Representations of Precipitation Diurnal Cycle in the Amazon as Simulated by Observationally Constrained Cloud‐System Resolving and Global Climate Models

Journal of Advances in Modeling Earth Systems

Jerome D. Fast¹  Po‐Lun Ma¹  Sheng‐Lun Tai¹  Zhe Feng¹  Courtney Schumacher² 

[1] Atmospheric Sciences and Global Change Division Pacific Northwest National Laboratory Richland WA USA;Department of Atmospheric Sciences Texas A&M University College Station TX USA;

关键词: precipitation;    Amazon;    diurnal cycle;    data assimilation;    mesoscale convective system;    sea breeze;   

DOI  :  10.1029/2021MS002586

来源: DOAJ

【 摘 要 】

Abstract The ability of an observationally‐constrained cloud‐system resolving model (Weather Research and Forecasting; WRF, 4‐km grid spacing) and a global climate model (Energy Exascale Earth System Model; E3SM, 1‐degree grid spacing) to represent the precipitation diurnal cycle over the Amazon basin during the 2014 wet season is assessed. The WRF model coupled with a 3‐D variational data assimilation scheme reproduces the spatial variability of the precipitation diurnal cycle over the basin and the lifecycle of westward propagating MCSs initiated by the coastal sea‐breeze front. In contrast, a single morning peak in rainfall is produced by E3SM for simulations despite the nudging of large‐scale winds toward global reanalysis, indicating precipitation in E3SM is largely controlled by local convection associated with diurnal heating. The role of propagating MCS on the environment are discussed by using a multivariate perturbation analysis. We also find that the advection of moisture perturbations from ocean to inland regions have a higher correlation with the occurrence of MCSs in the Amazon than the intensity of colder air intrusion associated with sea breezes along the coast. Moreover, the presence of large cold pools over the central Amazon basin are responsible for the maintenance of propagating deep convection.

【 授权许可】

Unknown