Background

Visualization of Earth system model (ESM) data is a vital step in the scientific process. It can reveal issues and aid analysis in an ESM experiment, but often occurs last due to the time and labor intensive nature of current methods. Currently used visualization methods often involve writing code, in-depth knowledge of software, including complex drivers and interfaces, and produce static, non-interactive images that represent snapshots of data. Furthermore, these methods tend to be niche and specific to a model or data type.

The ASTG provides visualization support to several Earth System Models (ESM), including the GEOS-Chemistry Climate Model (CCM), GEOS-Composite Forecast (CF), the Land Information System (LIS), and the NASA-Unified Weather Research and Forecasting (NU-WRF) model. Our effort includes maintenance and development of visualization software to aid in ESM workflow integration as well as customized plotting solutions to aid ESM experiments. Newer plotting capabilities and simpler methods of execution (innovations in Python visualization), combined with the labor and time intensive nature of the current process, lead to the development of eViz. eViz consists of two tools in one package: a plotting tool (eViz) and an interactive tool (iViz).

The Plotting Tool (eViz)

Maps produced by eViz.

eViz is a python CLI visualization package that features a simple and easy to use interface. Users are not required to write any code as the tool is configurable by YAML file. By offering model specific ESM configuration, eViz is able to produce highly specialized plots, as well as an easy-to-use interface that can be integrated into model workflow or used by those who are not familar with python. Visualizations are Matplotlib based, and the software is capable of comparing and re-gridding data of different sizes, and offers many relevant plot types for investigating ESM experiment results.

The Interactive tool (iViz)

iViz is a highly interactive visualization and exploratory data analysis GUI that produces Bokeh-based plots. The tool is capable of processing NetCDF model data and can be further configured with specialized plots for supported ESM’s. iViz allows comparing and re-gridding files, visualizing many files at once, customizing plots, and exploring data. The tool leverages several modern Python packages, including hvPlot, geoviews, Cartopy, Panel, datashader, and xarray.

The iViz dashboard.

Impact

The eViz plotting tool is extensible and easily integrated into an ESM workflow. It is currently used in GEOS-Composite Forecast (GEOS-CF) experiment workflows and used by the ASTG to provide visualization support for several supported projects, including GEOS-Chemistry Climate Model (GEOS-CCM) and the NASA-Unified Weather Research and Forecasting (NU-WRF) model.

Software

The eViz source code is publicly available in the ASTG SMCE Gitlab repository. The eViz user’s guide is available here. Both tools are installed on the NCCS Discover system, with access to iViz via the JupyterHub platform. Please refer to the user guide for further details on use of the tools on Discover.

Eviz development has been aided by the contributions of ASTG interns Aarav Khanna, Deon Kouatchou-Ngongang and Deepthi Raghunandan.

Background

In stratiform rainstorms, frozen precipitation (snowflakes) melt into rain drops as they fall towards the earth and temperatures rise. Over the span of several decades leading up to the present, a great number of observational and theoretical studies of melting precipitation have been carried out, motivated by the expectation that an improved knowledge of the properties and distributions of melting precipitation could have impacts on weather prediction and other important applications in remote sensing and communication. Explicit descriptions of partially melted hydrometeors in the microphysics schemes of prediction models are a relatively recent development, and improvements in both the representation of melting precipitation and the assimilation of melting-layer-affected reflectivities and radiances are needed.

SnowMeLT

Evolution of melting snowflakes using SnowMeLT.

To study melting precipitation, ASTG has developed and implemented a numerical algorithm, the Snow Meshless Lagrangian Technique (SnowMeLT) that is currently capable of scaling across large clusters and can simulate the evolving properties of fully three-dimensional melting hydrometeors with realistic shapes (snowflakes). NASA scientists have recently developed algorithms to numerically generate synthetic snowflakes that have improved predictive weather models, and a variety of synthetic snowflake shapes are now publicly available in the NASA OpenSSP database. SnowMeLT was used to melt a series of snowflakes from this database that are actively being studied to improve our understanding of melting precipitation. Here we show snapshots of the evolution of a few melting snowflakes from this study.

Publications

• Pelissier, C., Olson, W., Kuo, K. S., Loftus, A., Schrom, R., & Adams, I. (2022). A Physically-based, Meshless Lagrangian Approach to Simulate Melting Precipitation. Journal of the Atmospheric Sciences.

Acknowledgements

This work is funded by the NASA ROSES grant NNH18ZDA001N-PMMST.

TERRAHydro

TERRAHydro gave a featured talk at the 2023 NASA Earth Science Technology Forum ‘Building AI-based Earth Systems Models and the TERRAHydro Terrestrial Digital Twin’

In the last few years, advances in machine-learning-based hydrometeorological models have led to operational models with capabilities that surpass traditional process-based modeling in at least a number of critical applications (e.g. streamflow and flood prediction). Today, there exist machine-learning models of most of the key land surface processes. To take the next step in the evolution of data-driven hydrology, ASTG is assembling these components into a coupled water, energy, and vegetation terrestrial Earth System Digital Twin, the Terrestrial Environmental Rapid-Replicating and Assimilation Hydrometeorological system (TERRAHydro). TERRAHydro aims to advance NASA capabilities with full scale demonstrations targeted for 2025. Stay tuned.

The TERRAHydro project begins in August, 2022.

Acknowledgements

This work is funded by the NASA ROSES grant NNH21ZDA001N-AIST.