Biological and Environmental Research - Earth and Environmental System Sciences
Earth and Environmental System Modeling

Flood Inundation Generation Mechanisms and Their Changes in 1953–2004 in Global Major River Basins

TitleFlood Inundation Generation Mechanisms and Their Changes in 1953–2004 in Global Major River Basins
Publication TypeJournal Article
Year of Publication2019
AuthorsMao, Yuna, Zhou Tian, L. Leung Ruby, Tesfa Teklu K., Li Honga-Yi, Wang Kaicun, Tan Zeli, and Getirana Augusto
JournalJournal of Geophysical Research: Atmospheres
Volume124
Number22
Pages11672-11692
Abstract / Summary

Despite the serious threats posed by floods, the driving mechanisms of floods are still not well understood. Here we apply a physically based inundation model coupled with a river routing model (Model for Scale Adaptive River Transport (MOSART)) within the Energy Exascale Earth System Model (E3SM) framework to investigate flood inundation dynamics. After calibration using observed streamflow and satellite‐derived flood extent, the model is used to simulate global flood inundation from 1953 to 2004. The mean date and seasonality of annual maximum flood, defined based on flood extent, exhibit significant regional differences across 16 major basins. Generally, soil moisture and monthly maximum daily rainfall (MMR) are the dominant drivers of flood in tropical basins while monthly maximum daily snowmelt (MMS) is the dominant driver in high‐latitude basins. From 1953–1982 to 1975–2004, significant changes in flood generation mechanisms are found in some basins such as Amazon, Lena, Yenisey, and Kolyma. Analysis of the rainfall seasonality and water balance at grid scale reveals a stronger rainfall seasonality in the Amazon during the later period that increases the synchrony between extreme rainfall and wet soil. With high antecedent soil moisture coinciding with rainfall, MMR contributes more to flood in the later period. Fewer extreme rainfall events and increasing soil moisture reduced the contribution of MMR and increased the role of MMS in floods in the Lena and Yenisey basins, respectively. Lastly, increased soil moisture and frequency of large MMS reduced the contribution of the latter to floods in the Kolyma basin.

URLhttp://dx.doi.org/10.1029/2019jd031381
DOI10.1029/2019jd031381
Journal: Journal of Geophysical Research: Atmospheres
Year of Publication: 2019
Volume: 124
Number: 22
Pages: 11672-11692
Publication Date: 11/2019

Despite the serious threats posed by floods, the driving mechanisms of floods are still not well understood. Here we apply a physically based inundation model coupled with a river routing model (Model for Scale Adaptive River Transport (MOSART)) within the Energy Exascale Earth System Model (E3SM) framework to investigate flood inundation dynamics. After calibration using observed streamflow and satellite‐derived flood extent, the model is used to simulate global flood inundation from 1953 to 2004. The mean date and seasonality of annual maximum flood, defined based on flood extent, exhibit significant regional differences across 16 major basins. Generally, soil moisture and monthly maximum daily rainfall (MMR) are the dominant drivers of flood in tropical basins while monthly maximum daily snowmelt (MMS) is the dominant driver in high‐latitude basins. From 1953–1982 to 1975–2004, significant changes in flood generation mechanisms are found in some basins such as Amazon, Lena, Yenisey, and Kolyma. Analysis of the rainfall seasonality and water balance at grid scale reveals a stronger rainfall seasonality in the Amazon during the later period that increases the synchrony between extreme rainfall and wet soil. With high antecedent soil moisture coinciding with rainfall, MMR contributes more to flood in the later period. Fewer extreme rainfall events and increasing soil moisture reduced the contribution of MMR and increased the role of MMS in floods in the Lena and Yenisey basins, respectively. Lastly, increased soil moisture and frequency of large MMS reduced the contribution of the latter to floods in the Kolyma basin.

DOI: 10.1029/2019jd031381
Citation:
Mao, Y, T Zhou, L Leung, T Tesfa, H Li, K Wang, Z Tan, and A Getirana.  2019.  "Flood Inundation Generation Mechanisms and Their Changes in 1953–2004 in Global Major River Basins."  Journal of Geophysical Research: Atmospheres 124(22): 11672-11692.  https://doi.org/10.1029/2019jd031381.