水文循环模拟中下垫面参数化方法综述

针对水文循环模拟中地形、土地利用覆被等流域下垫面参数化方法众多,且模拟效果相差较大的现状。本文首先根据水文循环模拟中产汇流原理,对常用水文循环模拟中产汇流模拟方法进行汇总和分类;在此基础上,对产流模拟中的降水径流相关系数法、蓄满产流和超渗产流等及汇流模拟中的等流时线、单位线、圣维南方程、马斯京根法等主要模拟方法中地形、土地利用覆被和土壤类型参数化方法进行分析和讨论;根据其中流域地形、土地利用覆被和土壤类型参数化方法对机理过程的描述程度,将其分为无明确表示类、率定型参数类、确定型参数类、物理过程表达类;进而阐明不同参数化方法中流域地形、土地利用覆被和土壤类型对水文循环模拟结果的响应和贡献。最后回归模型本质,阐述水文循环模拟中流域下垫面参数化方法中存在经验关系对复杂机理简单表述的合理性和物理机理过程描述的欠缺性问题,并预估未来水文循环模拟中下垫面参数化方法朝着简洁实用化和复杂机理化两个方向发展。     

A review of historical reconstruction methods of land use/land cover

Understanding long-term human-environment interactions requires historical reconstruction of past land-use and land-cover changes. Most reconstructions have been based primarily on consistently available and relatively standardized information from historical sources. Based on available data sources and a retrospective research, in this paper we review the approaches and methods of the digital reconstruction and analyze their advantages and possible constraints in the following aspects: (1) Historical documents contain qualitative or semi-quantitative information about past land use, which also usually include land-cover data, but preparation of archival documents is very time-consuming. (2) Historical maps and pictures offer visual and spatial quantitative land-cover information. (3) Natural archive has significant advantages as a method for reconstructing past vegetation and has its unique possibilities especially when historical records are missing or lacking, but it has great limits of rebuilding certain land-cover types. (4) Historical reconstruction models have been gradually developed from empirical models to mechanistic ones. The method does not only reconstruct the quantity of land use/cover in historical periods, but it also reproduces the spatial distribution. Yet there are still few historical land-cover datasets with high spatial resolution. (5) Reconstruction method based on multiple-source data and multidisciplinary research could build historical land-cover from multiple perspectives, complement the missing data, verify reconstruction results and thus improve reconstruction accuracy. However, there are challenges that make the method still in the exploratory stage. This method can be a long-term development goal for the historical land-cover reconstruction. Researchers should focus on rebuilding historical land-cover dataset with high spatial resolution by developing new models so that the study results could be effectively applied in simulations of climatic and ecological effects.     

A method to dynamically subdivide parcels in land use change models

Spatial simulation models have become a popular tool in studying land use/land cover (LULC) change. An important, yet largely overlooked process in such models is the land subdivision, which is known to govern LULC change and landscape restructuring to a large extent. To fill this gap, we propose an efficient and straightforward method to simulate dynamic land subdivision in LULC change models. Key features in the proposed method are implementing a hierarchical landscape where adjacent cells of the same LULC type form patches, patches form properties, and properties form the landscape and incorporating real subdivision layouts. Furthermore, we use a queue-based modified flood-fill algorithm to dynamically reset LULC patches following a subdivision. The proposed subdivision method is demonstrated in action using a prototype agent-based LULC model developed for an amenity landscape in Australia. Results show that it is computationally feasible to run the subdivision method even as spatial resolution is increased, thus providing a proven means for spatial simulation models to dynamically split parcel land.     

国际LUCC模型研究进展及趋势

LUCC模型有助于深刻理解土地利用系统动态.经过10多年的发展,LUCC模型在理论和实践方面有了很大发展.开发新一代LUCC模型成为了GLP的一项重要任务.在大量阅读分析国际上LUCC模型应用研究的基础上.基于土地利用变化与骄动力之间相互作用表征方法的差异,从认识论的角度出发,本文将LUCC模型概括为经验一统计模型、概念机理模型和综合模型,并分别对各类模型的概念、技术方法、应用以及存在的缺陷等进行了分析.发现各种模型均能够解决特定的LUCC问题,同时也存在着缺陷和局限性.目前,LUCC建模中仍存在着时空尺度和数据方面的问题,未来LUCC模型发展趋势主要表现在解决LUCC中多尺度问题,评价和解决空间领域效应和时间动态方而的问题,土地系统可持续性综合分析与建模等方面.     

