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1.
陆面过程和大气边界层相互作用敏感性实验 总被引：18，自引：1，他引：18
文中建立了一个研究陆面物理过程与大气边界层相互作用的模式。模拟了草原下垫面的土壤 环境物理、地面热量通量、蒸发、蒸散及大气边界层结构特征。并对主要的环境物理参数进 行了敏感性实验。结果表明，本模式能合理地模拟地表热量平衡、土壤体积含水量、植被蒸 发阻抗、地表水汽通量日变化和湍流交换系数、湍流动能、位温和比湿廓线等。该模式还可 进一步应用于研究城市陆面物理过程与大气边界层相互作用机制，及与中尺度大气模式耦合用于区域气候的研究。 相似文献
2.
森林下垫面陆面物理过程及局地气候效应的数值模拟试验 总被引：5，自引：0，他引：5
文中基于大气边界层和植被冠层微气象学基本原理 ,建立了一个森林植被效应的陆面物理过程和二维大气边界层数值模式。并应用该模式进行了植被和土壤含水量等生物和生理过程在陆面过程和局地气候效应方面的数值模拟试验。所得数值模拟试验结果与实际情况相吻合。结果表明 ,应用该模式可获得植被温度、植被冠层内空气温度、地表温度日变化特征 ;森林下垫面大气边界层风速、位温、比湿、湍流交换系数的时空分布和日变化特征。该模式还可应用于不同下垫面 ,模拟陆面物理过程与大气边界层相互作用机制及其局地气候效应的研究 ,这将为气候模式与生物圈的耦合研究奠定一个良好的基础。 相似文献
3.
利用"中国西北干旱区陆—气相互作用实验"观测的资料,分析了大气湿度、土壤含水量、与土壤含水量相关的陆面参数及其他陆面参数特征。为了验证新的陆面参数及参数化公式,将新陆面参数与参数化公式输入陆面模式进行模拟,将模拟值与观测值进行了比较。结果表明输入新参数及参数化公式的模拟效果更好。 相似文献
4.
陆面过程模式的研究进展简介 总被引：1，自引：0，他引：1
陆面过程是影响大气环流和气候变化的基本物理、生化过程之一。根据陆面过程研究的发展进程,介绍了三代陆面过程模式的不同特点和发展历程,指出在未来陆面方案中,引入光合作用和碳循环,可以更加真实地反映土壤、地表、大气、生物圈相互作用。陆面过程模式发展应该着眼于综合并且动态考虑植被类型变化、光合作用、碳循环和水循环的真实水文生化模型建立,将有效增强对气候变化的研究,提高天气预报模式的准确率。 相似文献
5.
根据沿海地区实际情况,集成以往的研究成果及相关数据,建立沿海缺水灌区地表水地下水联合调配管理信息系统.该系统具有友好的界面,是地理信息系统、数据库技术以及水资源系统模拟优化等多技术综合集成的动态管理系统.模型具有一定的通用性,可为沿海缺水灌区地表水地下水规划管理服务,也可为各级水管部门准确及时提供水资源信息. 相似文献
6.
陆面过程对2007年淮河流域强降水数值预报的影响分析 总被引：3，自引：0，他引：3
基于GRAPES中尺度数值天气预报模式,研究了不同复杂程度陆面过程和不同土壤初始条件对2007年中国夏季淮河流域降水数值预报的影响。重点分析了下垫面非均匀性对造成我国夏季强降水的中小尺度对流系统的启动和发展的影响,探讨了中小尺度对流发生发展中陆气相互作用的可能影响。对2007年7月8日发生在淮河流域的一次对流过程采用两组敏感性试验进行研究,结果表明对流启动对陆面过程有很强的敏感性。Noah陆面模式能合理地模拟出对流的启动,而Slab陆面模式模拟的对流会延迟1～2小时,这与Noah陆面模式能合理描述地表感、潜热通量有关。GLDAS初始土壤资料能更加合理地描述实际土壤温湿的分布状况,有利于更加准确地模拟出对流降水的启动和分布位置。另外,对2007年7月淮河流域的持续性强降水天气过程进行了对比模拟,研究表明:不同复杂程度陆面过程对连续强降水数值预报有明显的影响。使用Noah陆面模式能提高对强降水预报的能力,而且随着模式分辨率的提高,降水的TS评分也在提高,Noah的TS评分总体上高于Slab。 相似文献
7.
