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全球变化下地表反照率研究进展 总被引：12，自引：0，他引：12
地表反照率表征地球表面对太阳辐射的反射能力,决定着地表与大气之间辐射能量的分配过程,是影响地球气候系统的关键变量。在全球变化日益突出的今天,地表反照率与全球变化的相互影响机制已经成为地球科学研究领域的热点问题之一。地表反照率的细微变化,会影响到地气系统的能量收支平衡,进而引起区域以至全球气候变化。详细介绍地表反照率影响... 相似文献
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Precipitation runoff is a critical hillslope hydrological process for downslope streamflow and piedmont/floodplain recharge. Shimen hillslope micro‐catchment is strategically located in the central foothill region of Taihang Mountains, where runoff is crucial for water availability in the piedmont corridors and floodplains of north China. This study analyzes precipitation‐runoff processes in the Shimen hillslope micro‐catchment for 2006–2008 using locally designed runoff collection systems. The study shows that slope length is a critical factor, next only to precipitation, in terms of runoff yield. Regression analysis also shows that runoff is related positively to precipitation, and negatively to slope length. Soil mantle in the study area is generally thin and is therefore not as critical a runoff factor as slope length. The study shows a significant difference between overland and subsurface runoff. However, that between the 0–10 and 10–20 cm subsurfaces is insignificant. Runoff hardly occurs under light rains (<10 mm), but is clearly noticeable under moderate‐to‐rainstorm events. In the hillslope catchment, vertical infiltration (accounting for 42–84% of the precipitation) dominates runoff processes in subsurface soils and weathered granite gneiss bedrock. A weak lateral flow (at even the soil/bedrock interface) and the generally small runoff suggest strong infiltration loss via deep percolation. This is critical for groundwater recharge in the downslope piedmont corridors and floodplains. This may enhance water availability, ease water shortage, avert further environmental degradation, and reduce the risk of drought/flood in the event of extreme weather conditions in the catchment and the wider north China Plain. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Changes in potential evapotranspiration and surface runoff in 1981–2010 and the driving factors in Upper Heihe River Basin in Northwest China 
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下载免费PDF全文 Changes in potential evapotranspiration and surface runoff can have profound implications for hydrological processes in arid and semiarid regions. In this study, we investigated the response of hydrological processes to climate change in Upper Heihe River Basin in Northwest China for the period from 1981 to 2010. We used agronomic, climatic and hydrological data to drive the Soil and Water Assessment Tool model for changes in potential evapotranspiration (ET0) and surface runoff and the driving factors in the study area. The results showed that increasing autumn temperature increased snow melt, resulting in increased surface runoff, especially in September and October. The spatial distribution of annual runoff was different from that of seasonal runoff, with the highest runoff in Yeniugou River, followed by Babaohe River and then the tributaries in the northern of the basin. There was no evaporation paradox at annual and seasonal time scales, and annual ET0 was driven mainly by wind speed. ET0 was driven by relative humidity in spring, sunshine hour duration in autumn and both sunshine hour duration and relative humility in summer. Surface runoff was controlled by temperature in spring and winter and by precipitation in summer (flood season). Although surface runoff increased in autumn with increasing temperature, it depended on rainfall in September and on temperature in October and November. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Juana Mireya Mendoza-Vera Samba K Corinne Cuoc Marc Bouvy Marc Pagano 《Estuarine, Coastal and Shelf Science》2008,79(4):740-750
Pseudodiaptomus hessei is a key species in many water bodies in the Senegal River hydrosystem but it became rare or completely disappeared from two ecosystems (Lake Guiers and Dakar Bango Reservoir; Senegal, West Africa) after major hydrological changes caused by human action, mainly impoundments on the river in 1985, and the opening of a new estuary mouth in 2003. Kâ et al. [Kâ, S., Pagano, M., Ba, N., Bouvy, M., Leboulanger, C., Arfi, R., Thiaw, O.T., Ndour, E.H.M., Corbin, D., Defaye, D., Cuoc, C., Kouassi, E., 2006. Zooplankton distribution related to environmental factors and phytoplankton in a shallow tropical lake (Lake Guiers, Senegal, West Africa). International Review of Hydrobiology 91(5), 389–405] put forward several hypotheses to explain the reasons for this decline: salinity and chemical changes in the water, predation by a cyclopid predator Mesocyclops ogunnus and/or the inhibiting effects of cyanobacteria and/or diatoms (allelopathy). This study assessed these hypotheses by studying the distribution of P. hessei in 13 stations (including the Dakar Bango reservoir and Lake Guiers) in relation to physical, chemical and biological (phyto- and zooplanktons) factors at each station. We produced a distribution pattern for this species in the Senegal River hydrosystem. Rank correlations and principal component analysis showed that P. hessei was not correlated with conductivity but was positively correlated with pH and alkalinity, suggesting chemical effects. The clear association with two filamentous cyanobacteria (Cylindrospermopsis raciborskii and Anabaena sp.) did not appear to support the hypothesis of cyanobacteria inhibition but blooming conditions were never encountered during the study. Negative correlation with diatoms (especially with Fragilaria sp.) suggested that aldehyde producing diatoms had a negative effect. Negative correlations with cyclopids such as Mesocyclops supported the hypothesis of cyclopid predation to explain the decline of P. hessei. This study proposes several lines of research for future studies to test these hypotheses. 相似文献
