Background source: http://blog.thetechnonaut.com/?p=91

Better modeling through MATLAB:Connecting the auroral oval and the convection reversal boundary

Mentors:Dr. Barbara EmeryDr. Delores Knipp Dr. Liying QianDr. Wenbin Wang

Liam Kilcommons

Motive, Means, and Opportunity

Granted, the aurora is beautiful, but why bother studying it?

Actually, it's pretty important:

Auroral particle precipitation associated with Joule heating, biggest energy input (besides solar radiation) into upper atmosphere

Ionospheric disturbances and accompanying electric and magnetic fields cause:

Power grid damageGPS inaccuracyAir travel re-routePigeon loss

You can't really get to the aurora, so where do you get your data?

The aurora is pretty well studied, what else is there to know?

In general:

ground based remote sensing

direct satellite measurements

In this case:

Defense Meteorology Satellite Program satellites – aurora data

OMNI – satellite solar wind and ground based data from various sources

Lots!

Need better representation of atmosphere response to solar storms

Models' representation of aurora needs to be improved (2nd biggest energy input!)

What's this Joule thing?

Most familiar incarnation: Wires getting hotter due to current flow (a.k.a ohmic heating)

In upper atmosphere:

Neutral atoms getting hotter due to collisions with energetic electrons and ions

Drives 'neutral winds'

Momentum transfer

Strong solar storms (lots of precipitation and fast ion convection) cause worldwide changes in neutral winds

ion

ve

vp

vi

p

e

Neutrals

Auroral precipitation: e- and p+Ion convection: ions of O, O2, N2 etc

http://www.atigun.com/photography/aurora-photographs/47-aurora-photographs

Duskward, anti-sunward, and other mysterious directional adjectives

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Graphing as if one were looking down on the magnetic north pole

Noon

Midnight

Dawn

Dusk

80º70º

N Pole (90º)

Angular coordinate = magnetic local time (MLT)Radial coordinate = magnetic latitude (MLAT)

Not to scale

Ion Convection (or ion drift; the physics are the same)

N

S

The Earth

Looks familiar...

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E B 0/24

View from the top

Dawn-Dusk E-field!

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6

E x B gives direction of v

i

Vi? The Ion Drift Velocity

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vi

Convection Reversal Boundary (CRB)

DMSP Satellite in a dawn-dusk orbit

Our Data Sources: DMSP Satellites

IDM – Ion Drift Meter

SSJ4 – Electron Flux

+X indicates Along-Track DirectionY indicates Cross-Track Direction-Z is Earthward Direction

The beginning of this presentation, finally

The (scientific) problem: TIE-GCM needs to calculate Joule heating

Joule heating calculation requires relative locations (difference in radii) of CRB and auroral oval

Positions change constantly and drastically with changes in solar wind

TIE-GCM uses a constant (CRB 2 degrees duskward of auroral max flux)

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My goal:Gather statistics on real life relative CRB and aurora positions

Revise a MATLAB data display program to display the CRB and aurora positions for a particular pass of a particular DMSP satellite on a particular day.

How I Spent My Summer VacationThe (Programming) Problem: Need a flexible graphical display environment to visualize many kinds of data with different formats

Why?'Big picture' view of sun interacting with high latitude upper atmosphere

The Specifics:Incorporate solar data, auroral flux, and ion drift velocities Visualize many different variables, whatever user wants

Data Name Data Source Date Range(DMSP F-13)(on site)

Frequency of Measurements

Format Headache Rating

Particle Flux DMSP SSJ4 1987-2005 Every second Binary High

Ion Drift Velocity DMSP IDM 1987-2002 Every 4 seconds

ASCII Text

Low

OMNI Solar Wind Composite

Various:ACE, Ground Based, etc.

1978 to Present

Every Hour ASCII Text

Low

No Need to Reinvent the Wheel, Just Figure Out How It Rolls

Feature Original Program: Data Plotter

Desired Features for New Program

Input Data Type Heavily Preprocessed Raw Satellite Data

Available Times Only Selected Events,2004,2005

Any date for which data for desired plots exists

Available Datasets DMSP PF, IDM, SSJCHAMP Neutral Density

DMSP IDM, SSJOMNI Solar Data

Types of Plots Polar, Cartesian Polar, Cartesian

Calculations None Convection Reversal Boundary, Auroral Max Flux Points

The foundation for our visualization tool was Data_Plotter:

Matlab GUI ~ 6000 lines of code

Originally designed to study neutral density response for specific solar

events

No Need to Reinvent the Wheel, Just Figure Out How It Rolls

The foundation for our visualization tool was Data_Plotter:

Matlab GUI ~ 6000 lines of code

Originally designed to study neutral density response for specific solar

events

Feature Original Program: Data Plotter

Desired Features for New Program

Input Data Type Heavily Preprocessed Raw Satellite Data

Available Times Only Selected Events,2004,2005

Any date for which data for desired plots exists

Available Datasets DMSP PF, IDM, SSJCHAMP Neutral Density

DMSP IDM, SSJOMNI Solar Data

Types of Plots Polar, Cartesian Polar, Cartesian

Calculations None Convection Reversal Boundary, Auroral Max Flux Points

Biggest Challenge

My Solution: DMSP_Plot.m

CRB CRB

Max Flux

Max Flux

....and then, last night, around 11 pm there were: (Preliminary) Results!

CRB

Max Flux

CRB

Max Flux

Progress Report

Feature Original Program: Data Plotter

Desired Features for New Program

Goal Met?

Input Data Type Heavily Preprocessed Raw Satellite Data Yes

Available Times Only Selected Events,2004,2005

Any date for which data for desired plots exists

Yes

Available Datasets DMSP PF, IDM, SSJCHAMP Neutral Density

DMSP IDM, SSJOMNI Solar Data

Yes

Types of Plots Polar, Cartesian Polar, Cartesian Partially; Code still a little buggy

Calculations None Convection Reversal Boundary, Auroral Max Flux Points

Partially;Partial functionality in seperate code

Future Work

Perfect CRB and auroral maximum-flux-point finding algorithms

Gather statistics on position of aurora center and CRB center and their relative radii as a function of solar wind parameters

Compare results to modeled results

Use results to devise empirical model for estimating center position and radii of auroral oval with respect to CRB

Integrate model into TIEGCM for better Joule heating calculation

THANK YOU!QUESTIONS?