Estimation and Compensation of the Ionospheric Path Delay Phase in PALSAR-3 and NISAR-L Interferograms

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 

1. Eq.1

According to Meier et al. (2006), this equation is defined as the phase shift (in radian), not phase delay (in meter). The delay is proportional to 1/f^2, as in Eq.4 therein.

2. What is SLC?

3. Because coefficients (a, b, c, d, z) are relatively large, the resulting ionospheric corrections will likely have an uncertainty much larger than the original phase measurement uncertainty. It would be helpful for the reader to better understand these uncertainties. What is the expected SAR phase measurement uncertainty? What is the amplified uncertainty after the ionospheric correction?

For example, the difference of measurements x and y, or (x-y), would have an amplified uncertainty of sqrt(dx^2 + dy^2).

Comments on the Quality of English Language

The paper is overall written well. No major language issues were found.

Author Response

"Please see the attachment." 

It includes on the first two pages the point-by-point response to the reviewer’s comments, followed by the updated manuscript

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The study use simulated data to investigate and estimate the ionospheric delay in upcoming two L-band SAR sensors, which is meaningful for the future applications. The research design is reasonable and the results are reliable. The main problem is the Section Introduction.

(1)Line 11, "is" should be "are".

(2)Line 35, the writing of light speed is inapposite. It shoud be "10⁸" but not "e⁸".

(3)The section Introduction don't provide efficient background on the upcoming SAR sensors, the research status on ionospheric delay correction methods and so on. In addition, the motivation also needs to be strengthened. 

(4)Section 2.1, please provide more detailed description on the simulated method.

(5)All the equations, please adjust all the variables to suitable size.

Author Response

"Please see the attachment." 

It includes on the first two pages the point-by-point response to the reviewer’s comments, followed by the updated manuscript

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have responded all my concerns. so, it can be accepted in present form.