Bacterial responses in activity and community composition to photo-oxidation of dissolved organic matter from soil and surface waters   总被引：1，自引：0，他引：1  

Kristin E. Judd  Byron C. Crump  George W. Kling 《Aquatic Sciences - Research Across Boundaries》2007,69(1):96-107

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Effect of ultraviolet and visible radiation on iron lability in boreal and artificial waters     

Nadia Kelton  Lewis A. Molot  Peter J. Dillon 《Aquatic Sciences - Research Across Boundaries》2007,69(1):86-95

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Cloud and Radiation Processes Simulated by a Coupled Atmosphere-Ocean Model          下载免费PDF全文

WANG Fang  DING Yihui  XU Ying 《Acta Meteorologica Sinica》2007,21(4):397-408

Using NCC/IAP T63 coupled atmosphere-ocean general circulation model (AOGCM),two 20-yr integra- tions were processed,and their ability to simulate cloud and radiation was analysed in detail.The results show that the model can simulate the basic distribution of cloud cover,and however,obvious differences still exist compared with ISCCP satellite data and ERA reanalysis data.The simulated cloud cover is less in general,especially the abnormal low values in some regions of ocean.By improving the cloud cover scheme, simulated cloud cover in the eastern Pacific and Atlantic,summer hemisphere's oceans from subtropical to mid-latitude is considerably improved.But in the tropical Indian Ocean and West Pacific the cloud cover difference is still evident,mainly due to the deficiency of high cloud simulation in these regions resulting from deep cumulus convection.In terms of the analysis on radiation and cloud radiative forcing,we find that simulation on long wave radiation is better than short wave radiation.The simulation error of short wave radiation is caused mostly by the simulation difference in short wave radiative forcing,sea ice,and snow cover,and also by not involving aerosol's effect.The simulation error of long wave radiation is mainly resulting from deficiency in simulating cloud cover and underlying surface temperature.Corresponding to improvement of cloud cover,the simulated radiation (especially short wave radiation) in eastern oceans, summer hemisphere's oceans from subtropical to mid-latitude is remarkably improved.This also brings obvious improvement to net radiation in these regions.  相似文献   

Analysis of UVB values in the centre of the Iberian Peninsula     

E. Gutirrez-Marco  E. Hernndez  J.L. Camacho  A. Labajo 《Atmospheric Research》2007,84(4):345-352

Records of UV data started in Madrid at the beginning of the 90's decade. After some quality control on the data a seven year period from 1996 to 2002 was selected to perform an analysis of daily and seasonal variability of solar ultraviolet B (UVB) values at the centre of the Iberian Peninsula. Instruments used are a Brewer MKIV spectrophotometer and a YES UVB-1 broadband pyranometer. Both instruments provided integrated daily values according with the Diffey spectrum although they have different measurement procedures. Data statistics from each instrument for the same period and statistical relationships between daily values from both instruments are shown. As broadband YES provided a record with fewer time gaps, analysis of UVI extreme values is performed using that instrument. The relationship between UVB values with ozone, cloudiness and visible radiation has been described in several papers for different places in the world. In this paper, those relationships are shown for Madrid. A discussion about specific problems found when trying to isolate every effective factor is also included. Some of those relationships could be helpful to retrieve UVB values from other ancillary data as visible radiation and cloudiness. Finally, a detailed study for 10 days in June 1997 when the maximum record of daily values from the present time series was obtained, highlight the close correlation between total ozone content and the daily variability of UVB for similar amounts of incoming radiation.  相似文献   

宁夏区域太阳日辐射通量计算方法的研究   总被引：1，自引：0，他引：1  

杨勤 《干旱气象》2007,23(3):23-27

利用银川站过去5 a的太阳日辐射观测资料(1981~1985)与大气外太阳辐射、日照时数、日照长度间的相关关系,确定了区域系数as。通过对bs的取值进行敏感测试,可得到一组最佳推算太阳辐射通量的区域系数:as=0.3,bs=0.5。用此系数和太阳日辐射通量计算公式,推算了银川站1986、1987年太阳日辐射通量并用观测值进行验证,结果表明:两者之间有很好的线性相关,R2=0.94,验证了区域系数的可信度。通过对银川站2 a(1986,1987)资料的平均误差、平均偏差、平均绝对偏差和均方根偏差的计算表明,结果与国内相关报道基本一致。对宁夏永宁站1989~2000年的太阳日辐射通量用区域系数进行估算,并与银川站的实际观测资料比较,结果显示永宁站太阳日辐射通量估算值和银川站实测值间有很好的线性关系,12 a间的方差最小值R2=0.88。  相似文献   

Radiatively driven electron–positron jets from two-component accretion flows     

Indranil Chattopadhyay  Santabrata Das  Sandip K. Chakrabarti 《Monthly notices of the Royal Astronomical Society》2004,348(3):846-856

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Gamma-ray bursts from synchrotron self-Compton emission   总被引：1，自引：0，他引：1  

Boris E. Stern  Juri Poutanen † 《Monthly notices of the Royal Astronomical Society》2004,352(3):L35-L39

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Effects of polypeptide from Chlamys farreri on amino acid con-tent in guinea pig skin irradiated by chronic ultraviolet A and B     

于国英  曹鹏利  郭昆  王跃军  孙谧  王春波 《中国海洋湖沼学报》2004,22(4)

1 INTRODUCTION Long-term exposure of the skin to ultraviolet (UV) radiation results in degenerative processes involved in photoaging and photocarcinogenesis (Differy, 1987). As UVC is absorbed entirely by the stratospheric ozone layer and does not reach the earth抯 surface, sunlight is composed of UVA (320 nm 400 nm) and UVB (290 nm 320 nm). Human skin is exposed constantly to both UVA and UVB radiation, it is, therefore, important to protect the skin against UVA and UVB-induce…  相似文献   

A pulsar outer gap model with trans-field structure     

J. Takata  S. Shibata  K. Hirotani 《Monthly notices of the Royal Astronomical Society》2004,354(4):1120-1132

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X-ray beaming caused by resonance scattering in the accretion column of magnetic cataclysmic variables     

Y. Terada  M. Ishida  K. Makishima  T. Imanari  R. Fujimoto  K. Matsuzaki  H. Kaneda 《Monthly notices of the Royal Astronomical Society》2001,328(1):112-126

Extremely strong ionized Fe emission lines, with equivalent widths reaching ∼4000 eV, were discovered by ASCA from a few Galactic compact objects, including AX J2315−0592, RX J1802.1+1804 and AX J1842.8−0423. These objects are thought to be binary systems containing magnetized white dwarfs (WDs). A possible interpretation of the strong Fe K line is the line-photon collimation in the WD accretion column, as a result of resonance scattering of line photons. The collimation occurs when the accretion column has a flat shape, and the effect is augmented by the vertical velocity gradient, which reduces the resonant trapping of resonant photons along the magnetic field lines. This effect was quantitatively confirmed with Monte Carlo simulations. Furthermore, with ASCA observations of the polar V834 Centauri, this collimation effect was clearly detected as a rotational modulation of the equivalent width of the Fe K emission line. The extremely strong emission lines mentioned above can be explained consistently by our interpretation. Combining this effect with other X-ray information, the geometry and plasma parameters in the accretion column were determined.  相似文献