Snow albedo is an important factor influencing the snow surface energy budget and snow melting, yet uncertainties remain in the calculation of spectrally resolved snow surface albedo because the spectral composition ...Snow albedo is an important factor influencing the snow surface energy budget and snow melting, yet uncertainties remain in the calculation of spectrally resolved snow surface albedo because the spectral composition （visible versus near infrared） of the incident solar radiation is seldom available. The influence of the spectral composition of the incoming solar radiation on the snow surface albedo, snow surface energy budget, and final snow ablation is investigated through sensitivity experiments of four snow seasons at two open sites in the Alps by using a multi-layer Snow-Atmosphere-Soil-Transfer scheme （SAST）. Since the snow albedo in the near infrared （NIR） spectral band is significantly lower than that in the visible （VIS） band, and almost the entire NIR part of the solar radiation is absorbed in the top layer of the snow pack, given a fixed amount of incoming solar radiation, a lower VIS/NIR ratio implies that more NIR radiation is reaching the ground surface and more is absorbed by the top layer of the snow pack, therefore, speeding up the snow melting and increasing the surface runoff, although a lesser part of the solar radiation in the visible band is transmitted into and trapped by the sub-layer of the snow pack. The above VIS/NIR ratio effect of the incoming solar radiation can result in a couple of days difference in the timing of snow ablation and it becomes more significant in late spring when the total solar radiation is intensified with seasonal evolution. Snow aging also slightly intensifies this VIS/NIR ratio effect.展开更多
A flux-form semi-Lagrangian transport scheme （FFSL） was implemented in a spectral atmospheric GCM developed and used at IAP/LASG. Idealized numerical experiments show that the scheme is good at shape preserving with...A flux-form semi-Lagrangian transport scheme （FFSL） was implemented in a spectral atmospheric GCM developed and used at IAP/LASG. Idealized numerical experiments show that the scheme is good at shape preserving with less dissipation and dispersion, in comparison with other conventional schemes, hnportantly, FFSL can automatically maintain the positive definition of the transported tracers, which was an underlying problem in the previous spectral composite method （SCM）. To comprehensively investigate the impact of FFSL on GCM results, we conducted sensitive experiments. Three main improvements resulted： first, rainfall simulation in both distribution and intensity was notably improved, which led to an improvement in precipitation frequency. Second, the dry bias in the lower troposphere was significantly reduced compared with SCM simulations. Third, according to the Taylor diagram, the FFSL scheme yields simulations that are superior to those using the SCM： a higher correlation between model output and observation data was achieved with the FFSL scheme, especially for humidity in lower troposphere. However, the moist bias in the middle and upper troposphere was more pronounced with the FFSL scheme. This bias led to an over-simulation of precipitable water in comparison with reanalysis data. Possible explanations, as well as solutions, are discussed herein.展开更多
The densification and the fractal dimensions of carbon-nickel films annealed at different temperatures 300, 500, 800, and 1000℃ with emphasis on porosity evaluation are investigated. For this purpose, the refractive...The densification and the fractal dimensions of carbon-nickel films annealed at different temperatures 300, 500, 800, and 1000℃ with emphasis on porosity evaluation are investigated. For this purpose, the refractive index of films is determined from transmittance spectra. Three different regimes are identified, T 〈 500℃, 500℃ 〈 T 〈 800℃ and T 〉 800℃. The Rutherford baekscattering spectra show that with increasing the annealing temperature, the concentration of nickel atoms into films decreases. It is shown that the effect of annealing temperatures for increasing films densification at T 〈 500℃ and T 〉 800℃ is greater than the effect of nickel concentrations. It is observed that the effect of decreasing nickel atoms into films at 500℃ 〈 T 〈 800℃ strongly causes improving porosity and decreasing densification. The fractal dimensions of carbon-nickel films annealed from 300 to 500℃ are increased, while from 500 to 1000℃ these characteristics are decreased. It can be seen that at 800℃, films have maximum values of porosity and roughness.展开更多
[ Objective] The physiological radiation spectrum and fruit quality in different canopies of sweet cherry tree were studied. [ Method] Opti- cal fiber spectrum was applied to determine the physiological radiation spec...[ Objective] The physiological radiation spectrum and fruit quality in different canopies of sweet cherry tree were studied. [ Method] Opti- cal fiber spectrum was applied to determine the physiological radiation spectrum in different canopies of sweet cherry tree. The fruit quality in differ- ent canopies was determined. [Result] The results showed that from the top part to the lower part and from the outer part to inner part of sweet cherry canopy, Me physiological radiation intensity and ratio of short wave light reduced significantly, while ratio of long wave light increased. Fruit mass, Vc, TSS and total sugar content were significantly decreasing, while organic acid content increasing, but the fruit edible percent was similar. Furthermore, the physiological radiation intensity was strong, fruit mass, TSS, Vc and total sugar content increased, but organic acid content re- duced. [ Condusion] The higher and bigger canopy of sweet cherry, the poor and lower physiological radiation intensity, photosynthesis accumula- tion and fruit quality. The study provided theoretical foundation and reference for the trim of sweet cherry.展开更多
Examines the development of the composite legendre approximation in unbounded domains. Proof of the stability and convergence of a proposed scheme; Discussion of two-dimensional exterior problems; Error estimations.
