Moderate Resolution Imaging Spectroradiometer (MODIS) Product and Download Information

Customers who have used the MODIS database previously can fast track the ordering process by

• visiting the pre–processed product download online; or
• Order MODIS data (to be processed) from the Australian Centre for Remote Sensing (ACRES) archive

MODIS data is available through two different mechanisms depending on the age of the data.

• MODIS online pre–processed products less than seven days old
• MODIS Product Delivery Schedule
• Product specifications
• Level 1B Swath online product
• Level 1B Map Oriented online product
• Surface Reflectance Swath online product
• Surface Reflectance Map Oriented online product
• Detailed ordering procedure to download online pre–processed products less than seven days old

• MODIS online Nadir BRDF–Adjusted Reflectance (NBAR) products

• MODIS products from the archive (more than seven days old)
  • Level 1B archive product specifications

• Importing and georeferencing MODIS data
• Enquiries
• Trading conditions

More information about the MODIS instrument can be obtained here.

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MODIS online pre–processed products

Processed MODIS data is available free of charge from the ACRES download site for acquisitions over the past seven days. Processed data older than seven days will be removed from the download site, while its source date remains in the MODIS archive.

The MODIS products described below result from ACRES changing Level 1 processing software from International MODIS and AIRS Processing Package (IMAPP) to SeaWiFS Data Analysis System (SeaDAS MODISL1DB).

Level 1B products contain calibrated and geolocated at–aperture radiances for 36 bands generated from MODIS Level 1A sensor counts (MOD01).

Surface Reflectance products are the result of the implementation of the MODIS Surface Reflectance algorithm (MOD09). Surface Reflectance products represent an estimate of the land surface spectral reflectance as it would be measured at ground level in the absence of atmospheric absorption and scattering and assumes the surface is isotropic ie.no Bi–Directional Reflectance Distribution Factor (BRDF) correction.

Description	Format	Processing	Projection
Level 1B Swath	HDF – EOS	SeaDAS	Not Projected
Level 1B Map Oriented	GEOTIFF, ENVI / ER Mapper header	SeaDAS –MRTSwath	Map Oriented – Equirectangular
Surface Reflectance Swath	HDF – EOS	SeaDAS – MOD09	Not Projected
Surface Reflectance Map Oriented	GEOTIFF, ENVI / ER Mapper header	SeaDAS – MOD09 – MRTSwath	Map Oriented – Equirectangular

Surface Reflectance Swath and Map Oriented online products are generated by using the SeaWiFS Data Analysis System (SeaDAS v4.9). The Surface Reflectance product also provides aerosol optical depths (AODs) and water vapour as bi–products. The Surface Reflectance Swath product is available in the HDF–EOS format and the Surface Reflectance Map Oriented is available in 16 bit GEOTIFF in Equirectangular Projection and includes both ER Mapper and ENVI Headers

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MODIS Product Delivery Schedule

MODIS products are available around 24 hours after image acquisition and have a sub 250 metre pixel registration accuracy.

The generation of surface reflectance product requires the use of observed climatic data. This data is not available for up to four days after image acquisition. The availability of the climatic data will determine the earliest availability of the surface reflectance products.

MODIS Products	Attitude and Ephemeris Source	Delivery time
L1B Swath and Map Oriented	Post – pass (observed)	≅ 1 day after acquisition *
Surface Reflectance Swath and Map Oriented	Post – pass (observed)	≅ 3–4 days after acquisition*

*Note: Depends on Post – pass ancillary data availability

A summary of MODIS Product availability is provided below.

Product	Day 0	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6	Day 7
L1B (Post – pass ephemeris)
Surface Reflectance

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Product specifications

Level 1B Swath online product

Scene Size (Granule)	ACRES offer Level 1B full length pass products and 10 degree Granule products.
Pixel size and File sizes for download	Pixel size (metres)	Bands	Approximate zipped archive size – total (Mb)
	250	1–2	330
	500	1–7 (bands 1–2 resampled)	300
	1000	1–36 (bands 1–7 resampled)	300
Processing level	Level 1B
Format	HDF – EOS
Software	SeaDAS v4.9
File naming convention for Level 1B HDF files	<product>_<satellite>_<granule start time>_<granule end time>.hdf example: MOD021KM.Terra20031005T123241Z20031005T124320Z.hdf MOD02HKM.Terra20031005T123241Z20031005T124320Z.hdf MOD02QKM.Terra20031005T123241Z20031005T124320Z.hdf MOD03.Terra20031005T123241Z20031005T124320Z.hdf

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Level 1B Map Oriented online product

