When the software is launched, a short video plays and the ATP-45 Nuclear Fallout Predictor is displayed, as shown below.  The Weapons Control Panel is expanded and used to make or clear target selections, choose weapon types, and “detonate” the weapon by requesting the latest weapon effects pattern for the current upper-air weather conditions on the target.

ATP-45 Initial View

Note the menu choices in the left navigation pane.  The active choice has a small blue bar next to its icon.  Choices within the application are:

  • NATO ATP-45 Fallout Predictor depicted above.
  • NUKEMAP Fallout Predictor by Alex Wellerstein, Stevens Institute of Technology
  • CONUS Surface Wind Map, by HINT.FM, with real-time NOAA surface winds
  • The video “Radiological Defense”, from the former Office of Civil and Defense Mobilization
  • Relevant chapters from NATO Allied Technical Publication 45, explaining the detailed procedures used in the ATP-45 Fallout Predictor software.
  • This Help contents.

You may collapse the application navigation pane by clicking the “Hamburger” button above the menu choices.  This maximizes the screen space available to the content area.  To extend the pane, simply click the Hamburger button again to toggle the display.


Map View Controls

On the right-hand side of the application, you’ll see four small circular controls.  These controls manipulate visual aspects of the map view.

ATP-45 Map View Controls

The top button is a small compass and indicates the cardinal direction of the map view.  The red portion of the arrow always points to North.  You may change the direction simply by sliding the button to the left or right to rotate the map in either direction or click on the button to automatically reposition the map directly to North.

The second button is the Tilt button.  When active, you may tilt the map view towards the horizon or away from it by sliding the button to the right or left.  Clicking the button moves the map view to a directly perpendicular position over the current location.  When the map is zoomed out sufficiently, this button becomes disabled.  You may also tilt the map view by holding the Control key and click/dragging your mouse cursor over the map.

The third and fourth buttons zoom the map view in and out, respectively.  You may also zoom the map view in and out using the mouse wheel.


Weapons Control Panel

Targets locations and weapon selections are made using the Weapons Control Panel.  With controls on this panel, you may select target location, select a weapon type, the desired fallout prediction wind model, view weather stations (advanced version only), and “detonate” the weapon, which triggers a call to the ATP-45 server to calculate weapon effects for the current weather conditions.

ATP-45 Weapons Control Panel

To select a weapon type, click on the Weapon Select combo box and pick a weapon from the drop-down panel.  To enter a custom weapon yield in kilotons (1-50000), select the last entry (Enter Custom Yield) and enter a weapon yield in the textbox that appears to the right.  This selection may be made before or after a target has been selected, but before you press the DETONATE button.

As explained in the ATP-45 methodology paper, included with this software, there are two “wind models” used to predict fallout zones.  The default choice is the Fixed Angle Wind Model, which projects lethal hazard zone radial lines 20 degrees to the left and right of the cloud radius circle in the effective downwind direction, unless a wider angle is required.  This simple model is used by units deployed in the field without access to detailed meteorological data over the target area, particularly for pre-strike maneuver planning.

The Variable Angle Wind Model is used when detailed wind data is available, as it is in this software, and is the model of choice when effective downwind speeds over the target area are low.  The Variable Angle Wind Model is optimized for climates in North America and northern Europe.  This model will produce a fallout pattern similar in size to that of the NUKEMAP fallout predictor by Alex Wellerstein.

As a practical matter, use the Fixed Angle Wind Model first, and if you see a fallout pattern that looks “squashed” or looks too wide, use the Target Control Panel to delete the prediction and make the prediction again using the Variable Angle Wind Model.  Also use the Variable Angle Wind Model if you wish to compare fallout patterns between ATP-45 and NUKEMAP.

The main practical difference between ATP-45 and the NUKEMAP model is that NUKEMAP only uses surface wind data as a general guide to predicting fallout pattern direction whereas ATP-45 uses upper-air layer wind predictions, as the military does.

To select a target location, click on the green Target Select button.  The button will change color and start to pulse.  Move your cursor over the map to the desired location.  You may zoom in and out with the mouse wheel and move the map by clicking and dragging the map until your target is in view (clicking and dragging will not select a target).  Then, simply click on the map where you want the weapon to detonate.  The Weapon Control Panel will indicate the target coordinates, and the Target Clear and DETONATE buttons will both be enabled.

If you are not satisfied with your target location, simply select Target Clear and select it again.  You may also choose a different weapon type from the Weapon Select combo box if you like.

When you press the DETONATE button, the program will contact the ATP-45 server to calculate blast and fallout effects patterns and return them.  Once received from the server, you should see blast and fallout patterns that look like this example of a 150-kiloton weapon over downtown Seattle, Washington.

ATP-45 Fallout Prediction, Seattle, WA, 150 Kilotons

The large outer yellow circle is the area of light to moderate destruction to ordinary houses.  The inner yellow circle is the area of moderate destruction to reinforced concrete structures.  The area under where the mushroom cloud touches the ground is the area of complete destruction to all structures.

The red area projecting forward in the downwind direction is the Zone 1 (or “lethal”) radiation hazard area for unprotected troops.  Personnel exposed in this area can expect whole body radiation doses more than 150 cGy (centiGrays) within less than 4 hours after arrival of fallout.

