Earth Science SeminarM. D. Eastin Effective Visual Aids Eye Eyewall Rainband Maximum Winds are ~1 km above the surface Eyewall Rainband MM5 Simulation

Earth Science Seminar M. D. Eastin

Effective Visual Aids

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MM5 Simulation of Hurricane Andrew Courtesy of Da-Lin Zhang at Univ. Maryland


Effective Visual AidsKnow your Audience and the Purpose for your visual aids:

One-time presentation at a scientific meeting?

One-time presentation to a local group (non-scientific)?

Lecture and reference material for a group?


Effective Visual AidsLimit the Text and Maximize the Imagery

Each slide should contain only one figure or table with a few lines of textto illustrate one idea / concept

General Rule: Readability is maximized by following the “7 x 7 Rule”: No more that seven words per line and 7 lines per slide



The global mean radiative forcingglobal mean radiative forcing experienced by the Earth system can be divided into many categories. For each, we can approximate the sign and magnitude of the forcing, but at a variety of confidence levels.

• Long-lived Greenhouse Gases (CO2, NO2, etc): Produce between +0.34 and +1.66 W/m2 of forcing on the global scale and we have a high level of scientific understanding (i.e. confidence) in this estimate

• Ozone: Stratospheric ozone produces a -0.05 W/m2 of forcing, and tropospheric ozone produces +0.35 W/m2 on the global scale and we have a medium level of scientific understanding.

• Stratospheric Water Vapor and Methane: Produces +0.07 W/m2 of forcing on the global scale and we have a low level of scientific understanding in this estimate

• Surface Albedo: Produces between -0.2 and +0.1 W/m2 of forcing on the regional scale and we have a medium-low level of scientific confidence in this estimate

• Aerosols: Produce between -0.5 and -0.7 W/m2 of forcing on the global scale and we have a low level of scientific understanding in this estimate

• Linear Contrails: Produce +0.01 W/m2 of forcing on the regional scale and we have a low level of scientific confidence in this estimate




Effective Visual AidsVisual aids should be readable for all audience members:

General Rule: If you can read all aspect of the slide on the computer screen when standing 4-5 feet away, then the font size is adequate

Avoid large (>36) and small (<16) font sizes

Can you see me now

Can you see me now

Can you see me now


Effective Visual AidsUse Color Effectively:

Colors can be used to emphasize a particular point

Colors can be used to distinguish between two categories: Warm and Cold

Use “cool’ colors (blues and greens) for backgroundsUse “warm” colors (reds and yellows) for foreground

White backgrounds with black text can cause eye strain…

GOODShows warm

foreground color on cool

background color

BADShows cool

foreground color on warm

background color


Effective Visual AidsVisual aids should look professional:


Effective Visual AidsDo not show “corny” images

Do not use ClipArt

Imagery should illustrate / demonstrate a familiar conceptImagery should supplement your oral presentation


Effective Visual AidsAvoid “grainy” images

Scan a higher quality imageSearch the internet for adapted versionsContact the author to obtain an originalAdapt the figure yourself

From Landsea and Gray (1993)


Effective Visual AidsAvoid distracting images:

PressureGradient

Force

CoriolisForce

CentrifugalForce

Air Motion

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Non-Effective Visual AidsAvoid video clips that are too long or move too fast:

The Last Image Bad Movie


Non-Effective Visual AidsAvoid copyright theft

Easy: Simply acknowledge your source (either on the slide or verbally)

Note: Use of imagery and video for educational purpose is permitted by law if no more than 10% of the original content is shown and no profit is

gained from its showing

Photograph courtesy of Brian McNoldy From Bluestein (1993)


Effective Visual AidsAvoid too many slides:

General Rule: One slide per minute in a well rehearsed presentation 15 minute presentations should not have more than 15 slides

Too many slides result in long presentations that are often ended abruptly.

Nobody likes a long presentation…


Example: An Effective SlideDownslope Winds:

Chinook Winds:

• Temperature of the downslope flowing air is warmer than the air it replaces

• Warming winds → dry adiabatic descent

Examples:• Santa Ana (CA)• Sundowner (Santa Barbara, CA)• Föhn (Alps)• zonda and pulche (Andes)• kachachan (Sri Lanka)

Bora Winds:

• Temperature of the downslope flowing air is colder than the air it replaces

• Cooling winds → evaporational cooling


Mountain Wave Clouds:

• If the air parcel forced aloft is moist enough to achieve saturation (or cloud drops form)

• Also called “lenticular” clouds

• Multiple rows of clouds can form downstream of a mountain range

• The cloud rows are often oriented parallel to the mountain range

θ EL

θ+Δθ

Lenticular Clouds

Examle: An Effective Slide


Example: An Effective Slide

Tornadoes form from the titling andstretching of horizontal vorticity by astrong updraft

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Earth Science SeminarM. D. Eastin Effective Visual Aids Eye Eyewall Rainband Maximum Winds are ~1 km above the surface Eyewall Rainband MM5 Simulation