WSA-Enlil is a large-scale, physics-based prediction model of the heliosphere, used by the Space Weather Forecast Office to provide 1-4 day advance warning of solar wind structures and Earth-directed coronal mass ejections (CMEs) that cause geomagnetic storms. Solar disturbances have long been known to disrupt communications, wreak havoc with geomagnetic systems, and to pose dangers for satellite operations.

Space Weather and GPS Systems Electric Power Transmission Satellite Communications Satellite Drag

The modeling system consists of two main parts: 1) a semi-empirical near-Sun module that approximates the outflow at the base of the solar wind; and 2) a sophisticated 3‑D magnetohydrodynamic numerical model that simulates the resulting flow evolution out to Earth. The former module is driven by observations of the solar surface magnetic field, as taken over a solar rotation and composited into a synoptic map; this input is used to drive a parameterized near-Sun expansion of the solar corona, which is subsequently input into the second, interplanetary module to compute the quasi-steady (ambient) solar wind outflow. Finally, when an Earth-directed CME is detected, coronagraph images from NASA spacecraft are used to characterize the basic properties of the CME, including timing, location, direction, and speed. This input (the “cone” model) is injected into the pre-existing ambient conditions, and the subsequent transient evolution forms the basis for the prediction of the CME arrival time at Earth, its intensity, and its duration. In the movie, the Sun is represented as a yellow dot, the Earth by a green dot, and the STEREO spacecraft by the red and blue dots. The top row represents the WSA-Enlil predicted solar wind density and the bottom row the predicted solar wind velocity. On the left is a pinwheel plot of the ecliptic plane, showing all of the solar wind structures that are likely to encounter Earth or which have recently encountered Earth, in what is effectively an ‘overhead’ view. While the STEREO spacecraft are shown, this ecliptic slice does not normally pass through these satellites, though it is typically fairly close. In the middle are meridional slices that go through the Earth, showing the solar wind structures that will encounter Earth from a ‘side’ view. On the right, the predicted density and velocity values for the location of Earth and the two STEREO spacecraft are plotted.

Model implementation at SWPC occurred in October of 2012.

The WSA-Enlil archive is available through the National Centers for Environmental Information.

References & Acknowledgement Swedish Institute of Space Physics (IRF) & (SSWC).The ENLIL forecasts are provided by NOAA/SWPC.

		EUHFORIA 3D MHD Heliosphere Model

EUHFORIA (v 1.0.3) is a 3D MHD heliosphere model that propagates near-Sun solar wind properties and transient related to CME events out into the heliosphere. This product is a daily run of the EUHFORIA model executed by the Virtual Space Weather Modelling Centre product operated by KU Leuven. The model is initialised with inputs that correspond as closely as possible to those used for the operational Enlil MHD model runs provided by the UK Met Office and available through the Enlil/E product. The inputs include an equivalent magnetogram file for the EUHFORIA Corona model and the same CME (cone file) characterisation determined by UK Met Office forecasters from coronagraph observations.

Space Weather and GPS Systems
Electric Power Transmission
Satellite Communications
Satellite Drag

EUHFORIA (v 1.0.3) is a 3D MHD heliosphere model that propagates near-Sun solar wind properties and transient related to CME events out into the heliosphere. This product makes use of the version of EUHFORIA that is installed and accessible via the Virtual Space Weather Modelling Centre VSWMC as described in S. Poedts, 2018. Access to the full capabilities of the VSWMC to generated bespoke chained model runs are being provided separately under the heading of product VSWMC.

In support of heliospheric weather forecasting we provide a set of pre-generated products (EUHFORIA/E, EUHFORIA/Me, EUHFORIA/V and EUHFORIA/Ma) giving the latest results for the heliospheric targets (Earth, Mercury, Venus and Mars). The model is run once a day and makes use of the same input information as the operational Enlil 3D MHD model run by UK Met Office to allow cross comparison and validation of the different models.

The products are generated on a daily schedule with the latest model results being presented to the user. The EUHFORIA product is run automatically each morning and makes use of the current published Enlil/E configuration available from UK Met Office at that time. Note that this may be from the previous day since the forecasters will make an expert assessment and release the model output from the last 24 hours that is considered most consistent with observed conditions. The job is submitted to the VSWMC using the provided API (see https://pypi.org/project/vswmc-cli/ ). Usually the job will be processed within a few hours but this is dependent on the load on the KU Leuven processing systems and could be significantly longer at busy times but is not anticipated to exceed 24 hours under normal situations. The job is routinely monitored and once completes the results and log information are collected for post processing. It should be noted that the EUHFORIA/E/Me/V/Ma are all products of the same run and therefore where one exists there should be corresponding data for all products.

The movie shows the latest forecast solar wind density (top panels) and speed (lower panels). The left hand panel contains an ecliptic plane slice (a top-down view) with the Sun-Earth line fixed along the X-axis. Markers are shown for the inner planets and the STEREO-A (STA) spacecraft (see expanded version of the legend below).

 

 

 

The middle panel (which is only provided for EUHFORIA/E) shows a latitudinal slice along the Sun-Earth line (a side-on view).

It is important to note that for EUHFORIA/Me/V/Ma products, the orientation of the ecliptic slice plot has not been rotated to put the sun-target line on the x-axis as has been done for the equivalent Enlil/Me/V/Ma products availble through the portal.

