Diurnal cycle of precipitation over global monsoon systems in CMIP6 simulations
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Brookhaven National Lab. (BNL), Upton, NY (United States)
Accurate simulation of the diurnal cycle of precipitation over different climate regimes, including global monsoon systems, is an ongoing challenge for current state-of-the-art climate models. Here, in this study, the diurnal cycles of summertime precipitation from 21 CMIP6 historical simulations are evaluated with the NASA IMERG data via the diurnal harmonic amplitude and phase from the Fourier analysis in seven regional monsoon systems: Northern and Southern Africa monsoons, South Asia monsoon, East Asia monsoon, Australia monsoon, and North and South America monsoons. Particularly, we focus on four subregions including ocean, coastal ocean, land, and coastal land considering the different underlying physical processes. It is found that the CMIP6 historical simulations perform fairly well on reproducing the diurnal cycle of precipitation over ocean and coastal ocean, while the simulated diurnal harmonic phase and amplitude over land and coastal land show larger biases and model spread compared to biases over ocean and coastal ocean. The simulation of precipitation diurnal cycle is substantially improved in the multi-model mean of both CMIP6 historical and CMIP6 AMIP simulations compared with that of CMIP5 historical simulations. But the model bias of precipitation diurnal cycle is in general similar between CMIP6 AMIP and CMIP6 historical simulations, which suggests that the impact of the interactive ocean on the simulated diurnal precipitation averaged over a large domain is generally minor. The influence of model resolution on the diurnal cycle is shown in mixed directions across various subregions, and significant improvement from the low- to high-resolution models is only notable over coastal ocean.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Laboratory Directed Research and Development (LDRD) Program
- Contributing Organization:
- Lawrence Livermore National Laboratory (LLNL); Pacific Northwest National Laboratory (PNNL); Brookhaven National Laboratory (BNL); Argonne National Laboratory (ANL)
- Grant/Contract Number:
- AC52-07NA27344; AC05-76RL01830; SC0012704
- OSTI ID:
- 1972036
- Alternate ID(s):
- OSTI ID: 1899058; OSTI ID: 1900387
- Report Number(s):
- LLNL-JRNL-825946; BNL-223724-2022-JAAM; 1040168
- Journal Information:
- Climate Dynamics, Vol. 60; ISSN 0930-7575
- Publisher:
- Springer-VerlagCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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