MODIS Sensor Startpage ------------------------ MODIS Sensor Navigation ------------------------ MODIS Archive Available Data

MODIS (or Moderate Resolution Imaging Spectroradiometer) is a key instrument aboard the Terra (EOS AM, launched on 18 December 1999) and Aqua (EOS PM, launched on 4 May 2002) satellites. Terra's orbit around the Earth is timed so that it passes from north to south across the equator in the morning, while Aqua passes south to north over the equator in the afternoon. Terra MODIS and Aqua MODIS are viewing the entire Earth's surface every 1 to 2 days, acquiring data in 36 spectral bands, or groups of wavelengths between 0.405 and 14.385 µm, and it acquires data at three spatial resolutions -- 250m, 500m, and 1,000m. The MODIS instrument has a viewing swath width of 2,330 km.

Objectives

The MODIS is measuring visible and infrared radiation and obtaining data that are being used to derive products ranging from vegetation, land surface cover, and ocean chlorophyll fluorescence to cloud and aerosol properties, fire occurrence, snow cover on the land, and sea ice cover on the oceans. The MODIS scanner with the 36 channels covers those parts of the spectrum currently imaged by AVHRR and SeaWiFS plus a great deal more. MODIS' bands are particularly sensitive to fires; they can distinguish flaming from smoldering burns and provide better estimates of the amounts of aerosols and gases fires release into the atmosphere.

The MODIS Aerosol Product monitors the ambient aerosol optical thickness over the oceans globally and over a portion of the continents. Further, the aerosol size distribution is derived over the oceans, and the aerosol type is derived over the continents. The MODIS Precipitable Water product consists of column water-vapour amounts. During the daytime, a near-infrared algorithm is applied over clear land areas of the globe and above clouds over both land and ocean. Over clear ocean areas, watervapor estimates are provided over the extended glint area. The MODIS Cloud Product combines infrared and visible techniques to determine both physical and radiative cloud properties. Daily global Level 2 data are provided. Cloud-particle phase (ice vs. water, clouds vs. snow), effective cloudparticle radius, and cloud optical thickness are derived using the MODIS visible and near-infrared channel radiances. An indication of cloud shadows affecting the scene is also provided. Cloud-top temperature, height, effective emissivity, phase (ice vs. water, opaque vs. non-opaque), and cloud fraction are produced by the infrared retrieval methods both day and night The MODIS Atmospheric Profiles product (MOD 07) consists of several parameters: they are total-ozone burden, atmospheric stability, temperature and moisture profiles, and atmospheric water vapor.

Instrument

Orbit: 705 km, 10:30 a.m. descending node (Terra) or 1:30 p.m. ascending node (Aqua), sun-synchronous, near-polar, circular

Data Access (Atmosphere)

After Level 0 processing at EDOS, the Goddard Space Flight Center Earth Sciences Distributed Active Archive Center (GES DAAC) produces the Level 1A, Level 1B, geolocation and cloud mask products. Higher-level MODIS land and atmosphere products are produced by the MODIS Adaptive Processing System (MODAPS). MODIS Level 1 data, geolocation, cloud mask, and Atmosphere products:
http://ladsweb.nascom.nasa.gov/data
https://lpdaac.usgs.gov/lpdaac/products/modis_products_table and http://modis-atmos.gsfc.nasa.gov/

MOD 04 - Aerosol Product
The MODIS Aerosol Product (MOD 04) monitors the ambient aerosol optical thickness over the oceans globally and over a portion of the continents. Further, the aerosol size distribution is derived over the oceans, and the aerosol type is derived over the continents. Daily Level 2 (MOD 04) data are produced at the spatial resolution of a 10 x 10 1-km (at nadir)- pixel array.

MOD 05 - Total Precipitable Water (Water Vapor)
The MODIS Precipitable Water product (MOD 05) consists of column water-vapor amounts. During the daytime, a near-infrared algorithm is applied over clear land areas of the globe and above clouds over both land and ocean. Over clear ocean areas, watervapor estimates are provided over the extended glint area. An infrared algorithm for deriving atmospheric profiles is also applied both day and night for Level 2. The Level 2 data are generated at the 1-km spatial resolution of the MODIS instrument using the nearinfrared algorithm during the day, and at 5 � 5 1-km pixel resolution both day and night using the infrared algorithm when at least nine FOVs are cloud free.

