粮食储备对维护粮食安全和保障社会安定具有重大意义。在我国粮食产供需的时空差异持续加剧背景下,以省域为单元,利用空间探索性分析法研究我国近年来区域粮食储备的时空演变和地区差异,并利用空间计量模型对区域粮食储备规模的影响因素进行分析,给出分区域的粮食储备规模确定方式。结果发现：我国粮食储备具有显著空间正相关性,高储备区向东北地区扩展,低储备区进一步向西部地区转移,两者的显著集聚范围逐渐扩大,致使地区差异逐渐增大;区域粮食储备规模与粮食生产能力、人口规模、经济发展、灾害影响、交通条件和社会影响力紧密相关;综合考虑空间效应和相关因素确定区域粮食储备规模,为我国分区域粮食储备研究提供新思路。

Grain reserves are of great significance to the maintenance of food security and social stability. Recently, the gap between the time and space in production, supply, and demand of grain in China has been continuously increasing, which leads to the unreasonable regional grain reserves scale problems of China. Taking province as research unit, this paper analyzed the temporal evolution and regional differences of regional grain reserves by utilizing spatial exploratory analysis and dissected influencing factors of regional grain reserves scale through spatial econometric model. It provided a definite method of regional grain reserves scale for different sub-regions. The results showed that: China's grain reserves spatial correlation index is bigger than zero and increased year by year, indicating that different regional reserves scales have significant positive spatial correlation. The overall distribution of China's grain reserves shows a polarization from east to west and has undergone a significant spatial-temporal evolution with high reserves area expanding to the northeast and low reserves area transferring to the west, which caused the increasing regional differences. Regression analysis shows that the scale of regional grain reserves is closely related to grain production capacity, population size, economic development, disaster influence, transportation conditions and social influence. The regression coefficient of the spatial lag term was 0.2451, manifesting that the geographical positive spatial correlation of regional reserves scales transmits through adjacent areas. Based on this, this paper put forward the prediction range of regional grain reserves scale in 2020 by considering the spatial effect and correlative factors, which provides a new perspective for researches on regional grain reserves in China.

西藏粮食安全事关当地的长治久安以及社会经济的可持续发展。论文基于2010年农户层面的食物消费调研数据,并且结合粮食市场调研、粮食加工企业调研以及政府部门调研数据等,在研究西藏粮食生产和消费基础之上,重点分析了西藏主要粮食（青稞、小麦和水稻）供应和需求之间的关系。结果显示,全区粮食供应数量较高,特别是外地调入粮食供给能力不断增强,提高了西藏粮食安全保障程度。2010年全区主要粮食生产为85.09万t,而家庭层面主要粮食消费为88.81万t,粮食生产和消费基本持平;但是考虑到本地粮食消费比重为60.8%,2010年本地粮食消费只有54.0万t。从整个西藏地区来看,虽然西藏地区粮食供应已经大于其需求（西藏地区三大粮食作物总供应146.3万t,而总需求超过95.9万t,供应为需求的1.5倍）,但是从不同地区来看,区域之间的粮食供需差别非常大,尤其是藏北牧区（主要是那曲地区）,粮食缺口比较大,未来需要加强藏北地区粮食的供给力度,提升其粮食安全的保障能力。随着内地粮食进藏数量和种类不断增加,未来需要进一步转变粮食购销体制系统,把粮食生产者（即农民）考虑在粮食流通市场之内,进一步加强和重视西藏粮食生产者在粮食流通中所发挥的作用,从而增加西藏农村地区家庭中余粮流通,增加青稞特色产业发展,提高农民收入。

