Article
Geochemistry & Geophysics
Moritz Link, Thomas Jagdhuber, Paolo Ferrazzoli, Leila Guerriero, Dara Entekhabi
Summary: The NASA SMAP satellite mission aims to produce enhanced resolution surface soil moisture products by combining L-band active and passive microwave measurements. This study tested the covariation between active and passive signals using numerical simulations and global satellite observations, focusing on the role of vegetation canopy in modulating the active-passive relationship. The results show that a linear relationship between backscatter and emissivity can be established under various vegetation conditions, with decreasing coupling between active and passive signals with increasing vegetation water content.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Geochemistry & Geophysics
Liang Gao, Xiao-Ning Song, Pei Leng, Jian-Wei Ma, Xin-Ming Zhu, Rong-Hai Hu, Yan-Fen Wang, Ya-Nan Zhang, De-Wei Yin
Summary: This study investigated the errors in soil moisture retrieval due to the absence of considering soil salinity impact. Three typical saline soil dielectric constant models were validated, with the WYR model showing excellent performance. The study found that soil salinity mainly affects the imaginary part of the dielectric constant, and the impact is more significant for higher soil moisture values.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Geochemistry & Geophysics
Nan Ye, Jeffrey P. Walker, Xiaoling Wu, Richard de Jeu, Ying Gao, Thomas J. Jackson, Francois Jonard, Edward Kim, Olivier Merlin, Valentijn R. N. Pauwels, Luigi J. Renzullo, Christoph Rudiger, Sabah Sabaghy, Christian von Hebel, Simon H. Yueh, Liujun Zhu
Summary: The fourth and fifth Soil Moisture Active Passive Experiments (SMAPEx-4 and -5) were conducted at the beginning of the SMAP operational phase in 2015 to evaluate and compare SMAP's microwave observations and derived soil moisture products with SMOS and Aquarius missions. Results showed a high agreement between the SMAP radar, radiometer, and derived soil moisture data with the SMAPEx-4 and -5 data sets.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2021)
Article
Engineering, Electrical & Electronic
Alexander Gruber, Rolf H. Reichle
Summary: This study investigates the assimilation of Soil Moisture Active Passive (SMAP) mission brightness temperature data into a land surface model to improve the simulation of soil moisture. The results show notable skill improvements in most regions, especially for the interannual variations.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2022)
Article
Green & Sustainable Science & Technology
Peng Zhang, Hongbo Yu, Yibo Gao, Qiaofeng Zhang
Summary: This study conducted a comprehensive verification and evaluation of ten global remote sensing/reanalysis soil moisture (SM) products and found that SMAP-IB, SMAP DCA, SMAP SCA-H, SMAP SCA-V, and ERA5-Land performed better in capturing the spatial and temporal variations in SM. These findings provide valuable reference for improving satellite/reanalysis SM products and conducting global-scale SM studies.
Article
Agronomy
Hao Sun, Jinhua Gao
Summary: Soil evaporative efficiency (SEE) is estimated by the relative difference between soil temperature (Ts) and its maximum (Ts(max)) and minimum (Ts(min)) values at 'minimum and maximum' soil moisture (SM). This thermal indicator of SM has been proven effective in downscaling satellite microwave SM in some local areas. However, the determination of Ts(max) and Ts(min) is usually empirical, limiting its wider application.
AGRICULTURAL WATER MANAGEMENT
(2023)
Article
Engineering, Electrical & Electronic
Nazmus Sazib, John D. Bolten, Iliana E. Mladenova
Summary: Wildfires have significant impacts on people's lives and the environment, and soil moisture is a key factor influencing their occurrences. However, the measurement of soil moisture is challenging, leading to its underutilization in wildfire risk applications. This study evaluates the use of remotely-sensed soil moisture observations to monitor and predict fire risk in Australia and California, finding a strong association between fire activity and soil moisture anomalies. Lagged correlation analysis shows that a remote-sensing based soil moisture product can predict fire activity with a lead-time of 1-2 months.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2022)
Article
Engineering, Civil
Peng Bai, Changxin Cai
Summary: Remotely sensed evapotranspiration (ET) models are commonly used to estimate ET over large areas, but one challenge is the lack of reliable soil moisture (SM) constraints. In this study, five proxy algorithms for SM constraints were evaluated in China, and it was found that the fdrying algorithm performed the best at flux sites.
