Phase Two of the Integrative Monsoon Frontal Rainfall Experiment(IMFRE-II)over the Middle and Lower Reaches of the Yangtze River in 2020

Phase Two of the Integrative Monsoon Frontal Rainfall Experiment(IMFRE-II)was conducted over the middle and lower reaches of the Yangtze River during the period 16 June to 19 July 2020.This paper provides a brief overview of the IMFRE-II field campaign,including the multiple ground-based remote sensors,aircraft probes,and their corresponding measurements during the 2020 mei-yu period,as well as how to use these numerous datasets to answer scientific questions.The highlights of IMFRE-II are:(1)to the best of our knowledge,IMFRE-II is the first field campaign in China to use ground-based,airborne,and spaceborne platforms to conduct comprehensive observations over the middle and lower reaches of the Yangtze River;and(2)seven aircraft flights were successfully carried out,and the spectra of ice particles,cloud droplets,and raindrops at different altitudes were obtained.These in-situ measurements will provide a“cloud truth”to validate the ground-based and satellite-retrieved cloud and precipitation properties and quantitatively estimate their retrieval uncertainties.They are also crucial for the development of a warm(and/or cold)rain conceptual model in order to better understand the cloud-to-rain conversion and accretion processes in mei-yu precipitation events.Through an integrative analysis of ground-based,aircraft,and satellite observations and model simulations,we can significantly improve our cloud and precipitation retrieval algorithms,investigate the microphysical properties of cloud and precipitation,understand in-depth the formation and dissipation mechanisms of mei-yu frontal systems,and improve cloud microphysics parameterization schemes and model simulations.

Continuous and comprehensive atmospheric observations in Beijing:a station to understand the complex urban atmospheric environment

Due to profound impact on climate and human health,air quality has attracted attention from all levels of the civil society.The key step in the provision of required tools for the society to tackle the complex air quality problem is to characterize it in a comprehensive manner with a long-term perspective.Here,we describe a continuous and comprehensive observation station and its accompanying state-ofthe-art instrumentation that was established to investigate the complex urban atmospheric environment in a rapidly developing Chinese Megacity.The station,located in downtown Beijing,aims to study air quality by identifying the major atmospheric pollutants and key processes determining their formation and loss mechanisms.A few hundreds of parameters are continuously measured with the state-of-the-art instruments,including trace gas concentrations,aerosol particle size distributions,and mass concentrations,covering aerosol particle chemical composition from molecules to micrometer-sized aerosol particles.This produced long-term,comprehensive big data with around 1�10^(11)bytes per year.In this paper,we provide an overview on the facilities of the station,the instrumentation used,the workflow of continuous observations and examples of results from 2018 to 2019 and a basis for establishing a modern long-term,comprehensive atmospheric urban observation station in other megacities.

中国生态水文学发展趋势与重点方向

In recent decades, the ecohydrology discipline was developed to provide theoretical and technical foundations for the protection and restoration of complex ecological systems(e.g., mountains, rivers, forests, farmlands, and lakes), and to further ecological civilization construction and green development in China. In this study, the progress and challenges of the ecohydrology discipline are elaborated, and the future development directions are proposed according to international scientific frontiers and national ecological civilization construction demands. Overall, the main discipline directions are to develop new ecohydrological monitoring methods, to comprehensively understand ecohydrological mechanisms and their basic theories, to promote integration of multi-scale and multi-variable models by considering both terrestrial and aquatic ecosystems, and to encourage multidisciplinary integration, particularly with the social sciences. Furthermore, the future research interests in China include: combining multi-source information, constructing comprehensive monitoring systems, studying spatiotemporal patterns of key ecohydrological variables and their variation characteristics, developing integrated models of ecological, hydrological, and economic processes, estimating their uncertainty;and conducting interdisciplinary studies that include the natural and social sciences. The application prospects in China are further explored for a variety of ecosystems, including forests, grasslands, rivers, lakes, wetlands, farmlands, and cities. This study will provide a reference to support the development of the ecohydrology discipline in China, and will provide a solid theoretical and technical foundation for the implementation of national ecological civilization construction.