It is important to be able to characterize the thermal conditions over the equatorial Indian Ocean for both weather forecasting and climate prediction. This study compared the equatorial eastern Indian Ocean (EEIO) te...It is important to be able to characterize the thermal conditions over the equatorial Indian Ocean for both weather forecasting and climate prediction. This study compared the equatorial eastern Indian Ocean (EEIO) temperature and relative humidity profiles from three reanalysis products (JRA-55, MERRA2, and FGOALS-f2) with shipboard global positioning system (GPS) sounding measurements obtained during the Eastern Indian Ocean Open Cruise in spring 2018. The FGOALS-f2 reanalysis product is based on the initialization module of a sub-seasonal to seasonal prediction system with a nudging-based data assimilation method. The results indicated that:(1) both JRA-55 and MERRA2 were reliable in characterizing the temperature profile from 850 to 600 hPa, with a maximum deviation of about <0.5℃. Both datasets showed a large negative deviation below 825 hPa, with a maximum bias of about 2℃ at 1000 hPa and 1.5℃ at 900 hPa, respectively.(2) JRA-55 showed good performance in characterizing the relative humidity profile above 850 hPa, with a maximum deviation of < 8%, while it showed much wetter conditions below 850 hPa. MERRA2 overestimated the relative humidity in the middle to lower troposphere, with a maximum deviation of about 15% at 925 hPa.(3) The FGOALS-f2 reanalysis product more accurately reproduced the temperature profile in the marine atmospheric boundary layer over the EEIO than that in JRA-55 and MERRA2, but showed much wetter conditions than the GPS sounding observations, with a maximum deviation of up to 20% at 600 hPa. Future applications of GPS sounding datasets are discussed.展开更多
A mono-window algorithm was introduced to retrieve sea surface temperature （SST） using Landsat data in coastal waters. In this algorithm, the effective mean air temperature and the water vapor content of air column ...A mono-window algorithm was introduced to retrieve sea surface temperature （SST） using Landsat data in coastal waters. In this algorithm, the effective mean air temperature and the water vapor content of air column were estimated with the local meteorological parameters of air temperature and relative humidity, based on the facts that in the troposphere, （ 1 ） air temperature decreases linearly with the altitude, and （2） water vapor content lapses exponentially with the altitude. The sea-truth temperature data and MODIS Terra SST product were used to validate the SST retrieved from Landsat TM and ETM ＋ thermal infrared （TIR） data with the algorithm. The results show that the algorithm can improve the spatial temperature contrast which is often masked due to water vapor effects, and the temperature derived from the algorithm is closer to the sea-truth SST. When applying the algorithm, the initial parameters of air temperature and relative humidity can be easily collected from local meteorological stations, and there is no need to identify the model of air profile.展开更多
Poor indoor air quality is a large problem in Swedish schools, since the health of occupants may be affected. The building itself is often in focus and other building-related problems may be neglected. The hypothesis ...Poor indoor air quality is a large problem in Swedish schools, since the health of occupants may be affected. The building itself is often in focus and other building-related problems may be neglected. The hypothesis of this study is that factors other than the building itself have decisive influence on indoor environment. An assessment of these nonspecific building-related reasons for bad indoor environment has been made in the present work using surveys combined with particle measurements and comfort measurements (air humidity and air temperature). People are experiencing poor indoor air quality, the air is too dry and the temperature is uneven and uncomfortable indoors in the winter. It is important to highlight the problem of indoor environments with high particulate emissions especially in the range from 5.0 microns and larger since they are conveyers of allergens and bacteria, combined with dry air. An interesting observation regarding the ventilation system is that mechanical systems are tending to generate drier indoor air than the natural ventilation system. Results show that it is possible to decrease emissions through eliminating activity-related sources of airborne contaminants and better the comfort indoors with relatively simple measures.展开更多
This project is based on measurements of the parameter relative humidity, RH (%), in two buildings: one with natural ventilation and one with mechanical ventilation. Both buildings are located in central Sweden, which...This project is based on measurements of the parameter relative humidity, RH (%), in two buildings: one with natural ventilation and one with mechanical ventilation. Both buildings are located in central Sweden, which constitutes a representative climate zone with respect to Swedish conditions. An important factor for the indoor environment, which affects human health and well-being, is the level of the relative humidity, RH (%). Research studies show that the healthiest level should be in the range of 40% - 60%. Surveys have revealed that about 70% of the employees at Swedish offices, schools and kindergartens experience that the air is too dry during the winter season. Previous studies show that the level of relative humidity in the indoor environment influences the prevalence of respiratory infections and allergies. The purpose of this study is to investigate how the relative humidity differ between the two buildings, and if this may be a cause of the health problems that users are affected by. During many years, users have complained about the environment in the building with mechanical ventilation and that they suffer from health problems. The method used in the study is air measurements of the two parameters, relative humidity and air temperature in the two buildings using data loggers. The indoor environment is affected by the outdoor climate and therefore instruments are placed outdoors to record seasonal variations. The measurements were carried out during the period October 2014 to September 2015 to include all of Sweden’s four seasons with completely different climatic conditions. The results of this study show that the relative humidity in the mechanically ventilated building is consistently significantly lower than in the building with natural ventilation whatever the time of year and temperature indoors. This study shows that mechanical ventilation in buildings affects the indoor environment negatively with respect to human health during most time of the year and this fact must be taken into consideration for the existing as well as the planning of new ventilation systems.展开更多
