Global Estimation and Assessment of Monthly Lake/Reservoir Water Level Changes Using ICESat-2 ATL13 Products

Nan Xu,Huiying Zheng,Xinyuan Liu,Xiaohua Wang,Yue Ma,Jian Yang

doi:10.3390/rs13142744

Abstract

Accurate and detailed information on lake/reservoir water levels and temporal changes around the globe is urgently required for water resource management and related studies. The traditional satellite radar altimeters normally monitor water level changes of large lakes and reservoirs (i.e., greater than 1 km2) around the world. Fortunately, the recent Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) makes it possible to monitor water level changes for some small lakes and reservoirs (i.e., less than 1 km2). ICESat-2 ATL13 products provide observations of inland water surface heights, which are suitable for water level estimation at a global scale. In this study, ICESat-2 ATL13 products were used to conduct a global estimation and assessment of lake/reservoir water level changes. We produced monthly water levels for 13,843 lakes and reservoirs with areas greater than 0.1 km2 and all-season ATL13 products across the globe, in which 2257 targets are smaller than 1 km2. In total, the average valid number of months covered by ICESat-2 is 5.41 months and only 204 of 13,843 lakes and reservoirs have water levels in all the months in 2019. In situ water level data from 21 gauge stations across the United States and 12 gauge stations across Australia were collected to assess the monthly lake/reservoir water levels, which exhibited a high accuracy (RMSE = 0.08 m, r = 0.999). According to comparisons between the monthly water levels and changes from ATL08 products in another study and ATL13 products in this study, we found that both products can accurately estimate the monthly water level of lakes and reservoirs, but water levels derived from ATL13 products exhibited a higher accuracy compared with water levels derived from ATL08 products (RMSE = 0.28 m, r = 0.999). In general, the ATL13 product is more convenient because the HydroLAKES mask of inland water bodies, the orthometric height (with respect to the EGM2008 geoid) of water surfaces, and several data quality parameters specific to water surfaces were involved in the ATL13 product.

Highlights

The ATL13 product was masked by the HydroLAKES database, which was developed from many existing coastline and inland water databases
Due to the gravity effect, the water level of large lakes/reservoirs is not a stable value when the ellipsoidal heights were used
13,843 lakes and reservoirs with areas greater than 0.1 km2 were determined from the HydroLAKES database and ICESat-2 ATL13 products in 2019

Summary

Introduction

Lakes only cover a small portion of the terrestrial surface, they can provide various important social and economic functions, such as freshwater storage, flood prevention, drought resisting, hydropower generation, industrial consumption, and agricultural production [1]. In addition to their socioeconomic needs, lakes are very important to ecosystems (e.g., biotic plants, animals, and micro-organisms) and biodiversity conservation [2]. Water levels can characterize the temporal change of the earth’s surface water from local to global scales well, and it is a useful indicator for detecting the response of lakes to natural forces (e.g., runoff, glacier melting, precipitation, and evaporation) and human.

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Conclusion