China News Service, Beijing, September 19 (Reporter Sun Zifa) The Institute of Aerospace Information Innovation, Chinese Academy of Sciences (CAS) announced on the 19th that the water environment remote sensing team of the academy has recently conducted a large-scale dynamic monitoring and simulation of lake water temperature. Important progress has been made—by integrating remote sensing and numerical simulation technologies, the daily water temperature data of 160 lakes on the Qinghai-Tibet Plateau from 1978 to 2017 have been reconstructed.
Based on the reconstructed time series of lake surface temperature, the research team revealed the temporal and spatial evolution of lake surface temperature on the Qinghai-Tibet Plateau. In the past 40 years (1978-2017), the surface temperature of most lakes on the Qinghai-Tibet Plateau has shown an upward trend, with a heating rate of about every 10 years 0.01-0.47℃, and the temperature in winter is more significant than that in summer (125 lakes show a warming trend in summer), and the warming rate of southern lakes is higher than that of northern lakes.
The plateau lake that the flight from Ngari, Tibet to Lhasa passes through.
Photo by China News Agency reporter Sun Zifa
The results of this research are of great value for further evaluating the impact of climate change on the changes in the water and heat budget of lakes on the Qinghai-Tibet Plateau in the future.
The related research papers were recently published in the international professional academic journal "Earth System Science Data".
The research team of the Academy of Aeronautics and Astronautics of the Chinese Academy of Sciences said that lake water temperature is an important variable of regional water and energy balance, and it is also a controlling parameter of the lake's aquatic ecosystem.
Due to the limitation of conventional ground observations, the observation data of lake water temperature on the Qinghai-Tibet Plateau are generally lacking.
The team integrates remote sensing and numerical simulation technology, develops a technical framework for water temperature data reconstruction, breaks through the limitations of high model data requirements and poor portability, realizes dynamic simulation of lake water temperature in multiphase states (ice, water, and ice-water mixture), and reveals the Qinghai-Tibet Plateau. The spatiotemporal evolution of lake water temperature and its response to climate change.
The plateau lake Bie Ruo Cuo (also known as Bie Ruo Zuocuo) in Ngari, Tibet is about 4470 meters above sea level.
Photo by China News Agency reporter Sun Zifa
Among them, the research team reconstructed a wide-coverage, long-series lake surface temperature data product.
In view of the basic characteristics and data basis of lake water and heat balance in the Qinghai-Tibet Plateau, the team improved the one-dimensional energy balance model of the lake, and used the "Google Earth Engine" (GEE) platform to obtain the time series of the average temperature of the entire lake based on relevant data. For calibration and verification, the daily lake surface temperature dataset from 1978 to 2017 for 160 lakes on the Qinghai-Tibet Plateau was reconstructed for the first time.
This data product has a wide coverage, a long time span and high time resolution, which can provide important technical and data support for understanding the response of the Qinghai-Tibet Plateau lake energy balance to climate change.
Further inspection shows that the data product is in good agreement with the ground-measured lake surface temperature.
In addition, the technical framework developed by the team has strong versatility and portability, and in the future can be used for the United Nations Sustainable Development Goal "protect and restore water-related ecosystems, including mountains, forests, wetlands, rivers, and underground aquifers." and lakes” (SDG-6.6) to provide monitoring data and reveal the impact of changes in water temperature on lake water quality and aquatic biota, providing important basic data and decision-making basis for the regulation of lake water quality and aquatic biota.
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