基于TM影像的荒漠绿洲交错带土壤有机质含量反演模型

选取Landsat TM影像的光谱反射率（R）、反射率之倒数（1/R）、反射率倒数之对数（lg（1/R））、反射率一阶导数（FDR）、波段深度（D）等5种光谱指标,分别建立了奇台县土壤有机质（SOM）含量的反演模型,并利用F检验来验证模型的显著性。结果表明：用各光谱指标建立的土壤各层和不同深度SOM含量的反演模型精度值由低到高的顺序均为lg（1/R）<R<1/R<FDR<D,以D反演SOM含量的模型效果最好,且对10～20 cm的SOM含量的反演精度最高,适用于对研究区SOM含量的反演,FDR的反演效果次之,1/R和R的模型精度一般,而lg（1/R）的模型精度最差;各层拟合模型的反演精准度由低到高的顺序为50～60 cm <40～50 cm <30～40 cm <20～30 cm <0～10 cm <10～20 cm,不同深度反演模型的优劣为0～60 cm <0～50 cm <0～40 cm <0～30 cm <0～10 cm <0～20 cm。     

Comparative study on Co<Subscript>2</Subscript> emissions from different types of alpine meadows during grass exuberance period

Potentilla fruticosa scrub,Kobresia humilis meadow andKobresia tibetica meadow are widely distributed on the Qinghai-Tibet Plateau. During the grass exuberance period from 3 July to 4 September, based on close chamber-GC method, a study on CO₂ emissions from different treatments was conducted in these meadows at Haibei research station, CAS. Results indicated that mean CO₂ emission rates from various treatments were 672.09±152.37 mgm^-2h^-1 for FC (grass treatment); 425.41± 191.99 mgm^-2h^-1 for FJ (grass exclusion treatment); 280.36±174.83 mgm^-2h^-1 for FL (grass and roots exclusion treatment); 838.95±237.02 mgm^-2h^-1 for GG (scrub+grass treatment); 528.48±205.67 mgm^-2h^-1 for GC (grass treatment); 268.97±99.72 mgm^-2h^-1 for GL (grass and roots exclusion treatment); and 659.20±94.83 mgm^-2h^-1 for LC (grass treatment), respectively (FC, FJ, FL, GG, GC, GL, LC were the Chinese abbreviation for various treatments). Furthermore,Kobresia humilis meadow,Potentilla fruticosa scrub meadow andKobresia tibetica meadow differed greatly in average CO₂ emission rate of soil-plant system, in the order of GG>FC>LC>GC. Moreover, inKobresia humilis meadow, heterotrophic and autotrophic respiration accounted for 42% and 58% of the total respiration of soil-plant system respectively, whereas, inPotentilla fruticosa scrub meadow, heterotrophic and autotrophic respiration accounted for 32% and 68% of total system respiration from GG; 49% and 51% from GC. In addition, root respiration fromKobresia humilis meadow approximated 145 mgCO₂m^-2h^-1, contributed 34% to soil respiration. During the experiment period,Kobresia humilis meadow andPotentilla fruticosa scrub meadow had a net carbon fixation of 111.11 gm^-2 and 243.89 gm^-2, respectively. Results also showed that soil temperature was the main factor which influenced CO₂ emission from alpine meadow ecosystem, significant correlations were found between soil temperature at 5 cm depth and emission from GG, GC, FC and FJ treatments. In addition, soil moisture may be the inhibitory factor of CO₂ emission fromKobresia tibetica meadow, and more detailed analyses should be done in further research.     

Reviews and Materials received

Abstract

The Human Geography of Ireland by J. H. Johnson New York: John Wiley & Sons. 1994. Bibliography, index, xi, and 221 pp. S39.95, hard. ISBN 0-47194-832-2.

Some Truth with Maps: A Primer on Symbolization & Design by Alan M. MacEachren Washington, DC: Association of American Geographers. 1994. Figures, bibliography. 129 pp. ISBN 0-89291-214-6.

