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1.
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. 相似文献
2.
Detecting land-use change has become of concern to environmentalists, conservationists and land use planners due to its impact on natural ecosystems. We studied land use/land cover (LULC) changes in part of the northwestern desert of Egypt and used the Markov-CA integrated approach to predict future changes. We mapped the LULC distribution of the desert landscape for 1988, 1999, and 2011. Landsat Thematic Mapper 5 data and ancillary data were classified using the random forests approach. The technique produced LULC maps with an overall accuracy of more than 90%. Analysis of LULC classes from the three dates revealed that the study area was subjected to three different stages of modification, each dominated by different land uses. The use of a spatially explicit land use change modeling approach, such as Markov-CA approach, provides ways for projecting different future scenarios. Markov-CA was used to predict land use change in 2011 and project changes in 2023 by extrapolating current trends. The technique was successful in predicting LULC distribution in 2011 and the results were comparable to the actual LULC for 2011. The projected LULC for 2023 revealed more urbanization of the landscape with potential expansion in the croplands westward and northward, an increase in quarries, and growth in residential centers. The outcomes can help management activities directed toward protection of wildlife in the area. The study can also be used as a guide to other studies aiming at projecting changes in arid areas experiencing similar land use changes. 相似文献
3.
Li Guodong Zhang Junhua Mirzaei Parham A. Ding Shengyan Ding Yapeng Liu Man 《地理学报(英文版)》2020,30(12):2015-2032
Journal of Geographical Sciences - Land use and land cover (LULC) alteration has changed original energy balance and heat fluxes between land and atmosphere, and thus affects the structure... 相似文献
4.
地表过程对全球变化的响应和反馈是地球系统科学研究的核心课题之一,目前的研究多关注全球变化对地表过程的影响,而地表动态过程对地表生物物理过程及气候的反馈研究较少。系统认识地表物候动态对生物物理过程及气候的反馈对深化地球系统科学研究有着重要的意义。本文从农业物候动态的事实、农业物候动态在陆面过程模型中的参数化表达、农业物候动态对地表生物物理过程及气候的反馈等方面进行综述,发现在气候变化和管理措施影响下,以种植期和灌浆期为代表的农业物候期发生了显著的规律性变化;耦合农业物候动态,改善了模型对地表动态过程、生物物理过程和大气过程的数字化表达;农业物候变化对地表净辐射、潜热、感热、反照率和气温、降水、环流等过程产生了影响,并表现出以地表能量分配为主的气候反馈机理。针对农业物候动态对地表生物物理过程及气候效应的时空重要性,需要继续开展以下方面的工作：① 加强全球变化对地表物候动态的影响及其反馈的综合研究;② 不同光谱波段地表反射率与农业物候动态的关系研究;③ 农业物候动态引起的作物生理学特征变化在地表生物物理过程中的贡献;④ 重视不同气候区物候动态对气候反馈效应的差异。 相似文献
5.
Using ASTER(Advanced Spaceborne Thermal Emission and Reflection Radiome-ter) infrared remote sensing data we inversed the parameters of urban surface heat fluxes applying the PCACA model and theoretical position algorithm,and then we analyzed the in-fluence of different land use types on the surface heat fluxes and energy balance.In this study,Kumagaya,a city in Saitama Prefecture,Japan,was selected as the experimental area.The result shows that the PCACA model is feasible for the surface heat fluxes estimation in urban areas because this model requires less parameters in the procedure of heat fluxes estimation in urban areas with complicated surface structure and can decrease the uncertainty.And we found that different land-use types have indicated the height heterogeneity on the surface heat fluxes significantly.The magnitudes of Bowen ratio in descending order are industrial,residential,transportation,institutional,dry farmland,green space,and water body.Under the same meteorological condition,there are distinct characteristics and regional differences in Bowen ratios among different surface covers,indicating higher sensible heat flux and lower latent heat flux in the urban construction land,while lower sensible heat flux and higher latent heat flux in the vegetation-covered area,the outskirt of the urban area.The increase of urban impervious surface area caused by the urban sprawl can enlarge the sensible heat flux and the Bowen ratio,so that it causes the increasing of urban surface temperature and air tem-perature,which is the mechanism of the so-called heat island effect. 相似文献
6.
