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1.
内蒙古草原气候特点与草原生态类型区域划分 总被引:6,自引:0,他引:6
为了合理开发利用气候资源,给草原畜牧业生产的分区管理提供科学依据,文章对内蒙古草原气候特点及气候对牧草生长、畜种分布和土壤环境的影响进行了分析,发现内蒙古气候湿润度的某些等值线与土壤带的分界线几乎完全重合,表明土壤带的形成与气候条件密切相关。而气候和土壤环境是草场类型及其生态系统的主要影响因素,因此以气候湿润度为主要依据,结合内蒙古土壤带的水平分布特征,进行草原生态类型区域的划分不仅具有合理性,而且具有稳定性。指出近年来的气候增暖以及由此引起的其他气候变化,虽使草原生产力有一定的提高,但并未使内蒙古草原的生态类型有所改变。 相似文献
2.
Carbon storage in the grasslands of China based on field measurements of above- and below-ground biomass 总被引:7,自引:0,他引:7
Jiangwen Fan Huaping Zhong Warwick Harris Guirui Yu Shaoqiang Wang Zhongmin Hu Yanzhen Yue 《Climatic change》2008,86(3-4):375-396
Above- and below-ground biomass values for 17 types of grassland communities in China as classified by the Chinese Grasslands
Resources Survey were obtained from systematic replicated sampling at 78 sites and from published records from 146 sites.
Most of the systematic samples were along a 5,000-km-long transect from Hailar, Inner Mongolia (49°15′N, 119°15′E), to Pulan,
Tibet (30°15′N, 81°10′E). Above-ground biomass was separated into stem, leaf, flower and fruit, standing dead matter, and
litter. Below-ground biomass was measured in 10-cm soil layers to a depth of 30 cm for herbs and to 50 cm for woody plants.
Grassland type mean total biomass carbon densities ranged from 2.400 kg m−2 for swamp to 0.149 kg m−2 for alpine desert grasslands. Ratios of below- to above-ground carbon density varied widely from 0.99 for tropical tussock
grassland to 52.28 for alpine meadow. Most below-ground biomass was in the 0–10 cm soil depth layer and there were large differences
between grassland types in the proportions of living and dead matter and stem and leaf. Differences between grassland types
in the amount and allocation of biomass showed patterns related to environments, especially aridity gradients. Comparisons
of our estimates with other studies indicated that above-ground biomass, particularly forage-yield biomass, is a poor predictor
of total vegetation carbon density. Our estimate for total carbon storage in the biomass of the grasslands of China was 3.32 Pg
C, with 56.4% contained in the grasslands of the Tibet-Qinghai plateau and 17.9% in the northern temperate grasslands. The
need for further standardized and systematic measurements of vegetation biomass to validate global carbon cycles is emphasised. 相似文献
3.
内蒙古典型草原N2O研究刍议 总被引:15,自引:1,他引:14
利用中国科学院内蒙古草原生态定位研究站(IMGERS)的气候、土壤、植被、土地利用方式和家畜等方面的资料,根据目前国际上N2O的研究进展,分析了内蒙古典型草原区影响N2O收支作用的可能控制因子,认为:(1)作为N2O主要来源的土壤,其理化性状,尤其是土壤温度、水分状况、土壤有机质和土壤结构等,是影响该地区N2O收支平衡的主要控制因子;(2)土地利用方式的改变对N2O的释放的影响还不十分清楚。草场农用与一定的耕作管理措施以及对天然草场的人为影响(割草、放牧等)是对N2O收支平衡影响的主要方面;(3)家畜排泄物,无论作为本地区的主要燃料,还是作为肥料,在典型草原区N2O的释放中起着不可忽视的作用。 相似文献
4.