JOURNAL OF HYDROLOGY
(2023)
Article
Chemistry, Analytical
Mina Moradizadeh, Prashant K. Srivastava, George P. Petropoulos
Summary: This study evaluates the influence of vegetation on soil moisture retrieval by integrating passive microwave and optical observations and proposes a new index named POVI to improve the representation of vegetation. The modified vegetation transmissivity is applied in the soil moisture retrieval model for more accurate estimation.
Article
Environmental Sciences
Tao Cheng, Siyang Hong, Bensheng Huang, Jing Qiu, Bikui Zhao, Chao Tan
Summary: Drought is a costly disaster in China and globally, especially in the important grain-producing region of Northeastern China. The study found that the SMOS-SM product effectively monitored drought patterns in this area, showing high correlation with in situ meteorological indices. The spatial distribution of drought was successfully captured using maps based on SMOS-SM and in situ indices, indicating the potential for enhanced monitoring capacity with additional field information.
Article
Engineering, Electrical & Electronic
Julie Z. Miller, David G. Long, Christopher A. Shuman, Riley Culberg, Molly Hardman, Mary J. Brodzik
Summary: Using L-band microwave radiometry, the spatial extent of englacial hydrological features in the Greenland Ice Sheet, such as ice slabs and perennial firn aquifers, has been mapped. A combination of enhanced-resolution imagery and a two-layer brightness temperature model is used to map water-saturated firn layers and analyze the variability in saturation parameter values. The results highlight the differences in firn saturation between areas with low and high snow accumulation. These findings are important for identifying large reservoirs of meltwater that are vulnerable to hydrofracturing and accelerated glacier flow.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2022)
Article
Environmental Sciences
Ali Farahani, Mahsa Moradikhaneghahi, Majid Ghayoomi, Jennifer M. Jacobs
Summary: This paper introduces the use of SMAP satellite data to measure soil moisture during global earthquakes and subsequent events. The study shows a clear relationship between soil moisture estimates and seismic events in most target earthquakes.
Article
Environmental Sciences
Tianhao Mu, Guiwei Liu, Xiguang Yang, Ying Yu
Summary: Soil moisture is an important component of soil parameterization and plays a significant role in the global hydrological cycle. Remote sensing is a crucial method for estimating soil moisture, and this study developed a new nonlinear Erf-BP neural network method using integrated multiple-resource remote sensing data to establish a soil moisture estimation model. The results showed that using multiple-resource remote sensing data provided better accuracy for the soil moisture estimation model. Moreover, the SMC predicted results using the new Erf-BP neural network with multiple-resource remote sensing data had a good overall correlation coefficient of 0.6838 and improved accuracy compared to the linear model.
Article
Geochemistry & Geophysics
Jiangyuan Zeng, Pengfei Shi, Kun-Shan Chen, Hongliang Ma, Haiyun Bi, Chenyang Cui
Summary: The study found a generally good linear relationship between sigma SUPERSCRIPT ZERO and TB globally, with environmental factors significantly affecting this relationship. The linear correlation between active and passive measurements is worsened in bare soils, dense vegetation areas, and arid/polar climate zones, while it is favorable in moderate vegetation and soil moisture conditions, as well as large soil moisture dynamic conditions.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Environmental Sciences
Hao Sun, Hao Liu, Yanhui Ma, Qunbo Xia
Summary: This study evaluated thirteen typical optical soil moisture indexes and found that the Visible and Shortwave Infrared Drought Index (VSDI) and Optical TRApezoid Model (OPTRAM) outperformed the other indexes in comparison with observed soil moisture. Both VSDI and OPTRAM utilize two sensitive bands, which may contribute to their superior performance. The study also made improvements to VSDI and OPTRAM to enhance their performance in soil moisture monitoring.
