Abstract
Using National Centers for Atmospheric Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data and observational data, the low-frequency oscillation characteristics of precipitation in eastern China during the decaying summer of central Pacific El Niño–Southern Oscillation (CP ENSO) and the corresponding low-frequency atmospheric oscillation characteristic were investigated. The results showed that summer precipitation in eastern China during the decaying year of CP El Niño (La Niña) was more (less) than the climatological mean and that 10–20 d was its dominant period. Low-frequency oscillations at different tropospheric levels had different effects on low-frequency precipitation. In the upper troposphere, Eastern China was dominated by low-frequency divergence and positive (negative) anomaly of low-frequency height during the decaying year of CP El Niño (La Niña), and there was strong (weak) northwest–southeast wave-active flux transport. In the middle troposphere, the range and intensity of the subtropical western Pacific High (SWPH) of CP El Niño was larger and stronger than that of CP La Niña, which may be related to the low-frequency height fields. Meanwhile, the correspnding low-frequency wind field, water vapor circulation systems and moisture transport channels in the lower troposphere, along with the low-frequency vertical movement were significantly different, causing the low-frequency precipitation of CP El Niño to be stronger than CP La Niña.
Highlights
As the strongest signal of global air–sea interaction, the mechanism and climate impacts of theEl Niño–Southern Oscillation (ENSO) have attracted substantial scientific attention [1,2,3,4]
China and research on interactions between atmospheric low-frequency oscillation and the two types of ENSO have been conducted, most of these aimed to reveal the relationship between ENSO and Madden–Julian Oscillation (MJO) or seasonal precipitation in China influenced by ENSO [19,20,21,22]
This study focused on low-frequency precipitation in eastern China during the decaying summer of central Pacific El Niño–Southern Oscillation (CP ENSO)
Summary
As the strongest signal of global air–sea interaction, the mechanism and climate impacts of the. Pointed that ENSO longitudinal positions during decaying phase can result in distinct meridional structures of the tropical Pacific convection anomalies They emphasize that the impacts of CP El Niño on the Spring precipitation over southern China depend crucially on the simultaneous zonal location of warm sea surface-temperature anomalies (SSTAs) in the tropical Pacific. China and research on interactions between atmospheric low-frequency oscillation and the two types of ENSO have been conducted, most of these aimed to reveal the relationship between ENSO and MJO or seasonal precipitation in China influenced by ENSO [19,20,21,22]. This study focused on low-frequency precipitation in eastern China during the decaying summer of CP ENSO. We investigated the evolution features of low-frequency oscillation of the atmosphere, how low-frequency atmospheric change influences low-frequency precipitation and compared the difference between CP El niño and La niña
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