Document Type

Article

Publication Title

PLOS One

Publication Date

9-2017

First Page

1

Last Page

14

Abstract

Gross primary production (GPP) is the Earth’s largest carbon flux into the terrestrial biosphere and plays a critical role in regulating atmospheric chemistry and global climate. The Moderate Resolution Imaging Spectrometer (MODIS)-MOD17 data product is a widely used remote sensing-based model that provides global estimates of spatiotemporal trends in GPP. When the MOD17 algorithm is applied to regional scale heterogeneous landscapes, input data from coarse resolution land cover and climate products may increase uncertainty in GPP estimates, especially in high productivity tropical ecosystems. We examined the influence of using locally specific land cover and high-resolution local climate input data on MOD17 estimates of GPP for the State of Hawaii, a heterogeneous and discontinuous tropical landscape. Replacing the global land cover data input product (MOD12Q1) with Hawaii-specific land cover data reduced statewide GPP estimates by ~8%, primarily because the Hawaii-specific land cover map had less vegetated land area compared to the global land cover product. Replacing coarse resolution GMAO climate data with Hawaii-specific high-resolution climate data also reduced statewide GPP estimates by ~8% because of the higher spatial variability of photosynthetically active radiation (PAR) in the Hawaii-specific climate data. The combined use of both Hawaii-specific land cover and high-resolution Hawaii climate data inputs reduced statewide GPP by ~16%, suggesting equal and independent influence on MOD17 GPP estimates. Our sensitivity analyses within a heterogeneous tropical landscape suggest that refined global land cover and climate data sets may contribute to an enhanced MOD17 product at a variety of spatial scales.

DOI

https://doi.org/10.1371/journal.pone.0184466

Comments

This work was funded by the U.S. Geological Survey Biological Carbon Sequestration Program (https://www2.usgs.gov/climate_landuse/land_carbon/) under an Interagency Agreement G13PG00084 to CPG with the USDA Forest Service Pacific Southwest Research Station (https://www.fs.fed.us/psw/). Research Joint Ventures 16-JV-11272136-056 to HK and 12-JV- 11272139-047 were awarded to PS. Funding was provided to AM and SR through the NASA Earth Observing System MODIS Project (https://earthdata.nasa.gov/), grant NNX08AG87A. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Rights

This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

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