Article
Geosciences, Multidisciplinary
Lei Fan, Jean-Pierre Wigneron, Philippe Ciais, Jerome Chave, Martin Brandt, Stephen Sitch, Chao Yue, Ana Bastos, Xin Li, Yuanwei Qin, Wenping Yuan, Dmitry Schepaschenko, Liudmila Mukhortova, Xiaojun Li, Xiangzhuo Liu, Mengjia Wang, Frederic Frappart, Xiangming Xiao, Jingming Chen, Mingguo Ma, Jianguang Wen, Xiuzhi Chen, Hui Yang, Dave van Wees, Rasmus Fensholt
Summary: Siberian forests have been considered an important carbon sink, but severe droughts and fire disturbances may have affected their carbon dynamics. Limited forest inventories have led to uncertainties in the carbon balance. This study analyzed microwave observations from 2010 to 2019 and found that the carbon balance of Siberian forests was close to neutral, with a small carbon sink. Fire and drought caused significant losses of live above-ground carbon, contrasting with the greening trends in leaf area index. This highlights the vulnerability of large forest carbon stores in Siberia to climate-induced disturbances.
Article
Agronomy
Guanyu Dong, Lei Fan, Rasmus Fensholt, Frederic Frappart, Philippe Ciais, Xiangming Xiao, Stephen Sitch, Zanpin Xing, Ling Yu, Zhilan Zhou, Mingguo Ma, Xiaowei Tong, Qing Xiao, Jean-Pierre Wigneron
Summary: Southwest China has been the largest terrestrial carbon sink in China, but recent droughts caused by high precipitation variability have posed a threat to vegetation productivity. The impact of precipitation anomalies on vegetation primary productivity is still poorly understood.
AGRICULTURAL AND FOREST METEOROLOGY
(2023)
Article
Meteorology & Atmospheric Sciences
Zdenko Heyvaert, Samuel Scherrer, Michel Bechtold, Alexander Gruber, Wouter Dorigo, Sujay Kumar, Gabrielle De Lannoy
Summary: In this study, the combination of active-passive ESA Climate Change Initiative soil moisture product with the Noah-MP land surface model is evaluated over Europe. The impact of different design choices on the performance of the data assimilation system is explored. The choice of observation errors, observation bias correction method, and atmospheric reanalysis dataset all affect the skill improvements.
JOURNAL OF HYDROMETEOROLOGY
(2023)
Article
Environmental Sciences
Ke Zhang, Long Zhao, Kun Yang, Lisheng Song, Xiang Ni, Xujun Han, Mingguo Ma, Lei Fan
Summary: This study quantifies the uncertainties in SM2RAIN-estimated precipitation using SMAP soil moisture data in the Tibetan Plateau. The original SM2RAIN algorithm underestimates precipitation, and the descending SMAP product performs better than the ascending one. The combination of both orbits improves the overall estimation accuracy.
Article
Ecology
Tichaona Mukunga, Matthias Forkel, Matthew Forrest, Ruxandra-Maria Zotta, Nirlipta Pande, Stefan Schlaffer, Wouter Dorigo
Summary: Fires are common on land and contribute to carbon emissions. Humans are responsible for most fire ignitions. Models are used to estimate fire effects, but there is no agreement on how to represent human-caused fire ignitions. This study examined globally available predictors of human activity to explain fire ignitions.
Article
Geosciences, Multidisciplinary
Bram Valkenborg, Gabrielle J. M. De Lannoy, Alexander Gruber, Diego G. Miralles, Philipp Koehler, Christian Frankenberg, Ankur R. Desai, Elyn Humphreys, Janina Klatt, Annalea Lohila, Mats B. Nilsson, Eeva-Stiina Tuittila, Michel Bechtold
Summary: This study investigates water-related vegetation stress in northern peatlands using satellite-observed Solar-Induced chlorophyll Fluorescence (SIF). The results show that most locations experience both drought and waterlogging stress, while some regions only experience waterlogging or drought stress. The study finds that the minimal water-related vegetation stress occurs at a water table depth of -0.22 m (short-term) and -0.20 m (long-term).