Geography of China: Environment, Resources, Population and Development by Songqiao Zhao New York; John Wiley & Sons. 1994. xix and 332 pp. Appendix and index. ISBN 0-471-57758-8. S67.95, cloth.     

Boston: A Center of Industry

Abstract

European Transport and Communications Networks: Policy Evolution and Change by David Banister, Roberta Capello, and Peter Nijkamp eds. Chichester, U.K.: John Wiley &; Sons. 1995. xxiii plus 348pp. Figures, tables, maps, index, list of contributors. ISBN 0-471-95737.

Geographical Excursions in London by Hugh J. Gayler, Lanham, MD: University Press of America. 1996. 186 pp. Maps, photos. ISBN 0-7618-0328-9.

Rivers: Curriculum Guide by Bob Ashley, White Plains, NY: Dale Seymour Publishing. 1997. 230 pp. Appendices, glossary. ISBN 0-201-49368-3. $23.95, paper.     

National Council at Work: Report of the Secretary

Abstract

Geography and Air Transport, by Brian Graham, New York: John Wiley &; Sons, Inc. 1995. 288 pp. Maps, diagrams, tables. ISBN 0-471-95757-7.

Geographies of Global Change: Remapping the World in the Late Twentieth Century, by R. J. Johnson, Peter J. Taylor, and Michael J. Watts, eds., Cambridge, MA: Blackwell Publishers, Inc. 1995. 462 pp. Bibliography, further reading, index. ISBN 0-631-19327-8. $19.95. paper.

Political Geography, by Martin Ira Glassner, New York: John Wiley &; Sons, Inc. 1996.2nd edition. 716 pp. Bibliographies, index. ISBN 0-471-11496-0. $64.95, hardcover.     

湖北利川二万多年来的古植被古气候演变

利用孢粉资料,讨论了利川地区古植被和古气候。     

BOOK REVIEW

Abstract

Children Map the WorldSelections from the Barbara Petchenik Children's World Map Competition Jacqueline M. Anderson, Jeet Atwal, Patrick Wiegand, and Alberta Auringer Wood editors. Redlands, CA: ESRI Press, 2005. 128 pages ISBN: 1-58948-125-9 $24.95

World Atlas of Natural Hazards Bill McGuire, Paul Burton, Christopher Kilburn, and Oliver Willetts Oxford University Press Inc./Arnold Publishers. 2004. 128 pages ISBN 03407640582004 $295.00     

植被恢复方式对黄土丘陵区土壤理化性质及微生物特性的影响

对甘肃省定西市黄土丘陵区不同植被恢复方式下的土壤水分、pH、有机碳（SOC）、全氮（TN）、碱解氮（AN）、全磷（TP）、速效磷（AP）、速效钾（AK）及微生物生物量、呼吸速率、呼吸熵（qCO₂）以及微生物熵（q_MB）进行了测定与分析。结果表明：不同植被恢复方式下,土壤pH值变化差异不显著（p>0.05）;0~20 cm土SOC、TN、AN、TP、AP、微生物量碳（SMBC）、微生物量氮（SMBN）含量及微生物呼吸速率（MR）均为天然植被（CL）下最高,AK为自然恢复（Q）方式下最高,qCO₂与q_MB在人工重建+自然恢复（RZ）方式下最高;20~40 cm土壤的SOC、TN、AN、TP、AP含量变化同0~20 cm,AK、SMBC、SMBN、 q_MB及MR在RZ方式下最高;40~60 cm土壤的SOC、TN、AN、AP及TP含量在CL方式下最高,SMBC、SMBN、 q_MB及MR在RZ方式下最高,AK、 qCO₂在Q方式下最高。相同植被恢复方式下,随土层深度增加,SOC、TN、AN、TP、AP、AK、SMBC、SMBN含量及q_MB、MR均逐渐降低,但qCO₂逐渐升高（除RZ方式）。不同植被恢复方式,SOC、TN、AN、SMBC、SMBN、q_MB、MR及qCO₂之间存在不同程度的相关性。     

