| Autor: |
Zhang, Juan1,2 (AUTHOR), Feng, Ziyang1 (AUTHOR), Niu, Jie1,3 (AUTHOR) jniu@jnu.edu.cn, Melack, John M.4 (AUTHOR), Zhang, Jin1,3,5 (AUTHOR), Qiu, Han6 (AUTHOR), Hu, Bill X.3,7 (AUTHOR), Riley, William J.8 (AUTHOR) |
| Abstrakt: |
The relationships and seasonal‐to‐annual variations among evapotranspiration (ET), precipitation (P), terrestrial water storage anomalies (TWSA), radiation (downward shortwave radiation, DSR), and phenology (leaf area index, LAI) are complex across the Amazon basin. To analyze how ET is controlled by these influencing factors, we used wavelet phase difference (WPD) to investigate the effects of P, TWSA, DSR, and LAI on ET at different spatiotemporal scales. The Amazon‐scale averaged ET has strong correlations with these factors at the annual and multi‐year periodicities. The patterns of WPDs have south‐north and west‐east divides due to the significant variation in climatic conditions. The results demonstrate that ET is mainly affected by water and energy availability while vegetation regulates both processes. The deep soil moisture/groundwater can provide strong subsidies to ET during the meteorological dry season in the water‐limited area of Amazon. The WPD can well reflect the responses of ET to the variations of P, TWSA, DSR, and LAI, and the process of vegetation sustaining ET in the dry years in the water‐limited area of the Amazon. Plain Language Summary: Evapotranspiration in the Amazon basin is essential for studying the global water cycle. Regional differences and climate change have exacerbated the complexity of the water cycle process, making the temporal and spatial changes of evapotranspiration in the Amazon basin and the relative contribution rates of multiple driving factors to its process uncertain. In this study, we analyze the relationships between precipitation, terrestrial water storage, radiation or vegetation, and evapotranspiration at different temporal and spatial scales by the wavelet phase difference. This method well reflects how these influencing factors affect the evapotranspiration process in the case of interaction. When a drought year arrives, precipitation and deep soil moisture/groundwater provide water to maintain evapotranspiration at the same time. The recharge of deep soil moisture/groundwater for evapotranspiration weakens when the area is no longer restricted by water. Drought events will intensify the impact of deep soil moisture/groundwater on evapotranspiration in the water‐limited area. We also show that the relationships between precipitation, terrestrial water storage anomalies, radiation or leaf area index, and evapotranspiration have a north‐south and west‐east difference pattern. The wavelet phase difference can provide an effective theoretical basis for the study of the factors driving the evapotranspiration of the entire Amazon basin. Key Points: Analyze the effects of precipitation, total water storage anomaly, radiation, and vegetation on ET using the wavelet coherence phaseThe phase patterns have a south‐north and west‐east divide due to significant variation in the climatic conditions of the AmazonDrought events are closely related to controls of ET by P, TWSA, DSR, and LAI [ABSTRACT FROM AUTHOR] |
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