Aug 2021 11:02 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/530862

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1175/JHM-D-21-0037.1

UKCEH and CEH Sections/Science Areas:

Water Resources (Science Area 2017-)

ISSN:

1525-755X

Additional Information. Not used in RCUK Gateway to Research.:

Open Access paper - full text available via Official URL link.

Additional Keywords:

rivers, climate variability, hydrologic cycle, hydrometeorology, interannual variability, interdecadal variability, seasonal cycle, trends