Presentation on theme: "Sea salt aerosols: Their generation and role in the climate system Ph. D. Dissertation Proposal Magdalena D. Anguelova November 12, 1999 College of Marine."— Presentation transcript:
Sea salt aerosols: Their generation and role in the climate system Ph. D. Dissertation Proposal Magdalena D. Anguelova November 12, 1999 College of Marine Studies University of Delaware
Outline What? n Problem statement How? n Implementation Why? n Implications
Problem statement n Modify the currently available sea-salt generation function. n Evaluate the effect of sea-salt aerosols on the climate system.
The Role of the Aerosols n In climate: n n In atmospheric chemistry: n n Scatter sunlight; n n Facilitate cloud droplet formation; n n Provide site for chemical reactions.
“...However, it generates too much big sea-salt particles at high wind speeds compared to observations and is therefore neglected in the simulation.” “... However, it generates too much big sea-salt particles at high wind speeds compared to observations and is therefore neglected in the simulation.” Aerosols in Climate Models n Improves model predictions; n Canadian Climate Model (Gong, Barrie, Blanchet, 1997) n n Use the first sea-salt generation function (Monahan et al., 1986)
Sea Spray Formation n n Direct; n n Indirect. Andreas et al., 1995
Sea Spray Sizes r, m 5001001010.1 Film drops: 0.5 to 5 m Jet drops: 3 to 50 m Spume drops: 20 to > 500 m Andreas, 1998
Sizes Relevant to Aerosol Forcing n Long residence time. n n Gravitational settling. Heat exchangeAerosol forcing r, m 5001001010.1
Modeling the Indirect Mechanism d F 0 /d r = 1.373 U 10 3.41 r -3 (1 + 0.057r 1.05 ) 10 1.19e -B2-B2 B = (0.38 - log r) / 0.65 Monahan et al., 1986 d F 0 /d r = f (U 10, r) Whitecap coverage W
Modeling the Direct Mechanism d F 1 /d r = C 1 (U 10 ) r -1 10 m r 37.5 m d F 1 /d r = C 2 (U 10 ) r -2.8 37.5 m r 100 m Andreas, 1998 d F 1 /d r = f (U 10, r) Coefficients C i
The Goal d F 0 /d r d F /d r = f (U 10, r) f (U 10, T, T s, S, f, d, C, r) ? W (U 10, T, T s, S, f, d, C) d F 1 /d r C i (U 10, T, T s, S, f, d, C) Method
TsTs The Concept e - e s e f - e s W = eT s =CalculatedObserved TBTB = e s (1-W )T s + W e f T s B A
The Procedure n Data n Compute W n n Preparation n n Brightness temperature; n n Wind mask; n n Cloud mask; n n Rain mask; n n Available T s ; n n Calculate e; n n Calculate e s ; n n Calculate e f ; n n Calculate W. e eses eses n n Salinity; n n Sea surface temperature;
Brightness Temperature T B (h), K March 27, 1998Ascending pass SSM/I 19 GHz Grid: 0.5 o 0.5 o Data