岷江上游近50a土地覆被的变化趋势

本文的目的是通过典型区的研究，揭示我国西南山地系统土地利用/覆被变化的规律。本文通过对岷江上游大量历史材料和数据的分析确定：耕地大幅度增加和林地内部结构的剧变是50a来岷江上游土地利用/覆被变化的最主要特点。本文在对二者变化过程进行分析的基础上，总结了岷江上游山地系统土地利用/覆被变化的规律，有以下结论：（1）研究区土地覆被变化受山地自然条件控制，将继续以林地与草地为主体；（2）通达性的改善往往是山区土地利用/覆被大规模变化的开端；（3）土地覆被变化存在一个演替序列；（4）土地利用效益增长潜力较大的土地覆被类型快的速度增长。此结合可指导研究萄生态重建工作。     

METHODOLOGY: A SIMPLE RAINFALL SIMULATOR AND TRICKLE SYSTEM FOR HYDRO-GEOMORPHOLOGICAL EXPERIMENTS

A simple rainfall simulator is described which consists of stand-alone sprinkling units with cone jet nozzles that spray downward. With a fall height of 4.57 m and water pressure of 67 kPa, the median drop size of the simulated rainfall is 2.40 mm. Rainfall from two units irrigating a 2 by 2.5 m plot has a total kinetic energy of 0.57 J/m²/s which is approximately 90% of the equivalent energy of natural rainfall at the simulation intensity of 72.4 mm/h. To simulate overland flow, perforated trickle pipes were designed that permit overland flow rates to be readily adjusted and closely controlled by simply varying the input water pressure. In field experiments in southern Arizona, rates between 572 to 1400 cm³/s were generated from a 19-mm pipe. Given their low cost, simplicity, and portability, the rainfall simulator and trickle system should be attractive to researchers working in a wide variety of geomorphic environments.     

丹江中游典型小流域土壤总氮的空间分布

在丹江鹦鹉沟小流域, 利用网格状取样和典型样地取样相结合的方法, 进行土样采集, 共计采样点268 个, 测定土壤0~40 cm的总氮含量。应用传统统计学和地统计学的方法, 对不同深度下土壤总氮含量进行分析。结果表明:土壤总氮含量随土壤深度的增加而降低, 不同土层间土壤总氮含量存在显著差异(P < 0.01), 0~10 cm (A1)、10~20 cm (A2) 和20~40cm (A3) 土壤总氮含量平均值分别为0.85、0.47 和0.30 g/kg。3 个土层下, 总氮的最优模型均为线性模型, 具有中等空间相关性。经Kriging 插值分析, 不同土层下土壤总氮的空间分布呈带状格局。ANOVA 分析表明A1 和A2 层不同土地利用下土壤总氮含量存在显著差异(P <0.05), 不同土层下土壤总氮在不同坡度均存在显著差异(P < 0.05)。农地不同土层下土壤总氮含量与海拔、坡度和坡向均呈显著相关性(P < 0.01)。研究区0~40 cm土壤总氮储量为562.37t, 不同土地利用下0~40 cm 每平方米土壤总氮含量表现为林地>农地>草地, 分别为0.343、0.299 和0.289 kg/m²。     

China’s agricultural land use change and its underlying drivers: A literature review

Understanding the manifestations and underlying drivers of agricultural land use change in China is of great importance for both domestic and global food security.However,little is known about the holistic pattern of agricultural land use change across China,espe-cially from the perspective of intensity since the evidence has been gathered mainly through case studies at local levels.This study conducts a systemic review of agricultural land use change and its underlying drivers in China by aggregating 169 relevant case studies from 123 publications.The cases related to intensification and disintensification,which are the two types of agricultural land use change,are generally equal,accounting for 50％ of the total number of cases.Intensification and disintensification can be further divided into the same three categories:expansion/contraction of agricultural land,changes in agricultural land use activities and changes in land management intensity.Demographic,economic,technological,and institutional drivers,together with location factors,are frequently noted as significant underlying drivers,while sociocultural drivers and farm(er) characteristics are less frequently recognized.Finally,three major land use change trajectories are summarized mainly con-ceming rising labor costs and the concomitant increase in off-farm employment,the ecologi-cal improvement policy,and advances in agricultural technology.     

