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1,293 results on '"Xiao, Xiangming"'

2. MMST-ViT: Climate Change-aware Crop Yield Prediction via Multi-Modal Spatial-Temporal Vision Transformer

Author

Lin, Fudong, Crawford, Summer, Guillot, Kaleb, Zhang, Yihe, Chen, Yan, Yuan, Xu, Chen, Li, Williams, Shelby, Minvielle, Robert, Xiao, Xiangming, Gholson, Drew, Ashwell, Nicolas, Setiyono, Tri, Tubana, Brenda, Peng, Lu, Bayoumi, Magdy, and Tzeng, Nian-Feng

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

Precise crop yield prediction provides valuable information for agricultural planning and decision-making processes. However, timely predicting crop yields remains challenging as crop growth is sensitive to growing season weather variation and climate change. In this work, we develop a deep learning-based solution, namely Multi-Modal Spatial-Temporal Vision Transformer (MMST-ViT), for predicting crop yields at the county level across the United States, by considering the effects of short-term meteorological variations during the growing season and the long-term climate change on crops. Specifically, our MMST-ViT consists of a Multi-Modal Transformer, a Spatial Transformer, and a Temporal Transformer. The Multi-Modal Transformer leverages both visual remote sensing data and short-term meteorological data for modeling the effect of growing season weather variations on crop growth. The Spatial Transformer learns the high-resolution spatial dependency among counties for accurate agricultural tracking. The Temporal Transformer captures the long-range temporal dependency for learning the impact of long-term climate change on crops. Meanwhile, we also devise a novel multi-modal contrastive learning technique to pre-train our model without extensive human supervision. Hence, our MMST-ViT captures the impacts of both short-term weather variations and long-term climate change on crops by leveraging both satellite images and meteorological data. We have conducted extensive experiments on over 200 counties in the United States, with the experimental results exhibiting that our MMST-ViT outperforms its counterparts under three performance metrics of interest.

Published
2023

3. Mega-cities dominate China's urban greening

Author

Zhang, Xiaoxin, Brandt, Martin, Tong, Xiaoye, Tong, Xiaowei, Zhang, Wenmin, Reiner, Florian, Li, Sizhuo, Tian, Feng, Yue, Yuemin, Zhou, Weiqi, Chen, Bin, Xiao, Xiangming, and Fensholt, Rasmus

Subjects
Computer Science - Computer Vision and Pattern Recognition, Physics - Physics and Society
Abstract

Trees play a crucial role in urban environments, offering various ecosystem services that contribute to public health and human well-being. China has initiated a range of urban greening policies over the past decades, however, monitoring their impact on urban tree dynamics at a national scale has proven challenging. In this study, we deployed nano-satellites to quantify urban tree coverage in all major Chinese cities larger than 50 km2 in 2010 and 2019. Our findings indicate that approximately 6000 km2 (11%) of urban areas were covered by trees in 2019, and 76% of these cities experienced an increase in tree cover compared to 2010. Notably, the increase in tree cover in mega-cities such as Beijing, and Shanghai was approximately twice as large as in most other cities (7.69% vs 3.94%). The study employs a data-driven approach towards assessing urban tree cover changes in relation to greening policies, showing clear signs of tree cover increases but also suggesting an uneven implementation primarily benefiting a few mega-cities.

Published
2023

6. Carbon loss from forest degradation exceeds that from deforestation in the Brazilian Amazon

Author

Qin, Yuanwei, Xiao, Xiangming, Wigneron, Jean-Pierre, Ciais, Philippe, Brandt, Martin, Fan, Lei, Li, Xiaojun, Crowell, Sean, Wu, Xiaocui, Doughty, Russell, Zhang, Yao, Liu, Fang, Sitch, Stephen, and Moore III, Berrien

Subjects
Physics - Biological Physics
Abstract

Spatial-temporal dynamics of aboveground biomass (AGB) and forest area affect the carbon cycle, climate, and biodiversity in the Brazilian Amazon. Here we investigate inter-annual changes of AGB and forest area by analyzing satellite-based annual AGB and forest area datasets. We found the gross forest area loss was larger in 2019 than in 2015, possibly due to recent loosening of forest protection policies. However, net AGB loss was three times smaller in 2019 than in 2015. During 2010-2019, the Brazilian Amazon had a cumulative gross loss of 4.45 Pg C against a gross gain of 3.78 Pg C, resulting in net AGB loss of 0.67 Pg C. Forest degradation (73%) contributed three times more to the gross AGB loss than deforestation (27%), given that the areal extent of degradation exceeds deforestation. This indicates that forest degradation has become the largest process driving carbon loss and should become a higher policy priority.

