Congo Basin Satellite Data Clearinghouse

• Landsat
• MODIS
• ASTER
• SPOT
• CBERS
• Very High Resolution
• Radar
• LiDAR

Landsat 5 scene from within the DRC

The Landsat program offers the longest continuous global record of land cover images beginning in 1972 with Landsat 1. The first five Landsats carried the Multispectral Scanner System (MSS) sensor that had a spatial resolution of 68 m by 83 m and contained four bands, while Landsat 3 contained an additional thermal band. Then beginning in 1982, Landsat 4 and later Landsat 5 both carried the Thematic Mapper (TM), which has seven bands at a 30 m spatial resolution except the thermal band that has a 120 m spatial resolution. Landsat 6 failed to achieve orbit and was lost. Landsat 7 was launched in 1999 and contained the Enhanced Thematic Mapper Plus (ETM+), which is an improved version of the TM sensor. The ETM+'s thermal band has an improved spatial resolution of 60 m compared to the TM's 120 m spatial resolution. In addition the ETM+ also contains a 15 m panchromatic band. Landsat 1-3 had repeat coverage every 18 days and Landsat 4, 5, and 7 repeat their coverage every 16 days.

Currently both Landsat 5 and Landsat 7 are still operational. However, Landsat 7 has suffered a failure of its Scan Line Corrector (SLC) assembly, which controls the cross track motion of the scan mirror. The Landsat 7 ETM+ images still acquire about 75% of the data for each scene with wedge shaped gaps along the edges of the scenes. Landsat 5 has been operational for 27 years, while its original mission was meant to last only for 3 years. The capabilities of the satellite to transmit data to earth have recently decreased enough to warrant NASA to make it suspend transmission for 3 months, and prepare for the satellite's eventual decommissioning.

The continuous global record, medium spatial resolution, and the opening up of the Landsat archives to the public in 2008 has made this dataset one of the most prevalent in earth system studies. However, once Landsat 5 is no longer able to transmit at all and with Landsat 7's imaging capacity reduced by the SLC malfunction, there is the concern that earth observations dependent on the Landsat system will be impaired. NASA is preparing the Landsat Data Continuity Mission (LDCM) that will have another Landsat satellite in space around 2013, however it is possible that there will be an earth observation data gap before the LDCM is operational.

• Further Information:
  NASA Landsat Program
  NASA Landsat Data Continuity Mission


• Helpful Data Tools:
  Band Information and Useful Combinations
  Useful Landsat Band Combinations


• Data Acquisition links:
  USGS Global Visualization Viewer FREE
  
  • USGS Global Visualization View (GloVis) offers ASTER, Landsat, MODIS, EO-1, and a number of other image collections.
  • Registration is required, but it can be done once you have completed your search for the necessary scenes.
  • Under the "Collection" tab you can select the satellite and the data collection/sensor you are interested in. Then you can refine your search by Lat/Long, Path/Row, date, cloud cover, etc.
  • If you already have an area of interest you can you can upload a shapefile from under the "Map Layers" tab to define your search area.
  • A scene list can be saved to your local machine for later upload back to GloVis before you send the list to your cart for ordering.
  • Optional viewing of scene Metadata and scene natural color image (JPEG) before you download.
  • The USGS product delivery is either through direct download, order, or FTP, depending on the product and if any processing is required.

  
  
  
  USGS EarthExplorer FREE
  
  • Earth Explorer offers a number of data products that include satellite imagery, imagery mosaics, digital elevation models, and other land cover products.
  • Easy to use interface starting with defining your location of interest, selecting data set, and defining additional criteria such as cloud cover or data level type.
  • Registration is required, but it can be done once you have completed your search for the necessary scenes.
  • Metadata and an image can be previewed before selecting any image for download or ordering.
  • The USGS product delivery is either through direct download, order, or FTP, depending on the product and if any processing is required.