根据土壤水分平衡原理，建立了一个反映土壤渍水、可与小麦生长模型耦合的土壤水分动态模型，尤其考虑了因地下水位较浅而引起的毛管上升水量和土壤导水率的变化对土壤含水量的影响。采用盆栽小麦水分试验资料验证了日蒸散量的模拟值，利用湖北荆州农业气象试验站和江苏金坛农业气象试验站的土壤水分历史资料对建立的模型进行了综合测试和验证，结果表明:蒸散量、地下水位和0～50 cm土壤含水量的模拟值与实测值具有较好的一致性，模型能可靠地预测多雨和渍水地区麦田土壤水分的变化动态 相似文献
8.
IAP94陆面过程模式在淮河流域的验证试验 总被引：3，自引：0，他引：3
利用ＩＡＰ９４陆面过程模式对淮河流域不同季节（春、夏、秋）、不同下垫面（旱地、森林、水田）进行了单点数值模拟试验，结果表明ＩＡＰ９４不但能较好地模拟出观测的地气间各种能量通量以及植被的冠层温度，同时还很好地模拟出整层土壤含水量的变化趋势，从而证实了ＩＡＰ９４陆面过程模式具有正确描述东亚半湿润季风区陆气相互作用的能力。另外比较结果还揭示了水田表面强烈蒸发作用的重要性，需要在陆过程模式中予以重视。 相似文献
9.
陆面过程对全球变暖的响应及可能机制—基于CMIP3的多模式集合分析 总被引：2，自引：0，他引：2
利用“国际耦合模式比较计划” (Phase 3 of the Coupled Model Intercomparison Project, CMIP3) 12个模式对20世纪 (The Twentieth-Century Climate in Coupled Models, 20C3M) 和21世纪SRES (Special Report on Emissions Scenarios) A1B 情景下的模拟结果, 通过21世纪 (2001～2099年) 与20世纪 (1901～1999年) 陆面能量和水文变量的对比分析, 揭示了陆面过程对全球变暖响应的基本特征, 并探讨了其可能的响应机制。结果表明, 与20世纪相比, 21世纪全球陆面平均的表面温度、 地表净辐射、 潜热通量明显增加; 而感热通量有所减小。降水、 径流、 蒸发等地表水循环分量也表现出不同程度的增加, 而土壤含水量有减小趋势。通过分析近地层主要大气强迫变量与陆面变量之间的联系, 发现陆面能量平衡过程对全球变暖的响应主要受向下长波辐射和气温变化的影响, 而温度的变化对陆面水文过程的影响起决定性的作用。进一步分析表明, 陆面过程对全球变暖的响应存在明显的区域性差异, 陆面温度和感热对全球变暖响应最显著的区域位于北半球中高纬, 而净辐射和潜热对全球变暖的响应在亚洲中部和非洲大陆最显著。相对于20世纪, 21世纪主要是长波辐射和温度对陆面能量平衡过程的贡献重要。对于陆面水文过程, 径流和土壤含水量对全球变暖的响应在亚洲中部以及北美最显著。在全球变暖背景下, 21世纪相对于20世纪, 温度对陆面水循环的影响更加显著, 主要体现在北半球中纬度地区。 相似文献
10.
干旱区绿洲与荒漠相互作用下陆面特征的数值模拟 总被引：25，自引：9，他引：16
用新发展的二维中尺度土壤－植被－大气连续体数值模式,系统地模拟了绿洲与荒漠相互作用下的陆面特征和地表面能量输送特征。这一模拟结果不仅部分地验证了陆面过程野外实验的观测结果。 相似文献
11.