利用1991—2015年夏季(6—8月)内蒙古地区111个国家气象站小时降水量资料,对内蒙古不同气候区(极干旱、干旱、半干旱、半湿润和湿润)短时强降水(1 h降水量≥20 mm)进行检验分析,采用累积概率方法定义内蒙古夏季不同气候区短时强降水。检验结果表明:内蒙古地区年平均降水量和小时降水量极值自西部极干旱区向东部半湿润、湿润区递增,高值区位于大兴安岭东部,次高值区位于阴山山脉以南。内蒙古极干旱区小时降水量极值低于20 mm,半湿润区和湿润区小时降水量极值高于50 mm,个别站点甚至达到100 mm以上。但在半湿润区和湿润区东部小时降水量超过20 mm年平均发生仅为1次,其余地区均1次。在内蒙古极干旱区、干旱区、半干旱区、半湿润区和湿润区小时降水量分别达到6.1、9.8、12.5、15.2和14.3 mm·h~(-1)属于极端降水事件,小时降水量≥20 mm不宜作为内蒙古短时强降水定义。综合上述研究,结合内蒙古地区地形、地貌等因素,将内蒙古极干旱区和干旱区短时强降水定义为5 mm·h~(-1),半干旱区、半湿润区和湿润区短时强降水定义为10 mm·h~(-1)。 相似文献
5.
放牧强度对内蒙古半干旱草原地气间能量和物质交换的影响 总被引:2,自引:1,他引:1
利用涡度相关技术, 于2006年7月27日至8月10日在内蒙古半干旱草原三种放牧强度的下垫面进行微气象观测。本文分析了放牧强度对内蒙古半干旱草原地气间能量和物质交换的影响, 发现: (1)放牧降低植被覆盖率, 使地表反射率增大。(2)放牧使潜热通量减小。而放牧强度最大的锡林河河道潜热通量最大,表明土壤水分状况是半干旱草原地表能量收支的决定性因素。(3)羊草和冬季放牧观测点日平均CO2通量分别为-1.92 g?m-2?d-1和0.73 g?m-2?d-1, 表明放牧可以使草地由CO2的汇转变为源。锡林河河道为CO2的汇, 日平均CO2通量-3.35 g?m-2?d-1, 与羊草比较, 锡林河河道吸收CO2更多, 表明土壤湿度是影响半干旱草原CO2通量交换的重要因素。(4) 放牧通过减小叶面积指数, 减弱植被的光合作用能力。 相似文献
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Effects of Irrigation on Nitrous Oxide, Methane and Carbon Dioxide Fluxes in an Inner Mongolian Steppe 总被引:2,自引:0,他引:2
LIU Chunyan Jirko HOLST Nicolas BRUGGEMANN Klaus BUTTERBACH-BAHL YAO Zhisheng HAN Shenghui HAN Xingguo ZHENG Xunhua 《大气科学进展》2008,25(5):748-756
Increased precipitation during the vegetation periods was observed in and further predicted for Inner Mongolia. The changes in the associated soil moisture may affect the biosphere-atmosphere exchange of greenhouse gases. Therefore, we set up an irrigation experiment with one watered (W) and one unwatered plot (UW) at a winter-grazed Leymus chinensis-steppe site in the Xilin River catchment, Inner Mongolia. UW only received the natural precipitation of 2005 (129 mm), whereas W was additionally watered after the precipitation data of 1998 (in total 427 mm). In the 3-hour resolution, we determined nitrous oxide (N20), methane (CH4) and carbon dioxide (CO2) fluxes at both plots between May and September 2005, using a fully automated, chamber-based measuring system. N20 fluxes in the steppe were very low, with mean emissions (±s.e.) of 0.9-4-0.5 and 0.7-4-0.5 μg N m^-2 h^-1 at W and UW, respectively. The steppe soil always served as a CH4 sink, with mean fluxes of -24.1-4-3.9 and -31.1-4- 5.3 μg C m^-2 h^-1 at W and UW. Nighttime mean CO2 emissions were 82.6±8.7 and 26.3±1.7 mg C m^-2 h^-1 at W and UW, respectively, coinciding with an almost doubled aboveground plant biomass at W. Our results indicate that the ecosystem CO2 respiration responded sensitively to increased water input during the vegetation period, whereas the effects on CH4 and N2O fluxes were weak, most likely due to the high evapotranspiration and the lack of substrate for N2O producing processes. Based on our results, we hypothesize that with the gradual increase of summertime precipitation in Inner Mongolia, ecosystem CO2 respiration will be enhanced and CH4 uptake by the steppe soils will be lightly inhibited. 相似文献
8.
