Simulation analysis on characteristics of land surface over western Qinghai-Xizang Plateau during freezing–thawing period

Using the Global Energy and Water Cycle Experiment—Asian Monsoon—Tibet Plateau Experiment (GAME-Tibet) observational data—from October 2002 through September 2003—of Gaize in the western Qinghai-Xizang Plateau (QXP), the land-surface characteristics of the Qinghai-Xizang Plateau are simulated by the improved land-surface model Common Land Model (CoLM). The results show that CoLM can reproduce the land-surface characteristics of plateau areas well. In the surface-energy balance of the western QXP in the winter half year, the sensible heat (SH) flux constituted the dominant energy, and the latent heat (LH, here and after) flux is very small. Although the LH flux nearly equals zero in freezing season, it cannot be ignored during the period of freezing–thawing in QXP. In the transition season from mid- to late-May, the frequent phase change of soil water that is caused by the freezing–thawing process leads to the increase of LH flux and decrease of the Bowen ratio. The simulation results also indicate that the changes of surface effective heat fluxes (SH and LH flux) are associated with precipitation and the frequent change between freezing and thawing processes in soil surface.     

内蒙古草原草本植物萌芽期时空变化（英文）

Phenological modeling is not only important for the projection of future changes of certain phenophases but also crucial for systematically studying the spatiotemporal patterns of plant phenology. Based on ground phenological observations, we used two existing temperature-based models and 12 modified models with consideration of precipitation or soil moisture to simulate the bud-burst date(BBD) of four common herbaceous plants—Xanthium sibiricum, Plantago asiatica, Iris lactea and Taraxacum mongolicum—in temperate grasslands in Inner Mongolia. The results showed that(1) increase in temperature promoted the BBD of all species. However, effects of precipitation and soil moisture on BBD varied among species.(2) The modified models predicted the BBD of herbaceous plants with R~2 ranging from 0.17 to 0.41 and RMSE ranging from 9.03 to 11.97 days, better than classical thermal models.(3) The spatiotemporal pattern of BBD during 1980–2015 showed that species with later BBD, e.g. X. sibiricum(mean: day of year 135.30) exhibited an evidently larger spatial difference in BBD(standard deviation: 13.88 days) than the other species. Our findings suggest that influences of temperature and water conditions need to be considered simultaneously in predicting the phenological response of herbaceous plants to climate change.     

The aboveground biomass of desert steppe and its spatiotemporal variation in western Inner Mongolia

A precise understanding of the aboveground biomass of desert steppe and its spatio-temporal variation is important to understand how arid ecosystems respond to climate change and to ensure that scarce grassland resources are used rationally. On the basis of 756 ground survey quadrats sampled in western Inner Mongolia steppe in 2005–2011 and remote sensing data from the Moderate Resolution Imaging Spectroradiometer (MODIS)—the normalized difference vegetation index (NDVI) dataset for the period of 2001–2011—we developed a statistical model to estimate the aboveground biomass of the desert steppe and further explored the relationships between aboveground biomass and climate factors. The conclusions are as follows: (1) the aboveground biomass of the steppe in the research area was 5.27 Tg (1 Tg=10¹² g) on average over 11 years; between 2001 and 2011, the aboveground biomass of the western Inner Mongolia steppe exhibited fluctuations, with no significant trend over time; (2) the aboveground biomass of the steppe in the research area exhibits distinct spatial variation and generally decreases gradually from southeast to northwest; and (3) the important factor causing interannual variations in aboveground biomass is precipitation during the period from January to July, but we did not find a significant relationship between the aboveground biomass and the corresponding temperature changes. The precipitation in this period is also an important factor influencing the spatial distribution of aboveground biomass (R²=0.39, P<0.001), while the temperature might be a minor factor (R²=0.12, P<0.01). The uncertainties in our estimate are primarily due to uncertainty in converting the fresh grass yield estimates to dry weight, underestimates of the biomass of shrubs, and error in remote sensing dataset.     

气候学 地方气候、小气候与应用气候

P4022007010036中国第二次北极科学考察路线上温室气体瓶采样结果分析=A result of greenhouse gases flask-sampled on the course of the 2nd Chinese Arctic research expedition,2003/张东启,徐建中…∥冰川冻土.—2006,28(3).—319~323研究结果表明:海洋表面不同纬度带上C     

Deformation monitoring and analysis at two frost mounds during freeze–thaw cycles along the Qinghai–Tibet Engineering Corridor

This paper presents various deformation-monitoring technologies employed to monitor the frost heave and thaw settlement of two mounds along the Qinghai–Tibet Engineering Corridor(QTEC), China. The QTEC is known as a critical infrastructure and passage connecting inland China and the Qinghai–Tibet Plateau(QTP). Three technologies—global navigation satellite system(GNSS), terrestrial laser scanning(TLS), and unmanned aerial vehicle(UAV)—were used to estimate the freeze/thaw–induced 3D surface deformation of two frost mounds. Our results showed that (1) the two frost mounds exhibited mainly thaw settlement in thawing periods and frost heave in the freezing period, but frost heave dominated after repeated freeze–thaw cycles;(2) different zones of the mounds showed different deformation characteristics;(3) active-layer thickness(ALT) and elevation changes were highly correlated during thaw periods;(4) integrated 3D-measurement technologies can achieve a better understanding and assessment of hazards in the permafrost area.     

