An operational global L-band soil moisture and vegetation optical depth dataset from optimized 40° SMOS brightness temperatures for 2010–2024

Xing, Zanpin; Li, Xiaojun; Frappart, Frédéric; De Lannoy, Gabrielle; Jagdhuber, Thomas; Peng, Jian; Fan, Lei; Ma, Hongliang; Karthikeyan, Lanka; Liu, Xiangzhuo; Wang, Mengjia; Zhao, Lin; Liu, Yongqin; Wigneron, Jean-Pierre

doi:10.5194/essd-18-4047-2026

Articles | Volume 18, issue 6

https://doi.org/10.5194/essd-18-4047-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/essd-18-4047-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 18, issue 6

Data description article

|

15 Jun 2026

Data description article |

| 15 Jun 2026

An operational global L-band soil moisture and vegetation optical depth dataset from optimized 40° SMOS brightness temperatures for 2010–2024

Zanpin Xing, Xiaojun Li, Frédéric Frappart, Gabrielle De Lannoy, Thomas Jagdhuber, Jian Peng, Lei Fan, Hongliang Ma, Lanka Karthikeyan, Xiangzhuo Liu, Mengjia Wang, Lin Zhao, Yongqin Liu, and Jean-Pierre Wigneron

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Final revised paper (published on 15 Jun 2026)
Preprint (discussion started on 26 Jan 2026)
Supplement to the preprint

Interactive discussion

Status: closed

RC1:
'Comment on essd-2025-728', Anonymous Referee #1, 12 Feb 2026

Comments are attached.

Citation: https://doi.org/10.5194/essd-2025-728-RC1
- AC1: 'Reply on RC1', Xiaojun Li, 29 Mar 2026
  
  We thank Anonymous Referee #1 for the time and effort devoted to reviewing our manuscript. The comments were very helpful in improving the quality of our manuscript. All comments have been carefully addressed, and our detailed responses are provided in the Supplement.
  
  Citation: https://doi.org/10.5194/essd-2025-728-AC1
RC2:
'Comment on essd-2025-728', Anonymous Referee #2, 26 Feb 2026
Overall assessment
This manuscript presents a well-documented and carefully evaluated global L-band dataset of optimized 40° SMOS brightness temperatures and associated soil moisture and vegetation optical depth products. The work represents an incremental but useful contribution to the community, particularly for users seeking harmonized SMOS–SMAP analyses and long-term global records. The dataset is clearly described, publicly available, and evaluated against multiple independent references. In my view, the paper is suitable for publication in a data-focused journal after minor revisions.
Strengths
- The dataset fills a practical gap by providing a consistent mono-angular SMOS product aligned with SMAP geometry and algorithms.
- The methodology is transparent and reproducible, and the validation strategy (ISMN, TCA, vegetation proxies) is appropriate for a global data product.
- The manuscript clearly documents the processing chain, metadata, and access information, which is essential for long-term usability.
- Performance improvements relative to existing SMOS products are demonstrated and generally convincing.
- The data archive and documentation meet the expectations for an operational community dataset.
Minor suggestions for revision

The manuscript is generally clear but could be streamlined slightly in the introduction and methods to better emphasize the dataset’s intended use cases rather than algorithmic detail.

Please ensure that all dataset layers, flags, and uncertainties are fully documented in the data repository metadata and user guide for long-term usability.

A short paragraph clarifying recommended applications and limitations (e.g., RFI-affected regions, frozen conditions, or dense vegetation) would help users interpret the dataset appropriately.

Consider briefly summarizing differences relative to existing SMOS-IC or SMAP-IB products in a concise user-oriented table.

Minor editorial corrections (typos, wording, and figure caption clarity) should be addressed during revision.
Citation: https://doi.org/10.5194/essd-2025-728-RC2
- AC2: 'Reply on RC2', Xiaojun Li, 29 Mar 2026
  
  Many thanks to Anonymous Referee #2 for the careful review and constructive comments. We have addressed all your comments point by point, and our detailed responses are provided in the Supplement.
  
  Citation: https://doi.org/10.5194/essd-2025-728-AC2

Peer review completion

AR – Author's response | RR – Referee report | ED – Editor decision | EF – Editorial file upload

AR by Xiaojun Li on behalf of the Authors (29 Mar 2026) Author's response Author's tracked changes Manuscript

ED: Publish subject to minor revisions (review by editor) (18 Apr 2026) by Birgit Heim

Dear authors and referees,
we would like to thank you for your supporting reviews of the satellite-based ‘operational global L-band soil moisture and vegetation optical depth dataset from optimized 40° SMOS brightness temperatures’ manuscript and time series datasets and the authors for your replies to the reviews and the edited manuscript and dataset. The reviewers highlight that this new product serves the research communities well and the product details and production and assessments are well described in the manuscript.
We are pleased to accept your dataset and manuscript for final publication in ESSD considering minor revisions by the editor.
Please undertake one minor change related to the title of your ESSD publication by including the time frame of your products (years) into the title.
Please consider optimizing the color scheme of Figure 2 and the figure captions by choosing stronger colors / thicker lines around the boxes at the base of the figure – described in the figure caption as green, yellow,… as it is not so clearly visible in the figure, please also specific in the figure caption that the color refers to box outlines.
In general, can you spell out abbreviations in table and figure captions as there are many occurring in the figure captions and this is not easy to read.
I would also recommend to put all the content of your supplement document directly in the manuscript as appendix, so these are not two separate documents and the readers can access all useful explanations, data visualizations and table of abbreviations directly in the manuscript.
We are looking forward to the final publication of your ESSD paper,
best regards, Birgit Heim

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AR by Xiaojun Li on behalf of the Authors (21 Apr 2026) Author's response Author's tracked changes Manuscript

ED: Publish as is (24 May 2026) by Birgit Heim

AR by Xiaojun Li on behalf of the Authors (27 May 2026) Manuscript

Short summary

Microwave satellite observations of Earth’s land surface are important for tracking global soil moisture and vegetation water content. We use data from the Soil Moisture and Ocean Salinity satellite to first reduce noise and contamination in microwave signals, then produce more reliable long-term records of these variables. Tests against ground stations and other satellites show that the new record performs better than existing products and supports drought, freeze-thaw, and carbon monitoring.