remotesensing-logo

Journal Browser

Journal Browser

Microwave Remote Sensing of Soil Moisture II

A special issue of Remote Sensing (ISSN 2072-4292). This special issue belongs to the section "Remote Sensing in Geology, Geomorphology and Hydrology".

Deadline for manuscript submissions: 15 January 2025 | Viewed by 3650

Special Issue Editors


E-Mail Website
Guest Editor
State Key Laboratory of Remote Sensing Science, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100101, China
Interests: remote sensing; soil moisture; hydrology; radar and radiometry; water cycle; climate change
Special Issues, Collections and Topics in MDPI journals
Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
Interests: mountain water and heat exchange; soil moisture estimation and downscaling; mountain climate change
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Key Laboratory of Remote Sensing of Gansu Province, Northwest Institute of Eco-Environment and Resources, Heihe Remote Sensing Experimental Research Station, Chinese Academy of Sciences, Lanzhou 730000, China
Interests: remote sensing; soil moisture; ecohydrology; precision agriculture; uncertainty quantification
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
INRAE, UMR 1114 EMMAH, UMT CAPTE, F-84000 Avignon, France
Interests: microwave/optical remote sensing; soil moisture; vegetation water/biomass; L-MEB; PROSAIL; hydro-ecological applications
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This is the 2nd volume of the Special Issue “Microwave Remote Sensing of Soil Moisture”, which achieved great success. Based on the previous research results, this volume is aimed at the presentation of recent advances in microwave remote sensing of soil moisture.

Soil moisture is well-recognized as a pivotal parameter to link the water, energy, and carbon cycles. Active and passive microwave remote sensing has been well-recognized as the most promising means to infer soil moisture spatially and temporally. Active microwave remote sensing, particularly the synthetic aperture radar (SAR), has a much finer spatial resolution than passive sensors but suffers more from the geometrical features of the scene (e.g., surface roughness, vegetation, and topography). Passive microwave remote sensing has higher sensitivity to soil moisture than active radar but is limited by its coarse spatial resolution. Moreover, active and passive microwave signals respond differently to soil and vegetation parameters and can thus provide complementary information for each other.

Over the past several decades, great progress has been made in microwave remote sensing of soil moisture. Several field or aircraft experiments (e.g., SGP, SMEX, HiWATER, SMAPEx1-5, and SMAPVEX) have been organized to support the assessment and refinement of active and passive microwave soil moisture retrieval algorithms. At the same time, a number of microwave spaceborne satellites/sensors have been successfully launched to provide valuable opportunities to obtain soil moisture with various spatial scales from meters to tens of kilometers. These include the passive microwave instruments, such as the multi-frequency AMSR-E/2 (2002-), FY-3 MWRI (2008-), L-band SMOS (2009-), and SMAP (2015-), as well as the active microwave instruments, such as the scatterometer-based Metop/ASCAT series (2006-), monostatic ALOS-2 (2014-), Sentinel-1 (2014-), and Gaofen-3 (2016-), bistatic CYGNSS (2016-), and the P-band Biomass (planned launch in 2023). All of these open a wide range of possibilities to estimate soil moisture at regional and global scales. In this context, this Special Issue aims to present the most advanced theories, models, algorithms, and products related to microwave remote sensing of soil moisture.

The topics of the Special Issue include, but are not limited to, the following:

  • Review on microwave remote sensing of soil moisture;
  • Introduction to field or aircraft experiments and future satellite missions for soil moisture;
  • Evaluation or comparison of remotely sensed soil moisture products using in situ measurements, model simulations, or other mathematical approaches (e.g., TCA, TCH, IVd, etc.);
  • Development, calibration, or validation of the theoretical or semi-empirical forward models (e.g., microwave scattering model and radiative transfer model) used for soil moisture retrieval;
  • Development, improvement, or comparison of remotely sensed soil moisture retrieval algorithms;
  • Development, improvement, or comparison of spatial downscaling/upscaling methods and spatiotemporal fusion techniques of remotely sensed soil moisture;
  • Application of remotely sensed soil moisture products in data assimilation, agriculture, ecology, hydrology, and other fields.