地方气候、小气候与应用气候

P339.92007042885影响阿克苏河年径流量变化的前期大气环流指数因子研究=The elements of the prophase atmospheric indexes whichin-fluence the annual runoff in the Aksu River/毛炜峄,王铁…∥冰川冻土.—2007,29(2).—242~249图4表4参30(洪明)BiP468.5,P463.32007042886     

IDENTIFICATION OF FINITE IMPULSE RESPONSE MODELS WITH CONTINUUM REGRESSION

The use of continuum regression(CR)for the identification of finite impulse response(FIR)dynamicmodels is investigated.CR encompasses the methods of principal component regression(PCR),partialleast squares(PLS)and multiple linear regression(MLR).PCR and MLR are at the two extremes of thecontinuum.In PCR and PLS,cross-validation is used to determine the optimum number of factors or‘latent variables’to retain in the regression model.CR allows one to vary the method in addition.Cross-validation then determines both the optimum method and the number of latent variables.The CR‘prediction error surface’—a function of the method and number of latent variables—is elucidated.Theoptimal model is defined as the minimum of this surface.Among the cases studied,the optimal modelusually comes from the region of the continuum between PCR and PLS.Few derive from the regionbetween PLS and MLR.It is also demonstrated that FIR models identified by CR have frequency domainproperties similar to those identified by PCR.     

生物多样性

S812.82006010227宁夏毛乌素沙地退化草原恢复演替过程中物种多样性与生产力的变化=Changes of productivity and species diversity inresume succession on the degraded steppe of Maowusu sands inNingxia/王占军,蒋齐…∥草业科学.—2005,22(4).—5~8图2表2参8(薛小芸)BeQ     

海洋水文

P7312006010080粤西水东单点系泊海域潮流和低频流特征=The character-istics of low frequency currents in the area of Shuidong an-chored floating whelf in the west of Guangdong coastal waters/严金辉,陈达森∥海洋湖沼通报.—2005(3).—8~15图4表2参6(许桂红)NX8242006010081长江口及其邻近海域悬浮物浓度和浊度的对应关系=Cor-responding relationship betweensuspended matter concentrationand turbidity on Changjiang estuary and adjacent sea area/翟世奎,张怀静…∥环境科学学报.—2005,25(5).—693~699根据该次调查…     

中国城市空气质量时空演化特征及社会经济驱动力（英文）

Air pollution is a serious problem brought by the rapid urbanization and economic development in China, imposing great challenges and threats to population health and the sustainability of the society. Based on the real-time air quality monitoring data obtained for each Chinese city from 2013 to 2014, the spatiotemporal characteristics of air pollution are analyzed using various exploratory spatial data analysis tools. With spatial econometric models, this paper further quantifies the influences of socioeconomic factors on air quality at both the national and regional scales. The results are as follows:(1) From 2013 to 2014, the percentage of days compliance of urban air quality increased but air pollution deteriorated and the worsening situation in regions with poor air quality became more obvious.(2) Changes of air quality show a clear temporal coupling with regional socioeconomic activities, basically "relatively poor at daytime and relatively good at night".(3) Urban air pollution shows a spatial pattern of "heavy in the east and light in the west, and heavy in the north and light in the south".(4) The overall extent and distribution of regional urban air pollution have clearly different characteristics. The formation and evolution of regional air pollution can be basically induced as "the pollution of key cities is aggravated—pollution of those cities spreads— regional overall pollution is aggravated—the key cities lead in pollution governance—regional pollution joint prevention and control is implemented—regional overall pollution is reduced".(5) At the national level, energy consumption, industrialization and technological progress are the major factors in the worsening of urban air quality, economic development is a significant driver for the improvement of that quality.(6) Influenced by resources, environment and the development stage, the socioeconomic factors had strongly variable impacts on air quality, in both direction and intensity in different regions. Based on the conclusion, the regional differentiation and development idea of the relationship between economic development and environmental changes in China are discussed.     