<p>Food security is related to the lasting stability and the sustainable development of social economy in Tibet. Based on data from household food survey and data from food market, food processing enterprises and government departments, we investigated grain production and consumption (highland barley, wheat and paddy) in Tibet. An analysis of grain supply and demand in the year of 2010 was carried out. The result showed that there was a high grain supply in 2010, which indicated that there was a high grain security in Tibet. The total grain production in 2010 was 85.09 thousand tons, and the total amount of grain consumed by local population was 88.81 thousand tons, so there was roughly a balance between grain production and consumption. But when considering that 60.8% of the grain consumed was from local production, the actual of local grain consumption was 54.0 thousand tons, which indicated that the amount of local grain production was higher than local grain consumption. Although the grain supply has been greater than the demand in Tibet (the total grain supply from major grain crop was 146.3 thousand tons, and the total grain demand was 95.9 thousand tons, and the supply was 1.5 times of demand), there was large regional disparities, especially in north Tibet (for example Nagqu prefecture) where there was an large grain supply gap in Nagqu. It is needed to strengthen the food supply in that region and improve the food security. With the increasing number and variety of foods from other provinces, the Tibetan government should transform the food marketing system of Tibet to take food producers (farmers) into the grain circulation market, and further strengthen and emphasize the role they played in food market, and focus on highland barley industry to raise local farmers&rsquo; income.</p>

青藏高原是中国粮食短缺地区之一,提高其粮食自给能力和确保粮食安全一直受到中央和地方政府的高度重视。在修订牧业区和半农半牧地区人均粮食消费需求量标准的基础上,利用1985-2015年青藏高原县级行政单元粮食产量和消费数据,采用波动系数法、分级法、重心模型以及粮食短缺指数模型,分析青藏高原粮食生产和消费的时空变化特征,并评估114个县市的粮食安全风险状况。结果表明：青藏高原粮食生产与消费空间分布不均衡,粮食生产呈环形分布在青藏高原东部湟黄谷地、藏东和藏南沿江河谷地带,中部和西部粮食产量较低,粮食消费呈东高西低格局;本地粮食生产不能满足居民消费需求,区域粮食缺口量达21.04万~121.69万t,相当于粮食消费需求的8.22%~40.11%,考虑旅游人口的影响,2015年区域粮食缺口达132.92万t;青藏高原粮食安全风险较高的地区广泛分布在藏北高原、青南高原、祁连山地以及城市化水平较高的拉萨市辖区和西宁市辖区,旅游业发展对林芝市的粮食安全风险影响显著;单纯依靠粮食增产不能解决区域粮食问题,建立完善的粮食储备和交通物流体系、加强与内地及周边国家的粮食贸易合作,是保障青藏高原粮食安全的关键。

The problem of grain shortages has long plagued the Tibetan Plateau, therefore both the state and the local government are scaling up efforts to achieve grain self-sufficiency and grain security in this region. Meanwhile, many researchers devoted themselves to study the grain security issues to provide rational advices. Here in this paper, we intended to analyze the temporal and spatial characteristics of grain production and consumption in the Tibetan Plateau and then evaluate the risk status of grain security in 114 counties. First, we revised the standards of per capita grain consumption demand in pasturing area and farming-pastoral region. Then, on this basis, we analyzed the corresponding data of the 114 counties during 1985-2015 by applying the fluctuation coefficient method, classification method, barycenter model and the index model of grain shortages. Analytical results showed that there was a non-uniform geographical distribution of grain production and consumption, moreover, the holistic status of grain security in the Tibetan Plateau was not optimistic. (1) The production of grain increased in fluctuation and the consumption of grain grew steadily, the local grain production could not meet the consumption demand, and the deficit amounts were between 0.21 and 1.22 million tons annually, which accounted for between 8.22% and 40.11% of the grain consumption. The gap between grain production and consumption including tourists increased to 1.33 million tons in 2015. (2) The spatial distributions of grain production and grain consumption in the Tibetan Plateau were imbalanced, the grain yields in Huang-Huang valley and the valley along the?Yarlung?Zangbo?River were higher, while the yields distributed in the central and western parts of the plateau were lower. Affected by population, city, and traffic distribution, the grain consumption was high in the eastern part and low in the western. (3) The spatial patterns of grain security in the Tibetan Plateau in 2015 showed that the higher-risk types involved 42 counties with a population of 2.92 million, and they were widely distributed in western Tibet, northern Tibet, southern Qinghai, Qilian Mountains, as well as in municipal districts of cities of Lhasa and Xining; compared to 1985, the risks of grain security on the midstream and downstream of Yarlung Zangbo River and southeastern Qinghai province were mitigated, while those in western Ngari and northeastern Qinghai were intensified. (4) The tourists increased the risks of grain security in Lhasa, Nyingchi, Shannan, Shigatse, Haidong and Hainan cities, and the negative influence of tourist on Linzhi city was most significant. (5) Production increase alone cannot solve the problem of grain shortage, so it is urgent for the Tibetan Plateau to improve the grain reserves, transportation facilities and expand the grain trade with other regions to achieve regional grain security.

