Impact of sensor degradation on the MODIS NDVI time series

Dongdong Wang, University of Maryland, ddwang@umd.edu (Presenter)
Douglas Morton, NASA GSFC, douglas.morton@nasa.gov (Presenter)
Jeffrey Masek, NASA GSFC, jeffrey.g.masek@nasa.gov
Aisheng Wu, Science Systems and Applications, aisheng.wu@sigmaspace.com
Jyoteshwar Nagol, University of Maryland, jnagol@umd. edu
Xiaoxiong Xiong, NASA GSFC, xiaoxiong.xiong-1@nasa.gov
Robert Levy, Science Systems and Applications, robert.c.levy@nasa.gov
Eric Vermote, University of Maryland, eric@ltdri.org
Robert E Wolfe, NASA GSFC, robert.e.wolfe@nasa.gov

Dongdong Wang, Douglas Morton, Jeffrey Masek, Aisheng Wu, Jyoteshwar Nagol, Xiaoxiong Xiong, Robert Levy, Eric Vermote, Robert Wolfe

Time series of satellite data provide unparalleled information on the response of vegetation to climate variability. Detecting subtle changes in vegetation over time requires consistent satellite-based measurements. Here, we evaluated the impact of sensor degradation on trend detection using Collection 5 data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on the Terra and Aqua platforms. For Terra MODIS, the impact of blue band (Band 3, 470nm) degradation on simulated surface reflectance was most pronounced at near-nadir view angles, leading to a 0.001-0.004 yr-1 decline in Normalized Difference Vegetation Index (NDVI) under a range of simulated aerosol conditions and surface types. Observed trends in MODIS NDVI over North America were consistent with simulated results, with nearly a threefold difference in negative NDVI trends derived from Terra (17.4%) and Aqua (6.7%) MODIS sensors during 2002-2010. Planned adjustments to Terra MODIS calibration for Collection 6 data reprocessing will largely eliminate this negative bias in NDVI trends over vegetation.

Presentation Type:  Poster

Session:  Global Change Impact & Vulnerability   (Tue 11:30 AM)

Associated Project(s): 

• Related Activity

Poster Location ID: 250