Fengyun Meteorological Satellite Products for Earth System Science Applications

Following the progress of satellite data assimilation in the 1990s, the combination of meteorological satellites and numerical models has changed the way scientists understand the earth. With the evolution of numerical weather prediction models and earth system models, meteorological satellites will play a more important role in earth sciences in the future. As part of the space-based infrastructure, the Fengyun (FY) meteorological satellites have contributed to earth science sustainability studies through an open data policy and stable data quality since the first launch of the FY-1A satellite in 1988. The capability of earth system monitoring was greatly enhanced after the second-generation polar orbiting FY-3 satellites and geostationary orbiting FY-4 satellites were developed. Meanwhile, the quality of the products generated from the FY-3 and FY-4 satellites is comparable to the well-known MODIS products. FY satellite data has been utilized broadly in weather forecasting, climate and climate change investigations, environmental disaster monitoring, etc. This article reviews the instruments mounted on the FY satellites. Sensor-dependent level 1 products (radiance data) and inversion algorithm-dependent level 2 products (geophysical parameters) are introduced. As an example, some typical geophysical parameters, such as wildfires, lightning, vegetation indices, aerosol products, soil moisture, and precipitation estimation have been demonstrated and validated by in-situ observations and other well-known satellite products. To help users access the FY products, a set of data sharing systems has been developed and operated. The newly developed data sharing system based on cloud technology has been illustrated to improve the efficiency of data delivery.

The independent service validation in GMES RESPOND:the flood validation exercise

This article is aimed at providing a detailed description of the Flood Validation Exercise organised by the Independent Service Validation Group of the Global Monitoring for Environment and Security(GMES)RESPOND project.The aims of the validation exercise were:(1)providing a practical example of validation procedures in the frame of the GMES Emergency Response services;(2)executing a full-scale validation exercise able to cope with the requirements of an emergency service;and(3)better understanding the performances and limitations of Earth observation services for Flood Damage Mapping.This validation exercise is a first step of the main task to define the whole validation process for GMES services.When this is achieved,there will be knowledge concerning how well services meet the service specifications derived from the user needs.The present exercise has the purpose of gathering this knowledge.The output of this validation exercise can be used to characterise and qualify the performance and timeliness of Crisis and Damage Mapping Services.This paper summarises the methodology for the flood exercise validation and the results of product validation and inter-comparison.

Active disturbance rejection control： some recent experimental and industrial case studies

This paper presents a summary of some recent experimental and industrial case studies of active disturbance rejection control （ADRC）. ADRC is a novel disturbance estimation and rejection concept, leading to a new technology with a distinct advantage where, unlike most existing methods, disturbances, internal and external, are actively estimated and rejected. Applications of the new approach in solving industry-wide bench mark problems have led to a slew of innovative solutions. The scope of the applications shown in this paper includes motion control, robotic-enhanced limb rehabilitation trainings, fuel cell systems, and the two-mass-spring benchmark problem. Recent production line validation results obtained are also included.

Evaluation and intercomparison of multiple satellite-derived and reanalysis downward shortwave radiation products in China

Downward shortwave radiation(DSR)is a critical variable in energy balance driving Earth’s surface processes.Satellite-derived and reanalysis DSR products have been developed and continuously improved during the last decades.However,as those products have different temporal resolutions,their performances in different time scales have not been well-documented,particularly in China.This study intended to evaluate several DSR products across multiple time scales(i.e.instantaneous,1-hourly,daily,and monthly average)and ecosystems in China.Six DSR products,including GLASS,BESS,CLARA-A2,MCD18A1,ERA5 and MERRA-2,were evaluated against ground measurements at Chinese Ecosystem Research Network(CERN)and integrated land-atmosphere interaction observation(TPDC)sites from 2009 to 2012.The instantaneous DSR of MCD18 showed a root mean square error(RMSE)of 146.02 W/m^(2).The hourly RMSE of ERA5(155.52 W/m^(2))was largely smaller than MERRA-2(188.53 W/m^(2)).On the daily and monthly scale,BESS had the most optimized accuracy among the six products(RMSE of 36.82 W/m^(2)).For the satellite-derived DSR products,the monthly accuracy at CERN can meet the threshold accuracy requirement set by World Meteorological Organization(WMO)for Global Numerical Weather Prediction(20 W/m^(2)).