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Hui Yang, Philippe Ciais, Frederic Frappart, Xiaojun Li, Martin Brandt, Rasmus Fensholt, Lei Fan, Sassan Saatchi, Simon Besnard, Zhu Deng, Simon Bowring, Jean-Pierre Wigneron
Summary: Changes in terrestrial carbon storage under environmental and land-use changes are crucial for regional and global carbon budgets. This study used L-band microwave vegetation optical depth to generate global maps of annual live vegetation biomass, and found that boreal and temperate forests contribute the most to the global carbon sink, while wet tropical forests serve as small carbon sources. Additionally, the study revealed that tropical deforested and degraded old-growth forests are nearly carbon neutral, while young and middle-aged forests in temperate and boreal regions are the largest sinks.
Article
Environmental Sciences
Iuliia Burdun, Michel Bechtold, Mika Aurela, Gabrielle De Lannoy, Ankur R. Desai, Elyn Humphreys, Santtu Kareksela, Viacheslav Komisarenko, Maarit Liimatainen, Hannu Marttila, Kari Minkkinen, Mats B. Nilsson, Paavo Ojanen, Sini-Selina Salko, Eeva-Stiina Tuittila, Evelyn Uuemaa, Miina Rautiainen
REMOTE SENSING OF ENVIRONMENT
(2023)
Article
Environmental Sciences
A. Al-Yaari, Y. Zhao, F. Cheruy, W. Thiery
Summary: This study analyzes the representation of heatwaves in CMIP6 models and evaluates their performance against global reanalysis and observations. It investigates how heatwaves are projected to change at different global warming levels. The results show that the models perform reasonably well in representing time-related criteria but have larger uncertainty in capturing the magnitude of heatwaves. The projections indicate that heatwave occurrence, spatial extension, and duration will increase globally at different global warming levels, but with strong regional variability and model dependency.
Article
Environmental Sciences
Amen Al-Yaari, Thomas Condom, Clementine Junquas, Antoine Rabatel, Victor Ramseyer, Jean-Emmanuel Sicart, Mariano Masiokas, Sophie Cauvy-Fraunie, Olivier Dangles
Summary: This study focuses on 25 glaciers in different climates and latitudes and investigates their recent and projected trends in precipitation, temperatures, ice mass loss, and their relationships with cloud properties. The findings show that almost half of the studied glaciers are likely to vanish by 2050, with widespread warming and drying trends. These results highlight the serious consequences for future water availability.
Article
Remote Sensing
Ling Yu, Lei Fan, Philippe Ciais, Stephen Sitch, Rasmus Fensholt, Xiangming Xiao, Wenping Yuan, Jingming Chen, Yingtong Zhang, Xiaocui Wu, Yuanwei Qin, Mingguo Ma, Zhongbing Chang, Mengjia Wang, Kai Yan, Lisheng Song, Jean-Pierre Wigneron
Summary: North American boreal forests have suffered extensive tree mortality and carbon loss due to stand-replacing disturbances, but the impacts on forest dynamics are still unknown. This study used remote sensing data and biomass datasets to estimate the effects of fires, logging, and insect outbreaks on the carbon balance of western North American boreal forests. The results showed significant losses in aboveground biomass for all three disturbances, with fire being the dominant factor for forest recovery. Environmental factors also played a role in forest recovery. These findings have important implications for effective forest management after disturbances.
INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION
(2023)
Article
Geosciences, Multidisciplinary
Remi Madelon, Nemesio J. Rodriguez-Fernandez, Hassan Bazzi, Nicolas Baghdadi, Clement Albergel, Wouter Dorigo, Mehrez Zribi
Summary: High-resolution (around 10-100m) surface soil moisture observations are important for various applications. This study adapted the (SMP)-M-2 algorithm to work at 1 km resolution and extended its application to herbaceous vegetation types. The algorithm combines Sentinel-1 and Sentinel-2 data and shows good agreement and accuracy compared to other datasets.
