Observations of atmospheric methane-sulfonic acid（MSA） and non-sea-salt sulfate（nss-SO4^2-） from December 2010 to November 2011 at Zhongshan Station are presented in this paper. MSA and nss-SO4^2- average concentr...Observations of atmospheric methane-sulfonic acid（MSA） and non-sea-salt sulfate（nss-SO4^2-） from December 2010 to November 2011 at Zhongshan Station are presented in this paper. MSA and nss-SO4^2- average concentrations were 24.2 ± 37.9 ng·m^-3（0.5-158.3 ng·m^-3） and 53.0 ± 82.6 ng·m^-3（not detected [n.d.]） - 395.4 ng·m^-3）, respectively. Strong seasonal variations of MSA and nss-SO4^2-, with maxima in austral summer and minima in winter, were examined. The high concentrations of sulfur compounds in December may be attributed the dimethyl sulfide（DMS） emissions from the marginal ice zone, when open water near the sampling site was important in impacting the sulfur species of January and February at Zhongshan Station. In austral winter, there was almost no phytoplanktonic activity in offshore waters, and atmospheric sulfur compounds likely had long-range transport sources.展开更多
he analysis of meteorological data obtained from the Installed Automatic Weather Station (AWS) at Jinnah Station (70. 24°S, 25. 45°E ). East Antarctica is presented. This paper describes the meteorological c...he analysis of meteorological data obtained from the Installed Automatic Weather Station (AWS) at Jinnah Station (70. 24°S, 25. 45°E ). East Antarctica is presented. This paper describes the meteorological conditions of Jinnah Station for the years of 1991 and 1993. Due to some technical problems the data could not be received continuously in the year 1992. The significant temperature difference is found between the warmest and the coldest months. Climate shows the moderating effect of ocean.Low pressure and strong wind are common which represents the location of the station lies in the circum-POlar low pressure belt. The prevailing wind direction for all over the year is ESE.展开更多
This paper has analyzed the perturbations of a GeoX-Sat （virtual satellite） in geostationary orbit （GEO）. And control methods, strategies and calculation processes are designed of the East-West （E/W） station-kee...This paper has analyzed the perturbations of a GeoX-Sat （virtual satellite） in geostationary orbit （GEO）. And control methods, strategies and calculation processes are designed of the East-West （E/W） station-keeping of the GeoX-Sat. The Attitude and Orbit Control Subsystem （AOCS） provides attitude information and maintains the required spacecraft attitude during all phases of the mission, starting at spacecraft separation from the launch vehicle and throughout its operational lifetime. For the GeoX-Sat exercising design, due to time limitations; only two modes of operation were considered after assumed launching operation： normal and station keeping.展开更多
Station keeping mode （SKM） for Attitude Orbit Control Subsystem （AOCS）; it is an operational approach regarding the attitude dynamics control. The essential features of the design methodology is researching the ba...Station keeping mode （SKM） for Attitude Orbit Control Subsystem （AOCS）; it is an operational approach regarding the attitude dynamics control. The essential features of the design methodology is researching the basic theory and then afterwards, make an iterative design approach using some premise/assumptions, implementing the system simulation through the Simulink Matlab software package, designing the required controllers, monitor and analyzing the responses until the design give the best results within the range required. Firstly the thruster configuration is designed to acquire the parameters of the torque on the satellite. Next, the controllers are based on the well known PID control law. Controllers optimize the attitude and are used during the maneuvers for SKM. Afterwards the simulation results are given, and presented to demonstrate the performance and validity of the AOCS design approach. Finally the simulation results demonstrate that all the requirements were accomplished and the Station Keeping Mode was successfully designed.展开更多
Although temperature extremes have led to more and more disasters, there are as yet few studies on the extremes and many disagreements on temperature changes in Antarctica. Based on daily minimum, maximum, and mean ai...Although temperature extremes have led to more and more disasters, there are as yet few studies on the extremes and many disagreements on temperature changes in Antarctica. Based on daily minimum, maximum, and mean air temperatures(Tmin, Tmax, Tmean) at Great Wall Station(GW) and Zhongshan Station(ZS), we compared the temperature extremes and revealed a strong warming trend in Tmin, a slight warming trend in Tmean, cooling in Tmax, a decreasing trend in the daily temperature range, and the typical characteristic of coreless winter temperature. There are different seasonal variabilities, with the least in summer. The continentality index and seasonality show that the marine air mass has more effect on GW than ZS. Following the terminology of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change(IPCC AR5), we defined nine indices of temperature extremes, based on the Antarctic geographical environment. Extreme-warm days have decreased, while extreme-warm nights have shown a nonsignificant trend. The number of melting days has increased at GW, while little change at ZS. More importantly, we have found inverse variations in temperature patterns between the two stations, which need further investigation into the dynamics of climate change in Antarctica.展开更多
