The Interaction of African Dust and Dryair Outbreaks

1
The Interaction of African Dust and Dry-air
Outbreaks

• Xiaoyu Liu
• Univ. of Miami/RSMAS

2
Outline

• Motivation
• Data and methodology
• Preliminary results
• Conclusion and future work

3
Motivation

• Aerosol and water vapor affect clouds and
  convection (e.g., in tropical cyclones and
  African monsoon) differently.
• Are African dust outbreaks always dry? Are
  African dry-air outbreaks always dusty?
• Can we study their relationship using satellite
  data?

4
dataset

• Aerosol
• TOMS Earth Probe satellite data
• 1996-present
• 1 x 1.25

• Water Vapor
• NVAP(NASA Water Vapor Project) data
• 1988-1997
• 1 x 1

Jan - Dec 1997 1 x 1
5
Methodology

• Aerosol
• Aerosol Index
• Column integrated

• Water Vapor
• Integrated precipitable water
• L1 surface-700mb
• L2 700-500mb
• L3 500-300mb

6
Seasonal mean
Aerosol Winter
PW Winter
Aerosol Spring
PW Spring
7
Seasonal mean
Aerosol Summer
PW Summer
Aerosol Fall
PW Fall
8
Seasonal Variance
Aerosol Winter
PW Winter
PW Spring
Aerosol Spring
9
Seasonal Variance
Aerosol Summer
PW Summer
Aerosol Fall
PW Fall
10
Synoptic-Scale Correlation
Winter
Summer
Fall
Spring
11
Time-series
Winter
Spring
12
Synoptic-Scale Correlation
Winter
Summer
Fall
Spring
13
Time-series
Winter
Spring
14
Time-series
Summer
Fall
15
Conclusion

• The character of African air is not simple. Dust
  and water vapor are related in certain ways, but
  can be independent of each other.
• Data of a longer record are needed to quantify
  their relationships.

16
Future Work

• Vertical Structure
• Inter-annual variability
• New satellite data (MODIS, AQUA)
• Acknowledgment Chidong Zhang, Jeremy
  Pennington, J. Lin