When I first started working at the NASA Ames Research Center in 2003, one of my first tasks was to move two large, dusty racks full of high-density digital tapes containing old Landsat data into a storage room and build a new high-performance computing cluster. We used this cluster to process satellite data from the Terra and Aqua satellites that had been recently launched by NASA. These satellites provided a global look at the Earth twice daily.
Today, using just a laptop and a web browser, my students can process far more data and answer questions I could only dream of asking 20 years ago, even with two racks full of computers and disk arrays.
How was satellite imagery used 20 years ago?
Over the past two decades, we have witnessed a number of key advances in the use of satellite data within agriculture. In 2001, the primary use of satellite data in day-to-day agricultural operations was through the use of GPS-enabled tractors for precision agriculture. Use of multispectral and thermal satellite imagery in agriculture was largely limited to retrospective analyses and mapping of crop type and productivity, as well as evaluation of evapotranspiration and crop water stress.
Use of satellite-based evapotranspiration by agricultural engineers for irrigation system evaluation and design was just emerging, and scientists would spend months processing data for a single region. Highly accurate data products could be produced, but analyses were usually conducted using high-end workstations or local computing clusters, and the initial data compilation and processing often required months of work.
We’ve come a long way
In the past 10 years, advances in instrument and spacecraft design, cloud computing and data processing, coupled with scientific advances, have facilitated rapid growth in the availability and utility of remote sensing from a constellation of public and private sources. UAVs, aircraft and commercial satellites provide a wide range of data at spatial scales from a few centimeters to a few meters.
Satellite data from NASA, the U.S. Geological Survey and the European Space Agency are widely and freely available, increasingly within 24 to 72 hours of the satellite overpass. These data are used in applications that include irrigation scheduling, monitoring crop water stress, nutrient management, yield mapping and forecasting, and monitoring of soil moisture and drought impacts on agricultural production. To continue to expand and advance the use of satellite data within agriculture and water resources management, NASA established the NASA Western Water Applications Office in 2016 and the NASA Harvest program in 2017.
What does the future hold?
In just the last few years, the growing use of cloud-based platforms and open data services are revolutionizing access to satellite data by ag producers. Following the path established by www.climateengine.org and others, the recent launch of platforms like the Crop Condition and Soil Moisture Assessment tool and upcoming launch of OpenET this summer support free access to information that in the past was difficult for producers to access, cost thousands of dollars or required specialized software tools to interpret the data. More importantly, the growing use of open data services is making it possible to integrate this information directly into other farm and ranch software systems, bringing satellite data to producers in the field where it can be used.
Future NASA satellite missions such as the Surface Biology and Geology mission will also provide field-scale hyperspectral data, supporting further advances in use of satellite data for nutrient management and accurate detection and mapping of crop pests and pathogens. In addition, ongoing field trials and demonstration studies are important for documenting the benefits that can be achieved through incorporation of remote sensing data into agricultural operations.
For remote sensing to truly achieve its full potential within agriculture, it will be critical to quantify these benefits in terms of how they affect a grower’s bottom line, either through reductions in production costs or increases in crop yields.
Author Forrest Melton is a senior research scientist with the NASA Ames Cooperative for Research in Earth Science and Technology and with California State University, Monterey Bay. He currently serves as the program scientist for the NASA Western Water Applications Office.