<p>The Tibetan Plateau is a unique geomorphic unit composed of some basic geomorphic types, such as extreme high mountains,high mountains, hills, plains, and tablelands of high altitude or sub-high altitude. Different opinions for the exact scope of Tibetan Plateau exist. According to latest research achievement and the long time fieldwork, questions related to the area and boundary of the Plateau have been discussed in view of geography, and the principles taking geomorphic characters as the main rule and considering the integrity have been made to define the boundary. The 1∶1 000 000 geomorphological map was compiled based on 1∶100 000 aerial photographic map,1∶500 000 topographic map and interpretation of satellite images. By refering to the 1∶3 000 000 relief map, the boundary of the Plateau was delineated.The position of the boundary was quantitatively determined with GIS and GPS.The map of electronic version of the Tibetan Plateau was compiled. The main conclusion is that Tibetan Plateau starts from the southern edge of the Himalayan Range, abuts on India,Nepal and Bhutan,connects the northern edge of Kunlun, Altun and Qilian Mts., and joins Tarim Basin and Hexi Corridor in Central Asia.The west of it is the Pamirs and Karakorum Mts., bordering on Kirghizistan, Tajikistan, Afghanistan, Pakistan and Kashmir. The east of it is Yulongxueshan, Daxueshan, Jiajinshan and Qionglaishan Mts.as well as south or east piedmont of Minshan Mts. Tibetan Plateau joins the Qinling Mts.and Loess Plateau with its eastern and northeastern part. Tibetan Plateau in China's territory starts from the Pamirs in the west and reaches to Hengduanshan in the east. It bestrides a longitude of 31 degrees with a length of 2 945 km from east to west,and bestrides a latitude of 13 degrees with a length of 1 532 km from south to north. It ranges from 26&deg;00&prime;12" N to 39&deg;46&prime;50" N and from 73&deg;18&prime;52"E to 104&deg;46&prime;59"E, covering an area of 2 572.4&times;10 3 km 2. Administratively, it embraces 201 counties (cities) in 6 provinces, namely, the Tibet Autonomous Region (73 counties/cities,1 176.0&times;10 3 km 2, part of Cona, M&ecirc;dog and Zay&uuml;), the Qinghai Province(40 counties/cities,721.0&times;10 3 km 2, some counties only partially), D&ecirc;qen Tibetan Autonomous Prefecture in Northwest Yunnan Province(9 counties/cities,33.5&times;10 3 km 2), West Sichuan Province (46 counties/cities about 254.0&times;10 3 km 2,such as Garze Autonomous Prefecture, Aba Tibetan and Qiangzu Autonomous Prefecture,and Muli Autonomous County, etc.),Gansu Province(21 counties/cities, 74.9&times;10 3 km 2), and Southern Xinjiang Uygur Autonomous Region (about 12 counties/cities, 313.0&times;10 3 km 2).</p>

中国人口发展的粮食安全与耕地保证程度研究表明,随着人口增长和消费扩张,中国未来的耕地规模和人均耕地面积会进一步下降,人均粮食消费水平和粮食需求总量将进一步提高;2020年在人均粮食420~435kg的消费水平上,基于18亿亩耕地保证的粮食生产能力可以基本满足14.36亿人口的粮食需求;在人均450kg的消费水平上,中国未来耕地的粮食生产能力足以支持人口高锋时间的14.73亿人,但受耕地资源有限约束,人均粮食占有水平很难有进一步提高。从耕地、粮食与人口关系看,中国未来人口的粮食安全必须向食物安全转变,从耕地资源约束的粮食生产与人口增长驱动的食物消费两端着眼:一方面要重视耕地与粮食安全&mdash;&mdash;藏粮于土,全面提高土地资源综合生产能力;一方面要关注食物与消费安全&mdash;&mdash;倡导适度消费,建立动植物并重型食物结构;从生产与消费两方面来认识和解决中国中长期人口发展的食物安全与耕地保障问题。