  
  
  
  ECHO's Reverb Client FREE
  
  • Reverb is NASA's replacement for the Warehouse Inventory Tool (WIST).
  • Search by spatial definition, temporal range, platform and instruments, processing level, and campaigns.
  • Download URLs for the data locations or download a FTP Batch Script for automatic download of selected files, handy for bulk downloads.

  
  
  
  OSFAC Satellite Data and Products
  
  • Observatoire Satellital des Forêts d'Afrique Centrale (OSFAC).
  • Offers Landsat, Landsat Mosaics, ASTER, and Shuttle Radar Topography Mission (SRTM) data.
  • Satellite database covering the entire Congo Basin based in Kinshasa, DRC and OSFAC focal points.
  • Ideal for data sharing requests coming from within the region.

  
  
  
  

MODIS, south eastern DRC.
Detected fires and borders are highlighted.

Source:
NASA LANCE Rapid Response

MODIS stands for MODerate Resolution Imaging Spectroradiometer. MODIS instruments are a part of the payloads on board NASA's Earth Observing System (EOS) Terra (EOS AM) and Aqua (EOS PM) satellites. Terra (EOS AM) was launched December 1999 and Aqua (EOS PM) was launched May 2002. The orbit of Terra goes from north to south across the equator in the morning and Aqua passes south to north over the equator in the afternoon, resulting in global coverage every 1 to 2 days with ground track repeat cycles every 16 days. The spatial resolution varies depending on the bands: 250 m, 500 m, or 1000 m.

MODIS is notable for being the first satellite imagery that was designed to be freely available to the public from the very beginning. Additionally, from the start MODIS has offered a number of useful data products such as: burned area, surface reflectance, vegetation indices, land surface temperature & emissivity, thermal anomalies & fire, leaf area index, gross primary productivity, albedo, land cover type, and many more. These data products are then distributed based on daily data or from temporal composites based on 8 days, 16 days, 32 days, or yearly observations.

• Further Information:
  NASA MODIS Web


• Helpful Data Tools:
  Band Information and Useful Combinations


• Data Acquisition links:
  USGS Global Visualization Viewer FREE
  
  • USGS Global Visualization View (GloVis) offers ASTER, Landsat, MODIS, EO-1, and a number of other image collections.
  • Registration is required, but it can be done once you have completed your search for the necessary scenes.
  • Under the "Collection" tab you can select the satellite and the data collection/sensor you are interested in. Then you can refine your search by Lat/Long, Path/Row, date, cloud cover, etc.
  • If you already have an area of interest you can you can upload a shapefile from under the "Map Layers" tab to define your search area.
  • A scene list can be saved to your local machine for later upload back to GloVis before you send the list to your cart for ordering.
  • Optional viewing of scene Metadata and scene natural color image (JPEG) before you download.
  • The USGS product delivery is either through direct download, order, or FTP, depending on the product and if any processing is required.

  
  
  
  USGS EarthExplorer FREE
  
  • Earth Explorer offers a number of data products that include satellite imagery, imagery mosaics, digital elevation models, and other land cover products.
  • Easy to use interface starting with defining your location of interest, selecting data set, and defining additional criteria such as cloud cover or data level type.
  • Registration is required, but it can be done once you have completed your search for the necessary scenes.
  • Metadata and an image can be previewed before selecting any image for download or ordering.
  • The USGS product delivery is either through direct download, order, or FTP, depending on the product and if any processing is required.

  
  
  
  NASA's LAADS Web FREE
  
  • LAADS Web is for accessing MODIS Level 1 and atmosphere data products through NASA.
  • No registration is required for access to the datasets.
  • Easy to use interface starting with defining product of interest, selecting temporal range, product collection, and then defining spatial area by either Lat/Long or tile identification.
  • A RGB view of the image can be viewed before downloading or ordering.
  • Most data is online for direct download, however selection of offline data will require data regeneration and later notification by email when it is ready for download.

  
  
  
  ECHO's Reverb Client FREE
  
  • Reverb is NASA's replacement for the Warehouse Inventory Tool (WIST).
  • Search by spatial definition, temporal range, platform and instruments, processing level, and campaigns.
  • Download URLs for the data locations or download a FTP Batch Script for automatic download of selected files, handy for bulk downloads.

