4.3. Glossary

The Weather Model configuration that runs only the standalone atmospheric model.

The Common Community Physics Package is a forecast-model agnostic, vetted collection of code containing atmospheric physical parameterizations and suites of parameterizations for use in Numerical Weather Prediction (NWP) along with a framework that connects the physics to the host forecast model.

CDEPS

The Community Data Models for Earth Predictive Systems repository (CDEPS) contains a set of NUOPC-compliant data components and ESMF-based “stream” code that selectively removes feedback in coupled model systems. In essence, CDEPS handles the static Data Atmosphere (DATM) integration with dynamic coupled model components (e.g., MOM6). The CDEPS data models perform the basic function of reading external data files, modifying those data, and then sending the data back to the CMEPS mediator. The fields sent to the mediator are the same as those that would be sent by an active component. This takes advantage of the fact that the mediator and other CMEPS-compliant model components have no fundamental knowledge of whether another component is fully active or just a data component. More information about DATM is available in the CDEPS Documentation.

CESM

The Community Earth System Model (CESM) is a fully-coupled global climate model developed at the National Center for Atmospheric Research (NCAR) in collaboration with colleagues in the research community.

CMEPS

The Community Mediator for Earth Prediction Systems (CMEPS) is a NUOPC-compliant mediator used for coupling Earth system model components. It is currently being used in NCAR’s Community Earth System Model (CESM) and NOAA’s subseasonal-to-seasonal (S2S) coupled system. More information is available in the CMEPS Documentation.

container

Docker describes a container as “a standard unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another.”

cron

cron job

crontab

cron table

Cron is a job scheduler accessed through the command-line on UNIX-like operating systems. It is useful for automating tasks such as regression testing. Cron periodically checks a cron table (aka crontab) to see if any tasks are are ready to execute. If so, it runs them.

cycle

An hour of the day on which a forecast is started. In the Land DA System, it usually follows YYYYMMDD-HHmmss format.

data assimilation

One of the major sources of error in weather and climate forecasts is uncertainty related to the initial conditions that are used to generate future predictions. Even the most precise instruments have a small range of unavoidable measurement error, which means that tiny measurement errors (e.g., related to atmospheric conditions and instrument location) can compound over time. These small differences result in very similar forecasts in the short term (i.e., minutes, hours), but they cause widely divergent forecasts in the long term. Errors in weather and climate forecasts can also arise because models are imperfect representations of reality. Data assimilation systems seek to mitigate these problems by combining the most timely observational data with a “first guess” of the atmospheric state (usually a previous forecast) and other sources of data to provide a “best guess” analysis of the atmospheric state to start a weather or climate simulation. When combined with an “ensemble” of model runs (many forecasts with slightly different conditions), data assimilation helps predict a range of possible atmospheric states, giving an overall measure of uncertainty in a given forecast.

DATM

DATM is the Data Atmosphere component of CDEPS. It uses static atmospheric forcing files (derived from observations or previous atmospheric model runs) instead of output from an active atmospheric model. This reduces the complexity and computational cost associated with coupling to an active atmospheric model. The Data Atmosphere component is particularly useful when employing computationally intensive Data Assimilation (DA) techniques to update ocean and/or sea ice fields in a coupled model. In general, use of DATM in place of ATM can be appropriate when users are running a coupled model and only want certain components of the model to be active. More information about DATM is available in the CDEPS Documentation.

ERA5

The ECMWF Reanalysis v5 (ERA5) dataset “is the fifth generation ECMWF atmospheric reanalysis of the global climate covering the period from January 1940 to present.” It “provides hourly estimates of a large number of atmospheric, land and oceanic climate variables.”

ESMF

Earth System Modeling Framework. The ESMF defines itself as “a suite of software tools for developing high-performance, multi-component Earth science modeling applications.” It is a community-developed software infrastructure for building and coupling models.

ex-scripts

Scripting layer (contained in land-DA_workflow/jobs/) that should be called by a J-job for each workflow component to run a specific task or sub-task in the workflow. The different scripting layers are described in detail in the NCO Implementation Standards document.

FMS

The Flexible Modeling System (FMS) is a software framework for supporting the efficient development, construction, execution, and scientific interpretation of atmospheric, oceanic, and climate system models.

forcing data

In coupled mode, data that are generated by one component of a model can be fed into another component to provide required input describing the state of the Earth system. When models are run in offline, or “uncoupled” mode, the model does not receive this input from another active component, so “forcing” files are provided. These files may consist of observational data or data gathered when running other components separately, and they contain values for the required input fields.

FV3

The Finite-Volume Cubed-Sphere dynamical core (dycore). Developed at NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL), it is a scalable and flexible dycore capable of both hydrostatic and non-hydrostatic atmospheric simulations. It is the dycore used in the UFS Weather Model.

GSWP3

The Global Soil Wetness Project Phase 3 dataset is a century-long comprehensive set of data documenting several variables for hydro-energy-eco systems.

HPC

High-Performance Computing.

J-jobs

Scripts (contained in land-DA_workflow/jobs/) that should be directly called for each workflow component (either on the command line or by the workflow manager) to run a specific task in the workflow. The different scripting layers are described in detail in the NCO Implementation Standards document.

