1. Cloud and Precipitation Variability Associated With the Madden‐Julian Oscillation Over the Maritime Continent.
- Author
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Shige, S., Kato, F., and Aoki, S.
- Subjects
MADDEN-Julian oscillation ,PRECIPITATION variability ,CLOUDINESS ,PRECIPITATION anomalies ,STRATUS clouds ,RAIN gauges - Abstract
This study reexamines cloud and precipitation variability associated with the Madden‐Julian Oscillation (MJO) over the Maritime Continent (MC), mainly using data acquired in 1998–2013 by the Tropical Rainfall Measuring Mission satellite. Infrared data indicated uniform, moderately deep stratiform cloud cover over the MC during MJO active phases, suggesting that an apparent MJO bypass of Borneo and New Guinea, observed in the brightness temperature anomaly distribution, was an artifact of climatologically low average brightness temperatures above the islands. Although previous satellite precipitation products indicated negligible anomalies over Borneo during MJO active phases, we identified positive precipitation anomalies in precipitation radar data and other recent satellite products. We hypothesize that previous satellite precipitation data products underestimated stratiform precipitation over Borneo during MJO active phases because ice‐particle scattering was weak. This is consistent with the moderately deep stratiform cloud layer identified from infrared data. Plain Language Summary: In this study, we investigated cloud and precipitation over the Maritime Continent, the region comprising thousands of islands between the Indian and Pacific Oceans, associated with a tropical intraseasonal oscillation propagating eastward along the equator. Previous studies reported that clouds associated with this oscillation apparently bypassed Borneo and New Guinea. Our analysis showed that the climatologically averaged cloud height over Borneo and New Guinea reached higher altitudes than in the surrounding areas. Previous satellite precipitation data products did not indicate notable rainfall variations over Borneo during active phases. However, analyzing more recent data from satellite instruments, including from a precipitation radar, we identified positive precipitation anomalies. This suggests that previous satellite data products underestimated widespread weak precipitation over Borneo during the active phases of the tropical intraseasonal oscillation, probably because scattering by ice particles was weak. Key Points: Bypass of the Maritime Continent by the Madden‐Julian Oscillation seen in brightness temperature anomaly is a climatology‐induced artifactPrevious satellite precipitation products underestimated Madden‐Julian Oscillation precipitation anomalies over the Maritime ContinentThe conventional understanding of processes governing cloud and precipitation variability over the Maritime Continent must be updated [ABSTRACT FROM AUTHOR]
- Published
- 2023
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