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1.
Lakes in China have undergone considerable environmental changes during the past 50 years, e.g. lake level, water area changes, as did in the past several thousands years. The enhanced human activities, such as land reclamation, application of chemical fertilizer, land use and cover, irrigation and industrialization in the catchment etc., have played an im-portant role on the recent decades’ changes of these lakes, although constrained to a great extent by the natural impact. Comparative study on variations of lake volume (water level, depth and area) in the eastern and western lake regions of China during 1950–2000 indicated that, lake volume in the eastern region had approximately undergone a two-stage change, i.e. a dramatic decrease from the 1950s to 1970s, and a continuous increase between the 1980s and 1990s; while, in the western region, lake volume had been decreasing nearly all the time. Further studies on some typical lakes concluded that, climatic change was a primary factor for the variations of lake volume during the past 50 years, although human activities showed important effect. 相似文献
2.
Lakes in China have undergone considerable environmental changes during the past 50 years, e.g. lake level, water area changes, as did in the past several thousands years. The enhanced human activities, such as land reclamation, application of chemical fertilizer, land use and cover, irrigation and industrialization in the catchment etc., have played an important role on the recent decades＇ changes of these lakes, although constrained to a great extent by the natural impact. Comparative study on variations of lake volume （water level, depth and area） in the eastern and western lake regions of China during 1950-2000 indicated that, lake volume in the eastern region had approximately undergone a two-stage change, i.e. a dramatic decrease from the 1950s to 1970s, and a continuous increase between the 1980s and 1990s; while, in the western region, lake volume had been decreasing nearly all the time. Further studies on some typical lakes concluded that, climatic change was a primary factor for the variations of lake volume during the past 50 years, although human activities showed important effect. 相似文献
3.
中国东西部平原区湖泊近期变化之比较 总被引：2，自引：1，他引：2
本文通过对中国部湖泊近期演化及其对环境影响的比较研究，认为导致东西部湖泊近期大面积退缩的主要原因都是人类活动。平原区湖泊的许多传统功能正逐渐被水利工程所取代，今后湖区资源的开发应充分注意这一趋势。 相似文献
4.
湖泊面积可反映区域气候变化和人类活动等信息。选取1989、1994、1999、2004、2009、2014年Landsat遥感影像数据，采用人工目视解译、ArcGIS空间分析等方法分析毛乌素沙地湖泊面积变化特征，并结合毛乌素周边气象站点气象数据、所在县区统计年鉴数据对湖泊面积变化的影响因素进行分析。结果表明：（1）毛乌素沙地湖泊近30年总体上处于萎缩状态，具体表现为1994年前湖泊面积增加，后持续减小，不同面积等级湖泊变化情况不同；从空间上看，30年间湖泊面积减小明显的湖泊主要在东北部地区，面积增大明显的湖泊主要在西南部地区，中部地区湖泊面积相对稳定；（2）气候变化和人类活动是近30年影响毛乌素沙地湖泊面积的主要因素。2000年前，湖泊面积主要受气温、降水的影响。特别是1989-1994年，湖泊面积变化量在空间上呈现显著的正相关关系；（3）2000年后，随着区域内人类活动的加剧，湖泊面积主要受人类活动的影响，在人类活动的干扰下，湖泊面积变化量在空间上未表现出显著的正相关关系。 相似文献
5.
Observational data on the response of lakes during modern-day periods of abundant precipitation and drought may provide analogs
for Holocene stratigraphic records and help elucidate the mechanisms that influence how lakes integrate climate. This study
evaluated the impacts of climatic variation during the past 50 years on the morphometry and salinity of two neighboring lake
systems in the central U.S. The two lakes were chosen, because paleolimnological reconstructions indicated that they had opposing
geochemical responses to climate change at AD1200. This divergence suggested that local differences in hydrological setting
had a major impact on the lake response to climate variation. Changes in surface area and volume were derived from aerial
photographs and historic measurements of lake conductivity to contemporaneous annual precipitation data, the Palmer Drought
Severity Index, and to groundwater table elevation. Hypsographic curves help to illustrate changes in lake surface area to
depth. Both lakes showed predictable changes in surface area, volume, and salinity in response to precipitation change, but
the magnitude of change in surface area and volume varied between the two lakes, likely because of differences in basin morphometry,
but mechanisms remain speculative. These differences in basin size and shape also affected the salinity response over time.
