Observation Impact of Moored Buoys in the Eastern Tropical Indian Ocean During Boreal Winter Using Ensemble‐Based Forecast Sensitivity to Observations

Understanding the impact of marine meteorological observations is crucial for improving atmospheric analyzes, particularly in data‐sparse oceanic regions. This study investigated the impact of marine meteorological observations on atmospheric forecasts over the eastern tropical Indian Ocean, using the Ensemble‐based Forecast Sensitivity to Observations (EFSO) technique. 17‐year statistics revealed pronounced seasonality; impacts were significantly greater during boreal winter than in summer, despite comparable observation frequencies. Focusing on moored buoys, the results showed a strong correspondence between observation impacts and the intensity of atmospheric disturbances. High impacts were spatially aligned with eastward‐propagating moist convective disturbances such as the Madden–Julian Oscillation (MJO). The impact of the buoys near 95°E increased across a broad area associated with MJO passage. Even behind the MJO‐active phase, enhanced impacts were detected from small‐scale moist convective disturbances, though their spatial influence was more limited. Observation type comparison revealed that near 95°E, the impact of surface marine observations increased markedly with convective activity, accompanied by enhanced satellite‐derived impacts. Moist energy accounted for the largest share of the total observation impacts, followed by kinetic energy, highlighting the role of near‐surface marine observations in improving the representation of low‐level moisture and wind structures essential for the development of moist atmospheric disturbances.