Rohan Wickramasuriya Laurie A. Chisholm Marji Puotinen Nicholas Gill Peter Klepeis 《International journal of geographical information science》2013,27(8):1497-1513
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. 相似文献
7.
Land change was assessed in the Albertine rift region (ARR) using its central section of north-western Rwanda as case study. This region is one of Africa's most ecologically sensitive environments under severe pressure from human activities. The study maps and quantifies the spatial extent of land use-land cover (LULC) changes between 1987 and 2016 from Landsat images. Transitions between five major land classes were identified in order to understand the trajectory of observed changes. In terms of gains, the forest class, the urban built-up and bare land class increased by 9% and 4% respectively over the study period. The gains of forest were mainly derived from the afforestation of some agricultural lands in the southern part, whereas the gains of built-up and bare lands were mostly from cultivated land which was a net losing class. Forest increase is in line with government's policy to increase the national forest cover to 30% by 2020. Forest losses occurred mostly outside protected areas due to land conversion for settlement and agricultural purposes. Much needed information about changes in LULC over the last three decades is provided. This study demonstrates in a timely manner how to analyse and monitor LULC change and the drivers in an environment where field based research is a challenge due to the mountainous terrain. The ecological richness of the region, which coincides with heightened human population pressure, necessitates the monitoring of land change as input for improving land use planning with focus on conserving biodiversity. 相似文献
8.
近20 a来,中国西北地区尤其是新疆降水显著增加、温度持续上升,冰川萎缩、冰川融水量持续增加、河川径流量增加、湖泊水位上升面积扩大、植被覆盖有增加迹象等等,这些事实都充分说明该地区的气候水文过程正在发生着重大的变化,但目前由于与水热过程有关的各个分量,如潜热、感热、蒸散、土壤湿度和径流等变量都缺少长时间、大范围的观测数据,因此,现有的研究还不能从整体上认识西北地区水热过程在全球增暖大背景下的变化特征和规律,无法客观地估算该地区水热过程的可能变化趋势。为了能够进一步深入研究这个问题,我们考虑以新疆地区108站1960—2004年气象站的观测数据为基础,并结合其他大气驱动场中结果检验的辐射数据来建立了一个长达45 a,时间分辨率3 h,空间分辨率0.5°×0.5°针对新疆区域的陆面模型大气驱动场,主要的变量包括降水、气温、风速、气压、比湿和辐射。最后得到的产品能够提供一个长期的、区域内具有良好均一性的近地面气象变量数据集,它可以用于驱动陆面、水文、生态过程模式,为研究整个新疆地区年际、年代际,甚至月季到日的连续水热过程变化奠定坚实的基础,并可以作为评估耦合模型以及其他陆面预测计划的初始化条件。 相似文献
9.
城市化发展,特别是下垫面特征的改变,对大气环境的外强迫是当前大气环境领域研究的热点问题。下垫面特征变化导致不同尺度气象场发生变化,而气象条件又决定着大气污染物的迁移转化。为了深入探讨这个问题,文章首先从3个方面总结了相关研究：1）城市气候的基本特征及其形成的内在机制;2）不同尺度下的城市污染气象学特征;3）定量描述城市下垫面地-气作用模式的相关进展。之后进一步综述了利用数值模式方法模拟城市化过程中下垫面变迁对大气环境（包括气象条件及空气质量）影响方面的研究进展。最后利用中尺度大气模式WRF/Chem和过程分析方法研究了中国东部地区城市下垫面扩张对臭氧（O3）和一氧化碳（CO）空间分布的影响。模拟结果显示：在人为源排放不变的情况下,城市下垫面扩张使得近地面和1~3 km高处的O3,以及距地面1~2 km高处的CO体积分数增大;但近地CO体积分数下降。 相似文献
10.
