Simulation of astronomical solar radiation over Yellow River Basin based on DEM

1IntroductionDistributed watershed hydrological model has become one of the hot topics in hydrology for its predominance in reflecting the influence of the spatial distributed features of terrains on hydrological processes (Wan etal., 2001; Abbott etal., 1986; Beven etal., 1992). However its demands on the spatio-temporal changeful surface elements such as solar radiation, precipitation, temperature etc. are strict. Being the limitations of observation techniques, data availability and study …     

Modelling of evaporation in a sparse millet crop using a two-source model including sensible heat advection within the canopy

During two successive growing seasons meteorological measurements were made in a pearl millet field in the Sahel to investigate the evaporation process in relation to crop growth. The evaporation was measured by eddy correlation and simulated using the Shuttleworth Wallace (SW) model [Q. J. R. Meteorol. Soc. 111 (1985) 839–855]. To take sun height and multi-layer scattering into account a radiation balance model was formulated. The model indicates that partitioning of the net radiation between the vegetation and the soil may be estimated (r²=0.94) from the fraction of diffuse radiation, the leaf area index and an attenuation coefficient, but that the attenuation coefficient may not be similar in different locations. To solve the SW-model with respect to the soil resistance an iterative solution was employed with the total evaporation estimated from the Bowen-ratio calculated from eddy correlation measurements. The procedure made it possible to derive stable estimates of soil resistance at soil evaporation rates down to 25 W m⁻². The soil resistance was found to be in accordance with evaporation through a dry surface layer. The SW-model indicates, that advection of sensible heat from the dry soil to the plants, increases transpiration considerably. This will cause management techniques, such as mulching and dry farming, aimed at reducing soil evaporation to be less effective than might be anticipated. The effects of raising the leaf area index to improve the microclimate is discussed in relation to management of the available water and crop security.     

Seasonal temperature responses to land-use change in the western United States

In the western United States, more than 79 000 km² has been converted to irrigated agriculture and urban areas. These changes have the potential to alter surface temperature by modifying the energy budget at the land–atmosphere interface. This study reports the seasonally varying temperature responses of four regional climate models (RCMs) – RSM, RegCM3, MM5-CLM3, and DRCM – to conversion of potential natural vegetation to modern land-cover and land-use over a 1-year period. Three of the RCMs supplemented soil moisture, producing large decreases in the August mean (− 1.4 to − 3.1 °C) and maximum (− 2.9 to − 6.1 °C) 2-m air temperatures where natural vegetation was converted to irrigated agriculture. Conversion to irrigated agriculture also resulted in large increases in relative humidity (9% to 36% absolute change). Modeled changes in the August minimum 2-m air temperature were not as pronounced or consistent across the models. Converting natural vegetation to urban land-cover produced less pronounced temperature effects in all models, with the magnitude of the effect dependent upon the preexisting vegetation type and urban parameterizations. Overall, the RCM results indicate that the temperature impacts of land-use change are most pronounced during the summer months, when surface heating is strongest and differences in surface soil moisture between irrigated land and natural vegetation are largest.     

上海世博会对周边城市旅游辐射效应研究

为了研究上海世博会对上海周边城市的旅游辐射效应以及对该地区旅游经济产生的影响,引入旅游辐射场强模型、旅游断裂点、旅游集中系数进行量化分析,结果表明:1)世博会使上海对周边城市的旅游辐射效应明显增强;2)世博会对周边城市的旅游辐射效应分布并不均匀,不同城市之间存在较大差异;3)上海在对周边城市的旅游辐射中占优势地位,世博会的举办使这种优势得以加强;4)世博会使上海及其周边地区的旅游经济趋于集中发展。     

