Water Level Change of Qinghai Lake from ICESat and ICESat-2 Laser Altimetry
Round 1
Reviewer 1 Report
Comments for author File: 
Comments.pdf
Author Response
Response to Reviewer 1 Comments
Dear Editors and Reviewers,
Thank you for your letter and comments concerning our manuscript entitled "Water level change of Qinghai Lake from ICESat and ICESat-2 laser altimetry "(remotesensing-2018425). The comments were valuable for improving our manuscript and guiding our research. We have studied the comments carefully and have made revisions accordingly. We hope that the revisions meet with your approval. The revised portions are marked in red font in the manuscript. Detailed point-by-point descriptions of the revisions are provided below.
Major comments:
Point 1: The new contribution of this study is not very clear. The aims of this study (Line84-87) need further explanation.
Response 1: Thanks for the comments, the new contribution and aim of this study has replenished and further explanation on the lines 85-87 in page 2/29, that is “meanwhile, the EGM2008 geoid and WGS84 reference ellipsoid is necessary to apply the each ground track, the long term water level change is easy to compare.”
The corrections are shown on the lines 87-89.
Point 2: Land water masks derived from MODIS (2000 to 2015) are employed in this study to extract the altimetry footprints? What water masks are used as the lake boundary to the ICESat-2 footprints after 2018?
Response 2: Thanks for the comments, the land water masks derived from the MOD44W V6 and JRC Yearly Water Classification History are employed in this study to extract the altimetry footprints. The JRC Yearly Water Classification History water mask is used as the lake boundary to the ICESat-2 footprint after 2018.
The corresponding context was replenished to Section 2.2.4 Land Water Mask in page 5/29. Which is “Meanwhile, the JRC Yearly Water Classification History, v1.4 dataset is the second land water mask data source, the spatial resolution is 30 m, the temporal resolution is one year. This dataset contains maps of the location and temporal distribution of surface water from 1984 to 2021. It is enough as the boundary of water body to replenish MOD44W V6.”
The corrections are shown on Section 2.2.4 Land Water Mask on lines 190-194.
Point 3: Some recent studies on lake water levels by combining two-generation satellite laser altimeters (ICESat/ICESat-2) are similar to this study, and the difference should be focused and discussed.
Luo S, Song C, Zhan P, et al. Refined estimation of lake water level and storage changes on the Tibetan Plateau from ICESat/ICESat-2[J]. Catena, 2021, 200: 105177.
Xu N, Ma Y, Wei Z, et al. Satellite observed recent rising water levels of global lakes and reservoirs[J]. Environmental Research Letters, 2022, 17(7): 074013.
Response 3: Thanks for the comments, the difference has been focused and discussed in the discussion section. The sentences have been added: “It is agreement with the increase and increase rate of the water level during the 2003-2020, but the water level derived from ICESat was estimated by subtracting 0.70 m from the orthometric height, and the water storage change was calculated by using water surface area in the TP[1].Furthermore, the global lake and reservoir water level changes were monitored for 22008 lakes and reservoirs greater than 1 km2, the large-scale rising water levels in the TP and Mississippi River basin of the Northern Hemisphere were detected[2]”. on lines 511-517.
The corrections are shown on lines 511-517.
Other specific comments:
Point 1: Superscript of the unit of square kilometers in the full text should be revised.
Response 1: Thanks for the comments, the superscript of the unit of square kilometers in the full text has been revised.
Point 2: In Figure 1, the label of geographical graticule should be unified in the format of degrees and minutes.
Response 2: Thanks for the comments, in Figure 1, the label of geographical graticule has been unified in the format of degrees and minutes on lines 121-122.
The corrections are shown on lines 121-122.
Point 3: In Figure 11, the in-situ water level during 2010-2018 should be added.
Response 3: Thanks for the comments, the sentence “as subfigure a and subfigure b” has been deleted on lines 483, and the in-situ water level during 2010-2018 has been added in figure 11 on lines 497-500, and the caption has been modified.
Fig. 11. The change and uncertainties in water level derived from ICESat and ICESat-2 with In-Situ Hydrological Station during 2003-2020.
The corrections are shown on lines 483, 497-500.
Point 4: Line 147, the website of the ICESat-2 ATL13 product should be checked, and data access web page should be added.
Response 4: Thanks for the comments, the website “ (https://nsidc.org/data/atl13/versions/5)”, the ICESat-2 ATL13 product data access page has been added on line 149, and the website of the ICESat-2 ATL13 product should be checked.
The corrections are shown on lines 149.
Author Response File: Author Response.pdf
Reviewer 2 Report
In this paper, Long-term satellite observations of the water level of lakes are crucial to our understanding of the lake hydrological basin system, have been carried conducted. The paper's findings have important implications. There are certain grammatical errors that should be fixed.
Have you looked at the Foreign Agricultural Service (USDA-FAS) global reservoir and lake monitoring database (GRLM; available at https://ipad.fas.usda.gov/cropexplorer/global_reservoir/).