Numerical analysis of applying special pavements to solve the frost heave diseases of high-speed railway roadbedsin seasonally frozen ground regions

The Haerbin-Dalian Passenger Dedicated Line is the first high-speed railway constructed in the seasonally frozen ground regions of northeastern China. Frost heave diseases occurred in the first winter of its operation(between October 2012 and January 2013), and frost heave was observed mainly in the roadbed fills that were considered not susceptible to frost heave. This paper proposes applying two special pavements — black pavement and insulation-black pavement — to improve the thermal regime of the roadbed. Three numerical models of the roadbed temperature field were built based on the field conditions of the Changchun section(D3K692+840 to D3K692+860). The results show that:(1) Compared with cement pavement, black pavement and insulation-black pavement could reduce the freezing index at the roadbed surface by 37% and 64%, respectively, which could influence the maximum frozen depth;(2) the maximum frozen depths under the black pavement and insulation-black pavement were respectively 1.3–1.4 m and 1 m. Compared with cement pavement, they could reduce the maximum frozen depth by 0.4 m and 0.7–0.8 m, respectively, which would reduce the permitted amount of frost heave by 4 mm and 7–8 mm, which would meet the deformation limit established by the Code for Design on Special Subgrade of Railway;(3) the freezing periods of the black pavement and the insulation-black pavement were, respectively, approximately four months and two months. Compared with cement pavement, they could reduce the freezing period by approximately 19 days and 40 days, respectively, and delay the initial freezing time by 9 days and 18 days; and(4) compared with cement pavement, black pavement and black-insulation pavement could reduce the frozen areas of roadbeds in the cold season, which suggests that these two special pavements could provide better thermal stability for roadbeds.     

社会、经济地理

F1272006010309南水北调中线工程与汉江中下游地区可持续发展=Effectof the middle route Project of South to North Water Transferon the sustainable development of the middle andlower reachesof Hanjiang River/蔡述明,殷鸿福…∥长江流域资源与环境.—2005,14(4).—40     

A Brief Report of the Investigation in the West Part of Tao-ho

(1) A General Statement.— The west part of Tao-ho which has become ourdominion since the Han Dynasty is still obscure for its geography. It containsnine districts of Kansu Province and two districts of Kokonor Province, andholds an important position in the development of the north-west China.     

湖沼学

P333.12007042944天目湖水文特征变化及其对上游湿地和湖泊生态环境的影响=Variation of hydrological characteristics of Tianmu Lakeandits effect on the Tianmuhu wetland and ecological environ-ment of the Tianmu Lake/黄群芳,张运林…∥湿地科学.—2007,5(1).—51~57     

Microbial production of CO2 in red soil in Stone Forest National Park

Lunan stone forest is a kind of typical karst in China,Which is mainly developed under red soil.In the winter of 1999,three study sites were chosen in stone forest national park according to vegetation cover,geomporphologic location and soil types,CO2 concentration was measured with Gastec punp at different dephts of soil (20,40,60cm) and at the same time soil samples were gatered and soil properties such as soil moisure,pH,soil organic content were analyzed and the total nmuber of viable microbes were counted in laboratory,In the study,dependent variable was chosen as the mean soil log(PCO2),and soil properties were chosen as the independent variables.Multiple stepwise regression analysis showed that the totla amount of microbes and soil moisture are the best indicators of the CO2 production,With the equation LOG(PCO2)=-0.039(TNM)-0.056 (Mo) 1.215 accounting for 86% of the variation of the soil CO2 concentration,where TNM is the total number of microbes in teh soil and Mo is the moisture of soil sample.     

不同辐射对土壤湿度长程相关性的影响——以黑河流域阿柔超级站为例（英文）

Analyses of the soil moisture evolution trend and the influence of different types of radiation on soil moisture are of great significance to the simulation and prediction of soil moisture.In this paper,soil moisture(2–60 cm) and various radiation data from 2014–2015 at the A’rou superstation were selected.The radiation data include the net radiation(NR),shortwave and longwave radiation(SR and LR).Using adaptive fractal analysis(AFA),the long-range correlation(LRC) of soil moisture and long-range cross correlation(LRCC) between moisture and three types of radiation were analyzed at different timescales and soil depths.The results show that:(1) Persistence of soil moisture and consistency between soil moisture and radiation mutate at 18-d and 6-d timescales,respectively.The timescale variation of soil moisture persistence is mainly related to the influence process of radiation on soil moisture;(2) Both the soil moisture persistence and soil moisture-radiation consistency vary substantially with soil depth.The soil depth variation of soil moisture persistence is related to the influence intensity of radiation;(3) From 2–6 day timescales,LR displays the strongest influence on soil moisture at depths of 2–10 cm through negative feedback of radiation on the soil temperature.The influence intensity decreases with depth from 2–15 cm.Therefore,the soil moisture persistence is weak and increases with depth from 2–15 cm;and(4) At more than 6 day timescales,SR and NR display a stronger influence on the soil moisture persistence at depths of 2–40 cm through positive feedback of radiation on the soil temperature,especially at depths of 2–10 cm.This influence also weakens with depth.The soil moisture persistence at depths of 2–10 cm is the weakest and increases with depth from 2–40 cm.The research results are instructive for determining timescales and soil depths related to soil water in hydrological models.     