Accurate information on land use and land cover (LULC) is critical for policy decisions especially for management of land and water resources’ activities in large river basins around the world. Phenology based LULC classification is the most promising approach particularly in the areas with diversified cropping patterns. Sometimes in large river basins, local climate and topography provides two different phenological information sets for the same crops in the same season. Based on accurate phenological information of the main crops in spatially segregated units, the remote sensing based classification was used to map the LULC changes for a period of 2003–2013 in the Kabul River Basin (KRB) of Afghanistan. We used remotely sensed Normalized Difference Vegetation Index (NDVI) products of Moderate-resolution Imaging Spectroradiometer (MODIS) from Terra (MOD13Q1) and Aqua (MYD13Q1) with 250 m spatial resolution for this study. The overall accuracy (mean) of the LULC classification throughout the study period was around 68.15% ± 9.45while the producer and user accuracies (mean) were 75.9 ± 11.3% and 76.4 ± 11.2%, respectively. Results show that the cropping patterns vary significantly in the spatially disaggregated units. From 2003 till 2013, the ground coverage of wheat, barley and rice was increased by 31%, 7% and 32%, respectively. Overall, there has been only 2% increment in the agricultural area across the KRB between 2003 and 2013. This relatively increased trend of land cover change has taken place as a result of partial improvement in political stability as well as investment in irrigation infrastructure and agricultural development in the region. This study further provides insight to develop new agriculture strategies in order to maintain the ecosystem required to fulfil the rising food demands. 相似文献
11.
Chandra Kant Pawe 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2018,118(1):88-100
Unplanned urban growth, particularly in developing countries has led to changes in land use/land cover (LULC). Numerous Indian cities face problems of unplanned LULC change due to nominal or non-existent planning efforts compounded by rapid urban population growth. The Guwahati Metropolitan Area (GMA) is one such urban centre. The present study assesses the trajectories of LULC change using Landsat imageries acquired in 1976, 1989, 2002 and 2015. Natural and semi natural vegetated area and artificial and natural water bodies decreased while built-up areas, cultivated and managed areas, and natural and semi natural non-vegetated areas increased. The built-up area increased from 23.9 in 1976 to 115.1 km2 in 2015 becoming the dominant land cover class accounting for 41.8% of the total geographical area. During this period, natural and semi natural vegetated land were reduced by 88.9 km2 at an annual rate of 2.2 km2. Over the years there was an increasing trend of built-up land and cultivated and managed areas in the peripheral areas of the city while natural and semi natural vegetated land diminished. Consequently, as in many other developing countries, there is an urgent need for the governmental authorities and other stakeholders to implement effective urban planning policies. 相似文献
12.
This study examines the changes in climate and land-use/land-cover (LULC) along the livestock seasonal migration routes in El Gedaref region (eastern Sudan). Analysis of temperature, rainfall and aridity index (ratio of rainfall to reference evapotranspiration) data during 1941–2009 shows significant warming of the climate, increasing rainfall variability and seasonality, and intensifying aridity conditions during the start and end of the wet season. The somewhat recent enhancement of the overall (annual) rainfall has reflected only in the mid wet season and were caused by few very wet days, indicating increased rainfall concentration and possible risk of soil erosion. Such climatic alterations and variability have inherent implications for land-use and land-cover over the region. LULC changes were investigated using multi-temporal satellite imagery from three sites along the livestock routes. The major trends were drastic conversions of natural vegetation areas into large-scale mechanized agricultural land. This resulted in a progressive loss and degradation of grazing area in the entire region. Overall, the documented LULC changes may cause an irreversible loss of biodiversity and a depletion of other ecological services provided by natural vegetation. The results of this study provide useful information when seeking to resolve complex land-management issues. 相似文献
13.
