AEROSOL SURFACE-AREAS DEDUCED FROM EARLY 1993 SAGE-II DATA AND COMPARISONS WITH STRATOSPHERIC PHOTOCHEMISTRY, AEROSOLS, AND DYNAMICS EXPEDITION MEASUREMENTS
Gk. Yue et al., AEROSOL SURFACE-AREAS DEDUCED FROM EARLY 1993 SAGE-II DATA AND COMPARISONS WITH STRATOSPHERIC PHOTOCHEMISTRY, AEROSOLS, AND DYNAMICS EXPEDITION MEASUREMENTS, Geophysical research letters, 22(21), 1995, pp. 2933-2936
Stratospheric Aerosol and Gas Experiment II (SAGE II) multi-wavelength
stratospheric aerosol extinction measurements are used to estimate ne
ar-global distributions of aerosol surface area density for early mont
hs of 1993. A comparison of monthly contour plots shows that the aeros
ol surface area density above the tropopause gradually decreased from
about 15 mu m(2)cm(-3) in January 1993 to about 10 mu m(2)cm(-3) in Ma
y 1993. Aerosol surface area density profiles measured by the Forward
Scattering Spectrometer Probe (FSSP-300) during the Stratospheric Phot
ochemistry, Aerosols and Dynamics Expedition (SPADE) campaign in May 1
993 are compared with estimated SAGE II surface area density profiles
obtained at nearby locations. FSSP measurements are in general, slight
ly lower than the SAGE II measurements. The possible sources of this d
iscrepancy are discussed. When 4-day average FSSP measurements are com
pared with the SAGE II zonal mean profile for May 1993 and 35 degrees
N-40 degrees N at altitudes above 16 km, the agreement is good. In add
ition, SAGE II aerosol surface area density profiles calculated by ass
uming a lognormal size distribution and by using principal component a
nalysis are compared, good agreement is shown at high altitudes. Howev
er, at low altitudes their differences may be as high as 25%.