Description and Application of a Model for Simulating Regional
Nitrogen Cycling and Calculating Nitrogen Flux 总被引:3,自引:0,他引:3
A regional nitrogen cycle model, named IAP-N, was designed for simulating regional nitrogen (N) cycling and calculating N fluxes flowing among cultivated soils, crops, and livestock, as well as human, atmospheric and other systems. The conceptual structure and calculation methods and procedures of this model are described in detail. All equations of the model are presented. In addition, definitions of all the involved variables and parameters are given. An application of the model in China at the national scale is presented. In this example, annual surpluses of consumed synthetic N fertilizer; emissions of nitrous oxide (N2O), ammonia (NH3) and nitrogen oxide (NOx); N loss from agricultural lands due to leaching and runoff; and sources and sinks of anthropogenic reactive N (Nr) were estimated for the period 1961-2004. The model estimates show that surpluses of N fertilizer started to occur in the mid 1990s and amounted to 5.7 Tg N yr^-1 in the early 2000s. N20 emissions related to agriculture were estimated as 0.69 Tg N yr^-1 in 2004, of which 58% was released directly from N added to agricultural soils. Total NH3 and NOx emissions in 2004 amounted to 4.7 and 4.9 Tg N yr^-1, respectively. About 3.9 Tg N yr^-1 of N was estimated to have flowed out of the cultivated soil layer in 2004, which accounted for 33% of applied synthetic N fertilizer. Anthropogenic Nr sources changed from 2.8 (1961) to 28.1 Tg N yr^-1 (2004), while removal (sinks) changed from to 2.1 to 8.4 Tg N yr^-1. The ratio of anthropogenic Nr sources to sinks was only 1.4 in 1961 but 3.3 in 2004. Further development of the IAP-N model is suggested to focus upon: Ca) inter-comparison with other regional N models; (b) overcoming the limitations of the current model version, such as adaptation to other regions, high-resolution database, and so on; and (c) developing the capacity to estimate the safe threshold of anthropogenic Nr source to sink ratios. 相似文献
9.
一维地气耦合模式及其在内蒙草原的应用 总被引:1,自引:0,他引:1
本文以内蒙草原大气边界层观测资料为基础,利用一个一维土壤一植被一大气模式对大气和地表进行耦合模拟。其中,地面过程采用NP89模式进行模拟,大气湍流参数化采用二阶闭合。运用观测与前人的研究成果对模拟结果的合理性进行验证,对比表明模式较好地解决了地表与大气的耦合,成功地对地表平坦的草原下垫面大气边界层进行模拟。分析表明,在半干旱内蒙草原草的生长季后期雨季8月,潜热通量占主导地位,最大可超过感热250W/m2;在内蒙高原云的作用比较明显,影响不可忽略,模式对云的作用比较敏感。 相似文献
10.
Aerodynamic parameters including the zero-plane displacement (d), roughness length (20), and friction velocity (u*) on the different underlying surfaces of heavy-grazing site, medium-grazing site, light-grazing site, no-grazing site, dune, inter-dune, grassland, rice paddy site, wheat site, soybean site, and maize site have been computed based on the Monin-Obukhov similarity theory by utilizing the micrometeorologically observed data of dune and vegetation in the semi-arid area at Naiman, Inner Mongolia of China, conducted jointly by the Institute of Desert Research, Chinese Academy of Sciences and the National Institute of Agro-Environmental Sciences of Japan in 1990-1994. And their relationships between wind speed and Richardson number are analyzed. The aerodynamic characteristics of different man-made disturbed grassland ecosystems are also compared. Result shows that the vegetation coverage and the above-ground biomass decrease with the increase in man-made stress of the grassland. The roughness length for different underlying surfaces is closely related to vegetation height, above-ground biomass, and ground surface undulation, and Richardson number Ri is also its influencing factor. The friction velocity varies largely on different underlying surfaces, and it is positively proportional to wind speed and roughness length. The aerodynamic parameters of various times on the same underlying surface are different, too. Above results indicate that grassland and vegetation are of significance in preventing desertification, especially in the arid and semi-arid land ecosystems. And the results of this paper are also important for constructing the land surface physical process as well as regional climate model. 相似文献
11.