In the modern systems, the influence of groundwater on the chemical budgets appears to be limited and does not clarify the
differential response of the lakes in the past. Yet, in the past the groundwater connection may have been different in turn
changing the way the basins responded to climate. Although this study furthers our understanding of differences in the impacts
of climate variations on Moon and Coldwater Lakes during recent times, it still does not clearly reveal why Moon and Coldwater
Lake show opposite patterns of salinity change at 1200 A.D. 相似文献
6.
随着全球变暖和社会经济发展,中国湖泊富营养化情况时有发生,迫切需要对中国湖泊的浮游植物生物量进行有效监测。本文选择了中国756个面积超过10 km2的湖泊进行研究,基于Google Earth Engine（GEE）云端运算平台,反演2003—2018年间叶绿素a（chl-a）浓度数据,以此来分析研究各个湖泊的营养状态及其时空变化,探索了中国五大湖区内湖泊各季节与年均chl-a浓度时空分布特征与气象、社会经济及湖泊特征等影响因素之间的关系。结果表明： ① 中国湖泊的营养状态变化具有明显的季节性与地域性,研究时段内处于中营养状态的湖泊约占90%,春季时大多数位于东部平原湖区与东北平原与山区湖区的湖泊表现为贫营养状态,而青藏高原湖区与云贵高原湖区的湖泊在春季多呈现富营养状态。由各个湖泊年均chl-a浓度变化可以看出中国约82%的湖泊年均chl-a浓度的变化率小于0.5,呈现出轻微变化,18%的湖泊chl-a浓度呈现剧烈变化趋势。② 温度和降水对湖表chl-a浓度影响较大,超过70%湖泊的chl-a浓度与其表面温度和降水存在正相关性,其中大部分分布在中国北部与东部。缓冲区人口和草地占比、湖泊海拔和湖泊地理位置也对湖泊浮游植物生物量具有一定影响。 相似文献
7.
近百年湖北省湖泊演变特征研究 总被引：9，自引：2，他引：7
利用20世纪初以来的地图、历史文献资料和1986～2005年期间7年不同时相的TM影像数据,采用遥感和地理信息系统技术和方法,分析近百年湖北省湖泊的时空演变特征。研究结果表明:①近100多年来,湖北省湖泊演化可以分为4个阶段,并且具有明显的地域差异性。②20世纪初期,湖北省湖泊面积约为26000km2,到2005年为3025.6km2,仅为百年前的11.64%;近百年来绝大部分湖泊面积都在缩小,部分湖泊因围垦或其他原因已完全消失或变为它用,部分湖泊形态发生了较大变化;人类活动是湖北省湖泊百年变迁的主导因素。③20世纪下半叶湖北省湖泊变化迅速,湖北省湖泊面积由50年代的约8503.7km2波动减小至80年代的约2977.3km2,发生在60～80年代的围垦是造成湖泊萎缩的主要原因;从90年代开始,因重视湖泊保护和退田还湖,使湖泊萎缩的态势得到遏制,局部湖泊面积有所恢复。 相似文献
8.
Lydia A. Olaka Eric O. Odada Martin H. Trauth Daniel O. Olago 《Journal of Paleolimnology》2010,44(2):629-644
Sequences of paleo-shorelines and the deposits of rift lakes are used to reconstruct past climate changes in East Africa.
