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1. Improving Australian Rainfall Prediction Using Sea Surface Salinity

   https://doi.org/10.1175/JCLI-D-20-0625.1  

   Rathore, Saurabh; Bindoff, Nathaniel L.; Ummenhofer, Caroline C.; Phillips, Helen E.; Feng, Ming; Mishra, Mayank (April 2021, Journal of Climate)

   null (Ed.)

   Abstract This study uses sea surface salinity (SSS) as an additional precursor for improving the prediction of summer [December–February (DJF)] rainfall over northeastern Australia. From a singular value decomposition between SSS of prior seasons and DJF rainfall, we note that SSS of the Indo-Pacific warm pool region [SSSP (150°E–165°W and 10°S–10°N) and SSSI (50°–95°E and 10°S–10°N)] covaries with Australian rainfall, particularly in the northeast region. Composite analysis that is based on high or low SSS events in the SSSP and SSSI regions is performed to understand the physical links between the SSS and the atmospheric moisture originating from the regions of anomalously high or low, respectively, SSS and precipitation over Australia. The composites show the signature of co-occurring La Niña and negative Indian Ocean dipole with anomalously wet conditions over Australia and conversely show the signature of co-occurring El Niño and positive Indian Ocean dipole with anomalously dry conditions there. During the high SSS events of the SSSP and SSSI regions, the convergence of incoming moisture flux results in anomalously wet conditions over Australia with a positive soil moisture anomaly. Conversely, during the low SSS events of the SSSP and SSSI regions, the divergence of incoming moisture flux results in anomalously dry conditions over Australia with a negative soil moisture anomaly. We show from the random-forest regression analysis that the local soil moisture, El Niño–Southern Oscillation (ENSO), and SSSP are the most important precursors for the northeast Australian rainfall whereas for the Brisbane region ENSO, SSSP, and the Indian Ocean dipole are the most important. The prediction of Australian rainfall using random-forest regression shows an improvement by including SSS from the prior season. This evidence suggests that sustained observations of SSS can improve the monitoring of the Australian regional hydrological cycle. 

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2. Atmospheric Rivers Linking Tropical Forcing to Winter Precipitation over Southern China

   https://doi.org/10.1175/JCLI-D-26-0035.1  

   Zhang, Yingxian; Ding, Qinghua; Yang, Song; Lu, Mengqian; Zhou, Botao; Liu, Yanju; Chao, Qingchen; Xiao, Chan; Wang, Guofu (June 2026, Journal of Climate)

   Abstract Significant winter [December–February (DJF)] precipitation over southern China (SC) is one of the key features of the East Asian winter monsoon, accounting for nearly 20% of annual precipitation in the area. While oceanic drivers of its interannual variability are extensively studied, the influence of atmospheric rivers (ARs), contributing approximately 30%–40% of the climatological wintertime precipitation in SC, remains unclear. Additionally, how seasonal forecast models capture the impact of tropical sea surface temperature (SST) variations on winter precipitation through ARs requires further investigation using objective metrics. This study identifies a tropical SST pattern involving El Niño–Southern Oscillation (ENSO), the Indian Ocean dipole, and the SST anomalies over the western North Pacific (WNP), whose coevolving structure rapidly develops from the preceding summer to winter. This anomalous SST configuration generates a hemispheric-scale circulation pattern from the tropics to the subtropics, which enhances vertical wind shear and meridional moisture transport over SC, favoring increased AR intrusion into the region. Consequently, significant precipitation anomalies occur particularly near SC along 20°–30°N, explaining over 50% of the interannual DJF precipitation variability. These ENSO-driven precipitation changes, mediated by AR activity, are reasonably predicted by two operational seasonal forecast systems, suggesting that ENSO and its interaction with WNP SST anomalies serve as the primary sources of forecast skill for winter ARs and SC precipitation. Furthermore, a screening scheme based on the observed SST and circulation states during October and November preceding the target winter is developed to determine the years in which the dynamical model forecast skill for SC DJF precipitation is higher than in other winters. Significance StatementA coupling pattern between atmospheric rivers (ARs), accounting for one-third of December–February (DJF) precipitation in climatology, and large-scale circulation plays a critical role in shaping the winter (DJF) precipitation variability in southern China (SC). This mode, characterized by a low pressure anomaly over central China and more active ARs steered into the region, explains at least 50% of the region’s total DJF precipitation variability. El Niño–Southern Oscillation (ENSO), along with related sea surface temperature anomalies in the western North Pacific, acts as the primary driver of this large-scale circulation–AR coupling. As this ENSO-driven process is reasonably well captured by current seasonal forecast systems, this process could be the main source enabling an improved seasonal forecast of SC winter precipitation. 

