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351.
Agricultural climatic resources (such as light,temperature,and water) are environmental factors that affect crop productivity.Predicting the effects of climate change on agricultural climatic resource utilization can provide a theoretical basis for adapting agricultural practices and distributions of agricultural production.This study investigates these effects under the IPCC (Intergovernmental Panel on Climate Change) scenario A1B using daily data from the high-resolution RegCM3 (0.25° ×0.25°) during 1951-2100.Model outputs are adjusted using corrections derived from daily observational data taken at 101 meteorological stations in Northeast China between 1971 and 2000.Agricultural climatic suitability theory is used to assess demand for agricultural climatic resources in Northeast China during the cultivation of spring maize.Three indices,i.e.,an average resource suitability index (Isr),an average efficacy suitability index (Ise),and an average resource utilization index (K),are defined to quantitatively evaluate the effects of climate change on climatic resource utilization between 1951 and 2100.These indices change significantly in both temporal and spatial dimensions in Northeast China under global warming.All three indices are projected to decrease in Liaoning Province from 1951 to 2100,with particularly sharp declines in Isr,Ise,and K after 2030,2021,and 2011,respectively.In Jilin and Heilongjiang provinces,Isr is projected to increase slightly after 2011,while Ise increases slightly and K decreases slightly after 2030.The spatial maxima of all three indices are projected to shift northeastward.Overall,warming of the climate in Northeast China is expected to negatively impact spring maize production,especially in Liaoning Province.Spring maize cultivation will likely need to shift northward and expand eastward to make efficient use of future agricultural climatic resources.  相似文献   
352.
东北地区玉米整地、播种和收获气象适宜度评价模型   总被引:5,自引:0,他引:5  
马树庆  陈剑  韩智平  王琪 《气象》2013,39(6):782-788
天气、土壤条件影响玉米整地、播种和收获作业的质量及作业效率,进而影响到苗情、产量和生产成本,东北地区相关的农业气象要素是土壤湿度、土壤解冻深度、温度、日雨量和风力等.根据气象、土壤条件对玉米整地、播种和收获的影响,用模糊隶属函数建立了这些农事活动气象适宜度评价函数及其农业气象指标,用权重法分别建立了整地、播种和收获综合气象适宜度评价模型.检验结果表明,这些模式和指标符合实际,可以用于相关农事活动的气象适宜度评价业务.在气温和降水等气象要素预报的基础上,该模型还可以用于相关农事气象适宜度和适宜期的预报.  相似文献   
353.
黄河三角洲地区蕴含着丰富的中低温地热,为2000m以浅经济型地热资源,经计算,全区地热资源总量折合标准煤相当于125×10~8t,其中仅地下热水总储存量就达到4570×10~8 m~3,可开采储量超过750×10~8 m~3,至少可以开采100a。如果形成以东营、河口、孤岛、广饶为中心的4个大面积系统的开发利用体系,并注重地热资源的综合利用和梯级利用,对于缓解能源紧张、促进经济的可持续发展等方面具有重要的意义。  相似文献   
354.
STUDY OF RURAL TOURISM IN TURPAN, CHINA   总被引:4,自引:0,他引:4  
~~STUDY OF RURAL TOURISM IN TURPAN ,CHINA@KEYIM Parhad$Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, P. R. China; The Graduate School of Chinese Academy of Sciences, Beijing 100039, P. R. ChinaBRAMWELL B, LANE B,…  相似文献   
355.
1 Introduction As a special kind of tourism, glacier tourism is popular to tourists all over the world owing to its meeting tourists’ needs for seeking after freshness, difference, surprise and risk. Differing from conventional tourism, glacier tour- ism has its special characters while there is little literature on it. It is of great significance to study its characters and seek after the harmonious development in exploitation and protection of glacier tourism resources. Glacier tourism refe…  相似文献   
356.
Considering nonthermal e±-pair production, this paper is focused on the radial structure of hot one-temperature accretion flows with advection under the condition of small viscous parameter ( = 0.1) and low mass-accretion rates. Self-similar relations of hot flow with advection have been adopted. The authors have used a scheme, in which the two regions of accretion flow are calculated separately and then joined together. Some typical features of hot flow with advection have been confirmed, and several new results obtained: there exists a critical radius rcr; the local cooling rate is inversely proportional to the square of the mass of the central object; the e±-pair process affects significantly the radiation of hot flows with advection.  相似文献   
357.