Climate�Csoil�Cvegetation control on groundwater table dynamics and its feedbacks in a climate model
Among the three dynamically linked branches of the water cycle, including atmospheric, surface, and subsurface water, groundwater is the largest reservoir and an active component of the hydrologic system. Because of the inherent slow response time, groundwater may be particularly relevant for long time-scale processes such as multi-years or decadal droughts. This study uses regional climate simulations with and without surface water?Cgroundwater interactions for the conterminous US to assess the influence of climate, soil, and vegetation on groundwater table dynamics, and its potential feedbacks to regional climate. Analyses show that precipitation has a dominant influence on the spatial and temporal variations of groundwater table depth (GWT). The simulated GWT is found to decrease sharply with increasing precipitation. Our simulation also shows some distinct spatial variations that are related to soil porosity and hydraulic conductivity. Vegetation properties such as minimum stomatal resistance, and root depth and fraction are also found to play an important role in controlling the groundwater table. Comparing two simulations with and without groundwater table dynamics, we find that groundwater table dynamics mainly influences the partitioning of soil water between the surface (0?C0.5?m) and subsurface (0.5?C5?m) rather than total soil moisture. In most areas, groundwater table dynamics increases surface soil moisture at the expense of the subsurface, except in regions with very shallow groundwater table. The change in soil water partitioning between the surface and subsurface is found to strongly correlate with the partitioning of surface sensible and latent heat fluxes. The evaporative fraction (EF) is generally higher during summer when groundwater table dynamics is included. This is accompanied by increased cloudiness, reduced diurnal temperature range, cooler surface temperature, and increased cloud top height. Although both convective and non-convective precipitation are enhanced, the higher EF changes the partitioning to favor more non-convective precipitation, but this result could be sensitive to the convective parameterization used. Compared to simulations without groundwater table dynamics, the dry bias in the summer precipitation is slightly reduced over the central and eastern US Groundwater table dynamics can provide important feedbacks to atmospheric processes, and these feedbacks are stronger in regions with deeper groundwater table, because the interactions between surface and subsurface are weak when the groundwater table is deep. This increases the sensitivity of surface soil moisture to precipitation anomalies, and therefore enhances land surface feedbacks to the atmosphere through changes in soil moisture and evaporative fraction. By altering the groundwater table depth, land use change and groundwater withdrawal can alter land surface response and feedback to the climate system. 相似文献
12.
集合Kalman滤波在土壤湿度同化中的应用 总被引：10，自引：4，他引：6
基于非饱和土壤水模型和集合卡尔曼滤波 (Ensemble Kalman Filter, 简称EnKF) 并结合陆面水文模型——可变下渗能力模型 (Variable Infiltration Capacity, 简称VIC模型) 发展了一个土壤湿度同化方案。利用1998年6~8月淮河流域能量和水循环试验 (HUBEX) 项目外场观测试验区——史灌河流域梅山站土壤湿度逐日观测资料及1986~1993年合肥和南阳两站点的土壤湿度旬观测资料进行同化试验, 结果表明该同化方案能完整估计土壤湿度廓线, 同化的土壤湿度与观测资料基本吻合, 反映了土壤湿度的日、 旬、 月、 季变化, 同化方案是合理的。与基于扩展卡尔曼滤波 (Extended Kalman Filter, 简称EKF) 的土壤湿度同化方案的结果比较, 基于EnKF的土壤湿度同化方案易于实现, 且通过选择恰当的集合样本数其同化效果总体上略优于EKF同化方案, 但前者同化时需要花费较多的计算时间。 相似文献
13.
具有Horton及Dunne机制的径流模型在VIC模型中的应用(英) 总被引：20，自引：0，他引：20
地表径流主要由蓄满(Dunne)和超渗产流(Horton)机制产生;土壤性质的空间变异性、前期土壤水、地形及降水的空间变异性导致不同的径流机制。在研究区域或模型网格内,蓄满产流及超渗产流可能同时出现,缺乏考虑任何一种机制以及土壤性质的次网格空间变率可能导致地表径流的过高或过低估计,从而影响土壤水的计算。利用Philip入渗公式用于时间压缩逼近(TCA)给出了一种径流参数化方法,该方法可以动态实现模型网格中的Horton及Dunne产流机理,它考虑了土壤空间变异性对Horton和Dunne径流的影响。该径流模型应用到基于水文原理的陆面过程模型VIC,在淮河流域及美国宾西法尼亚州的一个流域进行了测试,结果表明:新的参数化方法对地表径流和土壤水分含量的分配起着重要作用,对于改进径流和土壤水的模拟有重要意义。 相似文献
14.
