StrewnLAB Software

StrewnLABA computer simulation program, written by Jim Goodall.  For more information, please visit the StrewnLAB Page.... is a computer program for predicting meteorite strewn fields, written by Jim Goodall, the President of the General Motors Astronomy Club. The script is written in the MATLAB computing environment, and it simulates the entire flight of meteoroids through the atmosphere, from entry to landing. StrewnLAB differs from most existing meteor flight simulations, because it has the following features:

• Detailed weather data analysis – StrewnLAB automatically pulls data from the Integrated Global Radiosonde Archive (IGRA), from multiple stations, predicts a weather balloon flight path and and then interpolates in 4 dimensions to find wind speed along the path of the meteor. The model also estimates weather variation across the region and predicts a minumum and maximum possible wind speed.
• Models the entire flight path, including ablationBurning or melting away of solid meteoroid material (metal and/or rock), during atmospheric entry. Typical meteor velocities range from 15 to 30 kilometers per second. At this extreme speed, the air surrounding the meteor is superheated by pressure and friction which, in turn, heats the surface of the meteoroid, causing it to melt and flow away.... and fragmentationTypically, meteoroids breaks apart during flight through the atmosphere. Much of the material evaporates in a process called ablation, leaving only small stones to find. Occaisionally, large meteor events can drop meteorites as large as several kilograms, but it is much more likely to find the smaller, more numerous fragments, in the 10 to 100 gram size range...., not just dark flight – The advantage is that it does not assume all fragmentsTypically, meteoroids breaks apart during flight through the atmosphere. Much of the material evaporates in a process called ablation, leaving only small stones to find. Occaisionally, large meteor events can drop meteorites as large as several kilograms, but it is much more likely to find the smaller, more numerous fragments, in the 10 to 100 gram size range.... start from a single point (dark flight), so this enables a wider variety of masses landing in the same area, which is more realistic.
• Monte CarloA simulation approach used when the problem is very complex and there are many sources of error. Each input is characterized as having a known error range and distribution function and many scenarios are randomly generated to produce a "cloud" of answers. In the end, the exact answer is unknown, but the probability of any given answer is characterized.... scenario simulation, to capture all the known variation – No meteor trajectory is known perfectly, and StrewnLAB takes into account all the known variation in a witnessed fall, including error in latitude, longitude, dark flight altitude, bearingThe direction of travel of the meteoroid, relative to the ground, in clockwise degrees from North.  The terms "heading" and "bearing" may be used interchangeably for projectile motion...., slope, wind speed, entry mass, and meteoroid density.
• Random FragmentationTypically, meteoroids breaks apart during flight through the atmosphere. Much of the material evaporates in a process called ablation, leaving only small stones to find. Occaisionally, large meteor events can drop meteorites as large as several kilograms, but it is much more likely to find the smaller, more numerous fragments, in the 10 to 100 gram size range.... – Detailed fragmentation models are not necessary to comprehend the strewn fieldThe geographic area where meteorites landed, from a specific meteor event.  The strewn field size and shape are affected by the size of the event, the slope of the meteor, and the wind speed and direction.  Generally speaking, meteors that come in a steep angle will generate smaller strewn fields than those that come in at a shallow angle.  The presence of wind will affect the size and shape of the strewn field by scattering..., and this information is usually unknown anyway. Instead, StrewnLAB creates many random fragmentation models and plots all the results to capture the realm of possibility.
• Larger, More Realistic Mass Zones – because of the reasons listed above, StrewnLAB is capable of generating larger zones for each mass range (10 gram, 100 gram, 1 kg, etc), which actually have a lot of overlap.

• Find Probability Maps – StrewnLAB takes the results of all the Monte Carlo scenarios and generates a color shaded probability map, intended specifically for meteorite hunting. The map output indicates the best areas to search, with the highest probability of finding meteorites on the ground.

Jim Goodall wrote the original script for StrewnLAB in April of 2018, in response to the Hamburg Meteor, which fell only 30 km from his house in southeast Michigan. Since then, Jim has greatly expanded the capabilities of the program and the output has been validated against several popular witnessed falls, including Park Forest, Sutters Mill, and Chelyabinsk, with more than satisfactory results.

To see an example simulation in action, please visit YouTube and play the following video: Hamburg Meteor – Monte Carlo Simulation in MATLAB For best results, it should be viewed in 1080p on a monitor (not a phone). In the video, you can see how meteor fragments are greatly affected by wind, once they get into the troposphere.