兰渝铁路辐射带经济空间差异及其对策研究

以兰渝铁路沿线120 km范围内的主要行政单元为研究对象,选取衡量经济发展的9个指标,运用主成分分析法揭示辐射带经济差异,同时运用Geoda软件提供的空间分析方法揭示辐射带经济差异的空间分异特征。分析结果表明,辐射带经济发展水平差异显著,在地理空间上存在集聚性;铁路的重庆段为铁路经济发展的热点区,辐射带内除重庆外无二级节点城市引导经济发展,重庆的经济辐射能力随距离的增加呈现出明显的衰减效应。在此基础上分析了影响兰渝铁路辐射带经济发展的主要因素,并提出相应的发展对策。     

卫星反演太阳紫外辐射数据产品在东疆黑戈壁区域的适用性验证

论文利用2017年东疆哈密地区红柳河黑戈壁地面高精度紫外辐射实测数据与美国NASA Langely研究中心大气科学数据中心提供的CERES_SYN1 deg_Ed4A产品数据,对卫星反演的紫外辐射A、B波段(UVA和UVB)数据在该地区的适用性进行了对比验证。结果表明：① 在日尺度上,该地区地面实测紫外辐射UVA和UVB与卫星反演数据之间的相关系数达0.9以上,其中在全天空情况下UVA平均偏差为1.15 W·m ^-2、UVB 平均偏差为0.03 W·m ^-2,晴天条件下UVA和UVB的平均偏差分别为0.93 W·m ^-2和0.03 W·m ^-2;② 在季节尺度上,实测和卫星反演UVA和UVB的偏差夏季最大,分别为2.04 W·m ^-2和0.05 W·m ^-2,春冬两季次之,秋季最小;③ 红柳河地区在春夏两季受到气溶胶光学厚度(AOD)影响较大,呈现显著负相关;④ 云量越大,紫外辐射削弱程度越大,在多云条件下地面实测与卫星反演UVA与UVB偏差最大,分别为1.73 W·m ^-2和0.05 W·m ^-2。     

Terrain revised model for air temperature in mountainous area based on DEMs： A case study in Yaoxian county

In mountainous area, spatial interpolation is the traditional method to calculate air temperature by use of observed temperature data. Due to lack of sufficient observation data in mountainous areas many precise interpolation methods could give only coarse result which could not meet the demand of precision agriculture and local climate exploration. Based on DEMs of 25 m resolution, a reversed model is constructed, with which temperature is simulated to the corresponding slope unit from the solar radiation. Taking Yaoxian county as a test area, and mean monthly temperature data as basic information sources, which are collected from 15 weather stations around Yaoxian county in Shaanxi province from the year of 1970 to 2000, a simulation for the solar radiation cell by cell is completed. By simulating solar radiation at each slope and flat cell unit, the terrain revised temperature model could be realized. A comparison between the simulated temperature and the radiation temperature from TM6 thermal infrared image shows that the terrain improved model gets a finer temperature distribution at local level. The accuracy of simulated temperature in mountainous area is higher than it is in flat area.     

