Land Data Assimilation (DA) System
The Unified Forecast System (UFS) is a community-based, coupled, comprehensive Earth modeling system. It supports multiple applications covering different forecast durations and spatial domains. The UFS Land Data Assimilation (DA) System is an offline version of the Noah Multi-Physics (Noah-MP) land surface model (LSM) used in the UFS Weather Model (WM). Its data assimilation framework uses the Joint Effort for Data assimilation Integration (JEDI) software stack, which includes the Object-Oriented Prediction System (OOPS) for the data assimilation algorithm, the Interface for Observation Data Access (IODA) for observation formatting and processing, and the Unified Forward Operator (UFO) for comparing model forecasts and observations.
The offline Noah-MP LSM is a standalone, uncoupled model used to execute land surface simulations. In this traditional uncoupled mode, near-surface atmospheric forcing data is required as input forcing. This LSM simulates soil moisture (both liquid and frozen), soil temperature, skin temperature, snow depth, snow water equivalent (SWE), snow density, canopy water content, and the energy flux and water flux terms of the surface energy balance and surface water balance. Its data assimilation framework applies the Local Ensemble Transform Kalman Filter-Optimal Interpolation (LETKF-OI) algorithm to combine the state-dependent background error derived from an ensemble forecast with the observations and their corresponding uncertainties to produce an analysis ensemble (Hunt et al., 2007).
- The Land DA repository contains the source code for the Land DA System.
- The Land DA System User’s Guide for the v1.1.0 release can be found here. The User’s Guide for the develop branch can be found here.
- The Land DA Data Bucket contains data for use with the most recent release.
- For an introduction to the repository, see the Land DA wiki and the README.md file.
- The Land DA Docker Hub is a repository of Land DA System container images that users can download. These containers package the Land DA System together with all its software dependencies for an easier experience building and running Land DA.
- JEDI Documentation: The Land DA System uses JEDI code for DA. This documentation contains information about the JEDI code and how to work with it.
- Spack-stack: The required libraries for building the Land DA System are available via spack-stack. Spack-stack provides a Spack-based method for building the software stack required for numerical weather prediction (NWP) tools. Users working on unsupported platforms will need to install the spack-stack on their system following the instructions in the spack-stack User’s Guide.
UFS Development Team. (2023, March 6). Unified Forecast System (UFS) Land Data Assimilation (DA) System (Version v1.0.0). Zenodo. https://doi.org/10.5281/zenodo.7675721
Release Date: 2023-05-25
Release Description: The Land Data Assimilation (DA) System combines the Noah-MP land surface model with data assimilation capabilities into a user-friendly workflow. The Land DA workflow code base is charting a path forward to unify the Noah-MP forecast model with the UFS Weather Model (WM). Updates for this release include the migration of the Land DA System to the ufs-community GitHub space, the addition of a UFS WM build option, modulefile updates to use the spack-stack Unified Environment on Level 1 systems, and DA upgrades to utilize JEDI’s Skylab v3.0 release of the jedi-bundle.
- The Git Actions workflow yaml for the Docker-based build and CTest was turned off due to the limited disk space provided in the Git Actions free runner.
Release Date: 2023-03-06
Release Description: The Land DA System v1.0.0 combines the Noah-MP land surface model with data assimilation capabilities into a user-friendly workflow. The system is documented within the User’s Guide and supported through GitHub Discussions.
Land Data Assimilation (DA) System User’s Guide
This is the documentation for the Land DA System v1.1.0 release branch.
For Land DA topics, users should direct their questions to the land-DA_workflow GitHub Discussions page. Begin a new discussion by selecting “New Discussion” in the Q&A category.
For frequently asked questions about the UFS and associated applications, models, and components, users can refer to EPIC’s Technical FAQs page.