Preprints
https://doi.org/10.5194/essd-2021-227
https://doi.org/10.5194/essd-2021-227

  22 Jul 2021

22 Jul 2021

Review status: this preprint is currently under review for the journal ESSD.

Water clarity annual dynamics (1984–2018) dataset across China derived from Landsat images in Google Earth Engine

Hui Tao1,2, Kaishan Song1,3, Ge Liu1, Qiang Wang1, Zhidan Wen1, Pierre-Andre Jacinthe4, Xiaofeng Xu1, Jia Du1, Yingxin Shang1, Sijia Li1, Zongming Wang1, Lili Lyu1, Junbin Hou1, Xiang Wang1, Dong Liu5, Kun Shi5, Baohua Zhang3, and Hongtao Duan5 Hui Tao et al.
  • 1Northeast Institute of Geography and Agroecology, Chinese Academy of Science, Changchun, 130102, China
  • 2University of Chinese Academy of Sciences, Beijing, 100049, China
  • 3College of Urban Research and Planning, Liaocheng University, Shandong, China
  • 4Department of Earth Sciences, Indiana University Purdue University, Indianapolis, IN, USA
  • 5Nanjing Institute of Geography and Limnology, Chinese Academy of Science, Nanjing 210008, China

Abstract. Water clarity provides a sensitive tool to examine spatial pattern and historical trend in lakes trophic status. Yet, this metric has insufficiently been explored despite the availability of remotely-sensed data. We used three Secchi disk depth (SDD) datasets for model calibration and validation from different field campaigns mainly conducted during 2004–2018. The red/blue band ratio algorithm was applied to map SDD for lakes (> 1 ha) based on the first SDD dataset, where R2 = 0.79, RMSE = 100.3 cm, rRMSE = 61.9 %, MAE = 57.7 cm. The other two datasets were used to validate the SDD estimation model, which were indicated the model had a stable performance of temporal transferability. The annual mean SDD of lakes were retrieved across China using Landsat top of air reflectance products in GEE from 1984 to 2018. The spatiotemporal dynamics of SDD were analysed at the five lake regions and individual lake scales, and the average, changing trend, lake number and area, and spatial distribution of lake SDDs across China were presented. In 2018, we found that the lakes with SDDs < 2 m accounted for the largest proportion (80.93 %) of the total lakes, but the total area of lakes with SDD between 0–0.5 m and > 4 m were the largest, accounting for 48.28 % of the total lakes. During 1984–2018, lakes in the Tibetan-Qinghai Plateau lake region (TQR) had the clearest water with an average value of 3.32 ± 0.38 m, while that in the Northeastern lake region (NLR) exhibited the lowest SDD (mean: 0.60 ± 0.09 m). Among the 10,814 lakes with SDD results more than 10 years, 55.42 % and 3.49 % of lakes experienced significant increasing and decreasing trends, respectively. At the five lake regions, except for the Inner Mongolia-Xinjiang lake region (MXR), more than half of the total lakes in every other lake region exhibited significant increasing trends. In the Eastern lake region (ELR), NLR and Yungui Plateau lake region (YGR), almost more than 50 % of the lakes that displayed an increase or decrease in SDD were mainly distributed in an area of 0.01–1 km2, whereas that in the TQR and MXR were primarily concentrated in large lakes (> 10 km2). Spatially, lakes located in the plateau regions generally exhibited higher SDD than those situated in the flat plain regions. The dataset can now be accessed through the website of the National Tibetan Plateau Data Center (http://data.tpdc.ac.cn): DOI: 10.11888/Hydro.tpdc.271571.

Hui Tao et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on essd-2021-227', Anonymous Referee #1, 04 Aug 2021
    • AC1: 'Reply on RC1', Kaishan Song, 14 Sep 2021
  • RC2: 'Comment on essd-2021-227', Anonymous Referee #2, 15 Aug 2021
    • AC2: 'Reply on RC2', Kaishan Song, 14 Sep 2021

Hui Tao et al.

Data sets

Water clarity annual dynamics dataset across China (1990-2018) Hui Tao, Kaishan Song, Ge Liu, Qiang Wang, Zhidan Wen https://doi.org/10.11888/Hydro.tpdc.271571

Hui Tao et al.

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Short summary
During 1984–2018, annual mean SDD values in the TQR, YGR, MXR, ELR and NLR regions were 3.32 ± 0.38 m, 2.35 ± 0.21 m, 1.63 ± 0.38 m, 1.23 ± 0.17 m and 0.60 ± 0.09 m, respectively. Among the 10,814 lakes with > 10 years of SDD results, 55.4 % and 3.5 % experienced significantly increasing and decreasing trends of SDD, respectively. With the exception of the MXR, more than half of lakes in all the other regions exhibited a significant trend of increasing SDD.