https://ieeexplore.ieee.org/document/9837429
*Authors*
Kelsie M. Larson, Lyndsay Shand , Andrea Staid, Skyler Gray, Erika L.
Roesler, and Don Lyons
22 July 2022
Abstract:Ship emissions can form linear cloud structures, or ship tracks ,
when atmospheric water vapor condenses on aerosols in the ship exhaust.
These structures are of interest because they are observable and traceable
examples of MCB, a mechanism that has been studied as a potential approach
for solar climate intervention. Ship tracks can be observed throughout the
diurnal cycle via space-borne assets like the advanced baseline imagers on
the national oceanic and atmospheric administration geostationary
operational environmental satellites, the GOES-R series. Due to complex
atmospheric dynamics, it can be difficult to track these aerosol
perturbations over space and time to precisely characterize how long a
single emission source can significantly contribute to indirect radiative
forcing. We propose an optical flow approach to estimate the trajectories
of ship-emitted aerosols after they begin mixing with low boundary layer
clouds using GOES-17 satellite imagery. Most optical flow estimation
methods have only been used to estimate large scale atmospheric motion. We
demonstrate the ability of our approach to precisely isolate the movement
of ship tracks in low-lying clouds from the movement of large swaths of
high clouds that often dominate the scene. This efficient approach shows
that ship tracks persist as visible, linear features beyond 9 h and
sometimes longer than 24 h.
[image: Fig. 1. - These figures show the result of the optical flow method
applied to a manually-selected local cloud region, starting with an
intersection of two ship tracks on June 17, 2019, at 07:02 UTC (a) and
stepping forward in time, with snapshots shown at 6 (b), 12 (c), and 18 (d)
hr later. The tracking algorithm is able to follow the movement of the
cloud region well, and the tracks are still clearly visible 18 hr later.
The center location of these images is $33^{\circ }$27’02.0”N $138^{\circ
}$06’11.9”W.]
<https://ieeexplore.ieee.org/mediastore_new/IEEE/content/media/4609443/9656571/9837429/shand1-3193024-large.gif>
Fig. 1.
These figures show the result of the optical flow method applied to a
manually-selected local cloud region, starting with an intersection of two
ship tracks on June 17, 2019, at 07:02 UTC (a) and stepping forward in
time, with snapshots shown at 6 (b), 12 (c), and 18 (d) hr later. The
tracking algorithm is able to follow the movement of the cloud region well,
and the tracks are still clearly visible 18 hr later.
*Source: IEEE Xplore*
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