MOD 06 - Cloud Product
The MODIS Cloud Product (MOD 06) combines infrared and visible techniques to determine both physical and radiative cloud properties. Daily global Level 2 (MOD 06) data are provided. Cloud-particle phase (ice vs. water, clouds vs. snow), effective cloudparticle radius, and cloud optical thickness are derived using the MODIS visible and near-infrared channel radiances. An indication of cloud shadows affecting the scene is also provided. Cloud-top temperature, height, effective emissivity, phase (ice vs. water, opaque vs. non-opaque), and cloud fraction are produced by the infrared retrieval methods both day and night at 5 x 5 1-km-pixel resolution.

MOD 07 - Atmospheric Profiles
The MODIS Atmospheric Profiles product (MOD 07) consists of several parameters: they are total-ozone burden, atmospheric stability, temperature and moisture profiles, and atmospheric water vapor. All of these parameters are produced day and night for Level 2 at 5 x 5 1-km pixel resolution when at least 9 FOVs are cloud free.

MOD 08 - Gridded Atmospheric Product
There are three MODIS Level 3 Atmosphere Products, each covering a different temporal scale. The Earth Science Data Type names (and time spans) for each of the products are: MOD08_D3 (Daily), MOD08_E3 (8-Day), MOD08_M3 (Monthly). Each of these Level 3 products contains statistics derived from over 50 science parameters from the Level 2 Atmosphere products: MOD04_L2, MOD05_L2, MOD06_L2, and MOD07_L2. MOD 35 - Cloud Mask The MODIS Cloud Mask product (MOD 35) is a daily, global Level 2 product generated at 1-km and 250-m (at nadir) spatial resolutions. The algorithm employs a series of visible and infrared threshold and consistency tests to specify confidence that an unobstructed view of the Earth's ½s surface is observed. An indication of shadows affecting the scene is also provided. The 250-m cloud-mask flags are based on the visible channel data only. Radiometrically accurate radiances are required, so holes in the Cloud Mask will appear wherever the input radiances are incomplete or of poor quality.

The TERRA and AQUA Platforms

Terra is a multi-national, multi-disciplinary mission and was launched on 18 December 1999. The mission involves partnerships with the aerospace agencies of Canada and Japan. Managed by NASA's Goddard Space Flight Center, the mission also receives key contributions from the Jet Propulsion Laboratory and Langley Research Center. On February 24, 2000, Terra began collecting what will ultimately become a new, 15-year global data set on which to base scientific investigations about our complex home planet. Instruments include ASTER, CERES, MISR, MODIS and MOPITT. http://terra.nasa.gov/

Aqua was launched on May 4, 2002. Aqua, Latin for water, is a NASA Earth Science satellite mission named for the large amount of information that the mission will be collecting about the Earth's water cycle, including evaporation from the oceans, water vapor in the atmosphere, clouds, precipitation, soil moisture, sea ice, land ice, and snow cover on the land and ice. Additional variables also being measured by Aqua include radiative energy fluxes, aerosols, vegetation cover on the land, phytoplankton and dissolved organic matter in the oceans, and air, land, and water temperatures.The Aqua mission is a part of the NASA-centered international Earth Observing System (EOS). Aqua was formerly named EOS PM, signifying its afternoon equatorial crossing time.

Aqua carries six state-of-the-art instruments in a near-polar low-Earth orbit. The six instruments are the Atmospheric Infrared Sounder (AIRS), the Advanced Microwave Sounding Unit (AMSU-A), the Humidity Sounder for Brazil (HSB), the Advanced Microwave Scanning Radiometer for EOS (AMSR-E), the Moderate Resolution Imaging Spectroradiometer (MODIS), and Clouds and the Earth's Radiant Energy System (CERES). Aqua was the first member launched of a group of satellites termed the Afternoon Constellation, or sometimes the A-Train. The second member to be launched was Aura, in July 2004, the third member was PARASOL, in December 2004, and the fourth and fifth members are CloudSat and CALIPSO, in May 2006. Expected upcoming missions are OCO and Glory, with the placement of Glory not yet determined. Once completed, the A-Train will be led by OCO, followed by Aqua, then CloudSat, CALIPSO, PARASOL, and, in the rear, Aura. http://aqua.nasa.gov/

Links

MODIS home page http://modis-atmos.gsfc.nasa.gov/
http://modis.gsfc.nasa.gov/index.php

TERRA http://terra.nasa.gov

AQUA http://aqua.nasa.gov
http://mirador.gsfc.nasa.gov/

Contact

If you would like to have more information about the MODIS data, please contact wdc@dlr.de.