A new present weather identifier(PWI) based on occlusion and scattering techniques is presented in the study. The present weather parameters are detectable by the meteorological optical range(MOR) approximately up to ...A new present weather identifier(PWI) based on occlusion and scattering techniques is presented in the study. The present weather parameters are detectable by the meteorological optical range(MOR) approximately up to 50 km and by droplets with diameters ranging from 0.125 mm to 22 mm with velocities up to 16 m s-1. The MOR error is less than 8% for the MOR within 10 km and less than 15% for farther distances. Moreover, the size errors derived from various positions of the light sheet by the particles were checked within ± 0.1 mm ± 5%. The comparison shows that the MOR, in a sudden shower event, is surprisingly consistent with those of the sentry visibility sensors(SVS) with a correlation coefficient up to 98%. For the rain amounts derived from the size and velocity of the droplets, the daily sums by the PWI agree within 10% of those by the Total Rain Weighing Sensor(TRwS205) and the rain gauge. Combined with other sensors such as temperature, humidity, and wind, the PWI can serve as a present weather sensor to distinguish several weather types such as fog, haze, mist, rain, hail, and drizzle.展开更多
We propose a new exponential f（R） gravity model with f（R） = （R - λc） e^λ（c/R）n and n 〉 3, λ ≥ 1, c 〉 0 to explain late-time acceleration of the universe. At the high curvature region, the model behaves l...We propose a new exponential f（R） gravity model with f（R） = （R - λc） e^λ（c/R）n and n 〉 3, λ ≥ 1, c 〉 0 to explain late-time acceleration of the universe. At the high curvature region, the model behaves like the A CDM model. In the asymptotic future, it reaches a stable de-Sitter spaeetime. It is a cosmologically viable model and can evade the local gravity constraints easily. This model shares many features with other f（R） dark energy models like Hu-Sawicki model and ExponentiM gravity model. In it the dark energy equation of state is of an oscillating form and can cross phantom divide line ωde = -1. In particular, in the parameter range 3 〈 n ≤ 4, λ ～ 1, the model is most distinguishable from other models. For instance, when n = 4, λ = 1, the dark energy equation of state will cross -1 in the earlier future and has a stronger oscillating form than the other models, the dark energy density in asymptotical future is smaller than the one in the high curvature region. This new model can evade the local gravity tests easily when n 〉 3 and λ 〉 1.展开更多
基金supported by Automatic Observation System for Cloud, Visibility and Weather Phenomena (Grant No. GYHY200806031)Carbon Satellites Verification Systems and Comprehensive Observations (Grant Nos. GJHZ1207 and XDA05040302)
文摘A new present weather identifier(PWI) based on occlusion and scattering techniques is presented in the study. The present weather parameters are detectable by the meteorological optical range(MOR) approximately up to 50 km and by droplets with diameters ranging from 0.125 mm to 22 mm with velocities up to 16 m s-1. The MOR error is less than 8% for the MOR within 10 km and less than 15% for farther distances. Moreover, the size errors derived from various positions of the light sheet by the particles were checked within ± 0.1 mm ± 5%. The comparison shows that the MOR, in a sudden shower event, is surprisingly consistent with those of the sentry visibility sensors(SVS) with a correlation coefficient up to 98%. For the rain amounts derived from the size and velocity of the droplets, the daily sums by the PWI agree within 10% of those by the Total Rain Weighing Sensor(TRwS205) and the rain gauge. Combined with other sensors such as temperature, humidity, and wind, the PWI can serve as a present weather sensor to distinguish several weather types such as fog, haze, mist, rain, hail, and drizzle.
基金Supported by National Natural Science Foundation of China under Grant Nos.10975005 and 11335012
文摘We propose a new exponential f（R） gravity model with f（R） = （R - λc） e^λ（c/R）n and n 〉 3, λ ≥ 1, c 〉 0 to explain late-time acceleration of the universe. At the high curvature region, the model behaves like the A CDM model. In the asymptotic future, it reaches a stable de-Sitter spaeetime. It is a cosmologically viable model and can evade the local gravity constraints easily. This model shares many features with other f（R） dark energy models like Hu-Sawicki model and ExponentiM gravity model. In it the dark energy equation of state is of an oscillating form and can cross phantom divide line ωde = -1. In particular, in the parameter range 3 〈 n ≤ 4, λ ～ 1, the model is most distinguishable from other models. For instance, when n = 4, λ = 1, the dark energy equation of state will cross -1 in the earlier future and has a stronger oscillating form than the other models, the dark energy density in asymptotical future is smaller than the one in the high curvature region. This new model can evade the local gravity tests easily when n 〉 3 and λ 〉 1.
