As part of the ongoing research effort focusing on the interactions between land and atmosphere on the “Roof of the World,” an aerial observation experiment measuring water, heat, and carbon fluxes in the Mount Everest region commenced on August 1 and was successfully completed after a month. This experiment is a significant component of China’s second comprehensive scientific investigation of the Tibetan Plateau and has garnered considerable attention.
What exactly do we mean by land-atmosphere interactions? Why is it necessary to conduct such research in this high-altitude region? And how does this study serve to benefit not only China but also the world at large? To delve into these questions, we conducted an exclusive interview with Dr. Jia Li, a researcher at the Chinese Academy of Sciences’ Institute of Aerospace Information Innovation, who leads the research team for this experiment.
**Journalist:** Dr. Jia, your research team is currently conducting a study in the Everest region. Could you explain what land-atmosphere interaction is and its relationship to weather?
**Dr. Jia:** The full title of our project is “Integrated Observation Experiment of Complex Land-Atmosphere Interactions in the Cold Environments of the Everest Region on the Tibetan Plateau,” marking the first time scientists are using aerial platforms to gather observational data on water, heat, and carbon fluxes in this area.
When people hear “land-atmosphere,” they might think of whether someone’s approach is practical or relatable. However, in geoscience, “land” refers to the Earth’s surface, while “atmosphere” pertains to the layer of gases surrounding it. Thus, “land-atmosphere” encompasses two geographical domains: the Earth’s surface and its atmosphere.
Land-atmosphere interaction generally refers to the physical processes through which the surface and the atmosphere influence each other. Changes occurring on the ground can affect the atmosphere, and vice versa. This interaction plays a critical role in shaping the climate characteristics of the Earth system, significantly impacting issues like climate change.
Weather, on the other hand, pertains to the various atmospheric phenomena occurring over shorter time scales, including temperature variations and precipitation events.
**Journalist:** The Tibetan Plateau is often referred to as the “Roof of the World” and the “Third Pole.” Why is it crucial to conduct land-atmosphere interaction research in this area? What are the main scientific goals of this experiment?
**Dr. Jia:** It’s well-known that the Tibetan Plateau is the highest plateau on Earth, with a significant heating effect on the atmosphere, which then influences mid-latitude atmospheric circulation in the Northern Hemisphere. The exchange of materials and energy at the surface not only impacts the climate of the plateau and its surrounding areas but also has the potential to affect global climate through complex feedback mechanisms.
Our experimental area is located on the northern side of Everest, at an average elevation of about 4,200 meters. The land-atmosphere interactions here are not confined to the local environment; they can influence global climate patterns through atmospheric circulation. Conversely, global climate change can affect conditions on the Tibetan Plateau, such as accelerating glacier melt in the Himalayas.
The Tibetan Plateau is also aptly referred to as “Asia’s Water Tower.” We chose to conduct this experiment in July and August when the Asian monsoon brings abundant rainfall, coupled with melting snow, which leads to high soil moisture content. With strong solar radiation during the summer, the region experiences peak evaporation, significantly altering atmospheric convection and circulation. One of our objectives is to observe how energy and moisture exchanges at the surface influence atmospheric conditions.
However, the complex terrain of the Everest region means that localized ground-based observations are insufficient to capture the broader patterns of land-atmosphere water and heat exchanges. Therefore, our experiment utilizes drone platforms for extensive observational studies, combining ground stations and satellite remote sensing to create comprehensive data sets. Our aim is to understand the characteristics of land-atmosphere interactions under the unique climatic conditions and complex surface characteristics of Everest, focusing particularly on moisture cycles and the exchange of materials and energy.
**Journalist:** How do land-atmosphere interactions differ between the high-altitude “Roof of the World” and lower-elevation areas? What is the nature of their influence on one another?
**Dr. Jia:** There are significant differences between land-atmosphere interactions in high-altitude areas like the Tibetan Plateau and those in lower-elevation regions. Generally, interactions in high-altitude locales are more intense, as they absorb substantial solar radiation, which leads to strong convection. When there is moisture available on the surface, this can result in significant vapor transport from the land to the atmosphere. These vigorous, rapidly changing interactions contribute to dramatic weather patterns on the Tibetan Plateau — sometimes described as experiencing “four seasons in a single day” — in contrast to the clearly defined seasonal changes typically seen in low-elevation areas.
The heat and moisture generated by land-atmosphere interactions on the Tibetan Plateau can have cascading effects on lower-elevation regions through atmospheric circulation. However, this complex process impacts different areas and geographic conditions to varying degrees. For instance, heavy rainfall and flooding in the Yangtze River Basin may have links to the land-atmosphere interactions occurring in the Tibetan Plateau.
**Journalist:** Given that humanity has only one Earth and only one “Roof of the World,” how do studies of land-atmosphere interactions in the Everest region serve both China and the global community? How can international collaboration in this field be strengthened?
**Dr. Jia:** Due to the crucial role the Tibetan Plateau plays in the global climate system, China has placed high importance on researching land-atmosphere interactions in the region. We have established numerous ground observation stations on the plateau and are also utilizing satellite observations and model simulations to conduct large-scale studies. During the recent second comprehensive scientific expedition to the Tibetan Plateau, we made further enhancements to our observational networks.