BOOK REVIEWS

Book Reviewed in this article: Main Street: Northeastern Oregon: The Founding and Development of Small Towns . Barbara Ruth Bailey . Food Politics: The Regional Conflict . David N. Balaam and Michael J. Carey , eds. The International Economy and Industrial Development: Trade and Investment in the Third World . R. Ballance , J. Ansari and H. Singer . Neighborhoods in Urban America . Ronald H. Bayor , ed. The English Heartland . By Robert Beckinsale and Monica Beckinsale . Regional Dimensions of Industrial Policy . Michael E. Bell and Paul S. Lande , eds. Tension Areas of the World . D. Gordon Bennett , ed. Latin America: an Introductory Survey . B. W. Blouet and O. M. Blouet , eds. Integration and Division: Geographical Perspectives on the Northern Ireland Problem . Frederick W. Boal and J. Neville H. Douglas , eds. Energy and Land Use . Robert W. Burchell and David Listokin , eds. Slopes and Weathering . Michael Clarke and John Small . Alaska's Rural Development . Peter G. Cornwall and Gerald Mc Beath , eds. The Politics of Park Design: A History of Urban Parks in America . Galen Cranz . World Congress on Land Policy, 1980, Proceedings . Matthew Cullen and Sharon Woolery , eds. Oregon Divided: A Regional Geography . Samuel N. Dicken and Emily F. Dicken . Urban Food Marketing and Third World Rural Development . T. Scarlett Epstein . South Africa: Spatial Frameworks for Development . T. J. D. Fair . Institutions and Geographical Patterns . Robin Flowerdew , ed. Industrialization of U.S. Agriculture, An Interpretive Atlas . Howard F. Gregor . Planning Theory: Prospects for the 1980s . Patsy Healy , Glen Mc Dougall and Michael J. Thomas , eds. Neighborhood Mobilization: Redevelopment and Response . Jeffrey R. Henig . The American Urban System: A Geographical Perspective . R. J. Johnston . Climate, History and the Modern World . Hubert H. Lamb . Climate and History: Studies in Past Climates and Their Impact on Man . T. M. L. Wigley , M. J. Ingram and G. Farmer . China: Railways and Agricultural Development, 1875–1935 . Ernest P. Liang . A Desirable Energy Future—A National Perspective . Robert S. Livingston , T. D. Anderson , T. M. Besmann , M. Olszewski , A. M. Perry , and C. D. West . Topothesia: Essays Presented to T. S. Ó Máille . B. S. Mac Aodha , ed. Transportation for the Poor: Research in Rural Mobility . Hal S. Maggied . Land Uses in American Cities . Harold M. Mayer and Charles R. Haves . Industrial Organisation and Location . Philip Mc Dermott and Michael Taylor . Human Adaptability: an Introduction to Ecological Anthropology . Emilio F. Moran . Regional Analysis and the New International Division of Labor . Frank Moulaert and Patricia W. Salinas , eds. The Nuclear War Atlas. Victoriaville, Quebec, Canada : Urbanization and Environmental Quality . Isao Orishimo . The Garden of Eden: The Botanic Garden and the Re-Creation of Paradise . John Prest . Earthfire, The Eruption of Mount St. Helens . Charles Rosenfeld and Robert Cooke . Contest for the South China Sea . Marwyn S. Samuels . The Future of the Wetlands: Assessing Visual-Cultural Values . Richard C. Smardon , ed. Tucson: the Life and Times of An American City. C. L. Sonnichsen . The Geography of Multinationals . Michael Taylor and Nigel Thrift , eds. Impact of Marine Pollution on Society . Virginia Tippie and Dana Kester . Reviving the Industrial City: the Politics of Urban Renewal in Lyon and Birmingham . Jerry A. Webman . Andean Reflections: Letters from Carl O. Sauer While on a South American Trip under a Grant from the Rockefeller Foundation, 1942 . Robert C. West , ed. Cartographic Drawing with Computers . P. Yoeli .     

Characteristics of infrared point sources associated with OH masers

We collect 3249 OH maser sources from the literature published up to April 2007, and compile a new catalog of OH masers. We look for the exciting sources of these masers and their infrared properties from IRAS and MSX data, and make a statistical study. MSX sources associated with stellar 1612 MHz OH masers are located mainly above the blackbody line; this is caused by the dust absorption of stellar envelopes, especially in the MSX A band. The mid-IR sources associated with stellar OH masers are concentrate...     

Resonant cyclotron scattering in pulsar magnetospheres and its application to isolated neutron stars

Resonant cyclotron scattering(RCS)in pulsar magnetospheres is considered.The photon diffusion equation(Kompaneets equation)for RCS is derived.The photon system is modeled three dimensionally.Numerical calculations show that there exist not only up scattering but also down scattering of RCS,depending on the parameter space.RCS's possible applications to spectral energy distributions of magnetar candidates and radio quiet isolated neutron stars(INSs)are pointed out.The optical/UV excess of INSs may be caused by the down scattering of RCS.The calculations for RX J1856.5-3754 and RX J0720.4-3125 are presented and compared with their observational data.In our model,the INSs are proposed to be normal neutron stars,although the quark star hypothesis is still possible.The low pulsation amplitude of INSs is a natural consequence in the RCS model.