The extensive alteration of the earth's land cover during the anthropocene had widespread, and in some cases unknown, effects on terrestrial and atmospheric conditions and processes. Predicting future changes to the earth system therefore mandate a future-predicting framework of land use dynamics. However while future-predicting earth surface and atmospheric models tend to explicitly incorporate projected climatic conditions they all but ignore or overly simplify land use dynamics. As most surface and atmosphere dynamics models use gridded input datasets, and land use is a highly spatially-dynamic phenomena, a need clearly arise for spatially explicit representation of future land use dynamics. While a number of such datasets exists at regional and country scales, no fully gridded future-predicting global land use model and database has been reported to date. Here we present the Global Land Use Dynamics Model (GLUDM), a gridded and temporally explicit agricultural land use predictor. GLUDM calculates the relative area of a land use category (e.g. cropland) in each grid-cell by generating unique regression coefficients in each grid-cell based on local historic trends and global population dynamics. Spatial expansions or abandonment of agricultural land is simulated by propagating excesses or deficiencies in agricultural areas between neighboring grid-cells. This spatial connectivity is restricted by topographic, latitudinal and urban characteristics. A validation analysis shows that GLUDM corresponds well to observed land use distribution. GLUDM-predicted global cropland area dynamics between 2005 and 2100 are described herein. Globally, 18% increase in cropland area is predicted between 2005 and 2050 which corresponds very well to previous estimations. Following 2050, a general decrease in cropland area is predicted. The results reveal new insights about global cropland dynamics, demonstrating, for example, that changes in its spatial distribution will be highly heterogeneous, at both micro and macro scales, in some locations worldwide. 相似文献
14.
The most important climatological feature of the South Asian region is the occurrence of monsoons.With increasing concerns about climate change,the need to understand the nature and variability of such climatic conditions and to evaluate possible future changes becomes increasingly important.This paper deals with long-term above and below normal monsoon precipitation causing prolong meteorological droughts and floods in India.Five regions across India comprising variable climates were selected for the study.Apart from long-term trends for individual regions,long-term trends were also calculated for the Indian region as a whole.The results show that intra-region variability for monsoon precipitation is large and there are increasing numbers of meteorological summer droughts.Meteorological monsoon floods were found to have negative long-term trends everywhere except in the peninsular Indian region.The results overall suggest generic conclusions concerning the region-wide long-term trend of severity of monsoon droughts and floods in India and their spatial variability. 相似文献
15.
《自然地理学》2013,34(2):121-139
Using a hydrologic model to estimate daily soil moisture at 258 evaluation locations over a 30-year period, the spatial variability and persistence of soil moisture across Oklahoma is examined. The Soil and Water Assessment Tool (SWAT) uses readily available meteorological inputs with detailed land surface information. Spatial variability of soil moisture across Oklahoma is extremely dynamic and exhibits a remarkable range of individual characteristics due to the heterogeneous land surface. An autocorrelation analysis is used to evaluate the persistence of soil moisture at each evaluation location. In general, soil moisture across Oklahoma persists from 5 to 10 weeks in the eastern portion of Oklahoma to over 30 weeks in western Oklahoma as a result of the large-scale climatic variability of precipitation supply and evapotranspiration demand. However, the lags are not spatially coherent due to the heterogeneity of the land surface. Land surface characteristics potentially influencing the persistence of soil moisture across Oklahoma are examined, including vegetation type and soil texture and depth. Of the three parameters, soil depth plays a significant role in the memory of soil moisture conditions. As the soil profile depth increases, a corresponding increase in the persistence of soil moisture occurs. 相似文献
16.
THE ROLE OF ATMOSPHERIC CIRCULATION PATTERNS IN AGROCLIMATE VARIABILITY IN FINLAND, 1961–2011 
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下载免费PDF全文 MASOUD IRANNEZHAD DELIANG CHEN BJØRN KLØVE 《Geografiska Annaler: Series A, Physical Geography》2016,98(4):287-301
This study evaluates interannual variations and trends in growing season daily temperature sum and daily precipitation sum in Finland during 1961–2011, and their connections to well known atmospheric circulation patterns. Changes in summer (June–August) climate partially explain changes in growing season daily temperature sum and daily precipitation sum over Finland, which naturally decreased from south to north. On a national scale, growing season warmed and became wetter during 1961–2011, as growing season daily temperature sum and daily precipitation sum significantly (p < 0.05) increased by 5.01 ± 3.17°C year–1 and 1.39 ± 0.91 mm year–1, respectively. The East Atlantic pattern was the most influential atmospheric circulation pattern for variations in growing season daily temperature sum (rho = 0.40) across Finland and the East Atlantic/West Russia pattern was most influential for growing season daily precipitation sum variability (rho = –0.54). There were significant (p < 0.05) increasing trends in growing season daily temperature sum and daily precipitation sum throughout Finland during 1961–2011. Increased growing season daily temperature sum was mainly observed in northern, central, western, eastern and coastal areas of south‐western Finland. This warming was positively associated with the East Atlantic pattern in the north, centre and south, but negatively associated with the East Atlantic/West Russia pattern in eastern Finland. Increased GSP mostly occurred in southern, eastern, western, central, northern and north‐western Finland. These wetting trends were positively correlated with the East Atlantic pattern in the north and negatively correlated with the Polar pattern in the south and the East Atlantic/West Russia pattern in the east, west, centre and north‐east of Finland. The overall agroclimatic year‐to‐year variability in Finland between 1961 and 2011 was mostly linked to variations in the East Atlantic and East Atlantic/West Russia patterns. 相似文献
17.
