Forecasting the Arrival of ICMEs:
The Drag-Based Model



CME take-off date:
CME take-off time (UTC): h min
R0 - starting radial distance of CME (Rs)
v0 - speed of CME at R0 (km/s)
Γ - drag parameter (10-7 km-1)
w - asymptotic solar wind speed (km/s)
Rtarget - target heliocentric distance (AU)
CME take-off date:
CME take-off time (UTC): h min
R0 - starting radial distance of CME (Rs)
v0 - speed of CME at R0 (km/s)
Γ - drag parameter (10-7 km-1)
w - asymptotic solar wind speed (km/s)
Rtarget - target heliocentric distance (AU)
Θ - CME's angular width (deg)
ϕtarget - Earth-target heliocentric angular separation (deg)
ϕCME - source region central meridian distance (deg)

DBM stands for Drag-Based Model. The purpose of the basic form of the model is to provide a prediction of the arrival time and impact speed at the Earth. Calculations are based on the assumption that the dominant force in the heliospheric dynamics of ICMEs is the magnetohydrodynamical equivalent of the aerodynamic drag. For a given set of input parameters it provides the ICME Sun-Earth transit time, the arrival time, and the impact speed.
The advanced form of DBM provides this output for any target in the heliosphere and takes into account also the shape of ICME employing the so-called cone-geometry.

Documentation and description of calculation method for basic and advanced DBM you can find here. PDF


Batch version of DBM

The batch (non GUI) version of DBM program was implemented with a purpose to allow the user automatic calculation for more events or to connect DBM with various other models or interfaces. In the case of missing mandatory input parameters the DBM program will show the default html (GUI) interface.

Currently the batch version of DBM is available ONLY for DBM basic.

Mandatory input parameters:
cme_start_date - CME start date, allowed format: DD-MM-YYYY (DD - days from 01 to 31, MM - months from 01 to 12, YYYY - years from 1900 to 2100).
cme_start_time - CME start time (UTC), allowed format: hh:mm (hh - hours from 00 to 23, mm - minutes from 00 to 59).
R0 - starting radial distance of CME, unit: Rs (Sun diameter), allowed format: number in range from 1 to 214.
v0 - speed of CME at R0, unit: km/s, allowed format: number in range from 50 to 5000.
gamma - drag parameter, unit: 10-7 km-1, allowed format: number in range from 0.1 to 100.
w - asymptotic solar wind speed, unit: km/s, allowed format: number in range from 200 to 800.
Rtarget - target heliocentric distance, unit: AU, allowed format: number in range from 0.01 to 50.

Optional input parameters:
format - defines the output format, allowed value: csv, html, text, ascii, votable (example: format=html).
Without specified format parameter default csv format is set. Other supported formats are: html, text, ascii, votable.

Example (with output in html format):
http://oh.geof.unizg.hr/DBM/dbm.php?cme_start_date=01-01-2013&cme_start_time=01:10&R0=20&v0=1000&gamma=0.2&w=450&Rtarget=1&format=html

Hvar Observatory INSTITUTE FOR GEOPHYSICS, ASTROPHYSICS, AND METEOROLOGY (IGAM) COMESEP: forecasting the space weather impact SOlar-TERrestrial Investigations and Archives FP7 EU
POKRET - Povecanje Konkurentnosti Razvojem istrazivańća u fizici Sunca) Strukturni i investicijski fondovi ESF EU