Scene Size (Granule)	Across track	2,330 kilometres
	Along track	10 degrees of latitude measured along the centre line of the swath. Scene boundaries occur along the centre line at 10°S, 20°S, 30°S and 40°S. The amount of data acquired above 10°S and below 40°S varies with each acquisition.
Pixel size and File sizes for download	Pixel size (metres)	Bands	Approximate zipped archive size – total (Mb)
	250	1–2	200
	500	1–7 (bands 1–2 resampled)	180
	1000	1–36 (bands 1–7 resampled)	230
Processing level	Map Oriented Level 1B – 10 degree Granule product derived from Level 1B data. Pixel values are converted to radiance (W/m2/sr/µm) using 32 bit floating point calculations and scaled to 16 bit output to reduce the data volume.
Format	GEOTIFF signed 16 bit file with ER Mapper and ENVI headers.
Projection	Equirectangular.
Software	MRT Swath Tool v2.1
File naming convention for Level 1B Map Oriented GEOTIFF	<satellite>_<orbit>_<granule>_<res>_<band> example: TERRA_34071_1_1km_Level1B_Band_01.ers (ER Mapper) TERRA_34071_1_1km_Level1B_Band_01.tif (GEOTIFF) TERRA_34071_1_1km_Level1B_Band_01.tif.hdr (ENVI) TERRA_34071_1_1km_Level1B_Band_01.tfw (GEOTIFF world file) res– 250m, 500m, 1km Customers need to define the new projection file in ER Mapper and ENVI. Please see information on georeferencing ACRES MODIS data into image processing systems for more details.
Locational accuracy	Within 1 pixel for both TERRA and AQUA MODIS data.

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Surface Reflectance Swath online product

Scene Size (Granule)	ACRES offer Surface Reflectance full length pass products and 10 degree granule products.
Pixel size and File sizes for download	Pixel size (metres)	Bands	Approximate zipped archive size – total (Mb)
	Surface Reflectance Full Resolution	1–7 & 26	860
	Surface Reflectance Coarse Resolution (CRS)	1–7 & 26	10
Processing level	Surface Reflectance – 10 degree Granule product derived from Surface Reflectance data. Pixel values are scaled from reflectance units (*10000) to reduce the data volume.
Format	HDF – EOS
Software	MOD09 (Collection 4 equivalent LPDAAC)
File naming convention for Surface Reflectance HDF	<product>_<satellite>_<granule start time>_<granule end time>.hdf example: MOD09.Terra20031005T123241Z20031005T124320Z.hdf (full resolution output) MOD09CRS.Terra20031005T123241Z20031005T124320Z.hdf (coarse resolution output)

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Surface Reflectance Map Oriented online product

Scene Size (Full Swath)	Across track	2,330 kilometres
	Along track	Full Swath
Pixel size and File sizes for download	Pixel size (metres)	Bands	Approximate zipped archive size – total (Mb)
	250	1–2	520
	500	1–7	430
	1000	1–7 & 26	100
Processing level	Map Oriented Surface Reflectance. Pixel values are scaled from reflectance units (*10000) to 16 bit output to reduce the data volume.
Format	GEOTIFF signed 16 bit file with ER Mapper and ENVI headers.
Projection	Equirectangular.
Software	MRT Swath Tool v2.1
File naming convention for Surface Reflectance Map Oriented GEOTIFF	<satellite>_<orbit>_<0>_<res>_<band> example: TERRA_34071_0_1km_Surface_Reflectance_Band_01.ers (ER Mapper) TERRA_34071_0_1km_Surface_Reflectance_Band_01.tif (GEOTIFF) TERRA_34071_0_1km_Surface_Reflectance_Band_01.tif.hdr (ENVI) TERRA_34071_0_1km_Surface_Reflectance_Band_01.tfw (GEOTIFF world file) res– 250m, 500m, 1km Customers need to define the new projection file in ER Mapper and ENVI. Please see information on georeferencing ACRES MODIS data into image processing systems for more details.
Locational accuracy	Within 1 pixel for both TERRA and AQUA MODIS data.

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Detailed ordering procedure to download MODIS products less than seven days old

For the initial download, customers are required to go to the MODIS Register page and enter your relevant personal or company details and the purpose for which the product is being used. Customers also must also read and agree to the licence conditions.

After agreeing to the licence conditions, a login name and password will be generated to allow access to the relevant part of the ACRES download site. This information is automatically sent within 30 minutes via the e–mail address quoted in the licence page. The login name and password is valid for all subsequent MODIS downloads of free data.

Once a customer is registered to become a licensee, the MODIS Online Data pages provide details of scenes from the past seven days which are available for download. These pages may be viewed at any time, but whenever a file is selected for download, the login name and password must be provided for a successful download.