Standards-Directed Education: The Good,the Bad,and the Ugly

Abstract

GIS Concepts and ArcGIS Methods, David M. Theobald Fort Collins, CO: Conservations Planning Technologies, 2003. 342 pp. ISBN 0-9679208-2-5 $55.00 (paper)

Lies My Teacher Told Me: Everything Your American History Textbook Got Wrong, James W. Loewen New York: A Touchstone Book, Simon &; Schuster. 1995. 383 pp. Figures, references, and index, ISBN: 0684818868. $14.00 (paper).     

基于CSCS改进CASA模型的中国草地净初级生产力模拟

将草原综合顺序分类系统（CSCS）中的热量指标（∑θ）和湿润度指标（K）引入CASA模型。利用该模型模拟了2004-2008年中国41个草地类的净初级生产力（NPP）,并分析了其时空变化和不同草地类NPP变化。结果表明：2004-2008年中国草地NPP模拟平均值与实测平均值分别为503.8 g·m^-2·a^-1和567.3 g·m^-2·a^-1,两者较为接近。各类草地的平均误差和平均相对误差均值分别为4.85 g·m^-2·a^-1和7.6%。草地NPP的实测值和模拟值相关性较好。改进CASA模型模拟值比Miami和Thornthwaite Memorial模型模拟值更接近实测值。NPP空间分布呈东高西低,南高北低,从西北向东南逐渐增加的趋势,体现了K和∑θ的水平和垂直地带性分布规律。2004-2008年中国草地NPP总体呈现增加趋势,其总量增加了23.0%。草地NPP年均值在不同植被类型中差异显著,分布规律与CSCS划分草地类的K和∑θ密切相关。总之,改进后的CASA模型模拟精度较高,实现了草地NPP模拟与草地分类的相互关联。     

Screening of cellulose decomposing fungi in sandy dune soil of Horqin Sandy Land

Cellulose decomposing fungi play an important role in litter decomposition and are decisive in nutrient cycling in sandy land ecosystems. Thirty-one strains were isolated to select efficient cellulose decomposers, and four efficient cellulose decomposing fungi (NM3-1, NM3-2, NM3-3, and NM3-4) were screened using a CMC (carboxymethyl cellulose) carbon source in dune soil of Horqin Sandy Land. They were identified as Asperigillus calidoustus, Fusarium oxysporum, Fusarium solani, and Hypocrea lixii by rDNA-ITS molecular biological methods. Cloth decomposition rates were 15.71%, 15.89%, 17.29%, and 17.89% by the four efficient decomposers incubated for 30 days, respectively. Screening of efficient cellulose decomposers can not only increase the dune soil functional microbe bank, but can also accelerate litter decomposition and available nutrient input in the Horqin Sandy Land.     

Winter Leaf Conductance Rates of Pinus Strobus L. (Eastern White Pine)

Our knowledge of winter leaf conductance and transpiration rates during the winter and early spring is especially weak for Pinus strobus L. (eastern white pine). Hence, the present study was conducted to: (1) measure and examine the winter leaf conductance and transpiration rates among 10 P. strobus trees to supply preliminary data for an understudied tree species; and (2) investigate whether observed leaf conductance and transpiration rates are large enough to merit incorporation into existing water balance models. The fieldwork was conducted at the Fair Hill Natural Resources Management Area in northeastern Maryland (39°42'N, 75°50'W) using a Li-Cor 1600M Steady State Porometer. Meteorological data were acquired from a continuously recording meteorological station on-site. Meteorological data were recorded at five-minute intervals to ensure that weather conditions could be temporally sequenced with porometer readings. The 10 co-occurring P. strobus sample trees were of similar age and health on uniform soils in an open field. Winter and early spring leaf conductance values of the selected trees reached 20 mmol m^-2 s^-1, whereas transpiration reached 0.13 mmol m^-2 s^-1. Results of the study indicate that there is statistically significant differences in leaf conductance rates among co-occurring P. strobus trees (H = 16.74, p = .05). Since the upper winter leaf conductance and transpiration rates measured in this study overlap with growing season leaf conductance and transpiration values reported by others, it is suggested that winter leaf conductance of and transpiration from P. strobus trees are significant enough to incorporate into water balance calculations.     

