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The diurnal cycle of precipitation and its associated land‐sea breeze circulation over coastal northern Australia are investigated using surface wind speed and enthalpy (latent and sensible heat) fluxes from the Cyclone Global Navigation Satellite System. Composite results during the austral summer of 2018–2022 show that diurnal precipitation propagates westward from the Cape York Peninsula into the Gulf of Carpentaria. The diurnal cycle of precipitation and surface wind speed are strongly coupled, with the wind speed maximum slightly leading the precipitation maximum. Additionally, analysis of the moist static energy budget shows that surface fluxes help support the westward‐propagation of diurnal precipitation. These results—based on novel satellite data and reanalysis—are consistent with previous studies that have examined the impact of the land‐sea breeze on the diurnal cycle of precipitation. The results provide a benchmark for model representation of this important atmosphere‐ocean‐land interaction. Plain Language Summary: The modulation of the diurnal cycle of precipitation over coastal northern Australia by surface winds was studied using the recently launched NASA Cyclone Global Navigation Satellite System (CYGNSS). Results show a strong connection between the daily cycles of precipitation and surface wind speed, with an offshore wind speed maximum leading the precipitation maximum by a few hours. Westward propagation of diurnal precipitation and wind speed signals occurs from the Cape York Peninsula into the Gulf of Carpentaria. A thermodynamic analysis supports the importance of the wind speed signal and associated surface fluxes for fostering offshore precipitation propagation. The novelty of this paper lies in the use of the new CYGNSS retrievals, which provide better space and time coverage of surface wind speed than previous satellite‐based measurements and are not as negatively affected by precipitation contamination. Key Points: Cyclone Global Navigation Satellite System wind speeds and latent heat fluxes are used to study the diurnal cycle over the northern Australia coastal regionEnhanced diurnal precipitation is associated with enhanced surface wind speed and convergenceDiurnal precipitation and surface wind speed signals propagate westward in tandem from the Cape York Peninsula [ABSTRACT FROM AUTHOR]

The relationship between the seasonal Antarctic sea ice concentration (SIC) variability and the extratropical southern Indian Ocean (SIO) sea surface temperature (SST) is explored in this study. It is found that the Antarctic SIC in a wide band of the SIO, Ross Sea, and Weddell Sea is significantly related to an SIO dipole (SIOD) SST anomaly on the interannual time scale during austral spring. This relationship is linearly independent of the effects of El Niño–Southern Oscillation, the Indian Ocean dipole, and the Southern Hemisphere annular mode. The positive phase of the SIOD, with warm SST anomalies off of western Australia and cold SST anomalies centered around 60°E in high latitudes, stimulates a downstream wave train that induces large-scale cyclonic circulations over the SIO and the Ross and Weddell Seas. Subsequently, anomalous horizontal moisture advection causes water vapor divergence, changes the surface energy budget, and cools the underlying ocean, which leads to the increased SIC over the region in the SIO, Ross Sea, and Weddell Sea. This SIOD SST anomaly reached a record low during the austral spring of 2016 and promoted the prominent wave pattern at high latitudes, contributing to the dramatic decline of sea ice in the 2016 spring. In addition, the proportion of the SIC trend that is linearly congruent with the SIOD SST trend during austral spring is quantified. The results indicate that the trend in the SIOD SST may account for a significant component of the 1979–2014 SIC trend in the Ross Sea with the congruency peaking at 60%. [ABSTRACT FROM AUTHOR]