Published
2022

38. Temporal Changes of Virus-Like Particle Abundance and Metagenomic Comparison of Viral Communities in Cropland and Prairie Soils

Author

Cornell, Carolyn R, Zhang, Ya, Van Nostrand, Joy D, Wagle, Pradeep, Xiao, Xiangming, and Zhou, Jizhong

Subjects
Prevention, Vaccine Related, Biodefense, Aetiology, 2.2 Factors relating to the physical environment, Infection, Life on Land, Crops, Agricultural, Grassland, Metagenome, Metagenomics, Soil Microbiology, Spatio-Temporal Analysis, Virome, Viruses, agriculture, microbial ecology, soil virus, viral ecology, viral metagenomics, Immunology, Microbiology
Abstract

During the last several decades, viruses have been increasingly recognized for their abundance, ubiquity, and important roles in different ecosystems. Despite known contributions to aquatic systems, few studies examine viral abundance and community structure over time in terrestrial ecosystems. The effects of land conversion and land management on soil microbes have been previously investigated, but their effects on virus population are not well studied. This study examined annual dynamics of viral abundance in soils from a native tallgrass prairie and two croplands, conventional till winter wheat and no-till canola, in Oklahoma. Virus-like particle (VLP) abundance varied across sites, and showed clear seasonal shifts. VLP abundance significantly correlated with environmental variables that were generally reflective of land use, including air temperature, soil nitrogen, and plant canopy coverage. Structural equation modeling supported the effects of land use on soil communities by emphasizing interactions between management, environmental factors, and viral and bacterial abundance. Between the viral metagenomes from the prairie and tilled wheat field, 1,231 unique viral operational taxonomic units (vOTUs) were identified, and only five were shared that were rare in the contrasting field. Only 13% of the vOTUs had similarity to previously identified viruses in the RefSeq database, with only 7% having known taxonomic classification. Together, our findings indicated land use and tillage practices influence virus abundance and community structure. Analyses of viromes over time and space are vital to viral ecology in providing insight on viral communities and key information on interactions between viruses, their microbial hosts, and the environment. IMPORTANCE Conversion of land alters the physiochemical and biological environments by not only changing the aboveground community, but also modifying the soil environment for viruses and microbes. Soil microbial communities are critical to nutrient cycling, carbon mineralization, and soil quality; and viruses are known for influencing microbial abundance, community structure, and evolution. Therefore, viruses are considered an important part of soil functions in terrestrial ecosystems. In aquatic environments, virus abundance generally exceeds bacterial counts by an order of magnitude, and they are thought to be one of the greatest genetic reservoirs on the planet. However, data are extremely limited on viruses in soils, and even less is known about their responses to the disturbances associated with land use and management. The study provides important insights into the temporal dynamics of viral abundance and the structure of viral communities in response to the common practice of turning native habitats into arable soils.

Published
2021

39. Siberian carbon sink reduced by forest disturbances

Author

Fan, Lei, Wigneron, Jean-Pierre, Ciais, Philippe, Chave, Jérome, Brandt, Martin, Sitch, Stephen, Yue, Chao, Bastos, Ana, Li, Xin, Qin, Yuanwei, Yuan, Wenping, Schepaschenko, Dmitry, Mukhortova, Liudmila, Li, Xiaojun, Liu, Xiangzhuo, Wang, Mengjia, Frappart, Frédéric, Xiao, Xiangming, Chen, Jingming, Ma, Mingguo, Wen, Jianguang, Chen, Xiuzhi, Yang, Hui, van Wees, Dave, and Fensholt, Rasmus

Published
2023
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50. Global carbon balance of the forest: satellite-based L-VOD results over the last decade

Author

Wigneron, Jean-Pierre, primary, Ciais, Philippe, additional, Li, Xiaojun, additional, Brandt, Martin, additional, Canadell, Josep G., additional, Tian, Feng, additional, Wang, Huan, additional, Bastos, Ana, additional, Fan, Lei, additional, Gatica, Gabriel, additional, Kashyap, Rahul, additional, Liu, Xiangzhuo, additional, Sitch, Stephen, additional, Tao, Shengli, additional, Xiao, Xiangming, additional, Yang, Hui, additional, Espinoza Villar, Jhan Carlo, additional, Frappart, Frederic, additional, Li, Wei, additional, Qin, Yuanwei, additional, De Truchis, Aurélien, additional, and Fensholt, Rasmus, additional

Published
2024
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