H. Hübener M. Schmidt M. Sogalla M. Kerschgens 《Theoretical and Applied Climatology》2005,80(2-4):153-167
Summary In this work, simulations with the mesoscale meteorological model FOOT3DK for a semi-arid research site in southern morocco are presented. The main aim of this study is to introduce two different ways to improve the soil moisture distribution towards a more realistic pattern. One of them resembles the availability of groundwater resources below the lower boundary of the soil part of the model, the other one resembles irrigation practices in the region. Additionally, we introduce a newly derived land use/land cover data set obtained from analysis of LANDSAT data and compare the simulation results to those obtained with the USGS GLCC data. To evaluate the results with the refinements in soil moisture and land use/land cover, we focus on evapotranspiration, as the quantity which is most tentative to the changes in soil moisture and is an important part of the local hydrological cycle. To evaluate the importance of sub-grid scale surface heterogeneity in soil moisture and land use/land cover, we present simulations with enhanced surface resolution. Simulation results are compared to point measurements at different sites in the research area for validation.The results show, that a deep groundwater table and irrigation of parts of the research area can be represented by the methods we used. Simulated transpiration is overestimated compared to measured values, but this is due to the maximum approach used in this work. Finer tuning of the artificial enhancement of soil moisture with the two methods presented here are expected to lead to realistic distributions of evapotranspiration and related quantities, therewith drastically enhancing simulation accuracy for this site. As uncertainties of soil moisture distribution and restricted representation of soil moisture dynamics in meteorological models is a common problem especially for arid and semi-arid sites, we expect our results to be useful for meteorological simulations in other arid or semi-arid areas as well. 相似文献
15.
A simple hydrologic framework for simulating wetlands in climate and earth system models 总被引：1，自引：0，他引：1
Wetlands are ecosystems of important functions in the earth??s climate system. Through relatively high evapotranspiration, they affect surface water and energy exchange with the atmosphere directly influencing the physical climate. Through CH4, CO2 and N2O fluxes, they regulate the biogeochemical cycles, indirectly influencing the physical climate. However, current models do not explicitly include the water table, present under all large and stable wetlands; model wetlands are identified as flat land with wet soil resulting from precipitation events. That is, the wetlands are only ??wetted?? from above but not from below by the high water table. Furthermore, without the knowledge of the water table position, estimates of CH4 and other gases (e.g., CO2 and N2O) are poorly constrained. We present a simple hydrologic framework for simulating wetlands based on water table depth. A synthesis of hydrologic controls on wetlands highlights the key role that groundwater plays. It directly feeds wetlands, supports surface-water fed wetlands by maintaining a saturated substrate, and links land drainage to sea level by impeding drainage in lowlands. Forced by routine climate model output (precipitation?Cevapotranspiration-surface runoff), land topography, and sea level, we simulate the present-day water table in North America at the 1?km scale. We validate the simulation with water table observations and compare regions of shallow water table to mapped wetlands. Our results show that the framework captures the salient features of wetland distribution and extent at regional and continental scales, a direct result of large-scale groundwater convergence that nourishes the lowlands even in arid climates. The low requirement of forcing and computation make the framework easy to adopt in climate and earth system models for simulating wetland responses to climate and sea level change for the present, paleo reconstructions, and future projections. 相似文献
16.
Climatic responses to anthropogenic groundwater exploitation: a case study of the Haihe River Basin,Northern China 总被引：5，自引：0，他引：5
In this study, a groundwater exploitation scheme is incorporated into the regional climate model, RegCM4, and the climatic responses to anthropogenic alteration of groundwater are then investigated over the Haihe River Basin in Northern China where groundwater resources are overexploited. The scheme models anthropogenic groundwater exploitation and water consumption, which are further divided into agricultural irrigation, industrial use and domestic use. Four 30-year on-line exploitation simulations and one control test without exploitation are conducted using the developed model with different water demands estimated from relevant socioeconomic data. The results reveal that the groundwater exploitation and water consumption cause increasing wetting and cooling effects on the local land surface and in the lower troposphere, along with a rapidly declining groundwater table in the basin. The cooling and wetting effects also extended outside the basin, especially in the regions downwind of the prevailing westerly wind, where increased precipitation occurs. The changes in the four exploitation simulations positively relate to their different water demands and are highly non-linear. The largest changes in climatic variables usually appear in spring and summer, the time of crop growth. To gain further insights into the direct changes in land-surface variables due to groundwater exploitation regardless of the atmospheric feedbacks, three off-line simulations using the land surface model Community Land Model version 3.5 are also conducted to distinguish these direct changes on the land surface of the basin. The results indicate that the direct changes of land-surface variables respond linearly to water demand if the climatic feedbacks are not considered, while non-linear climatic feedbacks enhance the differences in the on-line exploitation simulations. 相似文献
17.
