Lightning is one of the most important natural sources of atmospheric NOx.The authors investigate the2000–2050 changes in NOx emissions from lightning using the global three-dimensional Goddard Earth Observing System...Lightning is one of the most important natural sources of atmospheric NOx.The authors investigate the2000–2050 changes in NOx emissions from lightning using the global three-dimensional Goddard Earth Observing System chemical transport model(GEOS-Chem)driven by meteorological fields from the Goddard Institute for Space Studies(GISS)general circulation model(GCM)3.Projected changes in climate over 2000–2050are based on the Intergovernmental Panel on Climate Change(IPCC)A1B scenario.The global NOx emission from lightning is simulated to be 4.8 Tg N in present day and to increase by about 16.7%over 2000–2050 as a result of the future climate change.The largest present-day emissions and climate-induced changes are found in the upper troposphere in the tropics.Regionally in eastern China(20–55 N,98–125 E),NOx emissions from lighting is simulated to be 0.3 Tg N(6.3%of the global total emission)in present day and to increase by 26.7%over2000–2050.The simulated changes in NOx from lightening correspond well with the projected future changes in convective precipitation.展开更多
A lightning warning system （LWS） which can predict the possibility of lightning strike and the position of lightning discharge was developed. The LWS uses the electric field intensity at the ground as a parameter to...A lightning warning system （LWS） which can predict the possibility of lightning strike and the position of lightning discharge was developed. The LWS uses the electric field intensity at the ground as a parameter to warn the possibility of lightning strikes. A planar shutter type electric field mill （EFM） with a rotating vane is studied to measure the electric field. From a calibration experiment, the sensitivity of the EFM was adjusted to 0.15 V/kV/m, and this covers the ranges from 200 V/m to 20 kV/m. Magnetic field waveform is detected by a crossed loop coil and an integral amplifier. Frequency bandwidth of the circuit ranges from 5 kHz to 1.2 MHz. The polarity of lightning discharges is discriminated by electric field component. After fixing the polarity, we can calculate the direction and distance of lightning discharge by the peak and the zero cross time of the detected magnetic field waveform.展开更多
Desalination processes have environmental impacts. The brine water discharge has an impact on marine ecosystem. This is mostly due to the highly saline brine that is discharged into the sea, which may be increased by ...Desalination processes have environmental impacts. The brine water discharge has an impact on marine ecosystem. This is mostly due to the highly saline brine that is discharged into the sea, which may be increased by temperature, contain residual chemicals from the pretreatment process, heavy metals from corrosion or intermittently used cleaning agents. The effluent from desalination plants is a multi-component waste, with multiple effects on water, sediment and marine organisms. Therefore, it affects the quality of the resource which it depends on. In this study, selected water quality parameters in the seawater and the presence of heavy metals of concern in the sediments and algae were monitored to investigate the impacts of the discharges by seawater desalination plants using reverse osmosis on the receiving marine environment. In light of the results obtained, the analyzed water has a physicochemical quality more or less adequate, moreover, chemical analyzes in seaweed and sediments show relatively low levels of heavy metals.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA05100503)the National Natural Science Foundation of China(Grant Nos.40775083,40825016,and 41021004)the China Meteorological Administration special funding inatmospheric science(Grant No.GYHY200906020)
文摘Lightning is one of the most important natural sources of atmospheric NOx.The authors investigate the2000–2050 changes in NOx emissions from lightning using the global three-dimensional Goddard Earth Observing System chemical transport model(GEOS-Chem)driven by meteorological fields from the Goddard Institute for Space Studies(GISS)general circulation model(GCM)3.Projected changes in climate over 2000–2050are based on the Intergovernmental Panel on Climate Change(IPCC)A1B scenario.The global NOx emission from lightning is simulated to be 4.8 Tg N in present day and to increase by about 16.7%over 2000–2050 as a result of the future climate change.The largest present-day emissions and climate-induced changes are found in the upper troposphere in the tropics.Regionally in eastern China(20–55 N,98–125 E),NOx emissions from lighting is simulated to be 0.3 Tg N(6.3%of the global total emission)in present day and to increase by 26.7%over2000–2050.The simulated changes in NOx from lightening correspond well with the projected future changes in convective precipitation.
文摘A lightning warning system （LWS） which can predict the possibility of lightning strike and the position of lightning discharge was developed. The LWS uses the electric field intensity at the ground as a parameter to warn the possibility of lightning strikes. A planar shutter type electric field mill （EFM） with a rotating vane is studied to measure the electric field. From a calibration experiment, the sensitivity of the EFM was adjusted to 0.15 V/kV/m, and this covers the ranges from 200 V/m to 20 kV/m. Magnetic field waveform is detected by a crossed loop coil and an integral amplifier. Frequency bandwidth of the circuit ranges from 5 kHz to 1.2 MHz. The polarity of lightning discharges is discriminated by electric field component. After fixing the polarity, we can calculate the direction and distance of lightning discharge by the peak and the zero cross time of the detected magnetic field waveform.
文摘Desalination processes have environmental impacts. The brine water discharge has an impact on marine ecosystem. This is mostly due to the highly saline brine that is discharged into the sea, which may be increased by temperature, contain residual chemicals from the pretreatment process, heavy metals from corrosion or intermittently used cleaning agents. The effluent from desalination plants is a multi-component waste, with multiple effects on water, sediment and marine organisms. Therefore, it affects the quality of the resource which it depends on. In this study, selected water quality parameters in the seawater and the presence of heavy metals of concern in the sediments and algae were monitored to investigate the impacts of the discharges by seawater desalination plants using reverse osmosis on the receiving marine environment. In light of the results obtained, the analyzed water has a physicochemical quality more or less adequate, moreover, chemical analyzes in seaweed and sediments show relatively low levels of heavy metals.