基金supported by the National Natural Science Foundation of China (NSFC) (Grant nos. 41476172, 41230529, 40671062, and 41106168)the Chinese Polar Environment Comprehensive Investigation & Assessment Programs (Grant no. CHINARE2012-15 for 01-04-02, 02-01, and 03-0402)International Cooperation Programs, Chinese Arctic and Antarctic Adminstration (Grant nos. 2G22010, IC201201, IC201308, and IC201513)
文摘Observations of atmospheric methane-sulfonic acid（MSA） and non-sea-salt sulfate（nss-SO4^2-） from December 2010 to November 2011 at Zhongshan Station are presented in this paper. MSA and nss-SO4^2- average concentrations were 24.2 ± 37.9 ng·m^-3（0.5-158.3 ng·m^-3） and 53.0 ± 82.6 ng·m^-3（not detected [n.d.]） - 395.4 ng·m^-3）, respectively. Strong seasonal variations of MSA and nss-SO4^2-, with maxima in austral summer and minima in winter, were examined. The high concentrations of sulfur compounds in December may be attributed the dimethyl sulfide（DMS） emissions from the marginal ice zone, when open water near the sampling site was important in impacting the sulfur species of January and February at Zhongshan Station. In austral winter, there was almost no phytoplanktonic activity in offshore waters, and atmospheric sulfur compounds likely had long-range transport sources.
文摘he analysis of meteorological data obtained from the Installed Automatic Weather Station (AWS) at Jinnah Station (70. 24°S, 25. 45°E ). East Antarctica is presented. This paper describes the meteorological conditions of Jinnah Station for the years of 1991 and 1993. Due to some technical problems the data could not be received continuously in the year 1992. The significant temperature difference is found between the warmest and the coldest months. Climate shows the moderating effect of ocean.Low pressure and strong wind are common which represents the location of the station lies in the circum-POlar low pressure belt. The prevailing wind direction for all over the year is ESE.
文摘This paper has analyzed the perturbations of a GeoX-Sat （virtual satellite） in geostationary orbit （GEO）. And control methods, strategies and calculation processes are designed of the East-West （E/W） station-keeping of the GeoX-Sat. The Attitude and Orbit Control Subsystem （AOCS） provides attitude information and maintains the required spacecraft attitude during all phases of the mission, starting at spacecraft separation from the launch vehicle and throughout its operational lifetime. For the GeoX-Sat exercising design, due to time limitations; only two modes of operation were considered after assumed launching operation： normal and station keeping.
文摘Station keeping mode （SKM） for Attitude Orbit Control Subsystem （AOCS）; it is an operational approach regarding the attitude dynamics control. The essential features of the design methodology is researching the basic theory and then afterwards, make an iterative design approach using some premise/assumptions, implementing the system simulation through the Simulink Matlab software package, designing the required controllers, monitor and analyzing the responses until the design give the best results within the range required. Firstly the thruster configuration is designed to acquire the parameters of the torque on the satellite. Next, the controllers are based on the well known PID control law. Controllers optimize the attitude and are used during the maneuvers for SKM. Afterwards the simulation results are given, and presented to demonstrate the performance and validity of the AOCS design approach. Finally the simulation results demonstrate that all the requirements were accomplished and the Station Keeping Mode was successfully designed.
基金funded by the National Natural Science Foundation of China (Grant Nos. 41476164, 41671073, 41425003, and 41671063)the State Key Laboratory of Cryospheric Science
文摘Although temperature extremes have led to more and more disasters, there are as yet few studies on the extremes and many disagreements on temperature changes in Antarctica. Based on daily minimum, maximum, and mean air temperatures(Tmin, Tmax, Tmean) at Great Wall Station(GW) and Zhongshan Station(ZS), we compared the temperature extremes and revealed a strong warming trend in Tmin, a slight warming trend in Tmean, cooling in Tmax, a decreasing trend in the daily temperature range, and the typical characteristic of coreless winter temperature. There are different seasonal variabilities, with the least in summer. The continentality index and seasonality show that the marine air mass has more effect on GW than ZS. Following the terminology of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change(IPCC AR5), we defined nine indices of temperature extremes, based on the Antarctic geographical environment. Extreme-warm days have decreased, while extreme-warm nights have shown a nonsignificant trend. The number of melting days has increased at GW, while little change at ZS. More importantly, we have found inverse variations in temperature patterns between the two stations, which need further investigation into the dynamics of climate change in Antarctica.
