Real-time monitoring of crop phenology in the midwestern United States using VIIRS observations

Authors: LIU, L. - South Dakota State University; ZHANG, X. - South Dakota State University; YU, Y. - National Oceanic & Atmospheric Administration (NOAA); Gao, Feng; YANG, Z. - National Agricultural Statistical Service (NASS, USDA)

Submitted to: Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2018
Publication Date: 9/25/2018
Citation: Liu, L., Zhang, X., Yu, Y., Gao, F.N., Yang, Z. 2018. Real-time monitoring of crop phenology in the midwestern United States using VIIRS observations. Remote Sensing. 10:1540. https://doi.org/10.3390/rs10101540.
DOI: https://doi.org/10.3390/rs10101540

Interpretive Summary: Crop progress information can benefit farmers in scheduling irrigation, fertilization and harvest operations. Satellite remote sensing data have been used to map historical crop phenology and crop growth stages. However, near real-time monitoring at the early crop development stages is still challenging due to the lack of sufficient clear observations. This paper presents a new approach to map near real-time crop phenology using historical Moderate Resolution Imaging Spectroradiometer (MODIS) data and timely available Visible Infrared Imaging Radiometer Suite (VIIRS) observations. Results show that crop phenology detected from VIIRS imagery captures spatial variability and is highly correlated to crop growth stages reported by the National Agricultural Statistics Service (NASS). The remote sensing approach provides an effective method to map crop progress and condition, which is required by NASS and the Foreign Agricultural Service for crop yield estimation.

Technical Abstract: Real-time monitoring of crop phenology is critical for assisting farmers managing crop growth and yield estimation. In this study, we presented an approach to monitor in real time crop phenology using timely available daily Visible Infrared Imaging Radiometer Suite (VIIRS) observations and historical Moderate Resolution Imaging Spectroradiometer (MODIS) datasets in the Midwestern United States. MODIS data at a spatial resolution of 500m from 2003 to 2012 were used to generate the climatology of vegetation phenology. By integrating climatological phenology and timely available VIIRS observations in 2014 and 2015, a set of temporal trajectories of crop growth development at a given time for each pixel were then simulated using a logistic model. The simulated temporal trajectories were used to identify spring green leaf development and predict the occurrences of greenup onset, mid-greenup phase, and maturity onset using curvature change rate. Finally, the accuracy of real-time monitoring from VIIRS observations was evaluated by comparing with summary crop progress (CP) reports of ground observations from the National Agricultural Statistics Service (NASS) of the United States Department of Agriculture (USDA). The results suggest that real-time monitoring of crop phenology from VIIRS observations is a robust tool in tracing the crop progress across regional areas. In particular, the date of mid-greenup phase from VIIRS was significantly correlated to the planting dates reported in NASS CP for both corn and soybean with a consistent lag of 37 days and 27 days on average (P<0.05), as well as the emergence dates in CP with a lag of 24 days and 16 days on average (P<0.05), respectively. The real-time monitoring of maturity onset from VIIRS was able to predict the corn silking dates with an advance of 9 days (P<0.01) and the soybean blooming dates with a lag of 7 days on average (P<0.01). These findings demonstrate the capability of VIIRS observations to effectively monitor temporal dynamics of crop progress in real time at a regional scale.