Monsoon depressions (MDs) constitute a large fraction of the total rainfall during the Indian summer monsoon season. In this study, the impact of high-resolution land state is addressed by assessing the evolution of inland moving depressions formed over the Bay of Bengal using a mesoscale modeling system. Improved land state is generated using High Resolution Land Data Assimilation System employing Noah-MP land-surface model. Verification of soil moisture using Soil Moisture and Ocean Salinity (SMOS) and soil temperature using tower observations demonstrate promising results. Incorporating high-resolution land state yielded least root mean squared errors with higher correlation coefficient in the surface and mid tropospheric parameters. Rainfall forecasts reveal that simulations are spatially and quantitatively in accordance with observations and provide better skill scores. The improved land surface characteristics have brought about the realistic evolution of surface, mid-tropospheric parameters, vorticity and moist static energy that facilitates the accurate MDs dynamics in the model. Composite moisture budget analysis reveals that the surface evaporation is negligible compared to moisture flux convergence of water vapor, which supplies moisture into the MDs over land. The temporal relationship between rainfall and moisture convergence show high correlation, suggesting a realistic representation of land state help restructure the moisture inflow into the system through rainfall-moisture convergence feedback. 相似文献
18.
以沩水河流域为例,基于陆面模式CLM4.5,建立了综合考虑作物种植、地下水开采及灌溉等人类活动的流域陆面水文模型。利用所发展模型,针对1981~2012年,取500 m空间分辨率,探讨人为扰动对陆面过程的影响。研究表明:1）地下水侧向流使得中下游地区地下水位有所提高,平原地下水埋深分布在4 m左右,山区埋深可达到几十米;模拟的叶面积指数较静态MODIS叶面积指数偏大1左右,由此使得种植区月蒸腾量提高约10 mm,土壤蒸发和地表产流有所减少;在灌溉作用下,作物叶面积指数略增长,蒸散发稍有提高,而在假设水稻采用漫灌的情况下,水库灌溉补偿了作物生长产生的水消耗,提高了该区域土壤湿度,增加潜热通量;研究区地下水开采存在但其水文效应并不显著。2）土地覆盖变化自1990年有较大变动,1990~2000年以林地为主,2000年后以耕地为主,其中,1990~2000年土地覆盖类型变化不明显,2001~2012年耕地面积呈先减少再增加又减少的趋势,林地面积则先增加再减少又增加,耕地与林地在2012年所占比例基本持平;同一土地类型内,植被类型变化较为明显,导致陆面水文模拟结果差异较大。 相似文献
19.
Satellite Monitoring of the Surface Water and
Energy Budget in the Central Tibetan Plateau 总被引：1，自引：0，他引：1
The water and energy cycle in the Tibetan Plateau is an important component of Monsoon Asia and the global energy and water cycle. Using data at a CEOP （Coordinated Enhanced Observing Period）-Tibet site, this study presents a first-order evaluation on the skill of weather forecasting from GCMs and satellites in producing precipitation and radiation estimates. The satellite data, together with the satellite leaf area index, are then integrated into a land data assimilation system （LDAS-UT） to estimate the soil moisture and surface energy budget on the Plateau. The system directly assimilates the satellite microwave brightness temperature, which is strongly affected by soil moisture but not by cloud layers, into a simple biosphere model. A major feature of this system is a dual-pass assimilation technique, which can auto-calibrate model parameters in one pass and estimate the soil moisture and energy budget in the other pass. The system outputs, including soil moisture, surface temperature, surface energy partition, and the Bowen ratio, are compared with observations, land surface models, the Global Land Data Assimilation System, and four general circulation models. The results show that this satellite data-based system has a high potential for a reliable estimation of the regional surface energy budget on the Plateau. 相似文献
20.
土壤湿度是影响天气和气候非常重要的因子之一,但目前针对土壤湿度可预报性的研究报道相对较少。该文在对BCC_CSM模式进行了适合的陆面初始化的条件下,设计了两组在中国东部地区采用不同土壤湿度初值的回报试验研究该地区土壤湿度的可预报性及初值对其可预报性影响问题。试验结果表明:BCC_CSM模式在真实的外场强迫下可以模拟出相对合理的土壤湿度;土壤湿度的可预报性在表层约为3候,随着深度的增加,土壤湿度的可预报性持续时间增加,在中层预报性甚至能达到月尺度以上;初值对于土壤湿度的预报存在影响,在表层影响时间约为2~3候,影响时间随着深度增加;浅层土壤湿度受降水的影响较大,浅层土壤湿度变化滞后降水变化约1~2 d,中层土壤湿度变化与降水变化存在5 d左右的滞后关系。 相似文献