Improving the monitoring of crop productivity using spaceborne solar-induced fluorescence

Thursday, 18 December 2014: 11:50 AM
Kaiyu Guan1, David B Lobell2, Joe A Berry3, Joanna Joiner4, Luis Guanter5, Yongguang Zhang6 and Badgley Grayson1,3, (1)Stanford University, Stanford, CA, United States, (2)Stanford University, Los Altos Hills, CA, United States, (3)Carnegie Institution for Science, Global Ecology, Washington, DC, United States, (4)NASA Goddard SFC, Greenbelt, MD, United States, (5)Institute for Space Sciences, Freie Universit├Ąt Berlin, Berlin, Germany, (6)Freie Univ Berlin, Berlin, Germany
Large scale monitoring of crop growth and yield has relied on empirical correlations between remotely sensed vegetation-indices and yield. However, the determinants of yield are complex with several processes including crop phenology, photosynthesis and respiration contributing to overall crop yield. It has not been possible to delve more deeply into environmental effects on these controls given the limitations of current remote sensing technology. Recent advances in the ability to monitor solar induced chlorophyll fluorescence (SIF) now provides a direct measurement of photosynthetic activity from space and opens up new approaches for understanding the controls on crop yield. Using county-level crop statistics in the United States, we find that spaceborne SIF measurements for 2007-2012 provided improved measures of crop productivity compared with various traditional crop monitoring approaches, despite the fact that SIF sensors are still not optimized for crop monitoring. We also demonstrate that SIF, when combined with other data, can be used to estimate light-use-efficiency and plant autotrophic respiration. SIF thus opens up an unprecedented opportunity for improved crop monitoring and mechanistic understanding of how crops respond to temperature and other climate drivers.