  
  
  
  NASA LANCE Imagery FREE
  
  • NASA's Land Atmosphere Near real-time Capability for EOS (LANCE)
  • Provides near real time (3 hours or less since observation time) imagery and data products from MODIS (Terra and Aqua), AMSR-E (Aqua), AIRS (Aqua), MLS (Aura), and OMI (Aura) instruments.
  • Data is freely available with registration.

  
  
  
  

ASTER image of the White Nile, 39.1 x 40.5 km

Source:
NASA/GSFC/METI/ERSDAC/JAROS,
and U.S./Japan ASTER Science Team

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is an imaging instrument on the Earth Observing System (EOS) Terra, which was launched in 1999. ASTER is a cooperative effort between NASA, Japan's Ministry of Economy, Trade and Industry (METI) and Japan's Earth Remote Sensing Data Analysis Center (ERSDAC).

ASTER consists of three subsystems: the Visible and Near Infrared (VNIR), the Shortwave Infrared (SWIR), and the Thermal Infrared (TIR). The VNIR subsystem operates in three spectral bands at the visible and near-IR wavelengths, with a spatial resolution of 15 m. It consists of two telescopes, one nadir looking with a three spectral band detector, and the other is a backward looking with a single band detector. The backward looking telescope provides a second view of the target area in Band 3 for stereo observations. The SWIR subsystem operates in six spectral bands in the near-IR region through a single, nadir-pointing telescope that provides a 30 m spatial resolution. The TIR subsystem operates in five bands in the thermal infrared region using a single, fixed-position, nadir-looking telescope with a spatial resolution of 90 m. ASTER is currently only available for free within the U.S. and its territories, except for NASA-supported researchers and their affiliates, as well as approved educational users.

• Further Information:
  NASA ASTER Site
  NASA-Land Process Distributed Active Archive Center (LP DAAC)


• Helpful Data Tools:
  Band Information and Useful Combinations


• Data Acquisition links:
  USGS Global Visualization Viewer $$$
  
  • USGS Global Visualization View (GloVis) offers ASTER, Landsat, MODIS, EO-1, and a number of other image collections.
  • Registration is required, but it can be done once you have completed your search for the necessary scenes.
  • Under the "Collection" tab you can select the satellite and the data collection/sensor you are interested in. Then you can refine your search by Lat/Long, Path/Row, date, cloud cover, etc.
  • If you already have an area of interest you can you can upload a shapefile from under the "Map Layers" tab to define your search area.
  • A scene list can be saved to your local machine for later upload back to GloVis before you send the list to your cart for ordering.
  • Optional viewing of scene Metadata and scene natural color image (JPEG) before you download.
  • The USGS product delivery is either through direct download, order, or FTP, depending on the product and if any processing is required.

  
  
  
  USGS EarthExplorer $$$
  
  • Earth Explorer offers a number of data products that include satellite imagery, imagery mosaics, digital elevation models, and other land cover products.
  • Easy to use interface starting with defining your location of interest, selecting data set, and defining additional criteria such as cloud cover or data level type.
  • Registration is required, but it can be done once you have completed your search for the necessary scenes.
  • Metadata and an image can be previewed before selecting any image for download or ordering.
  • The USGS product delivery is either through direct download, order, or FTP, depending on the product and if any processing is required.

  
  
  
  ECHO's Reverb Client $$$
  
  • Reverb is NASA's replacement for the Warehouse Inventory Tool (WIST).
  • Search by spatial definition, temporal range, platform and instruments, processing level, and campaigns.
  • Download URLs for the data locations or download a FTP Batch Script for automatic download of selected files, handy for bulk downloads.