Foliar carbohydrate differs between Picea crassifolia and Sabina przewalskii with the altitudinal variation of Qilian Mountains, China

Nonstructural carbohydrates(NSC) and nitrogen metabolism strongly influence growth and development in plants. The biosynthesis of cellulose and lignin(structural carbohydrates, SC) depends largely on the supply of NSC. We desire to examine which hypothesis, carbon limitation or growth limitation, best fits the alpine plant response between NSC, SC, carbon(C), nitrogen(N) and altitude. We compared the foliar concentrations of carbohydrates, C and N between the leaves of Picea crassifolia(lower-elevation tree-line species) and Sabina przewalskii(high-elevation tree-line species) in their response to changing elevation. Our site was located in the mid-northern area of Qilian Mountains, China. We found that foliar soluble sugar(SG) concentrations were significantly higher in P. crassifolia than in S. przewalskii at the 2,700–3,400 m level. Foliar NSC levels in P. crassifolia increased at the 2,700–3,100 m level, indicating that growth was limited gradually resulting in a surplus of NSC(to conform to GLH), subsequently decreasing at the 3,100–3,400 m level, the assimilation declined leading to C deficit(to conform to CLH). SC(SC metabolism disorders at 3,100–3,400 m), C, N and starch were significantly lower in P. crassifolia than in S. przewalskii. Conversely, foliar SG concentration shows a fall-rise trend with increasing elevation for S. przewalskii. SC concentration in S. przewalskii leaves decreased with an increase of elevation and has a significantly positive correlation to N concentration marking the assimilation of plants. Therefore, the high-elevation tree-line species(S. przewalskii) utilize or store more foliar SG leading to a decrease of SG concentration for survival and growth/regrowth in an adverse environment, higher total C, N, SC, starch contents and lower NSC level. Also, their change trends along the elevational gradient in leaves of S. przewalskii indicate better assimilation strategies for SG use under environmental stress compared to P. crassifolia. This indicates that foliar C metabolism along the elevation follows the principle of the growth-limitation hypothesis(GLH) or carbon limitation hypothesis(CLH), which depends on the acclimation of different alpine life-forms to the environment.     

Children's Understanding Of Regional Geography

Abstract

Teaching the Interpretation of Maps and Landscapes Through Examples From Four Books

Feminism and Geography: The Limits of Geographical Knowledge by Gillian Rose Minneapolis, MN: University of Minnesota Press. 205 pp. Paperback, $17.95. ISBN 0-8166-2417-6 (pb).     