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3. The interbasin modulation from Indo-Pacific climate modes on the salinity transport through the Malacca Strait

   https://doi.org/10.1186/s40562-025-00415-4  

   Zhao, Zhangzhe; Sprintall, Janet; Du, Yan (December 2025, Geoscience Letters)

   Abstract The Malacca Strait permits salt exchange between the western Pacific Ocean and the Andaman Sea in the northern Indian Ocean. Here, we show a joint inter-basin mechanism that modulates the freshwater exchange through the Malacca Strait using reanalysis and remote sensing datasets. The salinity variation within the Malacca Strait and the southern Andaman Sea is related to both the volume transport and the properties of the source water to the Malacca Strait that all experience interannual variability due to the climate modes from the Indian and Pacific Oceans. On interannual time scales, the Indian Ocean Dipole (IOD)-related anomalous wind pattern prevails in the boreal summer and autumn, acting to modulate the seasonal volume transport of the Malacca Strait such that there is a strengthened (weakened) transport in boreal summer-autumn during positive (negative) IOD events. An atmospheric moisture budget analysis shows that the moisture divergence term governs the source water through the Malacca Strait, with a saltier (fresher) transport during El Niño (La Niña). Taken together, the joint modulation reveals separate contributions from the Pacific and Indian Oceans through interbasin dynamics in governing salinity transport on interannual time scales, suggesting substantial impacts on water properties and exchange through the Malacca Strait. 

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4. The increased frequency of combined El Niño and positive IOD events since 1965s and its impacts on maritime continent hydroclimates

   https://doi.org/10.1038/s41598-022-11663-1  

   Xiao, He-Ming; Lo, Min-Hui; Yu, Jin-Yi (December 2022, Scientific Reports)

   Abstract The Indian and Pacific Oceans surround the Maritime Continent (MC). Major modes of sea surface temperature variability in both oceans, including the Indian Ocean Dipole (IOD) and El Niño–Southern Oscillation (ENSO), can strongly affect precipitation on the MC. The prevalence of fires in the MC is closely associated with precipitation amount and terrestrial water storage in September and October. Precipitation and terrestrial water storage, which is a measurement of hydrological drought conditions, are significantly modulated by Indian Ocean Dipole (IOD) and El Niño events. We utilize long-term datasets to study the combined effects of ENSO and the IOD on MC precipitation during the past 100 years (1900–2019) and find that the reductions in MC precipitation and terrestrial water storage are more pronounced during years when El Niño and a positive phase of the IOD (pIOD) coincided. The combined negative effects are produced mainly through an enhanced reduction of upward motion over the MC. Coincident El Niño-pIOD events have occurred more frequently after 1965. However, climate models do not project a higher occurrence of coincident El Niño-pIOD events in a severely warming condition, implying that not the global warming but the natural variability might be the leading cause of this phenomenon. 

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5. Impact of the mean state on El Niño induced western North Pacific anomalous anticyclone during its decaying summer in AMIP models

   https://doi.org/10.1175/JCLI-D-20-0747.1  

   Wang, Xieyuan; Li, Tim; He, Chao (August 2021, Journal of Climate)

   Abstract Through the diagnosis of 29 Atmospheric Model Inter-comparison Project (AMIP) experiments from the CMIP5 inter-comparison project, we investigate the impact of the mean state on simulated western North Pacific anomalous anticyclone (WNPAC) during El Niño decaying summer. The result indicates that the inter-model difference of the JJA mean precipitation in the Indo-western Pacific warm pool is responsible for the difference of the WNPAC. During the decaying summer of an Eastern Pacific (EP) type El Niño, a model that simulates excessive mean rainfall over the western North Pacific (WNP) reproduces a stronger WNPAC response, through an enhanced local convection-circulation-moisture feedback. The intensity of the simulated WNPAC during the decay summer of a Central Pacific (CP) type El Niño, on the other hand, depends on the mean precipitation over the tropical Indian Ocean. The distinctive WNPAC-mean precipitation relationships between the EP and CP El Niño result from different anomalous SST patterns in the WNP. While the local SST anomaly plays an active role in maintaining the WNPAC during the EP El Niño, it plays a passive role during the CP El Niño. As a result, only the mean-state precipitation/moisture field in the tropical Indian Ocean modulates the circulation anomaly in the WNP in the latter case. 

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