  
  
  
  OSFAC Satellite Data and Products
  
  • Observatoire Satellital des Forêts d'Afrique Centrale (OSFAC).
  • Offers Landsat, Landsat Mosaics, ASTER, and Shuttle Radar Topography Mission (SRTM) data.
  • Satellite database covering the entire Congo Basin based in Kinshasa, DRC and OSFAC focal points.
  • Ideal for data sharing requests coming from within the region.

  
  
  
  

SPOT-5 HRG at 10m spatial resolution within the central
Democratic Republic of Congo

CBERS-2B, Sensor: CCD.
Aripuanã region, in Mato Grosso, has presented
with deforestation. The red areas are exposed soil
and regular shapes indicate deforested area.

Source:
CBERS/INPE

A panchromatic Quickbird-2 image from within the DRC.
Individual trees and other features are clearly observable.

A multispectral Ikonos image from northeastern Rwanda.
Farm fields can be seen along the edge of the Volcanoes
National Park.

A multispectral WorldView-2 image from within the DRC.

A multispectral GeoEye-1 image from the eastern DRC.

Radar

A wide-swath Advanced Synthetic Aperture Radar (ASAR)
image of the Congo River in the eastern DRC.

Source:
Earth Snapshot

Radar is an active remote sensing system that utilizes the microwave/radio portion of the EM spectrum and can be used throughout all weather conditions and during night or day. One of the most common types of radar instruments is the Synthetic Aperture Radar (SAR). Over the years there have been a number of satellites with radar systems which include, but are not limited to: SIR-(A, B, C), RADARSAT-1-2, ERS-1-2, JERS-1, SEASat and ENVISAT. The radar ranging system works by emitting a pulse towards the target and then using an antenna to receive and record the round trip time and strength of the resulting backscatter. Backscatter will vary depending the target's electrical and water content properties, plus backscattering will change based on the use of different polarizations.

Some SARs can transmit pulses in either horizontal (H) or vertical (V) polarization and receive in either H or V, with the resultant combinations of HH (Horizontal transmit, Horizontal receive), VV, HV, or VH. Low-frequency SARs may be used under certain conditions to penetrate foliage and even soil. This provides the capability for imaging targets normally hidden by trees, brush, and other ground cover. To obtain adequate foliage and soil penetration, SARs operate at relatively low frequencies (10's of MHz to 1 GHz).

Another type of radar is the Phased Array type L-band Synthetic Aperture Radar (PALSAR). PALSAR uses the L-band frequency range (1.27 GHz), which allows it to cover a wider swaths of area compared to normal SAR sensors. Most notably this sensor was carried onboard the Japan Aerospace Exploration Agency (JAXA) Daichi - Advanced Land Observing Satellite (ALOS). The PALSAR sensor on board ALOS had a spatial resolution ranging from 10 to 100 meters depending on the observation mode and viewing angle. ALOS operated from January 2006 until it completed its mission in May 2011. A follow on mission, ALOS-2, is planned with a possible launch in 2013 in order to continue the radar component of ALOS.

• Further Information:
  Sandia National Laboratories: What is SAR?
  JAXA about ALOS
  Radar Polarimetry


• Helpful Data Tools:
  Tutorial in Radar Remote Sensing


• Data Acquisition links:
  ASF DAAC SAR Data Archive $$$
  
  • One of NASA's Distributed Active Achieve Centers (DAAC) operated by the Alaska Satellite Facility (ASF) specializing in SAR data.
  • SAR data is available from a number of different platforms including: ERS-1, ERS-2, JERS-1, ALOS, RADARSAT-1, AIRSAR, and UAVSAR.
  • Offers browse images for each granule and data products processed to Level 0 and Level 1 (L1.0, L1.1 and L1.5 for ALOS PALSAR).
  • Must have a NASA approved proposal to order data.

  
  
  
  JAXA EORC Data Distribution Service $$$/FREE
  
  • The data distribution center for the Japan Aerospace Exploration Agency's (JAXA) Earth Observation Research Center (EORC).
  • Offers a wide range of data products that includes both radar and non-radar sensors.
  • User registration is required before searching the database.
  • Online registration through the Earth Observation Information System (EOIS) as a general researcher who is planning academic and scientific research may download specific Earth Observing Satellite data through the internet free of charge.
  • The free data available for general researchers includes: TRMM (PR), ADEOS-II (AMSR, GLI), and Aqua (AMSR-E).