There are two ways to download this recent data from the ACRES site:

• FTP which requires ftp client software and may permit regular automatic download; and
• HTTP which uses the customer's current browser to download the file.

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MODIS online Nadir BRDF–Adjusted Reflectance (NBAR) products

The Bi–directional Reflectance Distribution Function (BRDF) models the anisotropic scattering effects of surfaces under different illumination and observation conditions. In simple terms, BRDF describes mathematically the changes in reflectance that we observe when an illuminated target is viewed from different angles. BRDF enables prediction of surface reflectance as a function of solar and viewing geometry. The BRDF is wavelength dependent and is determined by the structural and optical properties of the surface. These properties include shadowing, multiple scattering, transmission, reflection, and absorption and emission by surface elements.

The high temporal frequency and large area coverage of MODIS make it well suited to determine the land surface BRDF properties from multi–date observations that are useful for time series analyses which need to account for observations that have different sensor/solar geometries. The BRDF parameters derived from the BRDF fitting can be inverted to predict what reflectance should be in a given sensor/solar geometry. This allows prediction of reflectance for nadir observations at a mean solar zenith angle over the 16 days period to generate Nadir BRDF adjusted reflectance (NBAR) products.

MODIS NBAR products are operationally produced from 16 days of registered, multi–band, atmospherically corrected surface reflectance data from the MODIS instrument aboard the Terra and Aqua satellite at a 500m spatial resolution. ACRES use Direct Broadcast MOD43 package from Boston University to generate NBAR composite products. In addition to the NBAR composite products, the BRDF parameters for each band, the ancillary and band quality information are also provided for customer download.

Description	Format	Processing	Projection
NBAR Band 1~7	GEOTIFF	SeaDAS – MOD09 – MOD43 – MRT	Equirectangular
BRDF parameters Band 1~7	GEOTIFF	SeaDAS – MOD09 – MOD43 – MRT	Equirectangular
BRDF Ancillary Band 1~7	GEOTIFF	SeaDAS – MOD09 – MOD43 – MRT	Equirectangular
BRDF Band 1~7 quality	GEOTIFF	SeaDAS – MOD09 – MOD43 – MRT	Equirectangular

MODIS products from the archive

MODIS acquisitions more than seven days old are archived as raw data and can be accessed through the ACRES Digital Catalogue. The archive of raw MODIS data was started in May 2000 and is processed into products for each individual client order.

MODIS archive data is now processed using the SeaWIFS Data Analyaia System (SeaDAS and includes surface reflectance products (MOD 09).

To access MODIS archived data, log on to the digital catalogue as a registered user and perform a search. Select the scene required, add it to the shopping cart and then submit the scene selected for processing which will result in the option to proceed to the online ordering page for MODIS archived data.

Note that data from only one swath at a time can be selected for processing and customers will be notified at a later date when the scene has been processed and is ready for download. This can take one day or longer, depending on the demand placed on the system by the customers.

The products are generated using post–pass ephemeris information with orders processed on a first–come first–served basis. It can take up to one month after acquisition before archived products are available. Customers requiring recent MODIS data are advised to access the MODIS pre–processed products within seven days of acquisition.

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Level 1B Archive products

Products	Level 1B Swath – Full Pass. Level 1B Swath – 10 Degree Granule. Level 1B Map Oriented – 10 Degree Granule Level 1B Map Oriented – Full Swath MOD 09 HDF – Single Granule MOD 09 HDF – Full Swath MOD 09 Map Oriented – Single Granule MOD 09 Map Oriented – Full Swath PDS Level 0 – Full Swath
Bands available (pixel size at nadir)	Bands 1 and 2: 250 metres. Bands 3–7: 500 metres. Bands 8–36: 1000 metres.
Media	Online or DVD (file sizes are between approximately 1.5Gb and 2.5Gb, when compressed).
Data on offer	All ACRES archive data.
Price	Free online or $150 per swath on one DVD.
Format	Either as HDF Level 1B Swath full–pass or as HDF Level 1B Swath 10 degrees, or GEOTIFF with ER Mapper and ENVI header (scaled down from 32 bit) at 10 degrees.
Software	SeaDAS v 4.9
Quick–look imagery	Quick–look images for most of ACRES archived MODIS data are available on the ACRES Digital Catalogue.

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Importing and georeferencing MODIS data

See guidelines for importing and georeferencing ACRES MODIS data into image processing systems.

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Enquiries

Further enquiries and orders may be placed with ACRES MODIS Archived Product distributors and with ACRES Customer Services.

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Trading conditions

Special copyright conditions apply to the sale of satellite data. To purchase satellite data products, customers must agree to the licence conditions covering its use as outlined in ACRES End–User Licence Agreements.