Features of the long-term transformation of the Krasnodar reservoir,near the mouth of the Kuban River,Russia

The article considers the long-term(1941–2018) transformation of the Krasnodar valley reservoir, the largest in the North Caucasus. The main functions of the Krasnodar reservoir are irrigation of rice systems and flood protection of land in the Krasnodar reservoir region and the Republic of Adygea. According to topographic maps, Landsat satellite images(1974–2018) and field observations(2016–2018), four stages of transformation of the floodplain reservoir are identified. The selected stages are characterized by both natural causes(the transformation of the filling deltas into the extended deltas, etc.) and man-made causes(runoff diversions in the delta areas, etc.). The key factor of transformation is the formation of deltas of rivers flowing into the reservoir. Each of the selected stages, against the background of a gradual reduction in the area and volume of the reservoir, is characterized by the peculiarities of the formation of river deltas with the formation of genetically homogeneous sections of delta regions. During the period of operation of the reservoir, the delta of the main Kuban River moved up to 32.4 km and took away an area of 35.4 km~2 of the reservoir. During the formation of the deltas of the Kuban and Belaya rivers, a bridge was formed on the Krasnodar reservoir. The evolution of the delta regions led to the division of the reservoir into two autonomous reservoirs. The total area of the delta regions was 85.9 km~2 by 2018, i.e., 21% of the initial area of the reservoir. The transformation of the Krasnodar reservoir leads to a decrease in its regulated volume and gradual degradation.     

CROP-PLANTING FACTOR OF SOIL EROSION OF SLOPING CULTIVATED LAND IN THE NORTHEAST MOUNTAIN REGION OF YUNNAN PROVINCE

By means of setting up experimental spots of the influences of four representative crop_planting types—maize,potato,soybean and maize_soybean intercrop on rainfall erosion,and measuring continuously three years in the northeast mountain region of Yunnan province,the C value of crop_planting factor was analysed and calculated.The results showed1．the conserving effect of crops on the soil of slopeland increases with the growth of crops,i.e.the higher the covering rate of ground is,the lower the C value is.2．in four crop_planting types,the maximum conserving effect on the soil of slopeland is maize_soybean intercrop,its C value is 0.1990,the C values of other crops are respectivelymaize 0.3517,soybean 0.3551,potato 0.3721.     

土地资源

X372007010606长江岸线资源利用功能区划方法研究:以南通市域长江岸线为例=Method to make function division of waterfront re-sourses along the Yangtze River:a sample on the waterfront for Nantong city/段学军,陈雯…∥长江流域资源与环境.—2006,15(5).—621~626图3表5参10(宋金叶)HNF301.242007010607近50年来松嫩平原西部土地利用变化及驱动力分析=Dy-namic change of land-use patterns in west part of Songnenplain/刘殿伟,宋开山…∥地理科学.—2006,26(3).—277~283过去近50年里,松嫩平原西部耕地净增加29.65×104hm2,…     

Effects of freeze–thaw cycles on soil N_2O concentration and flux in the permafrost regions of the Qinghai–Tibetan Plateau

Nitrous oxide(N_2 O) is one of the most important greenhouse gases in the atmosphere; freeze–thaw cycles(FTCs) might strongly influence the emission of soil N_2 O on the Qinghai–Tibetan Plateau(QTP). However, there is a lack of in situ research on the characteristics of soil N_2 O concentration and flux in response to variations in soil properties caused by FTCs.Here, we report the effect of FTC-induced changes in soil properties on the soil N_2 O concentration and flux in the permafrost region of the higher reaches of the Shule River Basin on the northeastern margin of the QTP. We measured chemical properties of the topsoil, activities of soil microorganisms, and air temperature(AT), as well as soil N_2 O concentration and flux, over an annual cycle from July 31, 2011, to July 30, 2012. The results showed that soil N_2 O concentration was significantly affected by soil temperature(ST), soil moisture(SM), soil salinity(SS), soil polyphenol oxidase(SPO), soil alkaline phosphatase(SAP), and soil culturable actinomycetes(SCA), ranked as SMSSSTSPOSAPSCA, whereas ST significantly increased soil N_2 O flux, compared with SS. Overall, our study indicated that the soil N_2 O concentration and flux in permafrost zone FTCs were strongly affected by soil properties, especially soil moisture, soil salinity, and soil temperature.