基金supported by the Ministry of Science and Technology of China under Grant Nos.2007CB411505 and 2006CB403604the Ministry of Finance of China through Grant GYHY200706005
文摘Snow albedo is an important factor influencing the snow surface energy budget and snow melting, yet uncertainties remain in the calculation of spectrally resolved snow surface albedo because the spectral composition （visible versus near infrared） of the incident solar radiation is seldom available. The influence of the spectral composition of the incoming solar radiation on the snow surface albedo, snow surface energy budget, and final snow ablation is investigated through sensitivity experiments of four snow seasons at two open sites in the Alps by using a multi-layer Snow-Atmosphere-Soil-Transfer scheme （SAST）. Since the snow albedo in the near infrared （NIR） spectral band is significantly lower than that in the visible （VIS） band, and almost the entire NIR part of the solar radiation is absorbed in the top layer of the snow pack, given a fixed amount of incoming solar radiation, a lower VIS/NIR ratio implies that more NIR radiation is reaching the ground surface and more is absorbed by the top layer of the snow pack, therefore, speeding up the snow melting and increasing the surface runoff, although a lesser part of the solar radiation in the visible band is transmitted into and trapped by the sub-layer of the snow pack. The above VIS/NIR ratio effect of the incoming solar radiation can result in a couple of days difference in the timing of snow ablation and it becomes more significant in late spring when the total solar radiation is intensified with seasonal evolution. Snow aging also slightly intensifies this VIS/NIR ratio effect.
基金supported by the Chinese Academy of Science Strategic Priority Research Program (Grant No. XDA05110303)"973" Program (Grant Nos. 2010CB950403,2012CB417203,and 2013CB955803)+1 种基金"863" Program(Grant No. 2010AA012305)the National Natural Science Foundation of China (Grant Nos. 40925015,40875034,and 41023002)
文摘A flux-form semi-Lagrangian transport scheme （FFSL） was implemented in a spectral atmospheric GCM developed and used at IAP/LASG. Idealized numerical experiments show that the scheme is good at shape preserving with less dissipation and dispersion, in comparison with other conventional schemes, hnportantly, FFSL can automatically maintain the positive definition of the transported tracers, which was an underlying problem in the previous spectral composite method （SCM）. To comprehensively investigate the impact of FFSL on GCM results, we conducted sensitive experiments. Three main improvements resulted： first, rainfall simulation in both distribution and intensity was notably improved, which led to an improvement in precipitation frequency. Second, the dry bias in the lower troposphere was significantly reduced compared with SCM simulations. Third, according to the Taylor diagram, the FFSL scheme yields simulations that are superior to those using the SCM： a higher correlation between model output and observation data was achieved with the FFSL scheme, especially for humidity in lower troposphere. However, the moist bias in the middle and upper troposphere was more pronounced with the FFSL scheme. This bias led to an over-simulation of precipitable water in comparison with reanalysis data. Possible explanations, as well as solutions, are discussed herein.
文摘The densification and the fractal dimensions of carbon-nickel films annealed at different temperatures 300, 500, 800, and 1000℃ with emphasis on porosity evaluation are investigated. For this purpose, the refractive index of films is determined from transmittance spectra. Three different regimes are identified, T 〈 500℃, 500℃ 〈 T 〈 800℃ and T 〉 800℃. The Rutherford baekscattering spectra show that with increasing the annealing temperature, the concentration of nickel atoms into films decreases. It is shown that the effect of annealing temperatures for increasing films densification at T 〈 500℃ and T 〉 800℃ is greater than the effect of nickel concentrations. It is observed that the effect of decreasing nickel atoms into films at 500℃ 〈 T 〈 800℃ strongly causes improving porosity and decreasing densification. The fractal dimensions of carbon-nickel films annealed from 300 to 500℃ are increased, while from 500 to 1000℃ these characteristics are decreased. It can be seen that at 800℃, films have maximum values of porosity and roughness.
基金Supported by National Science and Technology Achievement Transition Program(2010GB2F000408)the Undergraduates Innovating Experimentation Project of Sichuan Agricultural University
文摘[ Objective] The physiological radiation spectrum and fruit quality in different canopies of sweet cherry tree were studied. [ Method] Opti- cal fiber spectrum was applied to determine the physiological radiation spectrum in different canopies of sweet cherry tree. The fruit quality in differ- ent canopies was determined. [Result] The results showed that from the top part to the lower part and from the outer part to inner part of sweet cherry canopy, Me physiological radiation intensity and ratio of short wave light reduced significantly, while ratio of long wave light increased. Fruit mass, Vc, TSS and total sugar content were significantly decreasing, while organic acid content increasing, but the fruit edible percent was similar. Furthermore, the physiological radiation intensity was strong, fruit mass, TSS, Vc and total sugar content increased, but organic acid content re- duced. [ Condusion] The higher and bigger canopy of sweet cherry, the poor and lower physiological radiation intensity, photosynthesis accumula- tion and fruit quality. The study provided theoretical foundation and reference for the trim of sweet cherry.
文摘Examines the development of the composite legendre approximation in unbounded domains. Proof of the stability and convergence of a proposed scheme; Discussion of two-dimensional exterior problems; Error estimations.
