HR: 1340h
AN: A33C-0927    [Abstracts]
TI: Testing MODIS retrievals of mineral dust properties
AU: * Redemann, J
EM: jredemann@mail.arc.nasa.gov
AF: BAER Institute, 4742 Suffolk Ct., Ventura, CA 93003 United States
AU: Wu, Y
EM: yhwu@atmos.washington.edu
AF: University of Washington, Box 351640 / 408 ATG, Seattle, WA 98195-1640 United States
AU: Anderson, T
EM: tadand@atmos.washington.edu
AF: University of Washington, Box 351640 / 408 ATG, Seattle, WA 98195-1640 United States
AU: Covert, D
EM: dcovert@u.washington.edu
AF: University of Washington, Box 351640 / 408 ATG, Seattle, WA 98195-1640 United States
AU: Russell, P
EM: prussell@mail.arc.nasa.gov
AF: NASA Ames Research Center, MS 245-5, Moffett Field, CA 94035 United States
AU: Schmid, B
EM: bschmid@mail.arc.nasa.gov
AF: BAER Institute, 4742 Suffolk Ct., Ventura, CA 93003 United States
AU: Livingston, J
EM: jlivingston@mail.arc.nasa.gov
AF: SRI International, G-274 333 Ravenswood Ave., Menlo Park, CA 94025 United States
AU: Remer, L
EM: Lorraine.A.Remer@nasa.gov
AF: NASA Goddard Space Flight Center, code 613.2 Bldg 33, Greenbelt, MD 20771 United States
AU: Chu, A
EM: achu@climate.gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, code 613.2 Bldg 33, Greenbelt, MD 20771 United States
AU: Jonsson, H
EM: hjonsson@nps.edu
AF: CIRPAS, 3200 Imjin Rd. Hangar #507, Marina, CA 93933 United States
AU: Buzorius, G
EM: Gbuzoriu@nps.navy.mil
AF: CIRPAS, 3200 Imjin Rd. Hangar #507, Marina, CA 93933 United States
AU: Hallar, G
EM: ahallar@arc.nasa.gov
AF: NASA Ames Research Center, MS 245-5, Moffett Field, CA 94035 United States
AU: Strawa, A
EM: astrawa@mail.arc.nasa.gov
AF: NASA Ames Research Center, MS 245-5, Moffett Field, CA 94035 United States
AB: Mineral dust aerosol is among the most difficult aerosol species to measure quantitatively from space. The observational challenges stem from the lack of knowledge on dust particle shape and absorption, and from the spatial inhomogeneity of dust plumes, which makes it difficult for certain cloud masking techniques to distinguish them from Cirrus clouds. In this paper, we first evaluate the retrievals of dust properties by the MODIS instruments during the EVE (Extended-MODIS-wavelength Validation Experiment, 2004) field campaign. Secondly, we will assess the accuracy of the retrievals of aerosol fine mode fraction (FMF) of mid-visible aerosol optical depth (AOD) based on airborne in situ and sunphotometer data collected in ACE-Asia (Aerosol Characterization Experiment - Asia, 2001), with and without mineral dust present. In EVE, a total of 36 and 49 coincident MODIS AOD validation measurements over dark water were collected for Terra and Aqua respectively, using the NASA Ames Airborne Tracking Sunphotometer, AATS-14. A preliminary analysis indicates that for MODIS-Terra about 80% of the AOD retrievals are within the estimated uncertainty of ±0.03±0.05AOD; this is true for both the visible and near-IR retrievals. For MODIS-Aqua about 50% of the AOD retrievals at all wavelengths are within the estimated uncertainty; the fraction of near-IR retrievals that fall within this uncertainty range is about 25%. The spatial variability of AOD as derived from the suborbital measurements during a few select flight segments is larger than that derived by MODIS, in particular in the near-IR. Only measurements within the scale of one retrieval box (~10 km) can be used for such a comparison. In the second part of our paper, we compare satellite retrievals of FMF from MODIS to suborbital data on the submicrometer fraction (SMF) of AOD collected in ACE-Asia. SMF is closely related to FMF and is directly measurable using in situ techniques. We find that in a limited number of case studies, the over-ocean MODIS retrievals of FMF are systematically higher by about 0.2 than the suborbital measurements of SMF. Based on our findings we recommend changes to the MODIS dust retrieval algorithm and changes to the framework for deriving and validating MODIS-based assessments of anthropogenic aerosol.
UR: http://geo.arc.nasa.gov/sgg/EVE-website/index.html
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 1640 Remote sensing (1855)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005