MODIS was launched aboard the Terra satellite on December 18, 1999 (10:30 am equator crossing time) as part of NASA's Earth Observing System (EOS) mission. MODIS with its 2330 km viewing swath width provides almost daily global coverage. It acquires data in 36 high spectral resolution bands between ... 0.415 to 14.235 micron with spatial resolutions of 250m(2 bands), 500m(5 bands),and 1000m (29 bands). MODIS sensor counts, calibrated radiances, geolocation products and all derived geophysical atmospheric and ocean products are archived at NASA Goddard DAAC and has been made available to public since April 2000.
The MODIS level-2 atmospheric aerosol product provides retrieved ambient aerosol optical properties (e.g., optical thickness and size distribution), mass concentration, look-up table derived reflected and transmitted fluxes, as well as quality assurance and other ancillary parameters, globally over ocean and near globally over land.
The shortname for this level-2 MODIS aerosol product is MOD04_L2 and the principal investigators for this product are MODIS scientists: Dr. Yoram Kaufman for aerosol retrieval over land, and Dr. Didier Tanre (firstname.lastname@example.org) for aerosol retrieval over ocean. The MODIS aerosol product (MOD04_L2) contains global data that has a spatial resolution of 10-km (at nadir). Each MOD04_L2 product file covers a five-minute time interval. The output grid is 135 pixels in width by 203 pixels in length. Every tenth file has an output grid size of 135 by 204 pixels. MOD04_L2 product files are stored in Hierarchical Data Format (HDF-EOS). The file consists of 53 pixel level gridded aerosol parameters. These pixel level gridded aerosol parameters are stored as Scientific Data Sets(SDS) within the file. Each file is roughly 10.46 MB in size, and the total data volume is approximately 1.44 GB/day.
MODIS Data Category & Parameters
Spatial & Temporal Resolution: latitude,longitude scan start time
Solar and Sensor Viewing Geometry: solar zenith angle, solar azimuth angle sensor zenith angle, sensor azimuth angle
Aerosol Parameters for Land & Ocean (Combined) aerosol optical depth (0.55 micron) over land and ocean scattering angle
Aerosol Parameters from Ocean Retrieval Algorithm (best/average retrieval) Aerosol Particle Properties: effective optical depth at 7 bands (0.47,0.55,0.66,0.87,1.24,1.64,2.13 micron) effective radius (based on 0.55 micron) optical depth for small & large particles ratio of small mode optical depth relative to total for 0.55 micron mass concentration & cloud condensation nuclei (based on 0.55 micron) Angstrom exponents 1 (based on 0.55 and 0.865 micron) Angstrom exponent 2 (based on 0.865 and 2.13 micron) asymmetry factor & back scattering ratio at 7 bands solution indices for small & large modes
Aerosol Parameters from Land Retrieval Algorithm:
aerosol type, continental optical depth corrected optical depth, mass concentration; Angstrom exponent and dust weighting factor
Aerosol Derived Radiation Parameters from both Algorithms (Land & Ocean): reflected flux, transmitted flux mean reflectance & uncertainty
Quality Assurance & Statistical Parameters from both Algorithms(land & Ocean) : quality assurance flag, cloud mask, cloud fraction, number of pixels used, least square error
These aerosol parameters will be used to study aerosol climatology, sources and sinks of specific aerosol types (e.g. sulfates and biomass burning aerosol), interaction of aerosols with clouds, and atmospheric corrections of remotely sensed surface reflectance over the land. This product will also be used to monitor aerosol mass concentration, aerosol optical properties, and radiative forcing on a global scale.
Near real-time (NRT) data are available from MODAPS for certain Aqua and Terra MODIS L0, L1, L2, L2G, and L3 products. Whereas the standard MODIS forward processing acquires 2-hour L0 files for Aqua and Terra from EDOS within 7-8 hours of real time, LANCE-MODIS acquires session-based L0 files from EDOS and the end of the session is available within 10-30 minutes after real time.
The 'version 004' or 'collection 004' product is better than 'version 003' and earlier versions. The quality of this version 004 product is ... established as 'Validated' . This means its accuracy has been assessed over a widely distributed set of locations and time periods via several ground-truth and validation efforts. Results are peer-reviewed and published at scientific conferences and workshops.For the latest information please see: http://modis-atmos.gsfc.nasa.gov/products_calendar_overview.html.
Available to public to gain familiarity with the data format and parameters.
This Data set (version 004/collection 004) is of 'Validated' Quality. This data is appropriate for use in scientific publications. ... Before using it in any publication please the contact science team representative for the known problems and updates.
Laboratorie d'Optique Atmospherique
Bat. P5, U.S.T. deLille
Villeneuve d'Ascq Cedex
Chu, D. A., K. Strabala, S. Platnick, E. Moody, M. King, S. Mattoo, R. Hucek, and B. Ridgway, 2000: MODIS Atmosphere QA Plan. Version 2.2 ,NASA Goddard Space Flight Center, 46 pp.
Chu, D. A., Y. J. Kaufman, L. A. Remer, and B. N. Holben,1998: Remote sensing of smoke from MODIS ... Airborne Simulator during SCAR-B experiment. Journal of Geophysical Research, 103, 31979-31988.
Gao, B.-C., and Y. J. Kaufman, 1995: Selection of the 1.375-m MODIS channelfor remote sensing of cirrus clouds and stratospheric aerosols from space, J. Atm. Sci., 52, 4231-4237.
Kaufman, Y. J., and D. Tanre,1998: Algorithm For Remote Sensing of Tropospheric Aerosol from MODIS,Algorithm Theoretical Basis Document, ATBD-MOD-02, NASA Goddard Space Flight Center,85 pp.
Kaufman, Y. J., and D. Tanre,1997: MODIS Aerosol Product, in MTPE EOS Data Products Handbook,107-108.
Kaufman, Y. J., and R. S. Fraser, 1997: The effect of smoke particles on cloudsand climate forcing. Science, 277, 1636-1639.
Kaufman, Y. J., D. Tanre, L. Remer, E. F.Vermote, A. Chu, & B. N. Holben, 1997: Operational remote sensing of tropospheric aerosol over the land from EOS-MODIS. Journal of Geophysical Research, 102(14), 17051-17068.
King, M., Y. Kaufman, P. Menzel, D.Tanre, B. Gao, 1999: MODIS Atmosphere Validation Plan, NASA Goddard Space Flight Center, 48 pp.
King, M. D., W. P. Menzel, P. S. Grant, J. S. Myers, G. T. Arnold, S. E. Platnick, L. E.Gumley, S. C. Tsay, C. C. Moeller, M. Fitzgerald, K. S. Brown and F. G.Osterwisch, 1996: Airborne scanning spectrometer for remote sensing of cloud, aerosol, water vapor and surface properties. J. Atmos. Oceanic Technol.,13, 777–794.
Remer, L. A., Y. J. Kaufman, and B. N. Holben, 1996: The size distribution of ambient aerosol particles: Smoke vs. urban/industrial aerosol. Global biomass burning. Cambridge MA: MIT Press.
Tanre, D., Y. J. Kaufman, M. Herman, and S. Mattoo, 1997: Remote sensing of aerosol properties over oceans using the MODIS/EOS spectral radiances. Journal of Geophysical Research, 102, 16971-16988.
Tanre, D., M. Herman, and Y. J. Kaufman, 1996: Information on aerosol size distribution contained in solar reflected radiances. Journal of Geophysical Research-Atmospheres, 101, 19043-19060.