Summary
Measurements of w0 are necessary for local estimates of aerosol forcing
Observations of aerosol climate forcing properties reveal pronounced differences for different aerosol types - variabilities large compared with values used in current models
w0 shows less variability in the vertical. Ground-based measurements may be representative of the lower column
Notes:
- w0 shows considerable variability on a variety of spatial and temporal scales. We need to understand this variability to accurately assess aerosol forcing questions. Using w0 = 0.95 in a model or satellite retrieval algorithm may not be good enough.
- Surface measurements may be representative of the vertical column, at least through several km AGL.