Coastal estuarine systems, vital for ecological health and economic stability, are highly vulnerable to extreme weather events such as hurricanes, which can profoundly alter fundamental properties, including salinity. This study addresses the critical need to understand these rapid changes by assessing the impact of Hurricane Nate (October 2017) on coastal salinity dynamics in the Pascagoula River estuary and the Mississippi Sound, USA. Hurricane-induced salinity fluctuations pose significant risks to estuarine ecosystems and coastal communities, yet their spatiotemporal dynamics remain poorly understood. We analyzed European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite sea surface salinity in combination with in-situ observations, using spatial autocorrelation analysis across pre-storm (September 1 – October 6, 2017), during-storm (October 7–11, 2017), and post-storm (October 12–31, 2017) phases. SMOS was selected over NASA’s Soil Moisture Active Passive (SMAP) based on its stronger and more coherent spatial clustering patterns. Hurricane Nate caused a three-stage salinity response: (1) landfall disruption with spatial heterogeneity on October 8 (2), basin-wide freshening to ~ 19.5–20.5 ppt by October 11 producing extensive low-salinity clusters, and (3) recovery with transient above-baseline rebound reaching ~ 23–24 ppt by October 19. Pixel-wise correlation analysis identified dominant hydrological drivers with spatially-variable influence. During the hurricane, Pascagoula River discharge exerted extremely strong negative control over salinity (r = -0.971, p < 0.05), with pixel-level correlations ranging from − 0.999 to -0.904 across the estuary, while Biloxi precipitation showed strong positive correlation (r = + 0.778, p < 0.05) reflecting temporal lag effects between rainfall timing and discharge-driven freshening. Pré-storm correlations were moderate and discharge-dominated (Pascagoula River r = -0.476, p < 0.05), while post-storm correlations weakened substantially (r = -0.351, p < 0.05) as freshwater forcing diminished during recovery. Overall, this integrated satellite-in-situ framework effectively captured rapid salinity changes and their controlling hydrological mechanisms, providing critical insights for predicting estuarine responses to extreme events and informing adaptive coastal management strategies under increasing climate variability. Graphical Abstract This visual summary serves as a pivotal entry point into the research, offering a concise overview of the study’s core findings and methodologies, designed to attract attention, facilitate rapid comprehension, and ultimately, promote the dissemination of scientific knowledge. Our study investigates the impact of Hurricane Nate (October 2017) on coastal salinity dynamics in the Mississippi Sound and the Pascagoula River estuary. Data utilized includes satellite-derived sea surface salinity from ESA’s Soil Moisture and Ocean Salinity (SMOS) mission, in-situ observations from USGS stations, USGS River discharge, and NOAA precipitation data. For Analyses, we employed spatial correlation (Pearson’s coefficient), Global Moran’s I, and Local Indicators of Spatial Association (LISA). The Model applied is an integrated satellite-in-situ framework for bias correction and comprehensive spatial analysis. Key Results reveal a three-stage salinity response: an initial spike at landfall, followed by widespread freshening primarily driven by the Pascagoula River discharge, then recovery with transient above-baseline rebound, while other hydrological inputs showed complex positive correlations during the storm peak. Pre-storm conditions exhibited moderate negative correlations with discharge, which rapidly weakened post-storm. In Conclusion, this integrated framework effectively captures the spatial variability and rapid evolution of estuarine salinity during extreme environmental events, providing valuable insights for coastal monitoring and enhancing resilience to environmental hazards.

Satellite-derived Salinity Dynamics in the Mississippi Sound: A Hurricane Nate Case Study

期刊论文
发表日期：

2026年2月11日

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Aashish Gautam,
Zaid Mustafa,
Rocky Talchabhadel

摘要

Coastal estuarine systems, vital for ecological health and economic stability, are highly vulnerable to extreme weather events such as hurricanes, which can profoundly alter fundamental properties, including salinity. This study addresses the critical need to understand these rapid changes by assessing the impact of Hurricane Nate (October 2017) on coastal salinity dynamics in the Pascagoula River estuary and the Mississippi Sound, USA. Hurricane-induced salinity fluctuations pose significant risks to estuarine ecosystems and coastal communities, yet their spatiotemporal dynamics remain poorly understood. We analyzed European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite sea surface salinity in combination with in-situ observations, using spatial autocorrelation analysis across pre-storm (September 1 – October 6, 2017), during-storm (October 7–11, 2017), and post-storm (October 12–31, 2017) phases. SMOS was selected over NASA’s Soil Moisture Active Passive (SMAP) based on its stronger and more coherent spatial clustering patterns. Hurricane Nate caused a three-stage salinity response: (1) landfall disruption with spatial heterogeneity on October 8 (2), basin-wide freshening to ~ 19.5–20.5 ppt by October 11 producing extensive low-salinity clusters, and (3) recovery with transient above-baseline rebound reaching ~ 23–24 ppt by October 19. Pixel-wise correlation analysis identified dominant hydrological drivers with spatially-variable influence. During the hurricane, Pascagoula River discharge exerted extremely strong negative control over salinity (r = -0.971, p < 0.05), with pixel-level correlations ranging from − 0.999 to -0.904 across the estuary, while Biloxi precipitation showed strong positive correlation (r = + 0.778, p < 0.05) reflecting temporal lag effects between rainfall timing and discharge-driven freshening. Pré-storm correlations were moderate and discharge-dominated (Pascagoula River r = -0.476, p < 0.05), while post-storm correlations weakened substantially (r = -0.351, p < 0.05) as freshwater forcing diminished during recovery. Overall, this integrated satellite-in-situ framework effectively captured rapid salinity changes and their controlling hydrological mechanisms, providing critical insights for predicting estuarine responses to extreme events and informing adaptive coastal management strategies under increasing climate variability.

Graphical Abstract

This visual summary serves as a pivotal entry point into the research, offering a concise overview of the study’s core findings and methodologies, designed to attract attention, facilitate rapid comprehension, and ultimately, promote the dissemination of scientific knowledge. Our study investigates the impact of Hurricane Nate (October 2017) on coastal salinity dynamics in the Mississippi Sound and the Pascagoula River estuary. Data utilized includes satellite-derived sea surface salinity from ESA’s Soil Moisture and Ocean Salinity (SMOS) mission, in-situ observations from USGS stations, USGS River discharge, and NOAA precipitation data. For Analyses, we employed spatial correlation (Pearson’s coefficient), Global Moran’s I, and Local Indicators of Spatial Association (LISA). The Model applied is an integrated satellite-in-situ framework for bias correction and comprehensive spatial analysis. Key Results reveal a three-stage salinity response: an initial spike at landfall, followed by widespread freshening primarily driven by the Pascagoula River discharge, then recovery with transient above-baseline rebound, while other hydrological inputs showed complex positive correlations during the storm peak. Pre-storm conditions exhibited moderate negative correlations with discharge, which rapidly weakened post-storm. In Conclusion, this integrated framework effectively captures the spatial variability and rapid evolution of estuarine salinity during extreme environmental events, providing valuable insights for coastal monitoring and enhancing resilience to environmental hazards.