Data from 40 meteorological stations have been used in investigating the changes of the precipitation regime on the territory of Azerbaijan during 1991–2006. It is shown that ubiquitous warming in most of the territory of the Republic is accompanied by a decrease of the annual mean amount of atmospheric precipitation, mainly through a reduction in precipitation during a warm period (April–October). 相似文献
18.
Trevor Fuller PhD student 《The Professional geographer》2013,65(2):272-274
A relatively simple modeling approach for estimating spatially distributed surface energy fluxes was applied to two small watersheds, one in a semi-arid climate region and one in a sub-humid region. This approach utilized a combination of ground-based meteorological data and remotely sensed data to estimate ‘instantaneous’ surface energy fluxes at the time of the satellite or aircraft overpasses. The spatial resolution in the watershed grid cells, which was on the order of 100-400 km, was selected to be compatible with ground measurements used for validation. The model estimates of surface energy fluxes compared well with ground-based measurements of surface flux (typically within approximately 40 Wm?2). The model accuracy may be slightly less for bare soil surfaces due to an overestimation of the soil heat flux. In addition to demonstrating the feasibility of computing spatially distributed values of surface energy fluxes, these maps were used to qualitatively infer the dominant factors controlling the energy fluxes for the time period shortly following precipitation events in the basins. For the semi-arid watershed, values of sensible heat flux varied considerably over the watershed and displayed a pattern very similar to that of the spatially variable cumulative precipitation for at least one to eight days prior to the image acquisition. Due to the large fraction of exposed bare soil in a semi-arid ecosystem, even very small precipitation events had a strong influence on the pattern of sensible heat fluxes observed shortly after the event (less than 24 hours). For the sub-humid watershed, the fluxes tended to be more uniform across the watershed, and were influenced by a combination of precipitation total and land cover type. 相似文献
19.
蒸散是地球表层物质循环与能量交换过程的重要组成部分,了解其时空特征和影响因素具有重要的科学意义。以鄱阳湖流域为研究区,基于WaSSI-C生态水文模型,利用气象数据、叶面积指数数据和土壤数据等估算1983-2011年鄱阳湖流域蒸散,分析其时空特征,并通过情景模拟定量分析植被恢复和气候变化对蒸散的影响。研究表明：鄱阳湖流域蒸散多年均值变化范围为741~914 mm/a,植被和降水量分布是造成流域蒸散空间差异的主要原因;近三十年来鄱阳湖流域蒸散呈阶段性增长趋势,增长率为1.495 mm/a;植被、气温和降水对鄱阳湖流域蒸散的单独影响均为正向,但气温和降水的联合效应会导致蒸散下降;鄱阳湖流域蒸散变化的主导因素具有空间差异性,从整体上看,植被恢复是驱动蒸散呈增加趋势的主要原因,而气候变化是导致蒸散年际波动的主要原因。 相似文献
20.
东亚土地覆盖动态与季风气候年际变化的关系 总被引：7，自引：1，他引：7
以东亚地区1982－1989年时间序列降水资料及AVHRR 8km NDVI数据为基本数据源，应用地理信息系统技术，分别研究了东亚地区夏季（5－9月）降水及土地覆盖的年际变化，并揭示了研究时间段内各自的变化规律。进一步用奇异值分解（SVD）模型方法分析了以降水变化为表征的东亚地区气候年际变化与土地覆盖年际变化之间的关系。 相似文献