About

GRIST（全球-区域一体化预测系统）是用于全球天气、气候建模的一体化数值模型系统。它的开发动机是为了探索模式一体化的可能性，以响应天气-气候一体化模型研发的广泛需求及呼吁。在实践中，由于全球天气和气候模型在应用的空间和时间尺度上存在显著差异，所谓的一体化遵循以下两条路线展开：（i）最大限度地利用单一模型框架和动力内核构建天气和气候模式；（ii）最大限度地使用一套“无缝”模式构造用于与大多数天气-气候预测业务需求相关的应用实践。

GRIST (Global-to-Regional Integrated forecast SysTem) is a unified model system for global weather and climate modeling. It is developed to explore the possibility of unification, in response to a broad need, voice for unified weather and climate modeling. In practice, because global weather and climate modeling differ significantly in terms of their spatial and temporal scales, the so-called unification is pursued following two routes: (i) to maximize the possibility of constructing weather and climate models using a single model framework and dynamical core; (ii) to maximize the possibility of using a unified model formulation with minimum application-specific changes for weather-to-climate forecast applications that are relevant to most operational business demands.

Overview

Multi-purpose global modeling

The multi-purpose modeling capabilities of GRIST are organized in terms of "working mode".

GRIST has 2 major working modes for global three-dimensional atmosphere modeling and forecast:
GRIST-AMIPW: this setup couples GRIST with a high-resolution (down to km-scale) oriented physics suite for weather-to-climate forecast applications.
GRIST-AMIPC: this setup couples GRIST with a comprehensive, long-term climate-modeling oriented physics suite for multi-centries applications.

AMIPW

1. Zhang, Y., R. Yu, J. Li, X. Li, X. Rong, X. Peng, and Y. Zhou, (2021), AMIP Simulations of a Global Model for Unified Weather-Climate Forecast: Understanding Precipitation Characteristics and Sensitivity Over East Asia. Journal of Advances in Modeling Earth Systems, 13(11), e2021MS002592.doi:https://doi.org/10.1029/2021MS002592.
2. Zhou, Y., Y. Zhang, J. Li, R. Yu, and Z. Liu, (2020), Configuration and evaluation of a global unstructured mesh atmospheric model (GRIST-A20.9) based on the variable-resolution approach. Geosci. Model Dev., 13(12), 6325-6348.doi:10.5194/gmd-13-6325-2020.
3. Zhang, Y., X. Li, Z. Liu, X. Rong, J. Li, Y. Zhou, and S. Chen, (2022), Resolution Sensitivity of the GRIST Nonhydrostatic Model from 120 to 5 km (3.75 km) during the DYAMOND winter. Earth and Space Science.
4. 陈苏阳, 张祎, 周逸辉, 李晓涵, 王一鸣, 陈昊明. GRIST模式夏季气候回测试验中东亚降水季节内特征的评估[J]. 气象学报. doi: 10.11676/qxxb2023.20220120.
5. Chen, T., J. Li, Y. Zhang, H. Chen, P. Li, and H. Che, (2023), Evaluation of Hourly Precipitation Characteristics from a Global Reanalysis and Variable-Resolution Global Model over the Tibetan Plateau by Using a Satellite-Gauge Merged Rainfall Product. Remote Sensing, 15(4), 1013.
   ...

AMIPC

1. Li, X., Y. Zhang, X. Peng, W. Chu, Y. Lin, and J. Li, (2022), Improved Climate Simulation by Using a Double-Plume Convection Scheme in a Global Model. Journal of Geophysical Research: Atmospheres, 127(11), e2021JD036069.doi:https://doi.org/10.1029/2021JD036069.
2. Li, Xiaohan,Yi Zhang, Yanluan Lin, Xindong Peng, Baiquan ZHOU, Panmao Zhai, Jian Li. 2022: Impact of a revised trigger-closure of the double-plume convective parameterization on precipitation simulation over East Asia. Adv. Atmos. Sci., https://doi.org/10.1007/s00376-022-2225-9.
3. 李晓涵, 张祎, 林岩銮, 彭新东, 李建. 一套湿物理参数化方案在GRIST全球模式中的应用及其对模式气候的影响[J]. 气象学报. doi: 10.11676/qxxb2023.20230001.
   ...

GRIST has 3 minor working modes, i.e., Shallow Water Model, Single-Column Model, DTP (Dycore-Tracer-Physics) model for isolated testing of individual component.

