박태진 (NASA Ames Research Center)

한빛사 논문

조회191

박태진Taejin Park

NASA Ames Research Center

CV File 259 kb

Nat. Ecol. Evol., Sep 14 2023 | https://doi.org/10.1038/s41559-023-02187-6 Structural complexity biases vegetation greenness measures.

Yelu Zeng ^#,1,2, Dalei Hao ^#,3, Taejin Park ^#,4,5, Peng Zhu ⁶, Alfredo Huete ⁷, Ranga Myneni ⁸, Yuri Knyazikhin ⁸, Jianbo Qi⁹, Ramakrishna R Nemani ^4,5, Fa Li ², Jianxi Huang ¹, Yongyuan Gao¹, Baoguo Li ¹, Fujiang Ji ², Philipp Köhler ¹⁰, Christian Frankenberg ¹¹, Joseph A Berry¹², Min Chen²

¹College of Land Science and Technology, China Agricultural University, Beijing, China.

²Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI, USA.

³Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA.

⁴NASA Ames Research Center, Moffett Field, CA, USA.

⁵Bay Area Environmental Research Institute, Moffett Field, CA, USA.

⁶Department of Geography and Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong SAR, China.

⁷Faculty of Science, University of Technology Sydney, Sydney, New South Wales, Australia.

⁸Department of Earth and Environment, Boston University, Boston, MA, USA.

⁹Centre d'Etudes Spatiales de la Biosphere, Toulouse, France.

¹⁰EUMETSAT, Darmstadt, Germany.

¹¹Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.

¹²Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, USA.

^#Contributed equally.

These authors contributed equally: Yelu Zeng, Dalei Hao, Taejin Park.

Corresponding authors : Correspondence to Yelu Zeng, Dalei Hao or Min Chen.

Abstract

Vegetation 'greenness' characterized by spectral vegetation indices (VIs) is an integrative measure of vegetation leaf abundance, biochemical properties and pigment composition. Surprisingly, satellite observations reveal that several major VIs over the US Corn Belt are higher than those over the Amazon rainforest, despite the forests having a greater leaf area. This contradicting pattern underscores the pressing need to understand the underlying drivers and their impacts to prevent misinterpretations. Here we show that macroscale shadows cast by complex forest structures result in lower greenness measures compared with those cast by structurally simple and homogeneous crops. The shadow-induced contradictory pattern of VIs is inevitable because most Earth-observing satellites do not view the Earth in the solar direction and thus view shadows due to the sun-sensor geometry. The shadow impacts have important implications for the interpretation of VIs and solar-induced chlorophyll fluorescence as measures of global vegetation changes. For instance, a land-conversion process from forests to crops over the Amazon shows notable increases in VIs despite a decrease in leaf area. Our findings highlight the importance of considering shadow impacts to accurately interpret remotely sensed VIs and solar-induced chlorophyll fluorescence for assessing global vegetation and its changes.

논문정보

형식Research article
게재일2023년 09월 (BRIC 등록일 2023-09-25)
연구진국외 연구진
분야 생명과학 > 분류/생태/환경생물학

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