These recorders of hydrological changes in the Rift Valley indicate extreme lake-level variations on the order of tens to
hundreds of meters during the last 20,000 years. Lake-balance and climate modeling results, on the other hand, suggest relatively
moderate changes in the precipitation-evaporation balance during that time interval. What could cause such a disparity? We
investigated the physical characteristics and hydrology of lake basins to resolve this difference. Nine closed-basin lakes,
Ziway-Shalla, Awassa, Turkana, Suguta, Baringo-Bogoria, Nakuru-Elmenteita, Naivasha, Magadi-Natron, Manyara, and open-basin
Lake Victoria in the eastern branch of the East African Rift System (EARS) were used for this study. We created a classification
scheme of lake response to climate based on empirical measures of topography (hypsometric integral) and climate (aridity index).
With reference to early Holocene lake levels, we found that lakes in the crest of the Ethiopian and Kenyan domes were most
sensitive to recording regional climatic shifts. Their hypsometric values fall between 0.23–0.29, in a graben-shaped basin,
and their aridity index is above unity (humid). Of the ten lakes, three lakes in the EARS are sensitive lakes: Naivasha (HI
= 0.23, AI = 1.20) in the Kenya Rift, Awassa (HI = 0.23, AI = 1.03) and Ziway-Shalla (HI = 0.23, AI = 1.33) in the Main Ethiopian
Rift (Main Ethiopian Rift). Two lakes have the graben shape, but lower aridity indices, and thus Lakes Suguta (HI = 0.29,
AI = 0.43) and Nakuru-Elmenteita (HI = 0.30, AI = 0.85) are most sensitive to local climate changes. Though relatively shallow
and slightly alkaline today, they fluctuated by four to ten times the modern water depth during the last 20,000 years. Five
of the study lakes are pan-shaped and experienced lower magnitudes of lake level change during the same time period. Understanding
the sensitivity of these lakes is critical in establishing the timing or synchronicity of regional-scale events or trends
and predicting future hydrological variations in the wake of global climate changes. 相似文献
9.
对中世纪暖期（MWP）的时空分异和区域影响进行综合分析,关系到对近百年来全球气候变暖驱动力的正确认识,也有助于客观地解析20世纪气候变化增暖的历史地位.本研究对中国疆域内各个地区MWP的一些成果进行梳理和再思考,表明MWP在中国疆域内的存在是毋庸置疑的,但不同地区MWP表现出明显的时空差异.中国中东部地区在800—1300 AD存在明显温暖期,各种地质记录和文献记载都有较明显反映;虽然西北部MWP表现不很明显,但是众多石笋、湖泊沉积和风沙沉积也记录了500—1500 AD间呈现温暖湿润的气候特征;青藏高原各地MWP的表现差异明显,其中800—1100 AD暖期是高原东北部最暖的时期,而南部和西部最暖期分别出现于1150—1400 AD和1250—1500 AD.太阳辐射变化和火山活动可能是形成MWP的基本原因,而中国三大自然区下垫面条件的复杂多样性造成MWP发生过程和表现形式的时空分异. 相似文献
10.
西藏玛旁雍错流域冰川与湖泊变化及其对气候变化的响应 总被引：12，自引：2，他引：10
利用遥感和地理信息系统技术,基于1974,1990,1999和2003年4个不同时期的遥感影像,包括Landsat系列影像,ASTER影像和地形图,研究了玛旁雍错流域(面积7786 km2)内冰川与湖泊的变化及其对气候变化的响应。研究结果表明,由于气候变暖,在过去30年里该流域冰川和湖泊都以退为主,有进有退。自1974年到2003年,冰川面积从107.92 km2减少到100.39 km2,冰川退缩明显加速。由于年降水量减少、蒸发量增大,30年中湖泊总面积从782.24 km2减少到748.08 km2。湖面的缩小与扩涨都在加速,尤其是小湖泊变化更明显,湖泊的加速变化可能是青藏高原高海拔内陆流域水循环过程加速的表征之一。 相似文献