Dycore-Tracer-Physics (DTP) model

1. Zhang, Y., J. Li, R. Yu, S. Zhang, Z. Liu, J. Huang, and Y. Zhou, (2019), A Layer-Averaged Nonhydrostatic Dynamical Framework on an Unstructured Mesh for Global and Regional Atmospheric Modeling: Model Description, Baseline Evaluation, and Sensitivity Exploration. Journal of Advances in Modeling Earth Systems, 11(6), 1685-1714.doi:10.1029/2018MS001539.
2. Zhang, Y., J. Li, R. Yu, Z. Liu, Y. Zhou, X. Li, and X. Huang, (2020), A Multiscale Dynamical Model in a Dry-Mass Coordinate for Weather and Climate Modeling: Moist Dynamics and Its Coupling to Physics. Monthly Weather Review, 148(7), 2671-2699.doi:10.1175/MWR-D-19-0305.1.
3. Li, J., and Y. Zhang, (2022), Enhancing the stability of a global model by using an adaptively implicit vertical moist transport scheme. Meteorology and Atmospheric Physics, 134(3), 55.doi:10.1007/s00703-022-00895-5.

Shallow Water Model (SWM)

1. Wang, L., Y. Zhang, J. Li, Z. Liu, and Y. Zhou, (2019), Understanding the Performance of an Unstructured-Mesh Global Shallow Water Model on Kinetic Energy Spectra and Nonlinear Vorticity Dynamics. Journal of Meteorological Research, 33(6), 1075-1097.doi:10.1007/s13351-019-9004-2.
2. Zhang, Y., (2018), Extending High-Order Flux Operators on Spherical Icosahedral Grids and Their Applications in the Framework of a Shallow Water Model. Journal of Advances in Modeling Earth Systems, 10(1), 145-164.doi:10.1002/2017MS001088.

Single-Column Model (SCM)

1. Li, X., Zhang, Y., Peng, X., and Li, J.: Using a single column model (SGRIST1.0) for connecting model physics and dynamics in the Global-to-Regional Integrated forecast SysTem (GRIST-A20.8), Geosci. Model Dev. Discuss., 2020, 1-28, 10.5194/gmd-2020-254, 2020.
2. Li, J., X. Peng, X. Li, Y. Lin, and W. Chu, 2021: Evaluation of a Flexible Single Ice Microphysics and a Gaussian Probability-Density-Function Macrophysics Scheme in a Single Column Model. Atmosphere.
3. Li, X., Zhang, Y., Peng, X., Zhou, B., Li, J., and Wang, Y.: Intercomparison of the weather and climate physics suites of a unified forecast/climate model system (GRIST-A22.7.28) based on single column modeling, Geosci. Model Dev. Discuss. [preprint], https://doi.org/10.5194/gmd-2022-283, in review, 2023.

Computing Infrastructure

1. Liu, Z., Zhang, Y., Huang, X., Li, J., Wang, D., Wang, M., and Huang, X.: Development and performance optimization of a parallel computing infrastructure for an unstructured-mesh modelling framework, Geosci. Model Dev. Discuss., 2020, 1-32, 10.5194/gmd-2020-158, 2020.
2. Wang, T., L. Zhuang, J. M. Kunkel, S. Xiao, and C. Zhao, 2020: Parallelization and I/O Performance Optimization of a Global Nonhydrostatic Dynamical Core Using MPI. Computers, Materials & Continua, 63.
3. ...

Unstructured grid

Standardized element and connectivity for grid flexibility

Switchable hydrostatic and nonhydrostatic modeling

With proper configurations, the hydrostatic and nonhydrostatic models of GRIST generate very consistent solutions for relatively coarse grid spacing

Global multi-resolution forecast

Uniform- and Variable-Resolution meshes

7.20 torrential rainfall event, Henan province, China. Forecasts produced by GRIST (HDC: hydrostatic; NDC: nonhydrostaic) The unstructured grid allows GRIST to be configured as a multi-resolution global model, so as to support regional km-scale forecast within a global model.

Applications

GRIST for DYAMOND global storm-resolving simulations

https://easy.gems.dkrz.de/DYAMOND/Winter/index.html

Fig. 2 Experimental global storm-resolving simulations by GRIST Nonhydrostatic Model during the DYAMOND winter. Visualization by Florian Ziemen/ESiWACE2/DKRZ

GRIST for medium-range global weather forecast

Fig. 3 Prototype global 0.125-degree/L60 medium-range NWP configuration of GRIST.

GRIST for conventional global climate modeling

Fig. 4 Cross-lag correlation of outgoing longwave radiation during the boreal winter to reflect MJO's propagation. Conventional global climate simulations at 1-degree.

Learning and working

The 6th PIE developer game:

GRIST is a developmental tool for the 6th PIE developer game.   
There are some educational resources for learning some basics of this model: https://engine.piesat.cn/live-show-list  

Job vacancy:

PIESAT is hiring people related to ALL aspects of numerical weather prediction and earth system modeling,   
including model development, data assimilation, software infrastructure, and AI-based NWP enhancement:  
https://mp.weixin.qq.com/s/2CkcF8YjPx09btDM0l2McA   

TermsAndConditions

The model code can be accessed by anyone who has interest. As a simple registration procedure, please just send a username (github) to [email protected] so as to activate access authority if wanted.