半干旱草原温室气体排放/吸收与环境因子的关系研究 总被引:13,自引:3,他引:10
静态箱一气相色谱法对内蒙古半干旱草原连续两年的实验观测研究结果表明,内蒙古草原是大气CO2和N2O的排放源,而是CH4的汇.在植物生长不同季节,草原生态系统排放/吸收温室气体CO2,CH4和N2O的日变化形式各有不同,其中在植物生长旺季日变化形式最具特征.3种温室气体的季节排放/吸收高峰主要出现在土壤湿度较大的春融和降雨较为集中时期.所有草原植物生长季节CO2净排放日变化形式均为白天出现排放低值,夜间出现排放高值.较高的温度有利于CO2排放,地上生物量决定着光合吸收CO2量值的高低.影响半干旱草原吸收CH4和排放N2O日变化形式的关键是土壤含水量和供氧状况,日温变化则主要影响日变化强度.吸收CH4和排放N2O的季节变化与土壤湿度季节变化分别呈线性反、正相关,相关系数均在0.4~0.6之间.自由放牧使CO2、N2O和CH4交换速率日较差降低,同时使N2O和CH4年度排放/吸收量减少和CO2年度排放量增加. 相似文献
12.
Communities living in the grasslands of present day Inner Mongolia have experienced dramatic social, economic and ecological changes over the past millennium. More recently, these grasslands have undergone widespread degradation, raising concern for securing local herders' livelihoods. To understand these changes in ecological and welfare outcomes over long time scales, we define five broad periods of relative institutional stability over the past millennium, characterize social-ecological system during each period, and then assess major changes between these periods. Looking at changes in institutional contexts helps explain some of our outcomes of interest. We find that while much attention has been given to the change in grassland lease structures in China, the role of market integration and buffers against historically natural constraints on livestock production (e.g., protection from the winter months) have decoupled formerly tight local social-ecological links. This decoupling, along with weak land tenure security due to a complex and volatile policy landscape, suppresses local incentives for grassland conservation. 相似文献
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Carbon storage in Chinese terrestrial ecosystems: approaching a more accurate estimate 总被引:2,自引:0,他引:2
Jian Ni 《Climatic change》2013,119(3-4):905-917
China is an important region for the global study of carbon because of its vast territory with various climate regimes, diverse ecosystems, and long-term human disturbances and land-use history. Carbon storage in ecosystems in China has been estimated using inventory and modeling methods in the past two decades. However, different methods may result in varied magnitudes and forms of carbon storage. In this study, the current status of carbon storage in terrestrial ecosystems in China, including the impacts of land use, is summarized in the national, regional, and biome scales. Significant differences in data have existed among studies. Such differences are mainly attributed to variations in estimation methods, data availability, and periods. According to available national-scale information on Chinese terrestrial ecosystems, vegetation carbon in China is 6.1 Pg C to 76.2 Pg C (mean 36.98 Pg C) and soil carbon is 43.6 Pg C to 185.7 Pg C (mean 100.75 Pg C). The forest sector has vegetation carbon of 3.26 Pg C to 9.11 Pg C (mean 5.49 Pg C), whereas the grassland sector has 0.13 Pg C to 3.06 Pg C (mean 1.41 Pg C). Soil carbon in the forest and grassland sectors exhibits more significant regional variations. Further studies need a comprehensive methodology, which combines national inventory, field measurement, eddy covariance technique, remote sensing, and model simulation in a single framework, as well as all available data at different temporal and spatial scales, to fully account for the carbon budget in China. 相似文献
16.