土地利用/土地覆被变化对大盈江流域径流的影响

为揭示大盈江流域土地利用/土地覆被变化对径流变化的影响,基于SWAT(Soil and Water Assessment Tool)模型,通过设置不同情景,定量分析了土地利用类型变化对流域内径流的影响。结果显示:(1)SWAT模型在大盈江流域径流模拟中具有较好的适用性,率定期的模型参数R2、Ens分别达到0.68、066,验证期的模型参数R2、Ens分别达到0.69、0.67;(2)大盈江流域月均径流量与土地利用类型关系密切:把农业用地变成林地或者草地,径流量均会减少,把林地变成草地径流量则会增加,农、林、草3种土地利用类型中产流由强到弱依次为农业用地、草地、林地。(3)2006~2015年,大盈江流域土地利用类型变化主要为农业用地和林地转化为草地,这种转变导致流域的月均径流量略有增加,增加的径流量主要是由林地转化为草地所致,且林地转化为草地引起的径流增加量强于农业用地转化为草地引起的径流减少量。     

考虑土地利用/覆被变化的集总式流域水文模型及应用

为了定量评估土地利用／覆被变化的水文水资源效应,提出考虑土地利用／覆被变化的集总式流域水文模型。该模型基于中国科学院土地资源分类系统的一级类型,将流域划分为6种不同土地利用及覆被变化类型;在每一类土地利用及覆被变化面积上,分别考虑蒸发和下渗的差异,并利用蓄满一超渗耦合产流模型计算该面积上的地表径流量和地面以下径流量;利用地貌汇流模型和线性水库模型将每类面积上的地表径流量和地面以下径流量演算至流域出El断面,从而得到流域的水文过程。模型参数包括流域地貌特征参数、产流参数和汇流参数,前者可以根据地理信息系统技术和遥感技术获得,而后者则需要根据流域的水文资料通过最优化方法求得。利用无定河流域1980-2000年的逐日降雨、蒸发及流量资料对该模型进行了参数率定与检验,率定期1986-2000年的水量平衡系数为0．999,年径流深合格率为100．0％;检验期1980-1985年的水量平衡系数为0．953,径流深合格率为83．3％,计算结果表明该模型在无定河流域具有良好的适应性。对模型产汇流参数进行合理性分析,得出无定河流域不同土地利用类型蒸发能力的相对大小关系为耕地〉林地〉草地〉未利用土地。     

Spatio-temporal dynamics of land cover and land surface temperature in Ganges-Brahmaputra delta: A comparative analysis between India and Bangladesh

Land use and land cover (LULC) change in the Ganges-Brahmaputra delta (GBD) poses significant challenges towards future environmental sustainability of the region and requires regional scale monitoring of key bio-physical variables and changes in their inter-relationship over space and time. Focusing on the southern part of the lower GBD region along the international border of India and Bangladesh, this study examined the spatio-temporal variability of LULC change and its relationship with Land Surface Temperature (LST). Furthermore, LULC-LST relationships were compared between Indian and Bangladesh part and its trend in and around big cities (with more than 1 million population) and towns (with more than 100,000 population) was investigated. Results showed that LST changes were predominantly driven by LULC changes on both sides of the border. Urban growth is the dominant form of LULC change, and the rate of land change was faster in 2005–2010 time period than 1989–2005. Over the period of 21 years, mean January LST decreased by approximately 1.83 °C in Indian part and 1.85 °C in the Bangladesh part. Areas that changed from to rural from agricultural experienced decrease in mean LST, whereas those areas that changed to urban from either agriculture or rural, experienced increase in mean LST. The relationship between LULC and LST are same on both sides of the Indo-Bangladesh border. In bigger cities like Kolkata (in India) and Khulna (in Bangladesh), there is a high spatial variability in relationship between LULC and LST compared to large towns. The LULC-LST relationship in large towns in India was influenced by proximity to Kolkata and coastal areas, whereas in Bangladesh no such influence was evident. The results and the data produced in this study are crucial for monitoring LULC changes, for developing spatial decision support system, and thus will be helpful to address the current challenges of land management in the GBD region. Changes in the LULC and LST are important indicators of GBD's environmental health and access its vulnerability and thus the present findings serve as baseline information for future studies seeking to examine the impact of differential policies on the LULC change in the region.     

