Evaluating the Impact of Summer Drought on Vegetation Growth Using Space-Based Solar-Induced Chlorophyll Fluorescence Across Extensive Spatial Measures Sanjeevi Pandiyan, 1 Govindjee Govindjee, 2 S. Meenatchi, 3 S. Prasanna, 3 G. Gunasekaran, 3 and Ya Guo 1,4, * Abstract Drought is the primary and dominant natural cause of stress on vegetation, and thus, it needs our full attention. Current understanding of drought across extensive spatial measures, around the world, is considerably limited. As case studies to evaluate the feasibility of utilizing space-based solar-induced chlorophyll fluorescence (SIF) across extensive spatial measures, here, we have used data from 2007 to 2017 in Heilongjiang and Jiangsu prov- inces of China. The onset of the 2015 drought was accompanied by a substantial response of SIF from vegetation in both the provinces; these data were associated with changes in soil moisture, standardized precipitation evapotranspiration index, and emissivity. Our findings suggest that SIF can effectively provide the spatial and temporal progress of drought, as inferred through substantial associations with SIF normalized by absorbed pho- tosynthetically active radiation (related to F F ) and by photosynthetically active radiation (SIF PAR ). For the de- piction of onset to drought, SIF, F F , and SIF PAR provide a significant association and a quicker response than the leaf area index and the normalized difference vegetation index. Furthermore, we found that the corre- lation between gross primary productivity and SIF is highly substantial in both Heilongjiang (R 2 = 0.85, p < 0.001) and Jiangsu (R 2 = 0.75, p < 0.001) during the drought period. Our results indicate that continuing evaluation from space-based SIF can indeed provide an understanding of the seasonal differences in vegetation for evaluating the impact of drought across extensive spatial measures. Keywords: solar-induced chlorophyll fluorescence; gross primary production; leaf area index; normalized differ- ence vegetation index; drought; vegetation Introduction Drought (water deficit) is a dominant natural stress on vegetation activity and thus requires our attention; 1,2 also see Pareek et al. 3 Extreme drought can substan- tially affect water storage, farming cultivation, ecolog- ical land systems, and later cause harmful effects on the evolution of economy and civilization. 4 Specifi- cally, when there is global warming and an expanding demand for water through human activities, drought becomes a serious problem. 5 Conceptually, efficient drought tracking across extensive spatial measures is necessary to solve the problems caused by drought. Drought is associated with either below-average rain- fall or above-average air warming, which remains con- stant for weeks, years, or even several decades; this has significant consequences for vegetation growth. The prevalence and time span of drought have been in- creasing over time due to climate change. 6–8 Several drought periods are known to have existed within vari- ous regions throughout the world, in particular, in north China from 2013 to 2014, 9 in Europe during 2018, 10 in North America from 2011 to 2012, 11 and in temper- ate areas in Southeast Asia and the Amazon from 2015 to 2016. 12,13 1 Key Laboratory of Advanced Process Control for Light Industry, Ministry of Education, Jiangnan University, Wuxi, China. 2 Department of Plant Biology, Department of Biochemistry, and Center of Biophysics & Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA. 3 School of Information Technology and Engineering, Vellore Institute of Technology, Vellore, India. 4 Department of Bioengineering, University of Missouri, Columbia, Missouri, USA. *Address correspondence to: Ya Guo, Department of Bioengineering, University of Missouri, Columbia, MO 65211, USA, E-mail: guoy@jiangnan.edu.cn; guoy@missouri.edu Big Data Volume 00, Number 00, 2021 ª Mary Ann Liebert, Inc. DOI: 10.1089/big.2020.0350 1 Downloaded by Southern Yangtze University from www.liebertpub.com at 05/14/21. For personal use only.