Preprints
https://doi.org/10.5194/egusphere-2026-5140
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/egusphere-2026-5140
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
23 Sep 2026
| 23 Sep 2026
Status: this preprint is open for discussion and under review for The Cryosphere (TC).
Brief communication: First NISAR Interferometric snow water equivalent change retrieval evaluated against airborne lidar
Abstract. NISAR's global L-band repeat-pass interferometry should be sensitive to snow water equivalent change (ΔSWE). We compare ΔSWE from an operational NISAR interferogram to near-coincident airborne lidar snow-depth change over a February 2026 pair in southwest Idaho. Across the scene, ΔSWE correlates well with the lidar depth change (r = 0.82, rising to r = 0.93 above a coherence of 0.2). The agreement is dominated by variability at scales above ~1 km (r ≈ 0.94), while the correlation at sub-kilometer scales is weaker (r ≈ 0.42), improving over open terrain and at incidence angles below 50°. These results provide the first direct evidence that NISAR phase can measure dry-snow accumulation.
How to cite. Hoppinen, Z., Marshall, H.-P., Palomaki, R., Kane, C., Ciafone, S., O'Neel, S., and Van Der Weide, T.: Brief communication: First NISAR Interferometric snow water equivalent change retrieval evaluated against airborne lidar, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2026-5140, 2026.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
Download & links
- Preprint
(5438 KB) - Metadata XML
-
Supplement
(1173 KB) - BibTeX
- EndNote
Status: open (until 04 Nov 2026)
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor
| : Report abuse
- RC1: 'Comment on egusphere-2026-5140', Anonymous Referee #1, 26 Oct 2026 reply
Viewed
Total article views: 722 (including HTML, PDF, and XML)
Cumulative views and downloads
(calculated since 23 Sep 2026)
| HTML | XML | Total | Supplement | BibTeX | EndNote | |
|---|---|---|---|---|---|---|
| 403 | 251 | 68 | 722 | 80 | 63 | 64 |
- HTML: 403
- PDF: 251
- XML: 68
- Total: 722
- Supplement: 80
- BibTeX: 63
- EndNote: 64
Viewed (geographical distribution)
Total article views: 722 (including HTML, PDF, and XML)
Thereof 722 with geography defined
and 0 with unknown origin.
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
1
Latest update: 03 Nov 2026
Geophysical Institute, University of Alaska Fairbanks, 2156 Koyukuk Drive, Fairbanks, AK, USA
Hans-Peter Marshall
Department of Geosciences, Boise State University, 1910 University Drive, Boise, ID 83725, USA
Ross Palomaki
Institute of Arctic and Alpine Research, University of Colorado, 4001 Discovery Dr, Boulder, CO 80303, USA
Coleman Kane
Department of Geosciences, Boise State University, 1910 University Drive, Boise, ID 83725, USA
Siobhan Ciafone
Cold Regions Research and Engineering Laboratory, US Army Engineer Research and Development Center, 72 Lyme Road, Hanover, NH 03755, USA
Shad O'Neel
Cold Regions Research and Engineering Laboratory, US Army Engineer Research and Development Center, 72 Lyme Road, Hanover, NH 03755, USA
Thomas Van Der Weide
Department of Geosciences, Boise State University, 1910 University Drive, Boise, ID 83725, USA
Short summary
Mountain snow stores water for millions of people, but no satellite yet maps how much water it holds. The new NISAR radar satellite may be able to, because its signal slows down as it passes through snow. We tested this over a mountain site in Idaho by comparing the satellite measurement of new snow with maps of snow depth change from an airplane-mounted laser scanner. The two agreed well, especially in open terrain, giving the first evidence that NISAR can measure snowfall from space.
Mountain snow stores water for millions of people, but no satellite yet maps how much water it...
Note for the authors.
The article introduces a demonstration of L-band dSWE retrievals using NISAR compared to lidar. The technique has been demonstrated before using L-band InSAR, hence the main aspect of the paper is the use of NISAR. The content is correct for the “Brief Communication” format. There are no major problems and it makes a good contribution.
General Comments:
The role of the ionosphere needs to be better discussed. Authors state TECU change of 0.8 which is significant at L-band. The paper needs to discuss the spatial variation of it, and whether its effect over the 6 by 6 km2 study is small enough to be negligible.
Line 35: Consider discussing partly wet interferograms (Ruiz et al., 2024). Broaden the discussion whether the few tenths of 0ºC are relevant, particularly since the seemed to be wet before the 07 Feb acquisitions, as presented in Figure 1 (right bottom).
Please specify in the paper what is the unwrapping algorithm used for NISAR postings.
Line 91: why not manually wrap the phase at the 80m posting? Then subtract and divide by 2pi pixel-wise.
Specific Comments:
Line 28: Equation 1 has not been introduced and should not be referenced before it, in my opinion. Just indicate the method assumes dry snow.
Line 39: The claim that dSWE in the area stays within one fringe needs justification or tighter language.
Line 43: I understand the idea behind this citation but is not well connected. Complete the idea or remove the sentence.
Line 55: This sentence gives the incorrect idea that Leinss et al., 2015 developed a dry-snow model derived from Guneriussen et al., 2001.
Line 68: Lidar implied dSWE.
Line 58: Is 0.238m for L-band or for NISAR?
Line 72: The idea of the offset is repeated.