This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put ...This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.展开更多
基金supported by funds from the National Key Research and Development Program Global Change and Mitigation Project [grant number 2017YFA0604004]the National Natural Science Foundation of China [grant numbers41675100,91737306 and U1811464]provided by the SCSIO under the project ‘Scientific investigation of the Eastern Indian Ocean in 2018’,funded by the NSFC(NORC2018-10)
文摘It is important to be able to characterize the thermal conditions over the equatorial Indian Ocean for both weather forecasting and climate prediction. This study compared the equatorial eastern Indian Ocean (EEIO) temperature and relative humidity profiles from three reanalysis products (JRA-55, MERRA2, and FGOALS-f2) with shipboard global positioning system (GPS) sounding measurements obtained during the Eastern Indian Ocean Open Cruise in spring 2018. The FGOALS-f2 reanalysis product is based on the initialization module of a sub-seasonal to seasonal prediction system with a nudging-based data assimilation method. The results indicated that:(1) both JRA-55 and MERRA2 were reliable in characterizing the temperature profile from 850 to 600 hPa, with a maximum deviation of about <0.5℃. Both datasets showed a large negative deviation below 825 hPa, with a maximum bias of about 2℃ at 1000 hPa and 1.5℃ at 900 hPa, respectively.(2) JRA-55 showed good performance in characterizing the relative humidity profile above 850 hPa, with a maximum deviation of < 8%, while it showed much wetter conditions below 850 hPa. MERRA2 overestimated the relative humidity in the middle to lower troposphere, with a maximum deviation of about 15% at 925 hPa.(3) The FGOALS-f2 reanalysis product more accurately reproduced the temperature profile in the marine atmospheric boundary layer over the EEIO than that in JRA-55 and MERRA2, but showed much wetter conditions than the GPS sounding observations, with a maximum deviation of up to 20% at 600 hPa. Future applications of GPS sounding datasets are discussed.
文摘A mono-window algorithm was introduced to retrieve sea surface temperature （SST） using Landsat data in coastal waters. In this algorithm, the effective mean air temperature and the water vapor content of air column were estimated with the local meteorological parameters of air temperature and relative humidity, based on the facts that in the troposphere, （ 1 ） air temperature decreases linearly with the altitude, and （2） water vapor content lapses exponentially with the altitude. The sea-truth temperature data and MODIS Terra SST product were used to validate the SST retrieved from Landsat TM and ETM ＋ thermal infrared （TIR） data with the algorithm. The results show that the algorithm can improve the spatial temperature contrast which is often masked due to water vapor effects, and the temperature derived from the algorithm is closer to the sea-truth SST. When applying the algorithm, the initial parameters of air temperature and relative humidity can be easily collected from local meteorological stations, and there is no need to identify the model of air profile.
文摘Poor indoor air quality is a large problem in Swedish schools, since the health of occupants may be affected. The building itself is often in focus and other building-related problems may be neglected. The hypothesis of this study is that factors other than the building itself have decisive influence on indoor environment. An assessment of these nonspecific building-related reasons for bad indoor environment has been made in the present work using surveys combined with particle measurements and comfort measurements (air humidity and air temperature). People are experiencing poor indoor air quality, the air is too dry and the temperature is uneven and uncomfortable indoors in the winter. It is important to highlight the problem of indoor environments with high particulate emissions especially in the range from 5.0 microns and larger since they are conveyers of allergens and bacteria, combined with dry air. An interesting observation regarding the ventilation system is that mechanical systems are tending to generate drier indoor air than the natural ventilation system. Results show that it is possible to decrease emissions through eliminating activity-related sources of airborne contaminants and better the comfort indoors with relatively simple measures.
文摘This project is based on measurements of the parameter relative humidity, RH (%), in two buildings: one with natural ventilation and one with mechanical ventilation. Both buildings are located in central Sweden, which constitutes a representative climate zone with respect to Swedish conditions. An important factor for the indoor environment, which affects human health and well-being, is the level of the relative humidity, RH (%). Research studies show that the healthiest level should be in the range of 40% - 60%. Surveys have revealed that about 70% of the employees at Swedish offices, schools and kindergartens experience that the air is too dry during the winter season. Previous studies show that the level of relative humidity in the indoor environment influences the prevalence of respiratory infections and allergies. The purpose of this study is to investigate how the relative humidity differ between the two buildings, and if this may be a cause of the health problems that users are affected by. During many years, users have complained about the environment in the building with mechanical ventilation and that they suffer from health problems. The method used in the study is air measurements of the two parameters, relative humidity and air temperature in the two buildings using data loggers. The indoor environment is affected by the outdoor climate and therefore instruments are placed outdoors to record seasonal variations. The measurements were carried out during the period October 2014 to September 2015 to include all of Sweden’s four seasons with completely different climatic conditions. The results of this study show that the relative humidity in the mechanically ventilated building is consistently significantly lower than in the building with natural ventilation whatever the time of year and temperature indoors. This study shows that mechanical ventilation in buildings affects the indoor environment negatively with respect to human health during most time of the year and this fact must be taken into consideration for the existing as well as the planning of new ventilation systems.
文摘This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.