The study aims to explore food security and arable land guarantee for population development in China. The results indicate that the increase of future population and food consumption will be definitely coupled with a decrease in total arable land and per capita arable land area, as well as an increase in per capita food consumption and total food demand. The findings highlight that a total of 120 million ha of arable land will have to be reserved for ensuring grain demand of about 1.44 billion people at a per capita consumption level of 420-435 kg grain. And at a per capita consumption level of 450 kg grain, the grain production capacity of arable land could meet grain demand of about 1.47 billion people-estimated peak of the Chinese population. However, further increase in per capita grain occupancy is not optimistic, thanks to the restriction of limited arable land resources. The relationship between arable land area, food production and population suggests that emphasis on future food security be transferred into grain security, and the focus be placed on food production restricted by arable land and on the increasing grain consumption driven by population growth. Thus, special attention should be paid, on the one hand, to the arable land area and food production, i.e., improvement in land productivity, and on the other hand, to the security of food production and consumption through formation of moderate consumption ideology and establishment of reasonable food structure for proper intake of animal and plant nutrition. The study concludes that both production and consumption factors should be taken into consideration for ensuring the Chinese food security and arable land for population development in the middle and long run.

Ecological experiments of wheats was arranged in Lasa during 1982—1985. Liaochun 6 is a typical spring wheat, on the other hand, Taishan 4 is a winter variety. Heading and maturation were postponed, so were the growth periods and periods from sowing to maturation for wheats in Lasa. The low temperature was an important influential factor. Plant height of wheats was higher in Lasa, because growth periods was longer. The difference of temperature between day and night was bigger, the night temperature was lower, and the radiation of sun was stronger than most places in China, this contributes to the bigger weight of the seed.

Urbanization has entered a key stage in China. Since the implementation of the policy of "small town, grand strategy", small towns have played a critical role in China's urbanization. However, China is one of the countries that have suffered various natural disasters, and is fighting against technological accidents as well as more terrorist attacks and criminal activities. China is confronted with a great challenge to strengthen the emergency management for small towns, so it seeks for a resource allocation system with flexibility, fluency, punctuality, rationality and effectiveness. The Chinese Government is therefore striving to intensify the emergency management system. For instance, according to the plan of Beijing government, every big community or neighborhood in Beijing will establish one to two emergency material depositories in the coming 3 to 5 years. So far there have been relatively few documents on the allocation of small-town emergency material depository with quantitative methods. Besides, the location of traditional facilities seldom focused on the satisfaction difference of demand points within the covering radius of facilities. In the light of this situation, we present a maximal covering location and build a maximal covering model as an integrated programming under the goal of maximizing the total satisfaction of demand points. After investigating the model, we introduced an ant colony optimization (ACO) algorithm to solve the considered problems. Then, we obtained the allocation result of emergency material depository of Fangshan District in Beijing. The computed results have shown that the model we proposed is a solution to facility location in a more effective manner. Finally, we give suggestions to future research.

青藏高原地区是地球上最独特的地理—生态—人口—交通单元,区域内交通网络的发展特征及规律是人地关系协同发展的一个重要切入点,对青藏高原地区交通网络开展研究具有重要意义。据此,分析1976-2016年青藏高原地区交通网络演化特征,并以省会、地级市、县级市和县城为节点,采用网络分析的时间距离计算模型探讨其通达性演变过程。研究表明：① 青藏高原地区交通网络复杂性、区域连通性增强,初步形成格状交通网络;② 青藏高原地区中心城市、县城之间的平均最短通达时间已极大缩短至11.89 h、18.84 h,呈自东向西逐渐增大的空间格局,时空收敛效应显著,通达性变化程度与其初始值有关;③ 中心城市为该地区的发展极,其与周围城市通达状况有极大提高,可达时间平均值下降到16.49 h;④ 中心城市和县城交通圈演变过程一致,青藏高原地区各地到最近城市、县城的通达时间不断缩小,沿重要交通干线已形成中心城市4 h、县城2 h短时交通圈连片分布格局,湟水河谷地、一江两河地区逐渐形成交通廊道,乡镇对外交通联系得到改善。