RECENT PUBLICATIONS

Analytical Tools Statistical Concepts in Geography. JOHN SILK Towards the Dynamic Analysis of Spatial Systems. R. L. MARTIN, N. J. THRIFT, and R. J. BENNETT, eds. Economic Geography Agro-Industrial Complexes and Types of Agriculture in Eastern Siberia. V. P. SHOTSKI Farmland, Food, and the Future. MAX SCHNEPF, ed. Environmental Management and Resources Planning the Uses and Management of Land. MARVIN T. BEATTY, GARY W. PETERSEN, and LESTER D. SWINDALE, eds. Historical Geography Planning the Past. ROBERT M. NEWCOMB Philosophy and Geographic Thought Spatial Dynamics and Optimal Space-Time Development. W. ISARD, P. LIOSSATOS, with assistance by Y. KANEMOTO and P. KANISS Carl Sauer's Fieldwork in Latin America. R. C. WEST Physical Geography Geographical Approaches to Fluvial Processes. ALISTAIR F. PITTY, ed. Physical Geography. P. GERSMEHL, W. KAMMRATH, and H. GROSS Population and Migration Location and Environment of Elderly Population. STEPHEN M. GOLANT, ed. Regional and Urban Planning Applied Models in Urban and Regional Analysis. Norbert Oppenheim Economic Development in Retrospect. Allan Rodgers Local Planning. SEBASTIAN LOEW Regional Planning and National Development. R. P. MISRA, D. V. URS, V. K. NATRAJ, eds. Regional Geography The Spatial Structure of Development: A Study of Kenya. R. A. OBUDHO and D. R. F. TAYLOR, eds. Social Geography Geographical Perspectives on Inequality. DAVID M. SMITH Teaching and Learning Geographical Education: Curriculum Problems in Certain European Countries with Special Reference to the 76-79 Age Group. NORMAN J. GRAVES, ed. Urban Geography and Settlements Urban Residential Location Models. STEPHEN H. PUTNAM City and Suburb: The Political Fragmentation of Metropolitan America, 1850-1970. Jon C. Teaford The Open Housing Market: Race and Housing in Chicago, 1966-1976. B. J. L. BERRY Spatial Inequalities and Regional Development. HENDRIK FOLMER and JAN OOSTERHAVEN, eds.     

种植于人工梭梭(Haloxylon ammodendron)林的肉苁蓉(Cistanche deserticola)个体质量特征

为掌握人工种植条件下肉苁蓉(Cistanche deserticola)个体质量特征,在塔克拉玛干沙漠腹地咸水滴灌人工梭梭林内,采用统一的开沟、撒种接种方式,对不同林龄、不同深度接种肉苁蓉以及造林当年接种连年采收肉苁蓉的质量进行了调查和分析。结果表明:(1)所有样地出土肉苁蓉个体间质量差异大,分布离散程度高。(2)接种时林龄越大,出土肉苁蓉个体平均质量、质量品质较好的比率以及质量分布离散程度都越高;不同林龄间肉苁蓉个体质量有极显著差异。造林当年接种、连年出土肉苁蓉个体质量的特征与不同林龄的相似,但质量品质较好的比率相对较低。(3)在40~120cm深度,随种植深度增加,出土2年生以上肉苁蓉个体的数量以及质量品质较好的比率总体呈现增加趋势,并可以分为3个层面:40cm、50~80cm、100~120cm。其中40cm深度质量指标明显较低,其他深度间没有表现出明显的差异和规律,100~120cm深度的肉苁蓉个体相对细长、品相差。     

Late-glacial and early-Holocene Trichoptera (Insecta) from Kråkenes Lake, western Norway

Fossil Trichoptera (caddisfly) remains have been identified and quantitatively recorded in the late-glacial and early-Holocene sediments from Kråkenes Lake, western Norway. The sediment sequence was deposited between 12,300 and 8850 ¹⁴C BP, covering the Allerød, Younger Dryas, and early-Holocene periods. The first Trichoptera were recorded at 12,000 ¹⁴C BP, and during the Allerod a diverse assemblage of Limnephilidae taxa developed in the lake. By about 11,400 ¹⁴C BP the relatively thermophilous Polycentropus flavomaculatus and Limnephilus rhombicus were present, suggesting that the summer water temperature was at least 17 °C. This temperature fell by 5-8 °C at the start of the Younger Dryas, and the thermophilous taxa were replaced within 20-40 ¹⁴C yrs by Apatania spp., including the arctic-alpine A. zonella, suggesting a maximum summer water temperature of 10-12 °C. The Trichoptera assemblage was impoverished in numbers and in diversity over the next 200 yrs as the severe conditions of the Younger Dryas developed. As soon as temperatures rose and glacial meltwater and silt input ended about 700 ¹⁴C yrs later, the resident Apatania assemblage expanded immediately, within 10 yrs. About 130 yrs later, thermophilous taxa replaced Apatania, and a much more diverse assemblage than in the Allerod occupied the varied habitats made available by the development of the Holocene lake ecosystem. The 130 yr delay may have been caused by a gradual temperature increase crossing a critical threshold, or by the time taken for thermophilous taxa to migrate from their Younger Dryas refugia.     

