1. Volcanic Clouds over the North Atlantic?
Nutshell: Multiple CALIPSO layers from PBL to 10 km on 8 May, mid-day. Layers extend
from 40-60N.
Notes: * CALIPSO feature ID is “cloud” for most of these layers.
* Horizontal texture of these layers is smooth compared to extensive cloud
features north of 60.
* CloudSat picks up no echoes in curtain containing these layers.
* CloudSat DOES pick up echoes in area of broad CALIPSO cloud north of 60.
* CloudSat also gets echoes off of some stratoCu below the thinner
CALIPSO layers.
* Back trajectory from a 9km CALIPSO feature at ~44N matches in location
and time the strong OMI AI feature on 6 May southeast of Iceland.
* Ray Hoff posted some 7 May CALIPSO curtains he suspected of volcanic
origin (
Relevance: Large AI on 6 May implicates a strong and high absorbing aerosol plume.
AI and SO2 (not shown) plumes on 7 and 8 May indicate movement in
the direction of the 8 May CALIPSO layers. If the 8 May CALIPSO layers are
not simply water-ice clouds, this suggests ash penetration to ~10 km and
elevated layers over a large area of the Atlantic. It may me important to examine these layers
critically to confirm or rule out ash.
Mike Fromm, NRL, 9 May 2010

2. Cut to the chase…
…next slide is CALIPSO/CloudSat composite showing the layers in question in the
context of nearby certain water-ice clouds.
… next next slide gives the trajectory and AI analysis
…all the rest of the slides are just the original CALIPSO and CloudSat granules used.

3. Back Trajectory start point (next) Volcanic clouds? No CloudSat
cloud except for strongest stratoCu
Where on Earth
we’re looking
CloudSat
cloud
extent
Back
Trajectory
start point
(next)
Land
Feature
synch
Volcanic clouds?

4. Endpoint time is 14 UTC 6 May
OMI AI
6 May 2010, ~11-14 UTC
Image credit: Simon Carn
Notice double-digit AI max near
Trajectory endpoint

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