Regionalization of precipitation and associated atmospheric background environmental characteristics over the tropical oceans
[Objective]Precipitation over tropical oceans plays a crucial role in the global energy and water cycle.The oceans provide moisture to the atmosphere through evaporation,and precipitation forms through the condensation of water vapor in the atmosphere.The release of latent heat during the formation of precipitation is a major driver of atmospheric circulation,influencing weather systems and cloud formation.However,there are large differences in the background environments over the tropical oceans.How these differences affect precipitation characteristics and the intrinsic mechanisms involved remain to be investigated.[Methods]In this study,monthly precipitation characterization data from the Tropical Rainfall Measuring Mission(TRMM)spanning from 1998 to 2013 are utilized,including convective precipitation rates,stratiform precipitation rates,convective storm heights,and stratiform storm heights.The European Center for Medium-Range Weather Forecasts fifth generation reanalysis monthly data(ERA5)are also used in this study to provide the atmospheric background environment field.Tropical precipitation regions are classified into five typical types using cluster analysis.The relationship between precipitation types and atmospheric environments is explored through diagnostic variables such as moist static energy and convective available potential energy.[Results]This study elucidates the underlying causes of different precipitation types within critical tropical regions through the perspective of large-scale atmospheric background environments and moist static energy.Notably,precipitation distribution across tropical oceans displays marked spatial heterogeneity,gradually diminishing from the tropics towards extra-equatorial regions.The study classifies the five precipitation types into categories of strong upwelling areas,strong subsidence areas,and weak upwelling zones based on vertical motion profiles.Notably,regions such as the western Pacific warm pool are characterized by robust convective precipitation due to favorable vertical motion and moisture backgrounds.Conversely,areas such as the continental subtropical western coasts exhibit weaker precipitation due to subsidence anomalies and drier atmospheric conditions.In open-ocean regions,precipitation is influenced by moisture anomalies and atmospheric stability,with lower stability and a moister lower and middle atmosphere favoring higher-altitude precipitation formation.These findings provide insight into the typical precipitation characteristics under various circulation backgrounds in the tropics,shedding light on the causes of these features from an environmental perspective.This understanding is pivotal for advancing research on tropical cloud-radiation-sea surface temperature(SST)interactions and their future trajectories.It should be noted that the analysis in this study is based on precipitation characteristics averaged over the period of 1998-2013,and does not take into account the effects of the annual circulation and interannual background(e.g.,El Nino-Southern Oscillation)on precipitation types,which are factors that deserve to be explored in depth in future studies.In this study,a region is categorized as one of the five types of precipitation regions,meaning that the precipitation occurring in the region is dominated by that type.However,multiple types of precipitation often occur simultaneously,but are characterized by the dominance of one precipitation type under the influence of large-scale circulation.Therefore,the proportion of various precipitation types other than the dominant precipitation type and their interrelationships in each region are also worthy of further study,which may provide reference significance for clarifying the occurrence mechanism of tropical convective precipitation.[Conclusions]This study highlights the relationship between the atmospheric background environment and precipitation types over tropical oceans,underscoring the critical influence of the dynamics and thermodynamics of large-scale climatic backgrounds on precipitation types over tropical oceans.Such insights contribute to a deeper understanding of the spatial distribution of precipitation over tropical oceans,which is essential for predicting and responding to the impacts of climate change on the global water cycle and weather patterns.However,other important factors affecting the spatial distribution of tropical precipitation,such as boundary layer convergence,sea surface temperature,and precipitable water,have not been explored in detail.Understanding how these physical processes affect the various types of precipitation represents an additional area of great interest for further study.
tropicconvective precipitationstratiform precipitationstorm heightmoist static energy
万方数据
维普