The Gray is an international standard unit of ionizing radiation dose equivalent to one joule of radiation energy per kilogram of matter.  The cGy (centiGray) is functionally equivalent to the old RAD unit (Radiation Absorbed Dose).  A single day’s unprotected exposure to radiation in Zone 1 may result in death.  You may read more about this here:

The yellow area projecting forward of the red area in the downwind direction is the Zone 2 (or “hazardous”) radiation area for unprotected troops.  Within this area, unprotected personnel may expect to receive a total dose of 50 cGy or greater within the first 24 hours after arrival of fallout.  Prolonged unprotected exposure in this area may lead to radiation sickness and long-term health problems, as well as an early death.

Prediction of fallout is an estimate only.  Radiation surveys after a blast will be necessary to determine the actual radiation hazards from a nuclear explosion.

You may expand or collapse both the Weapon and Target control panels by clicking or tapping on their title bars.


Fallout Prediction Details

Clicking on or near the mushroom cloud will launch a standard dialog box with details on the fallout prediction.

Fallout Prediction Details Dialog

All the information needed for a chemical or radiological defense officer to make an acetate overlay for a paper map may be found here, including weapon coordinates, yield, cloud parameters, effective downwind speed and direction, and more.  This is a modal dialog and must be dismissed by clicking the OK button before you can proceed.


Mushroom Cloud 3D Model

The mushroom cloud 3D model is scaled such that the base covers the area of complete destruction, but the height of the cloud on the map does not represent the actual maximum height of the cloud.  The relationship between cloud heights vs yield is given here.

Surface Detonation Cloud Height vs Weapon Yield

ATP-45 predictions were originally designed for tactical nuclear weapons and more suited to weapon yields below 2 megatons.  In recent years, as delivery systems have become more accurate, nuclear-capable nations have reduced their weapon yields from multi-megaton warheads to the original tactical yield range, so this is sufficient for all but the largest weapons.


Target Control Panel

The Target Control Panel lets you interact with targets on the map, to fly directly to their positions, to delete attacks, or to hide or show their effects patterns.

Target Control Panel with One Expired Prediction

Fallout predictions are valid for a maximum of 6 hours after they are made, depending on the underlying wind prediction data from NOAA.  These predictions are updated by NOAA every 6 hours and new wind patterns are then updated on the ATP-45 effects server.  When a prediction has expired, its Attack Time UTC will appear in red on the list.

All times in ATP-45 are Coordinated Universal Time (UTC), formally Greenwich Mean Time (GMT), the primary standard by which the world regulates its clocks.  In the military, this is also known as Zulu time.  This is the time at the Prime Meridian, which is a line of longitude defined to be at 0 degrees, passing through the Royal Observatory at Greenwich, United Kingdom.

At present, the only way to update an expired attack to new wind prediction data is to delete it with the Target Control Panel and make a new one with Weapon Control Panel.  A forthcoming Advanced Version of ATP-45 will feature automatic prediction updates.


Fly To Or Delete Fallout Prediction

To Fly To a specific target, simply select it in the list and press the Fly To button.  To delete the target from this list and from the map, select it in the list and toggle the Enable Delete button.  This will enable the Delete Target button.  Then, to delete the target, press the Delete Target button.  This safeguard is in place to protect your predictions from accidental deletion.

Target Control Panel With Selected Attack

To hide or show either the Fallout Zones or Blast Zones for all targets, select the appropriate toggle button and those zones will be hidden or shown respectively.


Release Notes

Because of a minor flaw in the Microsoft Windows 10 MapControl, sometimes the fallout zones will appear to be broken or disappear at various zoom levels, as in the figure below.

Fallout Prediction with Broken Zones

Should this happen, simply toggle the Fallout Zones off and then on again using the Target Control Panel.  This will cause them to be redrawn and repaired.  Microsoft will fix this in a future Windows Update.

Fallout Prediction After Turning Fallout Zones On and Off

Also, because of a flaw in Microsoft’s Universal Windows Platform navigation system, excessive switching back and forth between the main pages of the application will consume memory and resources and the application may unexpectedly terminate.  This may happen regardless of the amount of memory in your computer.  Microsoft is investigating this, and the condition should be fixed in a future update, hopefully soon.  We regret any inconvenience this may cause you.  We have worked extensively with Microsoft developers to raise this issue.


Future Enhancements for ATP-45 Advanced Version

We are planning some future enhancements to this software should it prove popular enough to justify the effort.  These include:

  • The ability to save and reload target lists.
  • Sub-kiloton bursts for Atomic Demolition Munitions.
  • Display of Weather Stations and upper-air wind data.
  • Automatically renewing expired fallout predictions.
  • The ability to switch wind models for a prediction without deleting it first.
  • Casualty estimation.  NUKEMAP does provide casualty estimation because it was made by an educational institution and has free access to the LandScan Global Population Database.  We would have to pay for such access, which is prohibitively expensive.
  • Fallout prediction capability for Alaska, Hawaii, and the US territories in the Pacific Ocean.  This will probably be our first enhancement as it requires no changes to your client software.
  • Chemical hazard prediction using ATP-45 chemical prediction models.

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