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Juana María Sanz Ángel de Miguel Irene de Bustamante Alberto de Tomás José Luis Goy 《Environmental Earth Sciences》2014,71(1):13-21
Conventional water treatments when downsized to cover the demands of small and scattered populations are costly and ineffective. In fact, many small towns cannot afford the high average treatment costs nor provide the skill and complex management requirements. Even when these facilities are available, waste water might not be properly treated. Land application system treatments (LAST) have been shown to be preferable on the basis of their technical effectiveness and financial viability. The recently approved Spanish regulations (RDL 1620/2007, pp 50369–50661) represent an opportunity for the implementation of well-designed LASTs. This paper presents an assessment methodology for the design of LASTs by combining technical, financial and location criteria. The method is applied to the design of LASTs to cover the water disposal demand of twelve municipalities located within the protected natural landscape, and surrounding areas of ‘El Rebollar’, Salamanca, Spain. 相似文献
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Juana P Moiwo 《东北亚地学研究》2006,9(1):80-93
IntroductionNever before hasit beensotrue than now,thatlandis ali mitedresource.Population growth and as-sociated human activities,especially agricultureacross the world have not only led to land degrada-tion,but soil loss at rates that have pushed arablesoils to frontier thresholds.In the absence of arablesoil,the human environment would cease to groworeven demise(Ramet al.,2006).Studies haveshownthat in many regions of the world,runoff andsoil erosion differ withland-use type.Judson(1965)re… 相似文献
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Water storage depletion is an increasing hydrological threat to agricultural production and social stability across the globe. It is fast approaching threshold levels especially in arid/semiarid regions with low precipitation and excessive evapotranspiration (ET). This study analyses water storage dynamics in the North China Region (NCR) – an important grain‐production base in China. It uses monthly Gravity Recovery and Climate Experiment (GRACE), Global Land Data Assimilation System (GLDAS) and field‐measured precipitation data products for 2002–2009. The datasets are analysed in a basin‐scale water balance equation to determine the state of storage in the NCR study area. Based on the validated satellite‐based data products with field‐measured values, average error/bias in the datasets is <10%. The analysis also shows favourable agreements among the GRACE‐derived and flux‐based storage changes at various temporal scales. Whereas the amplitudes and phases of the precipitation and ET fluxes are largely stable for 2002–2009, those of GLDAS runoff and GRACE total water storage anomaly apparently narrow out. The linear trends in the monthly, seasonal and annual storage changes are negative for the study period, suggesting storage loss. There is an apparent seasonality of storage change in the study area; with summer storage gain, winter storage loss and an overall storage loss that is on the average of 16.8 mm/yr. Storage loss is most severe in the central floodplain region (the main irrigated production zone) of the study area. Storage depletion in this important agro‐based semi‐arid region could have negative implications for the millions of people in the region and beyond in terms of water supply, crop production, food security and social stability. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Mercedes Muoz Juana Sagredo Cristina de Ignacio Javier Fernndez-Surez Teresa E. Jeffries 《Lithos》2005,85(1-4):140-153
Zircons from a nepheline-syenite of the Fuerteventura Basal Complex were dated by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The age obtained from a total of 21 U–Th–Pb analyses is 25.4 ± 0.3 Ma (2σ) indicating a late Oligocene–early Miocene crystallization. This age is consistent with new K–Ar ages on nepheline-syenites and pyroxenites, and contradicts previously published 39Ar–40Ar (feldspar) ages that were interpreted to represent a late Cretaceous–early Paleocene, pyroxenitic–syenitic magmatic episode. These new geochronological data are consistent with both field observations and most of the previously published ages on alkaline silicate rocks and associated carbonatites of Fuerteventura. Therefore, they strongly support the existence of a single, late Oligocene–early Miocene event of alkaline–carbonatitic magmatism in the Basal Complex of Fuerteventura, taking place at approximately 25 Ma and comprising: alkaline-pyroxenites, melteigites-ijolites, nepheline-syenites and carbonatites, as well as their volcanic equivalents and associated dykes.
These new data provide an estimate for the length of time that it took the island to grow, thus eliminating one of the major problems in explaining its development by a hot-spot model. 相似文献