This paper examines tourism development on Vancouver Island, B.C. in terms of the core-periphery approach to regional planning. It examines whether a core area (Victoria) is willing to share its tourism business with the rest of the island, and then focuses on the situation in a peripheral region (the Cowichan Valley Regional District–CVRD). A discriminant analysis of CVRD residents reveals they have different views regarding tourism's potential and future in their region. A follow-up analysis, reflecting a change in the scale of enquiry and local core-periphery conditions, shows residents'perceptions and priorities will change according to their respective area groupings. This analysis reveals that residents of a peripheral region, who are expected to participate in and welcome tourism development initiatives developed by senior levels of government, will in fact have different opinions regarding the industry and its potential. These differences are linked to present levels of tourism activity within the periphery and the varying community aspirations linking tourism's development potential with local needs and priorities.  相似文献   
358.
Basalt–basaltic andesite (<55 wt % SiO2) and dacite–rhyolite(66–74 wt % SiO2) are the predominant eruptive productsin the Sumisu caldera volcano, Izu–Bonin arc, Japan. Themost magnesian basalt (8·5% MgO), as well as some ofthe other basalts, has a low Zr content (20–25 ppm), andcannot yield basalts with higher Zr contents (29–40 ppm)through fractionation and/or assimilation. The high- and low-Zrbasalts have different phenocryst assemblages, olivine, plagioclaseand pyroxene phenocryst chemistries, REE (rare earth element)patterns, and fluid-mobile element/immobile element ratios.Estimated primary olivine compositions are more magnesian (>Fo91)in the low-Zr basalts compared with those in high-Zr basalts(<Fo89). The low-Zr basalts contain up to 11 vol. % augite,but many high-Zr basalts are free of augite, which appears onlyin their more differentiated products. The low-Zr basalts areconsidered to be hydrous magmas in which olivine crystallizesfirst followed by augite and plagioclase, whereas the high-Zrbasalts are dry. The low-Zr basalts have higher U/Th ratiosthan the high-Zr basalts. We suggest that both dry and wet primarybasalts existed in the Sumisu magmatic system, each having differenttrace element concentrations, mineral assemblages and mineralchemistry. The lower contents of Zr and light REE and magnesianprimary olivines in the wet basalts could have resulted froma higher degree of partial melting (20%) of a hydrous sourcemantle compared with 10% melting of a dry source mantle. TheSr, Nd and Pb isotope compositions of the wet and dry basaltsare similar and are limited in range. These lines of evidenceindicate that a mantle diapir model might be applicable to satisfythe configuration of such a mantle source region beneath a singlevolcanic system such as Sumisu. KEY WORDS: degree of melting; hot fingers; isotopes; mantle diapir; mantle wedge  相似文献   
359.
The desire to spend leisure time in natural settings represents a key factor behind the recent and rapid growth of ecotourism. A search by ecotourists for remote landscapes and locations has shaped the way in which geographers have defined ecotourism, but few scholars have explored, in detail, the mechanics of the spatial relationship between ecotourism and mass tourism, two forms of travel usually considered mutually exclusive in spatial terms. Using the island of Phuket — southern Thailands premier resort destination — as a case study, this paper investigates the spatial overlaps and connections between ecotourism and mass tourism and tests the assumption that ecotourism and mass tourism must exist spatially apart in order for the former to succeed. Despite Phukets association with mass tourism, and the small physical distances between built-up mass tourist areas and natural ecotourism settings, the communicative staging of natural authenticity allows ecotourism companies to convey geographical remoteness to tourists. Although ecotourism in Phuket must struggle constantly to overcome the perceptual impact of spatial proximity to resort locations, the tourist markets and business networks of the existing mass tourism industry remain crucial to the survival of ecotourism in this region. Thus, contrary to conventional notions that ecotourism and mass tourism must exist as separate entities, this paper argues that an interconnected, symbiotic, and spatially-contiguous relationship between the two is necessary in the case of Phuket.  相似文献   
360.
钟海铃  李栋梁  魏丽 《中国沙漠》2004,24(3):323-329
选用中国178个常规气象观测站建站~2000年历年春季沙尘暴日数资料,分析了近50a来中国北方春季沙尘暴的气候特征。在此基础上进一步揭示了我国北方沙尘暴的形成、发展以及造成的危害。结果表明:我国北方春季沙尘暴存在东西反位相差异,近50a来,春季沙尘暴日数总体趋势在减少,但20世纪末又有明显的回升趋势。这不仅与影响我国北方的冷空气路径有关,还与青藏高原冬季地面感热的异常密切相关。  相似文献   
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