北京地区土地利用/覆盖变化研究

本文利用1975、1984、1991和1997的LandsatTM/MSS数据,对北京地区改革开放以来22年的土地利用/覆盖变化进行了研究。结果表明从1975～1997年,北京地区发生了快速城市化背景下的大规模土地利用/覆盖变化,表现出城镇用地通过大量占用平原区耕地扩展,非城镇用地间结构变化明显的基本特征。同时土地利用/覆盖变化区域差异明显,近郊区和远郊区的土地利用/覆盖变化强度发生了逆转,远郊区土地利用/覆盖变化强度在90年代已经超过近郊区,而且该区高密度城镇用地的重心也向西北方向发生了一定程度的移动,显示出同期北京城镇用地向西北方向扩展的趋势     

The climatic impacts of land use and land cover change compared among countries

Land use and land cover change (LULCC) strongly influence regional and global climate by combining both biochemical and biophysical processes. However, the biophysical process was often ignored, which may offset the biogeochemical effects, so measures to address climate change could not reach the target. Thus, the biophysical influence of LULCC is critical for understanding observed climate changes in the past and potential scenarios in the future. Therefore, it is necessary to identify the mechanisms and effects of large-scale LULCC on climate change through changing the underlying surface, and thus the energy balance. The key scientific issues on understanding the impacts of human activities on global climate that must be addressed including: (1) what are the basic scientific facts of spatial and temporal variations of LULCC in China and comparative countries? (2) How to understand the coupling driving mechanisms of human activities and climate change on the LULCC and then to forecasting the future scenarios? (3) What are the scientific mechanisms of LULCC impacts on biophysical processes of land surface, and then the climate? (4) How to estimate the contributions of LULCC to climate change by affecting biophysical processes of land surface? By international comparison, the impacts of LULCC on climate change at the local, regional and global scales were revealed and evaluated. It can provide theoretical basis for the global change, and have great significance to mitigate and adapt to global climate changes.     

Simulated effect of soil freeze-thaw process on surface hydrologic and thermal fluxes in frozen ground region of the Northern Hemisphere

Soil freeze-thaw process is closely related to surface energy budget,hydrological activity,and terrestrial ecosystems.In this study,two numerical experiments(including and excluding soil freeze-thaw process)were designed to examine the effect of soil freeze-thaw process on surface hydrologic and thermal fluxes in frozen ground region in the Northern Hemisphere based on the state-of-the-art Community Earth System Model version 1.0.5.Results show that in response to soil freeze-thaw process,the area averaged soil temperature in the shallow layer(0.0175?0.0451 m)decreases by 0.35℃in the TP(Tibetan Plateau),0.69℃in CES(Central and Eastern Siberia),and 0.6℃in NA(North America)during summer,and increases by 1.93℃in the TP,2.28℃in CES and 1.61℃in NA during winter,respectively.Meanwhile,in response to soil freeze-thaw process,the area averaged soil liquid water content increases in summer and decrease in winter.For surface heat flux components,the ground heat flux is most significantly affected by the freeze-thaw process in both summer and winter,followed by sensible heat flux and latent heat flux in summer.In the TP area,the ground heat flux increases by 2.82 W/m2(28.5%)in summer and decreases by 3.63 W/m2(40%)in winter.Meanwhile,in CES,the ground heat flux increases by 1.89 W/m2(11.3%)in summer and decreases by 1.41 W/m2(18.6%)in winter.The heat fluxes in the Tibetan Plateau are more susceptible to the freeze-thaw process compared with the high-latitude frozen soil regions.Soil freeze-thaw process can induce significant warming in the Tibetan Plateau in winter.Also,this process induces significant cooling in high-latitude regions in summer.The frozen ground can prevent soil liquid water from infiltrating to deep soil layers at the beginning of thawing;however,as the frozen ground thaws continuously,the infiltration of the liquid water increases and the deep soil can store water like a sponge,accompanied by decreasing surface runoff.The influence of the soil freeze-thaw process on surface hydrologic and thermal fluxes varies seasonally and spatially.     