HYDROLOGY AND EARTH SYSTEM SCIENCES
(2023)
Article
Ecology
Luisa Schmidt, Matthias Forkel, Ruxandra-Maria Zotta, Samuel Scherrer, Wouter A. Dorigo, Alexander Kuhn-Regnier, Robin van der Schalie, Marta Yebra
Summary: Vegetation attenuates microwave emission from the land surface. This attenuation is quantified by vegetation optical depth (VOD) and can be used to estimate above-ground biomass, monitor phenology, and model wildfires at large scales. Different VOD products exist, but the relationships with vegetation variables are non-monotonic and complex, indicating the need for more sophisticated estimation methods.
Article
Geosciences, Multidisciplinary
Taylor Smith, Ruxandra-Maria Zotta, Chris A. Boulton, Timothy M. Lenton, Wouter Dorigo, Niklas Boers
Summary: Many widely used observational data sets consist of overlapping instrument records. A growing body of work explores using metrics such as variance and autocorrelation to quantify the stability or resilience of a system and detect critical transitions. This study examines how changes in noise structure of a data set affect resilience metrics, using both synthetic and empirical data from remote sensing vegetation indicators.
EARTH SYSTEM DYNAMICS
(2023)
Article
Geosciences, Multidisciplinary
Matthias Forkel, Luisa Schmidt, Ruxandra-Maria Zotta, Wouter Dorigo, Marta Yebra
Summary: The moisture content of vegetation canopies plays a crucial role in various ecosystem processes. Leaf moisture content, or live-fuel moisture content, is frequently used to estimate flammability and fire danger. This study aims to estimate leaf moisture content from microwave satellite observations at large scales and over decadal time series. The results show a strong correlation between microwave observations and leaf moisture content in grasslands, croplands, and shrublands.
HYDROLOGY AND EARTH SYSTEM SCIENCES
(2023)
Article
Environmental Sciences
Ruonan Chen, Liangyun Liu, Xinjie Liu, Zhunqiao Liu, Lianhong Gu, Uwe Rascher
Summary: This study presents methods to accurately estimate sub-daily GPP from SIF in evergreen needleleaf forests and demonstrates that the interactions among light, canopy structure, and leaf physiology regulate the SIF-GPP relationship at the canopy scale.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Daniel L. Goldberg, Madankui Tao, Gaige Hunter Kerr, Siqi Ma, Daniel Q. Tong, Arlene M. Fiore, Angela F. Dickens, Zachariah E. Adelman, Susan C. Anenberg
Summary: A novel method is applied in this study to directly use satellite data to evaluate the spatial patterns of urban NOx emissions inventories. The results show that the 108 spatial surrogates used by NEMO are generally appropriate, but there may be underestimation in areas with dense intermodal facilities and overestimation in wealthy communities.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Zhuoyue Hu, Xiaoyan Li, Liyuan Li, Xiaofeng Su, Lin Yang, Yong Zhang, Xingjian Hu, Chun Lin, Yujun Tang, Jian Hao, Xiaojin Sun, Fansheng Chen
Summary: This paper proposes a whisk-broom imaging method using a long-linear-array detector and high-precision scanning mirror to achieve high-resolution and wide-swath thermal infrared data. The method has been implemented in the SDGs satellite and has shown promising test results.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Dandan Wang, Leiqiu Hu, James A. Voogt, Yunhao Chen, Ji Zhou, Gaijing Chang, Jinling Quan, Wenfeng Zhan, Zhizhong Kang
Summary: This study evaluates different schemes for determining model coefficients to quantify and correct the anisotropic impact from remote sensing LST for urban applications. The schemes have consistent results and accurately estimate parameter values, facilitating the broadening of parametric models.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Jamie Tolan, Hung - Yang, Benjamin Nosarzewski, Guillaume Couairon, Huy V. Vo, John Brandt, Justine Spore, Sayantan Majumdar, Daniel Haziza, Janaki Vamaraju, Theo Moutakanni, Piotr Bojanowski, Tracy Johns, Brian White, Tobias Tiecke, Camille Couprie
