Data and Information
- Data Initiatives
- Satellite Sensing Systems
Data Systems for LCLUC Research
The unprecedented large volumes of data for land use research have necessitated the development of innovative data processing, delivery and analysis systems. The evolving EOS Data and Information System and a number of competed research opportunities such as REASON and ACCESS, have provided support for data systems research and development. The MODIS Advanced Data Processing System (MODAPS) at the Goddard Space Flight Center (GSFC) is generating land-cover related products from the daily MODIS instruments on board the Terra and Aqua platforms. Data products at 250m -1km are being reprocessed as the algorithms are improved to provide consistent data records. This system is currently being enhanced to provide MODIS land product distribution capabilities to augment the services provided by the NASA Distributed Active Archive Center at the Eros Data Center to meet the needs of the MODIS science community.
The Landsat Ecosystem Disturbance Adaptive processing system is developing procedures for automated atmospheric correction and mosaicing of Landsat data and the generation of high resolution disturbance time series. The Global Land Cover Facility (GLCF) at the University of Maryland has developed a low cost system for processing and distribution of large volumes of land-cover data and enhanced data sets. Similarly, the Landsat.org project developed at Michigan State University (MSU) has developed a platform independent user interface and search engine for on-line purchasing, ordering and sharing of Landsat data worldwide. The Tropical Rain Forest Information Center at MSU provides Landsat derived data sets associated with monitoring tropical deforestation.
In partnership with the private sector, NASA purchased a global data set of cloud-free Landsat imagery for 1990 and 2000. These data were orthorectified and are easily accessible and freely available. They have greatly increased the use of Landsat data for LCLUC studies worldwide. In May 2003 the Landsat 7 scan line corrector failed and although the instrument continues to receive data, the imagery are of limited use. With no Landsat instrument ready to replace Landsat 7, there is an increasing data gap, posing a critical impediment to LCLUC science. The LCLUC program, working with the USGS is developing a mid-decadal (2004-2006) high resolution global cloud-free data set to extend the previous global data sets. The data set will include data from Landsat 5, ASTER, EO1 and Landsat 7 temporal composites. This data set will include data provided by foreign ground stations and possibly foreign high resolution satellites. It is hoped that international cooperation concerning this data set could provide a prototype for future international efforts to coordinate high resolution global data acquisition from the increasing number of high resolution assets in the framework of GEOSS.
Land use and land cover change studies at regional to global scales require large numbers of field sites for algorithm development and accuracy evaluation. Rapid development in integration of digital camera, hand-held GPS device, computer and internet make it possible for both scientific communities and citizens to collect and share geo-referenced field photos. The Global Geo-Referenced Field Photo Library, developed at the Earth Observation and Modeling Facility of University of Oklahoma, offers the capacity for users to upload, query (by themes and geographically), and download geo-referenced field photos in the library. It offers interactive capacity for users to interpret and classify field photos into relevant land cover types and builds photo-based land cover database. The users can use both photos and associated databases to carry out land use and land cover analysis in a geographical information system. The users who provide field photos can decide whether individual photos are to be shared or not. This tool and the resultant photo library will enable our NASA LCLUC communities to share their field photos, and promote the NASA LCLUC effort in remote sensing.
Satellite Sensing Systems
Satellite data provide an important source of information for characterizing and monitoring land-cover and land-use change. In some regions it is the only feasible way to provide timely and reliable land-cover assessments and identify areas of rapid change. Recent land-cover history also provides a point of departure for modeling land-cover change.
NASA Current Missions for LCLUC Research
NASA currently has sensing systems at high, medium and low resolution, which meet the LCLUC program observation needs. NASA satellite systems supplement operational satellites providing systematic measurements to study long-term trends. For example, the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the EOS Terra (AM) and Aqua (PM) platforms have significantly improved on the capabilities of the operational NOAA Advanced Very High Resolution Radiometer (AVHRR). These moderate resolution data are used to classify and characterize land-cover at the global scale and to detect land-cover change at the regional scale. They also provide daily monitoring of fire activity which is often an indicator of land-cover change. The operational Defense Meteorological Satellite Program provides a capability to map the extent of night time lights and has been used by LCLUC scientists to document the extent and growth of urban areas.
Landsat 7 has provided the systematic high resolution observations necessary to map and quantify land-cover changes at the local to regional scale. The Landsat class observations are a critical underpinning for LCLUC research. The Landsat 7 global acquisition strategy providing multiple cloud-free scenes each year, has facilitated land-cover studies around the world. The LCLUC program has been pioneering methods for regional analysis of Landsat class observations setting the stage for periodic continental and global assessments of land-cover change. In this regard, the combination of systematic moderate and high resolution satellite remote sensing provides the opportunity for global scale studies and forms the basis for a global land observing system. Similarly, the NASA science programs are moving from Missions to Measurements with the aim of utilizing data from different instruments to address science questions.
Experimental measurements of limited duration are needed to better understand processes and to test new sensor technologies. For example, the Earth Observer 1 (EO1) system has provided a test-bed for new sensor technology and spaceborne hyper-spectral remote sensing. Similarly the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor has provided new high resolution thermal data collocated with MODIS data for improved surface characterization and validation of coarser MODIS thermal products. In the past experimental microwave satellite sensors operated by Europe and Japan have been used for mapping the extent of wetland areas. NASA LCLUC research in this part of the spectrum has been limited by the absence of a current US microwave sensing system.
NASA has also been exploring partnerships with industry for the commercial provision of data to meet the needs of its science community. In particular, hyperspatial data with 1-3m resolution from sensors such as IKONOS and Quickbird have been used to provide detailed validation of high resolution products.
NASA Future Missions for LCLUC Research
NASA as part of the Integrated Program Office is contributing to the NPOESS Preparatory Project (NPP). The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument is planned to transition MODIS class observations into the operational domain. The VIIRS instrument for launch in 2009 will continue the long term data records of vegetation indices, land-cover and fire. The NASA NPP Science Team is contributing to and evaluating the operational algorithms which will provide VIIRS Environmental Data Records (EDR's). The science team is determining whether these operational products will meet the needs of the science community and which additional or enhanced products will be needed.
NASA has been charged with providing a continuity mission for the Landsat class of observations. As the major science driver for this mission, the LCLUC program is concerned that the mission be launched as soon as possible to minimize the Landsat 7 data gap. There are a number of possible solutions to securing rapid high resolution data continuity including a micro satellite imaging constellation. Clearly, as part of this mission, it will be important to establish the pathway for operational provision of Landsat class observations. Additional mission requirements for LCLUC research are being developed through a NRC Decadal Survey for NASA.