地理加权回归在区域土地利用格局模拟中的应用——以常州市孟河镇为例

以江苏省常州市新北区孟河镇为研究区,在土地利用格局模拟的回归建模中考虑驱动因子对土地利用格局影响的空间不稳定性,实现基于地理加权的回归分析模型,并与基于全局最小二乘法(OLS)的Logistic回归模型进行比较。研究结果表明,运用地理加权回归(GWR)的建模方法,不但可以获得更好的拟合优度和更高的拟合准确率,而且可以获得各驱动因子对土地利用格局影响的空间分异特征。同时,研究结果也可以为孟河镇及其类似地区的土地利用规划决策提供科学依据。     

流域LUCC水文效应研究中的若干问题探讨

随着全球变化研究的深入,土地利用/覆被变化(LUCC)的水文效应研究日益成为热点问题。综合国内外研究进展,论文就流域土地利用/覆被变化水文效应研究中的几个问题进行了总结和探讨：子流域和水文响应单元是分布式水文模型对流域基本空间单元的理想划分;对国内外现有的土地利用分类系统进行了适当的调整和归并,建立了基于水文响应研究的土地利用分类系统,将土地利用分为9个Ⅰ级类和21个II级类;土地利用/覆被变化情景分析的常用方法有参照对比法、历史反演法、模型预测法、极端土地利用法、土地利用空间配置法等。     

榆林地区脆弱生态环境的景观格局与演化研究

作为干旱半干旱区农牧交错带的典型代表,榆林地区在自然地理上有其独特的空间分布格局,在生态上具有显著的脆弱生境特征和演化规律。本文运用景观生态学的基本理论与方法,选取分维数、形状指数和景观优势度等指标,对该区脆弱环境的景观格局进行了分析,同时对诱发该区景观生态演化的因素进行了定量诊断,并对区域生态环境的景观过程进行了探讨。     

紫荆关流域下垫面变化对洪水的影响

选择大清河水系的紫荆关流域为研究区,分析了其下垫面变化趋势,根据大清河水系的水文气象特点,建立了考虑下垫面变化的超渗-蓄满耦合产汇流模型,并利用实测暴雨洪水资料进行了参数率定和模型验证.利用该模型研究了流域洪水对下垫面变化的响应.结果表明:下垫面变化导致洪峰和洪量变小,其对大洪水影响小,对中小洪水影响较大.对于10年一...     

干旱区典型流域近30年土地利用/土地覆被变化的分形特征分析——以玛纳斯河流域为例

利用1976、1989、2005年三期遥感影像,运用GIS和分形理论研究干旱区典型流域——玛纳斯河流域近30年的土地利用/土地覆被变化的复杂性和稳定性。结果表明:玛纳斯河流域各时段的土地利用/土地覆被类型分布具有分形结构,土地利用/土地覆被类型形状复杂性和斑块的稳定性波动变化,1976、1989、2005年三时期的各种土地利用/土地覆被类型总平均分维值分别为1.394 0、1.363 4和1.389 9。总平均稳定性指数分别为0.606 0、0.636 6、0.610 1。三期土地利用/覆被类型平均稳定性排序为:沙地>未利用土地>居民点工矿用地>水域>林地>草地>耕地>盐碱地。耕地、林地、草地、盐碱地稳定性相对较差。通过对流域土地利用/土地覆被类型变化复杂性和稳定性的研究,可以为政府协调水土开发和调整土地利用结构提供支持。     

中国西部地区历史草地面积重建的方法——以甘宁青新区为例

历史草地面积重建作为历史土地利用与土地覆被变化研究的重要组成部分,可为区域乃至全球环境变化研究提供重要的基础数据。但受研究客体特性与重建资料多寡的制约,目前无论是数量估算上还是空间格局重建上均非常薄弱。本文试图在客观把握中国西部地区历史草地变化趋势与特征的基础上,利用现代遥感土地利用数据和潜在植被数据,确定土地垦殖前草地植被潜在分布范围;并结合历史耕地网格数据,构建以间接扣减为核心的草地面积重建方法;重建甘肃、宁夏、青海和新疆等省区过去300年的草地网格数据。结果表明：土地垦殖前,案例区草地覆被率高达40.87%。受土地垦殖的影响,在过去300年草地面积呈持续减少的态势。草地面积由1661年的1.11亿 hm²下降到1980年的1.03亿 hm²,并经历了1661—1724年的急剧减少、1724—1873年的缓慢减少和1873—1980年的快速减少三个时段,草地年均减少量分别为4.76万 hm²、0.75万 hm²和3.38万 hm²。在空间上,研究时段内草地垦殖区呈现出由甘肃、宁夏向青海、新疆转移的特点。以历史文献资料和1980年遥感草地网格数据为基础,对重建的草地数据开展了可靠性评估。评估显示,重建结果能够较好的再现草地变迁过程。本文构建的重建方法可被用于中国西部地区长时段的草地面积重建。