Links between precipitation and aerosol: a case study from MAGIC Johannes Mohrmann 3 rd June, 2015 ATMS 491: Aerosol-Cloud Interactions

Outline Background and Methods Aerosol budgets and precipitation terms The MAGIC dataset Parameterizations of precipitation losses Results so far Diurnal cycle Relative size of loss terms Future Work

(MBL) Aerosol budget Wood et al, 2012 Precipitation-driven loss of aerosol Hoose et al, 2008

Question: How relevant are coalescence scavenging and subcloud scavenging to the aerosol budget? Is there any signal from precipitation in the aerosol budget?

UHSAS Aerosol Measurements

Precip measurements Have direct measurements of surface precipitation Radar-derived estimates are better for coalescence scavenging (estimate cloud-base precipitation formation) Wood, 2005

Aerosol diurnal cycle Tomlinson et al, 2007 Peak in aerosol in afternoon (3pm), decline at night, minimum in early morning (7am) Consistent with results from south-east Pacific (Stratus)

Comparison of terms

Parameterization of subcloud scavenging From Henzing et al, 2006 Geometric sweepout, assume terminal velocity, gamma-dist DSD, collection efficiency = collision efficiency, from S&P (1998)

Coalescence scavenging, in-cloud From Wood, 2006 More conservative estimate:

Comparing magnitude

Future work