Jun Wang Daniel G. Brown Rick L. Riolo Scott E. Page Arun Agrawal 《Global Environmental Change》2013,23(5):1266-1276
There has been a decrease in grazing mobility in the Mongolian grasslands over the past decades. Sedentary grazing with substantial external inputs has increased the cost of livestock production. As a result, the livelihoods of herders have become more vulnerable to climate variability and change. Sedentary grazing is the formal institutional arrangement in Inner Mongolia, China. However, this may not be an efficient institutional arrangement for climate change adaptation. Self-organized local institutions for climate change adaptation have emerged and are under development in the study area. In this study, we did exploratory analyses of multiple local institutions for climate change adaptation in the Mongolian grasslands, using an agent-based modeling approach. Empirical studies from literature and our field work show that sedentary grazing, pasture rental markets, and reciprocal pasture-use groups are three popular institutional arrangements in the study area. First, we modeled the social–ecological performance (i.e., livelihood benefits to herders and grassland quality) of these institutions and their combinations under different climate conditions. Second, we did exploratory analyses of multiple social mechanisms for facilitating and maintaining cooperative use of pastures among herders. The modeling results show that in certain value-ranges of some model parameters with assumed values, reciprocal pasture-use groups had better performance than pasture rental markets; and the comparative advantage of cooperative use of pastures over sedentary grazing without cooperation becomes more evident with the increase in drought probability. Agent diversity and social norms were effective for facilitating the development of reciprocal pasture-use groups. Kin selection and punishments on free-riders were useful for maintaining cooperation among herders. 相似文献
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Eddy-Covariance Flux Measurements in the Complex Terrain of an Alpine Valley in Switzerland 总被引:1,自引:1,他引:0
We measured the surface energy budget of an Alpine grassland in highly complex terrain to explore possibilities and limitations
for application of the eddy-covariance technique, also for CO2 flux measurements, at such non-ideal locations. This paper focuses on the influence of complex terrain on the turbulent energy
measurements of a characteristic high Alpine grassland on Crap Alv (Alp Weissenstein) in the Swiss Alps during the growing
season 2006. Measurements were carried out on a topographic terrace with a slope of 25◦ inclination. Flux data quality is assessed via the closure of the energy budget and the quality flag method used within the
CarboEurope project. During 93% of the time the wind direction was along the main valley axis (43% upvalley and 50% downvalley
directions). During the transition times of the typical twice daily wind direction changes in a mountain valley the fraction
of high and good quality flux data reached a minimum of ≈50%, whereas during the early afternoon ≈70% of all records yielded
good to highest quality (CarboEurope flags 0 and 1). The overall energy budget closure was 74 ± 2%. An angular correction
for the shortwave energy input to the slope improved the energy budget closure slightly to 82 ± 2% for afternoon conditions.
In the daily total, the measured turbulent energy fluxes are only underestimated by around 8% of net radiation. In summary,
our results suggest that it is possible to yield realistic energy flux measurements under such conditions. We thus argue that
the Crap Alv site and similar topographically complex locations with short-statured vegetation should be well suited also
for CO2 flux measurements. 相似文献
20.
M. G. Sanderson W. J. Collins R. G. Derwent C. E. Johnson 《Journal of Atmospheric Chemistry》2003,46(1):15-28
Many previous assessments of the global hydrogen budget have used assumed global averages of temperatures and levels of key reactants to calculate the magnitudes of the various sinks. Dry deposition is by far the largest hydrogen sink but has not been considered in detail in previous estimates of the hydrogen budget. Simulations of hydrogen using a global three-dimensional Lagrangian chemistry-transport model and two different dry deposition schemes were compared with surface measurements. An improved dry deposition scheme which included the effects of soil moisture gave better agreement between the modelled hydrogen levels and surface measurements. The seasonal variation in the hydrogen levels was also simulated much more accurately with the new dry deposition scheme. The model results at high southern latitudes were insensitive to the relative partitioning of the sources between fossil fuel combustion and biomass burning. The results indicate a global mean hydrogen dry deposition velocity of 5.3×10–4 m s–1 which is lower than the previously used 7×10–4 m s–1. 相似文献