(music)
It's early morning
on February 15th, 2013.
A meteor weighing 10,000
metric tons is about to explode nearly 23 km
above Chelyabinsk.
Shortly after local sunrise:
a blinding sight for the stunned spectators on the ground,
(sound of explosion)
a massive explosion equivalent to 440 kilotons of TNT,
hundreds of tons of debris released, and quickly moved up into the atmosphere.
The highly sensitive
OMPS instrument on board the Suomi/NPP satellite made its first observation
of the plume nearly three and a half hours later, an entire
1.100km east of the explosion and already at
40km altitude well. into the Earth's stratosphere!
A surprising observation since the stratosphere usually acts as a
bumper that caps aerosols trying to rise up from the lower atmosphere.
By inserting a column of data
from the first plume observation into to two NASA models,
scientists were able to project the plume's trajectory.
The models showed that the plume had higher altitudes, shown in red, would
move ahead of the lower layer, shown in yellow.
The reason would be the difference in wind velocity at the lower and
higher altitudes. Also
illustrated here is how accurately the satellite observations coincided
with the projected path of the plume.
(music)
When OMPS made its second observation back at Chelyabinsk,
nearly 5 hours after the bolide, there was still evidence of
the plume at a lower 30km altitude.
On February 16, one day after the bolide, the OMPS instrument
detected the far end of the plume even further, at 1,700
to 4,300 km eastward from the explosion.
By February 19th,
four days after the explosion, the satellite observation showed that
the meteor debris had circumnavigated the entire globe and returned to
Chelyabinsk, forming a complete global belt.
The clean shape of the belt was another
surprising prediction, considering that Northern hemisphere winds during the winter
are usually rather inconsistent in direction.
A further look into the model simulation showed that evidence of the plume
persist for a long time, which also coincided with the satellite
observations.
We have now seen how accurately the models were able to project the plume's
trajectory. This is critical since the same models
are used to study climate and ozone depletion. The
unprecedented sensitivity of the OMPS instrument and its ability to see
vertical profile the atmosphere help scientists track
and study the meteor plume for months, revealing a much
better picture of what the aftermath on the atmosphere could be
from potential future, and even bigger events.
(beeping)