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 coarse 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 land surface temperature and 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.
NASA as part of the Integrated Program Office is contributing to the NPOESS Preparatory Project (NPP). The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument launched in 2011 serves as a transition from MODIS class observations into the operational domain. Together with MODIS, the VIIRS instrument has continued 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 currently 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 have been working collectively on product and algorithm refinements for several years. Some of the products derived from VIIRS important for LCLUC science have included the nighttime lights product providing moderate spatial and temporal resolution data to supplement and improve upon the operational Defense Meteorological Satellite Program which has also been used by LCLUC-funded research. Additional products such as finer-resolution active fire products have also been developed with the VIIRS sensor.
Landsat 7 has provided the systematic moderate resolution observations necessary to map and quantify land-cover changes at the local to regional scale for nearly 2 decades. 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.
Landsat 8 launched in 2013 has been providing improved moderately-fine resolution imagery building upon the success of the previous Landsat missions. It has included more refined bands than Landsat 7, including bands developed for cloud cover and aerosols. All bands have improved radiometric resolution making Landsat-8 sensor more sensitive. The NASA MuSLI projects funded by the LCLUC progam have been undertaking research to create a co-located Landsat 8 and Sentinel 2 product. They are also developing higher-level co-located satellite products for applications such as inundation mapping, burned area mapping, and forest cover mapping. This project is the first of its kind to integrate moderately-high spatial resolution imagery from two separate satellites. The benefits to LCLUC research have included reduction in satellite overpass time, increasing the number of satellite observations for analysis.
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 coarse resolution thermal data collocated with MODIS data for improved surface characterization and validation of 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 had been limited by the absence of a current US microwave sensing system until recently.
Various SAR systems have been used including airborne platforms such as UAVSAR which can be deployed as a fully polarimetric system with high spatial resolution to any given location in the world. Currently NASA collaborates with the European Space Agency for sharing of Sentinel-1 C-Band SAR which is available for public download at the Alaska Satellite Facility.
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, Quickbird, and Worldview have been used to provide detailed validation of high resolution products.
NASA Future Missions for LCLUC Research
Landsat 9 development is currently underway as a partnership between NASA and the USGS to continue the decades-long legacy of Landsat sensors and associated historical record. It will prove useful for land resources mapping, monitoring land cover and land use change consequences including ecosystem function and services with implications on human health, the economy, and society. Landsat system of sensors have helped stakeholders across the world to the better manage farm resources, wildland fire control, drought monitoring, flood mapping, and much more. Landsat 9 is planned for launch in 2020 and will include the OLI-2 and TIRS-2 science instruments with a design life of 5 years and is in essence a rebuild of Landsat-8 which may allow for a much quicker and safer launch and prolonged lifespan.
NASA is currently developing a SAR system in collaboration with the Indian Space agency. The system is called NASA-ISRO SAR Mission (NISAR) planned for launch in 2020. It will be the first earth orbiting satellite with dual-band frequency (S-band and L-band) SAR with applications for hazard monitoring, global environmental change, and more.
Additional planned mission details are available here.