Summary: Vegetation structure mapping is crucial for understanding the global carbon cycle and monitoring nature-based approaches to climate adaptation and mitigation. This study presents the first high-resolution canopy height maps for California and Sao Paulo, achieved through the use of very high resolution satellite imagery and aerial lidar data. The maps provide valuable tools for forest structure assessment and land use monitoring.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Regina Eckert, Steffen Mauceri, David R. Thompson, Jay E. Fahlen, Philip G. Brodrick
Summary: In this paper, a mathematical framework is proposed to improve the retrieval of surface reflectance and atmospheric parameters by leveraging the expected spatial smoothness of the atmosphere. Experimental results show that this framework can reduce the surface reflectance retrieval error and surface-related biases.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Chongya Jiang, Kaiyu Guan, Yizhi Huang, Maxwell Jong
Summary: This study presents the Field Rover method, which uses vehicle-mounted cameras to collect ground truth data on crop harvesting status. The machine learning approach and remote sensing technology are employed to upscale the results to a regional scale. The accuracy of the remote sensing method in predicting crop harvesting dates is validated through comparison with satellite data.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Oksana V. Lunina, Anton A. Gladkov, Alexey V. Bochalgin
Summary: In this study, an unmanned aerial vehicle (UAV) was used to detect and map surface discontinuities with displacements of a few centimeters, indicating the presence of initial geological deformations. The study found that sediments of alluvial fans are susceptible to various tectonic and exogenous deformational processes, and the interpretation of ultra-high resolution UAV images can help recognize low-amplitude brittle deformations at an early stage. UAV surveys are critical for discerning neotectonic activity and its related hazards over short observation periods.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Feng Zhao, Weiwei Ma, Jun Zhao, Yiqing Guo, Mateen Tariq, Juan Li
Summary: This study presents a data-driven approach to reconstruct the terrestrial SIF spectrum using measurements from the TROPOMI instrument on Sentinel-5 precursor mission. The reconstructed SIF spectrum shows improved spatiotemporal distributions and demonstrates consistency with other datasets, indicating its potential for better understanding of the ecosystem function.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Stephen Stehman, John E. Wagner
Summary: This article investigates optimal sample allocation in stratified random sampling for estimation of accuracy and proportion of area in applications where the target class is rare. The study finds that precision of estimated accuracy has a stronger impact on sample allocation than estimation of proportion of area, and the trade-offs among these estimates become more pronounced as the target class becomes rarer. The results provide quantitative evidence to guide sample allocation decisions in specific applications.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Jingyao Zheng, Tianjie Zhao, Haishen Lu, Defu Zou, Nemesio Rodriguez-Fernandez, Arnaud Mialon, Philippe Richaume, Jianshe Xiao, Jun Ma, Lei Fan, Peilin Song, Yonghua Zhu, Rui Li, Panpan Yao, Qingqing Yang, Shaojie Du, Zhen Wang, Zhiqing Peng, Yuyang Xiong, Zanpin Xing, Lin Zhao, Yann Kerr, Jiancheng Shi
Summary: Soil moisture and freeze/thaw (F/T) play a crucial role in water and heat exchanges at the land-atmosphere interface. This study reports the establishment of a wireless sensor network for soil moisture and temperature over the permafrost region of Tibetan Plateau. Satellite-based surface soil moisture (SSM) and F/T products were evaluated using ground-based measurements. The results show the reliability of L-band passive microwave SSM and F/T products, while existing F/T products display earlier freezing and later thawing, leading to unsatisfactory accuracy.
REMOTE SENSING OF ENVIRONMENT
(2024)