The time series plots show the predicted variation in the parameters at the location of the target. The vertical blue dotted line indicates the reference (start) time for the simulation, data to the left of this represents the model initialisation time (this may not be visible if all CMEs fall outside the model time interval). The vertical red line indicates the time of the left and middle plots.

The configuration used for the model run is provided below the plot. This includes the list of CMEs and their initial characteristics, the DATE: when the model run was requested, the GRID: resolution used by the model, the SIM_START_DATE: corresponding to the initial reference date for the model run, and the MAGNETOGRAM: file corresponding to SIM_START_DATE: used to initialise the background solar wind model.

The data files section provides the Time series data of the plasma parameters at the target location. These are the data that are used to produce the right hand panels in the animated plot. This file is in Delimiter Separated Value (DSV) format and contains the following columns.

Parameter	Description
Date[UTC]	UTC time of the predicted solar wind parameters at target (YYYY-MM-DDTHH:MM:SS)
r[AU]	Heliocentric distance of target
clt[rad]	HEE Latitude of target
lon[rad]	HEE longitude of target
n[1/cm^3]	Predicted solar wind density
P[Pa]	Predicted solar wind pressure
vr[km/s]	Predicted radial component of the solar wind velocity
vclt[km/s]	Predicted latitudinal component of the solar wind velocity
vlon[km/s]	Predicted longitudinal component of the solar wind velocity
Br[nT]	Predicted radial component of the interplanetary magnetic field
Bclt[nt]	Predicted latitudinal component of the interplanetary magnetic field
Blon[nT]	Predicted longitudinal component of the interplanetary magnetic field

Please note that the cone file characterisation of CMEs that is currently used does not model the magnetic field of these structures and therefore the vector magnetic field predictions will not be taken as representative.

Please refer to the VSWMC documentation for full details of the model operation and datafile outputs.

The model runs are dependent on several data inputs these are:

• GONG magentograms used as input to the EUFORIA Corona model which predicts the background solar wind at the inner boundary of the EUHFORIA MHD heliospheric model.
• The CME cone file characteristics (time at 21.5Rs, longitude, latitude, half width and speed). These are provided by the UK Met Office for both Earthbound and non-Earthbound CMEs. The forecasters analyse coronograph observations (SOHO/LASCO) in order to determine these parameters.
• Time series data [DSV file]
• Movie [MP4 file]

References & Acknowledgement Poedts,S.,Forecasting space weather with EUHFORIA in the virtual space weather modeling centre, Plasma Physics and Controlled Fusion, Volume 61, Number 1, 2018

Part of the European Space Agency’s network of space weather services and service development activities, and is supported under ESA contract number 4000134036/21/D/MRP.

KU Leuven, RAL Space, UK Met Office and The ESA Space Safety Programme.
For further information about space weather in the ESA Space Safety Programme see: https://www.esa.int/spaceweather

WSA-Enlil is a large-scale, physics-based prediction model of the heliosphere, used by the Space Weather Forecast Office to provide 1-4 day advance warning of solar wind structures and Earth-directed coronal mass ejections (CMEs) that cause geomagnetic storms. Solar disturbances have long been known to disrupt communications, wreak havoc with geomagnetic systems, and to pose dangers for satellite operations.

Space Weather and GPS Systems
Electric Power Transmission
Satellite Communications
Satellite Drag

The modeling system consists of two main parts: 1) a semi-empirical near-Sun module that approximates the outflow at the base of the solar wind; and 2) a sophisticated 3‑D magnetohydrodynamic numerical model that simulates the resulting flow evolution out to Earth. The former module is driven by observations of the solar surface magnetic field, as taken over a solar rotation and composited into a synoptic map; this input is used to drive a parameterized near-Sun expansion of the solar corona, which is subsequently input into the second, interplanetary module to compute the quasi-steady (ambient) solar wind outflow. Finally, when an Earth-directed CME is detected, coronagraph images from NASA spacecraft are used to characterize the basic properties of the CME, including timing, location, direction, and speed. This input (the “cone” model) is injected into the pre-existing ambient conditions, and the subsequent transient evolution forms the basis for the prediction of the CME arrival time at Earth, its intensity, and its duration.

In the movie, the Sun is represented as a yellow dot, the Earth by a green dot, and the STEREO spacecraft by the red and blue dots. The top row represents the WSA-Enlil predicted solar wind density and the bottom row the predicted solar wind velocity. On the left is a pinwheel plot of the ecliptic plane, showing all of the solar wind structures that are likely to encounter Earth or which have recently encountered Earth, in what is effectively an ‘overhead’ view. While the STEREO spacecraft are shown, this ecliptic slice does not normally pass through these satellites, though it is typically fairly close. In the middle are meridional slices that go through the Earth, showing the solar wind structures that will encounter Earth from a ‘side’ view. On the right, the predicted density and velocity values for the location of Earth and the two STEREO spacecraft are plotted.

Model implementation at CCMC.

The WSA-Enlil data is available through the Community Coordinated Modeling Center (CCMC).

References & Acknowledgement Community Coordinated Modeling Center (CCMC) The Community Coordinated Modeling Center (CCMC) is a multi-agency partnership. The CCMC provides, to the international research community, access to modern space science simulations. In addition, the CCMC supports the transition to space weather operations of modern space research models.