JEDI

The Joint Effort for Data assimilation Integration (JEDI) is a unified and versatile data assimilation (DA) system for Earth System Prediction. It aims to enable efficient research and accelerated transition from research to operations by providing a framework that takes into account all components of the Earth system in a consistent manner. The JEDI software package can run on a variety of platforms and for a variety of purposes, and it is designed to readily accommodate new atmospheric and oceanic models and new observation systems. The JEDI User’s Guide contains extensive information on the software.

JEDI is developed and distributed by the Joint Center for Satellite Data Assimilation, a multi-agency research center hosted by the University Corporation for Atmospheric Research (UCAR). JCSDA is dedicated to improving and accelerating the quantitative use of research and operational satellite data in weather, ocean, climate, and environmental analysis and prediction systems.

jedi-bundle

Skylab

JEDI Skylab is the name for roll-up releases of JCSDA’s jedi-bundle repository. This software provides an integrated Earth System Data Assimilation capability. JCSDA has tested Skylab capabilities internally via the SkyLab testbed for the following components: atmosphere, land/snow, ocean, sea-ice, aerosols, and atmospheric composition.

LND

land component

The Noah Multi-Physics (Noah-MP) land surface model (LSM) is an open-source, community-developed LSM that has been incorporated into the UFS Weather Model (WM). It is the UFS WM’s land component.

LETKF-OI

Local Ensemble Transform Kalman Filter-Optimal Interpolation (see Hunt et al. [HEJKS07], 2007).

Mediator

A mediator, sometimes called a coupler, is a software component that includes code for representing component interactions. Typical operations include merging data fields, ensuring consistent treatment of coastlines, computing fluxes, and temporal averaging.

MOM

MOM6

Modular Ocean Model

MOM6 is the latest generation of the Modular Ocean Model. It is numerical model code for simulating the ocean general circulation. MOM6 was originally developed by the Geophysical Fluid Dynamics Laboratory. Currently, MOM6 code and an extensive suite of test cases are available under an open-development software framework. Although there are many public forks of MOM6, the NOAA EMC fork is used in the UFS Weather Model.

MPI

MPI stands for Message Passing Interface. An MPI is a standardized communication system used in parallel programming. It establishes portable and efficient syntax for the exchange of messages and data between multiple processors that are used by a single computer program. An MPI is required for high-performance computing (HPC) systems.

NCAR

The National Center for Atmospheric Research.

netCDF

NetCDF (Network Common Data Form) is a file format and community standard for storing multidimensional scientific data. It includes a set of software libraries and machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data.

NCEP

National Centers for Environmental Prediction (NCEP) is an arm of the National Weather Service consisting of nine centers. More information can be found at https://www.ncep.noaa.gov.

NCO

NCEP Central Operations. Visit the NCO website for more information.

NUOPC

National Unified Operational Prediction Capability

The National Unified Operational Prediction Capability is a consortium of Navy, NOAA, and Air Force modelers and their research partners. It aims to advance the weather modeling systems used by meteorologists, mission planners, and decision makers. NUOPC partners are working toward a common model architecture — a standard way of building models — in order to make it easier to collaboratively build modeling systems.

NUOPC Layer

The NUOPC Layer “defines conventions and a set of generic components for building coupled models using the Earth System Modeling Framework (ESMF).” NUOPC applications are built on four generic components: driver, model, mediator, and connector. For more information, visit the NUOPC website.

NUOPC Cap

NUOPC Model Cap

A NUOPC “cap” is an interface between a given model component and the rest of a coupled model system. It is a small software layer that sits on top of the component model, making calls into it.

NWP

Numerical Weather Prediction (NWP) takes current observations of weather and processes them with computer models to forecast the future state of the weather.

RDHPCS

Research and Development High-Performance Computing Systems.

Spack

Spack is a package management tool designed to support multiple versions and configurations of software on a wide variety of platforms and environments. It was designed for large supercomputing centers where many users and application teams share common installations of software on clusters with exotic architectures.

spack-stack

The spack-stack is a collaborative effort between the NOAA Environmental Modeling Center (EMC), the UCAR Joint Center for Satellite Data Assimilation (JCSDA), and the Earth Prediction Innovation Center (EPIC). spack-stack is a repository that provides a Spack-based method for building the software stack required for numerical weather prediction (NWP) tools such as the Unified Forecast System (UFS) and the Joint Effort for Data assimilation Integration (JEDI) framework. spack-stack uses the Spack package manager along with custom Spack configuration files and Python scripts to simplify installation of the libraries required to run various applications. The spack-stack can be installed on a range of platforms and comes pre-configured for many systems. Users can install the necessary packages for a particular application and later add the missing packages for another application without having to rebuild the entire stack.

UFS

The Unified Forecast System (UFS) is a community-based, coupled, comprehensive Earth modeling system consisting of several applications (apps). These apps span regional to global domains and sub-hourly to seasonal time scales. The UFS is designed to support the Weather Enterprise and to be the source system for NOAA’s operational numerical weather prediction applications. For more information, visit the UFS Portal.

Umbrella repository

A repository that houses external code, or “externals,” from additional repositories.

Weather Enterprise

Individuals and organizations from public, private, and academic sectors that contribute to the research, development, and production of weather forecast products; primary consumers of these weather forecast products.