GEOGLAM’s collaboration between Space agencies and advancements in technology are opening the door for critical prediction of agricultural production and food security.For the last 43 years, NASA’s Earth Observation satellite program has created an unparalleled record of global change, revolutionizing our understanding of land use, climate, and agriculture production trends. Building on this foundation, partners working through GEO Global Agricultural Monitoring (GEOGLAM) are collaborating internationally to bring together new technology, both on the ground and in orbit, to enable timely and applicable agricultural monitoring.
The Earth Observation program first took flight in 1972 with the launch of ERTS-1 (later renamed Landsat). Since then, it has soldiered ahead without pause despite funding crises, changes of leadership, and even the tragic crash of Landsat 6 in 1993. In the last 43 years, the Landsat program has accumulated a vast archive of more than 10 million images and was the first Earth observation satellite operator to make data freely available to the public in 2009. The program currently depends on two active satellites: the two-year old Landsat 8 supported by the 16-year old Landsat 7. Both are collecting and transmitting data reliably, though Landsat 7 is well beyond its expected lifespan and is limited for agricultural monitoring due to a line scan corrector failure in 2003.
“The Landsat instruments have evolved and improved over the years with changing technologies, providing a dynamic data continuity,” says GEOGLAM principal Dr. Christopher Justice. The next in the series, Landsat 9, is under development and scheduled for launch in 2023.
The Landsat satellites capture an image of each location on the globe every 16 days. To achieve this rapid data collection, each satellite makes a full trip around the Earth approximately every 99 minutes, at an altitude of 438 miles. Landsat captures more than 50,000 scenes every day, each scene covering an area of 162 by 162 kilometers at a resolution of about 30 meters. Landsat sensors can distinguish between types and condition of crops by measuring the infrared response from vegetation, and also provide data for applications such as tracking forest loss, natural disasters, and urban growth. Although these massive images from Landsat (1 gigabyte each) are far less detailed than more-expensive satellite imaging provided by the private sector for applications such as Google Earth, they are free, publicly available and well-suited for measurements of cropland area and change.
The 16-day interval between images enables land and vegetation changes to be monitored over a time frame of years. But according to Justice, this isn’t sufficient for monitoring crop condition and yield. Cloud cover often occludes the satellites’ cameras, increasing that 16-day interval to weeks or months for some locations. More regular data collection is vital for accurately monitoring crop failures and predicting food insecurity, as well as for informing routine agricultural decisions such as adjusting a field’s irrigation.
For this reason, Justice and his GEOGLAM colleagues are working to forge a partnership between NASA, U.S. Geological Survey (USGS), the European Commission, and the European Space Agency’s (ESA) Copernicus program. In June of 2015, the European Space Agency (ESA) launched a Landsat-like satellite (Sentinel-2) and plans to launch an additional instrument in 2016. By coordinating the Landsats with ESA’s two new Sentinel-2 satellites, GEOGLAM aims to cut the scene capture interval to every two days, enabling crop condition monitoring and improving yield estimation. NASA’s Goddard Space Flight Center also is collaborating with European colleagues to develop a standard processing of data from the multiple instruments. In addition, new sensors are providing data sets that were previously challenging to collect.
“ESA has launched a microwave sensor (Sentinel 1) which views the surface even when cloudy and when combined with data from Landsat and Sentinel 2 provides enhanced monitoring capability over persistently cloudy regions,” says Justice.
Like the Landsat data, Sentinel data are free and openly available. The GEOGLAM program also is building connections with international land-based monitoring initiatives such as the Tanzanian Ministry of Agriculture, which with help from the Bill and Melinda Gates Foundation is building analysis tools for timely implementation of food security solutions in vulnerable countries. GEOGLAM’s growing work improving technology and encouraging collaboration between space agencies is opening the door for critical prediction of agricultural production.