The Qinghai-Tibet Plateau is a unique geography-ecology-population-traffic region on the earth. The characteristics and regularities of the transport network development are an important breakthrough for the coordinated development of man-land relationship, which is of great significance to the research in the Qinghai-Tibet Plateau. Accordingly, this paper analyzes the evolution of transport network in this region between 1976 and 2016, and explores its accessibility using a temporal distance calculation model based on network analysis by taking provincial capitals, prefecture-level cities and counties as transport nodes. Results suggest that, first, transport network is more complex and the regional connectivity is gradually enhanced in the plateau, preliminarily forming a grid-like transport network; second, the average minimum accessibility time between anchor cities and between counties has been vastly reduced to 11.89 hours and 18.84 hours, manifesting a gradually growing spatial pattern from east to west and remarkable effects of time-space convergence; third, anchor cities are the poles of regional development, with average accessibility time to around cities reduced to 16.49 hours, indicating that anchor cities tied with others have been improved; fourth, the traffic circles of anchor cities and counties are evolving consistently, accessibility time from various places in the study area to their nearest cities or counties are decreasing, presenting a contiguous pattern of short-time traffic circle with 4-hour access to central cities and 2-hour access to counties along important arterial roads, thus improving external transport connection of towns. And traffic corridors are gradually formed in the Huangshui River Valley, and the Middle Region of "One River and Two Streams" in Tibet.

青藏高原的特殊性长期约束着交通设施的建设与功能,科学评价其交通状况具有重要意义。论文以林芝市为例,考虑自然特征、多种交通方式及交通稳定性,构建综合交通优势度评价体系进行实证探讨。研究发现：① 综合交通优势度以巴宜区、米林县、工布江达县得分较高,其中中心乡镇尤其明显,分别在内部交通功能、对外交通功能、区位优势度方面具有优势,察隅县、墨脱县综合交通优势度及各分项得分均较低,G318、林拉公路、米林机场等重点交通设施影响突出;② 林芝市综合交通优势度的县域差距及空间极化效应趋于增强,但中心—外围结构的空间完整性被地形等因素隔离破坏,边境地区成为林芝市综合交通优势度最为薄弱的环节;③ 综合交通优势度与人口分布具有一定匹配性,多数乡镇二者之间呈协调水平,但以初、中级协调为主,边境和自然条件约束明显的地区尚需考虑优化。根据林芝市特点,改进后的综合交通优势度评价更好地揭示了区域交通薄弱地区,对青藏高原或其他类似特殊地域单元的交通设施评价具有参考意义。

The unique natural environment of the Qinghai-Tibet Plateau has restricted the construction and function of its transportation infrastructure. In order to evaluate the traffic facilities on the Qinghai-Tibet Plateau, taking Linzhi City, a typical area of southeastern Tibet with high altitude and uneven terrain, as an example and considering the natural characteristics, various transport modes, transport stability, and location advantage, this study established an evaluation system of comprehensive traffic advantage degree to empirically examine the situation in 2015 and 2020. The results show that: 1) Bayi District, Milin County, and Gongbujiangda County, especially their central towns, have much higher scores in internal traffic function, external traffic function, and location advantage degree, while the values of traffic advantage and many of its indicators in Chayu County and Motuo County are low, and the impact of some key transportation infrastructures such as the G318 Highway (national highway), Linzhi-Lhasa Highway, and Milin Airport is prominent. 2) The results of spatial difference analysis show that the comprehensive traffic advantage degree of Linzhi City is unbalanced, and the county-level gap and spatial polarization effect tend to increase. However, the core-periphery spatial structure is fragmented and interrupted by terrain factors of extreme difference in altitude, and the border area of Linzhi City becomes the weakest part with regard to the comprehensive traffic advantage degree. 3) There is a certain degree of matching between the comprehensive traffic advantage degree and the population distribution as shown by the linear trend line and coupling coordination relationship. Bayi District, Milin Town, and Gongbujiangda Town have reached the high-quality coordination level. However, most of the towns are at the preliminary or intermediate coordination level, while in the border area and areas with severe natural constraints, the coordination degree urgently needs to be optimized. Methodologically, by superimposing regional natural attributes, expanding the evaluation dimension of traffic advantage degree, and integrating various modes of transportation, the comprehensive traffic advantage evaluation conforms to the actual situation of the study area. Regional transport evaluation that incorporates the consideration of natural environment characteristics has practical significance for supporting territorial planning and transportation infrastructure evaluation and management, especially for regions such as the Qinghai-Tibet Plateau.