The following papers could be useful to your introduction:
Gravity applications in estimating the mass variations in the Middle East: a case study from Iran, https://doi.org/10.1007/s12517-020-05317-7, where he did monitor the changes in the Lake Urmia using a geographic information system technique.
Monitoring and Assessment of Water Level Fluctuations of the Lake Urmia and Its Environmental Consequences Using Multitemporal Landsat 7 ETM+ Images. doi: 10.3390/ijerph17124210.
Monitoring of Water-Level Fluctuation of Lake Nasser Using Altimetry Satellite Data. https://doi.org/10.1007/s41748-018-0053-y.
Please mention the aim and objectives of your study in the Introduction.
Please correct the legend of Figure 1.
Section 3.2 ICESat-2 should be improved.
Please improve the resolution of the figures.
Does GRACE mission help in this work?
Author Response
Response to Reviewer 2 Comments
Dear Editors and Reviewers,
Thank you for your letter and comments concerning our manuscript entitled "Water level change of Qinghai Lake from ICESat and ICESat-2 laser altimetry "(remotesensing-2018425). The comments were valuable for improving our manuscript and guiding our research. We have studied the comments carefully and have made revisions accordingly. We hope that the revisions meet with your approval. The revised portions are marked in red font in the manuscript. Detailed point-by-point descriptions of the revisions are provided below.
Point 1: Have you looked at the Foreign Agricultural Service (USDA-FAS) global reservoir and lake monitoring database (GRLM; available at https://ipad.fas.usda.gov/cropexplorer/global_reservoir/).
The following papers could be useful to your introduction:
Gravity applications in estimating the mass variations in the Middle East: a case study from Iran, https://doi.org/10.1007/s12517-020-05317-7, where he did monitor the changes in the Lake Urmia using a geographic information system technique.
Monitoring and Assessment of Water Level Fluctuations of the Lake Urmia and Its Environmental Consequences Using Multitemporal Landsat 7 ETM+ Images. doi: 10.3390/ijerph17124210.
Monitoring of Water-Level Fluctuation of Lake Nasser Using Altimetry Satellite Data. https://doi.org/10.1007/s41748-018-0053-y.
Please mention the aim and objectives of your study in the Introduction.
Response 1: Thanks for the comments, the aim and objectives of the study was mentioned in the introduction, the added as follows: “The mass variations in the Iran was estimated by the gravity applications, the main factor was groundwater” on lines 42-43;
“The popular water level related databases are Foreign Agricultural Service (USDA-FAS) global reservoir and lake monitoring database (GRLM; available at https://ipad.fas.usda.gov/cropexplorer/global_reservoir/), Database for Hydrological Time Series of Inland Waters (DAHITI, https://dahiti.dgfi.tum.de), HYDROWEB(http://hydroweb.theia-land.fr), Global Reservoirs and Lakes Monitor (G-REALM, https://ipad.fas.usda.gov/cropexplorer/global_reservoir).” on lines 67-72.
“The water level fluctuations of the Lake Urmia was monitored and assessed using multitemporal Landsat 7[2]. Meanwhile, the water level fluctuation of Lake Nasser was monitored using Landsat 8, Jason-2 and Jason-3” on lines 77-79.
“meanwhile, the EGM2008 geoid and WGS84 reference ellipsoid is necessary to apply the each ground track, the long term water level change is easy to compare.” on lines 95-97.
Point 2: Please correct the legend of Figure 1.
Response 2: Thanks for the comments, the legend of Figure 1 has been corrected on lines 121-122.
The corrections are shown on lines 121-122.
Point 3: Section 3.2 ICESat-2 should be improved.
Response 3: Thanks for the comments, the section 3.2.1 in section 3.2 has been improved as the sentences: “The water surface heights of ICESat-2 are provided as both height above the WGS 84 reference ellipsoid and height above the EGM2008 [37,71]. It is consistent with the result of ICESat reference ellipsoid and datum transform, so as to facilitate the combination and comparison with the in-situ water level data.”
And the section 3.2.2 in section 3.2 has been improved as the sentences: “Obviously, the elevation in the middle of the track IDs 568 and 652 was higher than the elevation of the lake surface because of the influence of the terrain around the lake. The six beams in each tracks had been considered as one track.”
The corrections are shown on lines 278-293.
Point 4: Please improve the resolution of the figures.
Response 4: Thanks for the comments, the resolution of Figure 1 has been improved and other figures also has been improved in the revised word version.
Point 5: Does GRACE mission help in this work?
Response 5: Thanks for the comments, the GRACE mission could support some helps in this work, the explanation has described as the sentences: “Meanwhile, the Gravity Recovery and Climate Experiment (GRACE) and GRACE-Follow-On (GRACE-FO) missions have the ability to calculate the water storage change for big lakes and reservoirs, the water surface area could be monitored by the optical satellite, therefore, the water level of lakes and reservoirs could be derived by inversion.”
The corrections are shown on lines 558-562.
Author Response File: Author Response.pdf