A 12,400 14c yr Offshore Diatom Record From East Central Lake Victoria, East Africa

The diatom record of V95-2P, a 7.6 m long sediment core collected from 67 m depth, is the first from the east central portion of Lake Victoria. A soil horizon developed at the coring site shortly before 12,400 ¹⁴C yr BP due to a lakewide desiccation event. The radiocarbon chronology of the older half of this core is problematic, but if our estimated chronology is correct, then aridity and evaporative concentration of the lake are indicated by the presence of Thalassiosira rudolfi from > 12,400 BP to about 10,000 BP. Abundant Aulacoseira and generally rising biogenic silica concentrations may reflect enhanced water column mixing and rising precipitation:evaporation ratios ca. 10,000-8400 BP. A lakewide reorganization of diatom assemblages occurred around 7200 BP, when Aulacoseira nyassensis largely replaced A. granulata and after which rainfall and wind-driven mixing became more seasonally restricted. Pronounced reductions in offshore diatom deposition, from about 8300-5800 BP and after 3500 BP, may have been related to declines in the duration and/or intensity of wind-driven mixing. Increased aridity, and possibly deforestation in the lake basin, is indicated after 1400 BP.     

Pollen-stratigraphical evidence of Holocene hydrological change in northern Fennoscandia supported by independent isotopic data

Pollen records from 21 sites were used to reconstruct Holocene hydrological changes in northern Fennoscandia. The inferred dominance of maritime-type Betula-forests from c. 9600 BP onwards indicate an oceanic climate in the region during the early Holocene, with high amounts of precipitation and low seasonal contrasts. This interpretation is supported by oxygen isotope records obtained on lacustrine carbonates from Abisko, northern Sweden. Enrichment of ¹⁸O during the early Holocene suggests enhanced zonal circulation and a pronounced influence of Atlantic air-masses in northern Sweden. The pattern of Pinus expansion in the area was time-transgressive, ranging from 9200-8000 BP in the extreme north-east to 7900-5500 BP in the western and south-western parts of the region. The replacement of Betula-forests by Pinus-forests indicates a climatic change towards drier summers and increased seasonality. At Abisko, a close correlation between regional Pinus expansion and depletion of ¹⁸O in lacustrine carbonates suggests that the expansion of Pinus was triggered by a gradual attenuation of the influence of westerlies. Thus, in large-scale palaeohydrological terms, the early expansion of Pinus in the north-easternmost parts of Fennoscandia as compared to the successively later expansion in the west and south-west may reflect a gradually decreasing influence of Atlantic air-masses in northern Fennoscandia during the early and mid Holocene.     

Knowledge diffusion from GIScience to other fields: the example of the usage of weighted surface networks in nanotechnology

This article demonstrates how the generalisation of topographic surfaces has been formalised by means of graph theory and how this formalised approach has been integrated into an ISO standard that is employed within nanotechnology. By applying concepts from higher-dimensional calculus and topology, it is shown that Morse functions are those mappings that are ideally suited for the formal characterisation of topographic surfaces. Based on this result, a data structure termed weighted surface network is defined that may be applied for both the characterisation and the generalisation of the topological structure of a topographic surface. Hereafter, the focus is laid on specific issues of the standard ISO 25178-2; within this standard change trees, a data structure similar to weighted surface networks, are applied to portray the topological information of topographic surfaces. Furthermore, an approach termed Wolf pruning is used to simplify the change tree, with this pruning method being equivalent to the graph-theoretic contractions by which weighted surface networks can be simplified. Finally, some practical applications of the standard ISO 25178-2 within nanotechnology are discussed.