Researching land-atmosphere interactions on the Tibetan Plateau helps us understand its climate patterns and responses to climate change, thereby providing valuable insights for both China and the world in formulating scientific strategies for addressing climate challenges. It contributes to global efforts in managing water resources and protecting ecosystems, aiding sustainable development worldwide.
Historically, the Chinese scientific community has prioritized international collaboration, engaging in various cooperative endeavors with foreign research institutions and universities, including those from neighboring countries. These collaborations span multiple disciplines beyond land-atmosphere interaction research, such as ecology, environmental science, and glaciology, all aimed at comprehensively understanding the physical processes at play on the Tibetan Plateau and their implications for global climate.
Looking forward, I advocate for enhanced data sharing and collaborative research among scientists worldwide, as well as improvements to related models to bolster our predictive capabilities regarding climate change trends and impacts. I hope that international cooperation on climate change can be aligned with global sustainable development goals, promoting a comprehensive approach to economic, social, and environmental sustainability in tackling shared global challenges.
**Journalist:** In 2023, a team of Chinese scientists donated seven “Global Water Resource Data Products (2023 Edition)” to the United Nations, with two of these sets developed by your team. What are your plans for future product development?
**Dr. Jia:** In March 2023, during the UN 2023 Water Conference in New York, CAS Academician Guo Huadong, who serves as the Director of the International Research Center for Sustainable Development Big Data, presented the “Global Water Resource Data Products (2023 Edition)” to the UN. This effort aims to share our expertise and experiences in the domain of water resources for global sustainable development, with two of the data sets being our team’s contributions — namely, the “Global Land Surface Evapotranspiration Product” and the “Global Agricultural Water Use Efficiency Product.”
Evapotranspiration encompasses the water flow between the surface and the atmosphere, serving as a key process in terrestrial water and carbon cycles. Accurately estimating evapotranspiration is crucial not only for understanding the Earth system and global climate change but also for practical applications in effective water resource development, crop water management, drought monitoring, and weather forecasting. Over the past decade, our team has developed a proprietary remote sensing model that offers high-accuracy evapotranspiration data products at various spatial and temporal resolutions. We intend to utilize this data to monitor the progress toward achieving the UN’s sustainable development goals. Recently, our evapotranspiration data product was also incorporated and published on the Food and Agriculture Organization’s data platform, broadening its potential applications.
**Journalist:** Agriculture is a significant consumer of water. With total water resources being limited and the demand for water rising, enhancing agricultural water use efficiency is one important strategy for addressing water scarcity. How can the “Global Agricultural Water Use Efficiency Product” aid in sustainable agricultural development?
**Dr. Jia:** The “Global Agricultural Water Use Efficiency Product” provides insights into the distribution and variability of water use efficiency in agriculture, helping to promote more efficient water utilization and support sustainable agricultural practices.
Our long-term research focus has been on land surface evapotranspiration and ecosystem water use efficiency. In the future, we will continue to refine and enhance these two products, making regular updates via data-sharing platforms such as the Earth Big Data Science Engineering and the FAO’s data sharing systems, thereby expanding their availability and accessibility globally.
**Journalist:** In 2019, you were appointed to the International Committee on Hydrometeorology of the Global Energy and Water Cycle Experiment (GEWEX) and will serve on the Scientific Steering Committee from 2024. How do you plan to use this platform to advance international and cross-disciplinary academic exchanges and cooperation?
**Dr. Jia:** The Global Energy and Water Cycle Experiment (GEWEX) is a core initiative of the World Climate Research Program and has become a prominent scientific research program since its inception in 1990.
During my tenure on the GEWEX committees, I aim to leverage my expertise in land-atmosphere interactions and satellite remote sensing applications to contribute positively to the program’s development. I also hope to encourage Chinese scientists’ participation in GEWEX activities and projects, fostering collaborations with leading international scientists.
Our team’s current experiment in the Everest region, focusing on water, heat, and carbon fluxes, aligns closely with the 2023-2032 scientific objectives set forth by GEWEX. For instance, GEWEX emphasizes understanding the roles of land-atmosphere interactions across various spatial and temporal scales in the water, energy, and carbon balance. One of the pressing questions we are addressing is the extent to which local surface-atmosphere interactions condition the characteristics of the atmospheric boundary layer.
Moreover, scientists abroad are conducting similar land-atmosphere interaction studies in other high-altitude locales, such as the Alps and Andes. We are eager for opportunities to engage in comparative research with these international teams.
**Interviewee Profile:**
Dr. Jia Li is a secondary researcher at the Institute of Aerospace Information Innovation of the Chinese Academy of Sciences, as well as a doctoral advisor and a key researcher at the Academy. His research focuses on water cycles, groundwater remote sensing, and global change. He was elected to the Hydrometeorology Committee of the Global Energy and Water Cycle Experiment in 2019 and is set to join the Scientific Steering Committee in 2024. He also chairs the Dryland Monitoring and Assessment Working Group of the Asia-Pacific Space Cooperation Organization and leads the water resources working group of the “Digital Silk Road” International Science Program. Additionally, he serves as an associate editor for the journal Remote Sensing and is on the editorial boards of several domestic and international scientific journals. Dr. Jia has led or participated in over 40 scientific projects from agencies such as the Ministry of Science and Technology, the National Natural Science Foundation of China, and the European Union’s Framework Program, and has published over 190 academic papers in various journals.
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