Satellite

摘要： Currently,there is a lack of sufficient ocean meteorological data required for mesoscale weather predictions and fog characteristics analysis in the North China Sea.This study presents a methodology to supplement deficiencies in wind information in retrieval data from the Geostationary Interferometric Infrared Sounder(GIIRS)onboard the FengYun-4A(FY4A)satellite and analyze mesoscale weather characteristics.Atmospheric semi-geostrophic wind data were derived from semi-geostrophic theory to complete the weather elements in FY4AGIIRS retrieval data.First,the retrieval data accuracy was analyzed between L-band radiosonde data from seven stations and retrieval data from FY4AGIIRS.The errors in the temperature,humidity,and geopotential height from 850 to 400 hPa were smaller than those of other atmospheric layers.Subsequently,the mesoscale weather characteristics of a fog event were analyzed by creating a mesoscale weather map with derived weather information between 875 and 500 hPa.The analyses showed that the derived weather information might provide a new means for fog mesoscale characteristics analysis,which can help forecasters understand the spatial inhomogeneity in the visibility of fog events.

摘要： In the new radio(NR)access technology,non-terrestrial networks(NTN)are intro-duced to meet the requirement of anywhere and anytime connections from the world market.With the introduction of NTN,the NR system is able to offer the wide-area coverage and en-sure the service availability for users.In this paper,the general aspects of NTN are intro-duced,including the NTN architecture overview,the impact of NTN on next-generation radio access network(NG-RAN)interface functions,mobility scenarios and other NTN related is-sues.The current progress in 3GPP Release 17 is also provided.

摘要： Analysis of the cloud macro characteristics of typhoon “Mekkhala” is based on FY-4A stationary meteorological satellite data. Aiming at the precipitation process during the “Mekkhala” tropical storm and typhoon, the precipitation structure characteristics were analyzed using the precipitation data retrieved from polar orbiting satellites. The results show that: in the life process of “Mekkhala”, its cloud system always presents an asymmetric structure, and the cloud area and cloud top height on the north and south sides also change constantly. When the intensity of “Mekkhala” reaches the maximum, its minimum brightness temperature range is also the largest, and the spiral structure is also the most obvious;during the precipitation process of the “Mekkhala” tropical storm and typhoon, the near-surface precipitation rate is roughly distributed in a ring shape, from the precipitation rate of the FY3-D polar-orbiting satellite and the GCOM-W1 satellite. In terms of product comparison, the precipitation rate product of the GCOM-W1 satellite responds better to low-level precipitation.

摘要： Satellite remote sensing is widely used to estimate snow depth and snow water equivalent(SWE)which are two key parameters in global and regional climatic and hydrological systems.Remote sensing techniques for snow depth mainly include passive microwave remote sensing,Synthetic Aperture Radar(SAR),Interferometric SAR(In SAR)and Lidar.Among them,passive microwave remote sensing is the most efficient way to estimate large scale snow depth due to its long time series data and high temporal frequency.Passive microwave remote sensing was utilized to monitor snow depth starting in 1978 when Nimbus-7 satellite with Scanning Multichannel Microwave Radiometer(SMMR)freely provided multi-frequency passive microwave data.SAR was found to have ability to detecting snow depth in 1980 s,but was not used for satellite active microwave remote sensing until 2000.Satellite Lidar was utilized to detect snow depth since the later period of 2000 s.The estimation of snow depth from space has experienced significant progress during the last 40 years.However,challenges or uncertainties still exist for snow depth estimation from space.In this study,we review the main space remote sensing techniques of snow depth retrieval.Typical algorithms and their principles are described,and problems or disadvantages of these algorithms are discussed.It was found that snow depth retrieval in mountainous area is a big challenge for satellite remote sensing due to complicated topography.With increasing number of freely available SAR data,future new methods combing passive and active microwave remote sensing are needed for improving the retrieval accuracy of snow depth in mountainous areas.

摘要： This chapter reports the recent progress on the space astronomy missions of China,including the following missions:currently operating in orbit,e.g.,DAMPE,Insight-HXMT,GECAM,Polar Light,GRID and Lobster-eye X-ray Satellite;approved and under development for launch in the next a couple of years,e.g.,SVOM and EP;planned experiments to be onboard China’s Space Station in the next several years,e.g.,CSST,HERD,POLAR-2,DIXE and Ly RIC;candidate missions that have passed the first round of review of Strategy Priority Program on space science(Ⅲ)of the Chinese Academy of Sciences,e.g.,eXTP,DAMPE-2,Earth 2.0,DSL and CHES.

摘要： At 00:25 Beijing time on January 20,China launched the Tiantong 1-03 satellite onboard a LM-3B carrier rocket from the Xichang Satellite Launch Center.The satellite entered its preset orbit,marking the success of China’s first launch mission in 2021.

摘要： A coplanar waveguide-fed quintuple band antenna with a slotted circular-shaped radiator for wireless applications with a high isolation between adjacent bands is presented in this paper.The proposed antenna resonates at multiple frequencies with corresponding center frequencies of 2.35,4.92,5.75,6.52,and 8.46 GHz.The intended functionality is achieved by introducing a circular disc radiator with five slots and a U-shaped slot in the feed.The proposed antenna exhibits coverage of the maximum set of wireless applications,such as satellite communication,worldwide interoperability for microwave access,wireless local area network(WLAN),long-distance radio telecommunications,and X-band/Satcom wireless applications.The simulation and measurement results of the proposed fabricated antenna demonstrate the high isolation between adjacent bands.A stable realized gain with an advantageous radiation pattern is achieved at the operating frequency bands.The proposed simple design,compact structure,and simple feeding technique make this antenna suitable for integration in several wireless communication applications,where the portability of devices is a significant concern.The proposed antenna is anticipated to be an appropriate candidate for WLAN,long-term evolution,and fifth-generation mobile communication because of its multi-operational bands and compact size for handheld devices.

摘要： China’s Beidou Navigation~2 Satellite~3 System has been used in more than half of the world’s countries and places.中国北斗导航卫星系统已在全球一半以上的国家和地区使用。Yang Changfeng, who is also a national political4adviser, said that the system will soon used for navigation and positioning5services to every user in "any corner of the planet".国家政治顾问杨长风(音)表示,该系统很快将为"地球任何角落"的每一位用户提供导航和定位服务。"This year the Beidou network will be finished. The last satellite in it has been taken to the Xichang Satellite Launch Center. It will be launched6in June," he said.

摘要： One of today’s actual problems in the field of antennas is the possibility of developing a small wideband antenna,which can work without grounding.Absence of these antennas can lead to serious problems for example in case of designing small transceivers for cellular systems.In this article we show a proposed version of these antennas.Today there do not exist theoretical investigations of connections between electromagnetic fields and currents in flat metallic plates.Therefore,the basis of this work is optimization of proposed antenna construction by simulations.

摘要： Correct precipitation data are essential for a hydrological study.However,the pluviometric stations provide us quite doubtful data.More satellites have explored this area.Therefore,the spatial estimates of precipitation can be extremely useful,since they present data of the whole surface,since the pluviometers do not exist in areas of difficult access.The objective of this work is to analyze the precipitation data obtained by the rain gauges and the Tropical Rainfall Measuring Mission(TRMM)satellite for the Muriaésub-basin,which belongs to the Paraíba do Sul Basin.It was used Thissen method and free software R for the manipulation of the data and its comparison.The results were satisfactory,showing that the estimates of this satellite can be an alternative source of data.