Project Funding: 2011 - 2014

NRA: 2009 NASA: The Science of Terra and Aqua   

Funded by NASA

Abstract:
While the current MODIS VI product suite continue to be the most searched, ordered and used land remote sensing product for research and application, their availability on a 16-day composite cycle is now seen as an inhibitor of ecosystems research, particularly during periods of rapid change and disturbances. Moreover, the current 3-band Enhanced Vegetation Index (EVI) algorithm reliance on the blue band is now acknowledged to be a drawback, largely because of the blue band’s poor performance (signal to noise). Furthermore, the 3-band EVI was found to perform poorly over areas with below canopy snow, sub-pixel cloud, or aerosol contamination, leading to unaccounted for and hard to trace errors. These issues were recognized early, and a new formulation of the EVI (EVI2) was proposed to address backward and forward compatibility with AVHRR and VIIRS, and other sensors, while maintaining the EVI superior performance over NDVI in dense canopies. Additionally, and after 10 years of steady MODIS VI data production, distribution and use, no detailed error and uncertainty assessment was ever conducted to understand the accuracy of these records. The current error and uncertainty estimates provided by the MODIS land team (±1% to 2.5% for NDVI and EVI) are anecdotal at best and irrelevant considering the spatial and temporal VI domains. To enable accurate terrestrial ecosystems research the error in these records must be properly established along with an annual reference baseline VI profile that depicts the long term land surface dynamic. This high accuracy annual baseline record with a precise error and uncertainty estimate would be extremely useful for global change research, for ecosystem characterization, and for the analysis of temporal and spatial land surface vegetation trends and anomalies. In this proposal we plan to introduce major improvements to the Terra and Aqua VI product suite and associated algorithms aiming at preserving the backward continuity of the algorithms, preparing them for routine core production, and readying them for the VIIRS era, while supporting full integration with the historical AVHRR data record. We’re proposing three key refinements to the current Terra and Aqua MODIS VI product suite and two major science reanalysis exercises. The specific objectives of this proposal are: 1. To continue to maintain, refine, improve, and support the Terra and Aqua MODIS VI product suite through these sub-goals: a. The implementation of a new data compositing approach aimed at preserving all useful daily data and limiting data losses that result from the current compositing scheme. b. The addition of a new 2-band EVI algorithm to the product suite. This should address the most pressing problems with the current 3-band EVI and ready the algorithm for the future VIIRS mission. c. The implementation of a new method for VI data quality assignment aimed at improving and facilitating data post-processing and error and uncertainty analysis. 2. To conduct a full scientific reanalysis of the Terra and Aqua MODIS VI record and generate an annual reference baseline profile in support of global change and ecosystem characterization and research. 3. To establish the accuracy envelope of the Terra and Aqua VI product suite, using a new noise related error analysis method supported by a well focused small scale field campaigns along an elevation gradient that spans multiple biomes, phenology conditions, and climate regimes. This proposal is specifically responding to section "2.2 Science Data Analysis" and "2.4 Algorithms - Existing Data Product Refinement", and to a lesser extent this work will contribute to section "2.1. Multi-Platform and Sensor Data Fusion" and "2.5 Real- or Near-Real-Time Data Algorithms".

Publications:

El-Vilaly, M. A. S., Didan, K., Marsh, S. E., van Leeuwen, W. J. D., Crimmins, M. A., Munoz, A. B. 2017. Vegetation productivity responses to drought on tribal lands in the four corners region of the Southwest USA. Frontiers of Earth Science. 12(1), 37-51. DOI: 10.1007/s11707-017-0646-z

2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• Remote Sensing Assessment of the Nile Basin Vegetation Cover Dynamic   --   (Kamel Didan, Armando Barreto, Muluneh Yitayew)   [abstract]

2013 NASA Terrestrial Ecology Science Team Meeting Poster(s)

• VIP DATA EXPLORER: 30 Years of Multi-Sensor Vegetation Index and Land Surface Phenology Data   --   (Kamel Didan, Armando Barreto Munoz)   [abstract]

2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)

• VIP Data Explorer: A Tool for Exploring 30 years of Vegetation Index and Land Surface Phenology   --   (Kamel Didan, Armando Barreto Munoz)   [abstract]   [poster]

More details may be found in the following project profile(s):

• NASA Terrestrial Ecology (TE) Project Profile