Dr. Jiangyuan Zeng
Prof. Dr. Jian Peng
Dr. Wei Zhao
Dr. Chunfeng Ma
Dr. Hongliang Ma
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Remote Sensing is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • soil moisture
  • active microwave remote sensing
  • passive microwave remote sensing
  • product validation and error analysis
  • retrieval algorithms
  • downscaling/upscaling methods
  • spatiotemporal fusion techniques
  • GNSS-R
  • data assimilation
  • eco-hydrological applications

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Related Special Issue

Published Papers (2 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

22 pages, 30326 KiB  
Article
Spatially Interpolated CYGNSS Data Improve Downscaled 3 km SMAP/CYGNSS Soil Moisture
by Liza J. Wernicke, Clara C. Chew and Eric E. Small
Remote Sens. 2024, 16(16), 2924; https://doi.org/10.3390/rs16162924 - 9 Aug 2024
Viewed by 1201
Abstract
Soil moisture data with both a fine spatial scale and a short global repeat period would benefit many hydrologic and climatic applications. Since the radar transmitter malfunctioned on NASA’s Soil Moisture Active Passive (SMAP) in 2015, SMAP soil moisture has been downscaled using [...] Read more.
Soil moisture data with both a fine spatial scale and a short global repeat period would benefit many hydrologic and climatic applications. Since the radar transmitter malfunctioned on NASA’s Soil Moisture Active Passive (SMAP) in 2015, SMAP soil moisture has been downscaled using numerous alternative fine-resolution data. In this paper, we describe the creation and validation of a new downscaled 3 km soil moisture dataset, which is the culmination of previous work. We downscaled SMAP enhanced 9 km brightness temperatures by merging them with L-band Cyclone Global Navigation Satellite System (CYGNSS) reflectivity data, using a modified version of the SMAP active–passive brightness temperature algorithm. We then calculated 3 km SMAP/CYGNSS soil moisture using the resulting 3 km SMAP/CYGNSS brightness temperatures and the SMAP single-channel vertically polarized soil moisture algorithm (SCA-V). To remedy the sparse daily coverage of CYGNSS data at a 3 km spatial resolution, we used spatially interpolated CYGNSS data to downscale SMAP soil moisture. 3 km interpolated SMAP/CYGNSS soil moisture matches the SMAP repeat period of ~2–3 days, providing a soil moisture dataset with both a fine spatial scale and a short repeat period. 3 km interpolated SMAP/CYGNSS soil moisture, upscaled to 9 km, has an average correlation of 0.82 and an average unbiased root mean square difference (ubRMSD) of 0.035 cm3/cm3 using all SMAP 9 km core validation sites (CVSs) within ±38° latitude. The observed (not interpolated) SMAP/CYGNSS soil moisture did not perform as well at the SMAP 9 km CVSs, with an average correlation of 0.68 and an average ubRMSD of 0.048 cm3/cm3. A sensitivity analysis shows that CYGNSS reflectivity is likely responsible for most of the uncertainty in downscaled SMAP/CYGNSS soil moisture. The success of 3 km SMAP/CYGNSS soil moisture demonstrates that Global Navigation Satellite System–Reflectometry (GNSS-R) observations are effective for downscaling soil moisture. Full article
(This article belongs to the Special Issue Microwave Remote Sensing of Soil Moisture II)
Show Figures

Graphical abstract

18 pages, 7741 KiB  
Article
Spatial Downscaling of Soil Moisture Based on Fusion Methods in Complex Terrains
by Qingqing Chen, Xiaowen Tang, Biao Li, Zhiya Tang, Fang Miao, Guolin Song, Ling Yang, Hao Wang and Qiangyu Zeng
Remote Sens. 2023, 15(18), 4451; https://doi.org/10.3390/rs15184451 - 10 Sep 2023
Cited by 3 | Viewed by 1375
Abstract
Large-area soil moisture (SM) data with high resolution and precision are the foundation for the research and application of hydrological and meteorological models, water resource evaluation, agricultural management, and warning of geological disasters. It is still challenging to downscale SM products in complex [...] Read more.
Large-area soil moisture (SM) data with high resolution and precision are the foundation for the research and application of hydrological and meteorological models, water resource evaluation, agricultural management, and warning of geological disasters. It is still challenging to downscale SM products in complex terrains that require fine spatial details. In this study, SM data from the Soil Moisture Active and Passive (SMAP) satellite were downscaled from 36 to 1 km in the summer and autumn of 2017 in Sichuan Province, China. Genetic-algorithm-optimized backpropagation (GABP) neural network, random forest, and convolutional neural network were applied. A fusion model between SM and longitude, latitude, elevation, slope, aspect, land-cover type, land surface temperature, normalized difference vegetation index, enhanced vegetation index, evapotranspiration, day sequence, and AM/PM was established. After downscaling, the in situ information was fused through a geographical analysis combined with a spatial interpolation to improve the quality of the downscaled SM. The comparative results show that in complex terrains, the GABP neural network better captures the soil moisture variations in both time and space domains. The GDA_Kriging method is able to merge in situ information in the downscaled SM while simultaneously maintaining the dynamic range and spatial details. Full article
(This article belongs to the Special Issue Microwave Remote Sensing of Soil Moisture II)
Show Figures

Graphical abstract

Back to TopTop