Volcanic ash and aerosol detection versus dust detection using GOES and MODIS imagery

1
Volcanic ash and aerosol detection versus dust
detection using GOES and MODIS imagery
Bernadette Connell Cooperative Institute for
Research in the Atmosphere Colorado State
University 2nd International Conference on
Volcanic Ash and Aviation SafetyJune 21-24,
2004Alexandria, Virginia, USA
2
Main Features

• Easy to implement techniques
• BT11.0um-BT12.0um
• BT11.0um-BT3.9um (night)
• Estimated reflected 3.9um (day)
• False color 3.9/11.0/12.0um product
• BT8.5um-BT12.0um (ash and/or aerosol)
• Examples of volcanic constituents vs. dust with
  GOES and MODIS data

3

• Ash/Dust in the 3.9 11.0 um range
• DAY higher reflectance for ash/dust clouds and
  water droplets lower reflectance for ice
  particles
• NIGHT BT11.0-BT3.9 negative for thin ash/dust
  clouds
• negative for ice cloud
• positive for water cloud
• Volcanic Aerosol vs. Ash/Dust in the 8.5 12.0
  um range
• BT8.3um BT12.0um negative for SO2 and H2SO4
• BT8.3um BT12.0um negative for silicates, but
  sensitive to particle size.
• Ash/Dust in the 11.0 12.0 um range
• BT11.0um-BT12.0um negative for ash/dust
• 
  positive for ice/water cloud

4
Visible
3.9 um
10.7 um
Popocatepetl Volcano, Mexico 22 January, 2001
2245 UTC GOES-8 imagery
5
Popocatepetl Volcano, Mexico 22 January, 2001
2245 UTC GOES-8 imagery
6
GOES imagery and products 23 January 2001
0445 UTC
10.7 um
BT10.7-BT3.9
Popocatepetl, Mexico
BT10.7-BT12.0
False color 10.9/BT10.7-BT12.0/BT10.7-BT3.9
7
(No Transcript)
8
22 January, 2001 0445 UTC GOES, 0450 UTC MODIS
Popocatepetl, Mexico
GOES-8 BT10.7-BT12.0
MODIS Terra BT11.0-BT12.0
MODIS Terra BT8.5-BT12.0
9
DUST detection with GOES imagery
10.7 um
visible
18 April, 2001 1930 UTC
BT10.7-BT12.0
Reflectance
10
(No Transcript)
11
DUST detection
MODIS Aqua true color
GOES-8 BT10.7-BT12.0
18 April, 2001 1930 UTC
MODIS Aqua BT11.0-BT12.0
MODIS Aqua BT8.5-BT12.0
12
Summary remarks and points to ponder

• Variability of eruption cloud
• If multi-channel imagery is available, use it!
• What is the significance of large (or small)
• BT10.7-BT12.0?
• What are we seeing using the 8.x um region
  (ash/dust/aerosol)?
• How can we best combine this information with
  other information on SO2 detection?