  
  
  
  TerraSAR-X/TanDEM-X Ordering $$$
  
  • TerraSAR-X and TanDem-X are part of a Public-Private Partnership (PPP) between the German Aerospace Center (DLR) and Astrium.
  • Offers X-band SAR data with a spatial resolution from 18 m to 1 m.
  • Will soon have a high quality global Digital Elevation Model (DEM) based upon the TerraSAR-X and TanDem-X constellation.

  
  
  
  OSFAC Satellite Data and Products
  
  • Observatoire Satellital des Forêts d'Afrique Centrale (OSFAC).
  • Offers Landsat, Landsat Mosaics, ASTER, and Shuttle Radar Topography Mission (SRTM) data.
  • Satellite database covering the entire Congo Basin based in Kinshasa, DRC and OSFAC focal points.
  • Ideal for data sharing requests coming from within the region.

  
  
  
  

LiDAR

A section of a LiDAR image of a forest near Rotorua,
the profile of nine seperate trees are clearly shown.

Source:
New Zealand Ministry for the Environment

Light Detection And Ranging (LiDAR) is an active optical remote sensing technology that discharges tens of thousands of infrared pulses a second from a laser, in order to determine elevation values based on the measured travel times of pulses. Combined with a Global Positioning System (GPS) and a gyroscope, LiDAR is able to collect highly accurate elevation values with high positional accuracy. LiDAR is typically collected from planes and because it is an active sensor providing its own energy source, it can be flown day or night. However, unlike radar, LiDAR cannot penetrate clouds, rain, or dense haze and therefore is only flown during periods of fair weather.

For terrestrial and topographical applications LiDAR typically use three different systems: Single return LiDAR, Multiple returns LiDAR, and Waveform LiDAR. Single return LiDAR records just a single return per pulse, which maps only the top of the vegetation canopy or the ground surface from any of the pulses that penetrated through holes in the vegetation canopy. Multiple return LiDAR records up to five return signals per individual laser pulse, allowing the system to record more information about the three dimensional surface environment. The first return provides the canopy height measurement, the last return provides the actual ground measurement, and the intermediate returns provide information on vegetation canopy and understory structure. Waveform LiDAR records the entire return waveform from each laser pulse. These systems are similar to the multiple returns LiDAR in their uses, but they record significantly more information on the canopy and understory structure. Waveform and Multiple return systems are especially helpful for determining forest structure and biomass levels.

Currently one of the only satellite based LiDAR systems is from ICESat (2003-2009) using the GLAS (the Geoscience Laser Altimeter System), which was the first LiDAR instrument for continuous global observations. ICESAT-2, scheduled for launch in 2016 will have an updated sensor system with an along track sampling density of about 70 cm.

• Further Information:
  USGS center for LiDAR
  NSIDC ICESat/GLAS Data Summaries


• Data Acquisition links:
  NSIDC DAAC ICESat/GLAS Data FREE
  
  • One of NASA's Distributed Active Achieve Centers (DAAC) operated by the National Snow and Ice Data Center (NSIDC) specializing in ICESat/GLAS data.
  • Offers a number of data products across the globe specializing in land surface altimetry data, ocean altimetry data, cloud/aerosol data, and sea ice data.
  • Access ICESat/GLAS data directly through the NSIDC by FTP through the Data Pool or request ICESat/GLAS data through the Data Subsetter.

  
  
  
  ECHO's Reverb Client FREE
  
  • Reverb is NASA's replacement for the Warehouse Inventory Tool (WIST).
  • Search by spatial definition, temporal range, platform and instruments, processing level, and campaigns.
  • Download URLs for the data locations or download a FTP Batch Script for automatic download of selected files, handy for bulk downloads.