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1.
亚洲树轮稳定氧同位素研究进展 总被引：1，自引：0，他引：1
树轮稳定氧同位素作为一种高精度的古气候代用指标,在亚洲地区的发展起步晚进步快。树轮稳定氧同位素比率（δ18O）对区域气候信息有较强的记录能力,且与水汽循环关系密切,对于理解复杂的亚洲气候起着重要作用。亚洲地区树轮δ18O对温度的响应主要出现在高纬度地区,中低纬度树轮δ18O主要记录与水分（降水、相对湿度、PDSI等）有关的信号。对亚洲地区已发表的树轮δ18O与气候要素（温度、降水、相对湿度）的相关分析显著性统计显示,生长季气候对树轮δ18O至关重要,树轮δ18O 与温度的显著相关关系呈正相关,与降水和相对湿度的呈负相关,温度和降水通过降水δ18O影响树轮δ18O,但各自的信号强度存在区域差异,而相对湿度信号则广泛记录在不同区域不同树种之中。亚洲树轮稳定氧同位素研究集中于中低纬度地区,因而对大气水文循环的响应主要侧重于对亚洲夏季风和ENSO的研究,对季风降水的记录反映了季风活动的变化特征以及与之有关的环流信息;季节分辨率的树轮稳定氧同位素研究限于低纬热带亚热带区域,但对于理解区域气候和季风活动的年内变化、挖掘年轮不清晰树种的树轮学研究潜力具有重要的意义。 相似文献
2.
An investigation of moisture sources and secondary evaporation in Lanzhou,Northwest China 总被引：4，自引：1，他引：3
Qian Ma Mingjun Zhang Shengjie Wang Qiong Wang Wenli Liu Fei Li Fenli Chen 《Environmental Earth Sciences》2014,71(8):3375-3385
The purpose of this study is to investigate the atmospheric water cycle in Lanzhou and surrounding areas, a place sensitive to climatic conditions and located in the vertex of the “Monsoon Triangle” of China; this study obtained 243 event-based precipitation samples from four stations in Lanzhou, Yongdeng, Yuzhong and Gaolan for 1 year from April 2011 to March 2012. The seasonal variations of δ 18O and d excess indicate that westerly water vapor, local moisture and summer monsoon all have an influence in this region on a large scale. The westerlies play a dominant role. However, the impact of monsoon moisture has a seasonal limitation, mainly during the period from June to early August. On a local scale, the transportation of moisture appears via two routes. The contribution rate of recycling moisture, over the region, is only 3.6 % on average due to the deficiency of water resource in arid and semi-arid land. Additionally, the effect of secondary evaporation has also been discussed, and the results show that relative humidity, temperature and precipitation amount have different impacts on the effect. However, the influence of precipitation amount is not obvious when the rainfall amount is below 10 mm, while the meteorological parameters of relative humidity and temperature play a significant role in that scope. 相似文献
3.
近40年中国平均气候与极值气候变化的概述 总被引：47，自引：0，他引：47
随着中国气象局对近50年来逐日气象观测资料的释放,人们从不同的角度对中国平均气候和极端气候的分布特征有了更多的了解.从目前研究的结果来看,这些认识需要有一个集成,即需要有一个总体的归纳和解释.通过中国近40年来的温度极值和降水极值事件的分析认识到全球增暖和区域环流异常决定着气候极值事件的分布格局.与全球增暖相联系的是:我国微量降水在空间上表现为一致的减少趋势,我国北方寒潮事件显著减少,冷夜和冷日的减少与暖夜和暖日的增多并存,以及极端强降水有增多的趋势.与东亚季风气流和西风带气流异常对应的我国有效降水在区域分布上发生了显著变化,东部季风区中的"北涝南旱"从1970年代末转型为"南涝北旱",与华南的偏干一起形成了东部季风区降水从华南、长江到华北的"-、 、-"异常分布型,但华南在1991年出现了转湿的突变;东北和西北先后从1983年和1987年前后转为暖湿气候.极端温度和极端降水趋势的空间分布与平均温度和平均降水趋势的空间分布一致. 相似文献
4.
1971-2010年内蒙古干湿变化特征及对水资源影响 总被引：3，自引：2，他引：1
利用1971-2010年内蒙古地区96个气象站的月降水量、月平均气温、月平均风速等气象资料,通过FAO Penman-Monteith 潜在蒸散量计算模型作为基础计算干湿指数,采用气候倾向率、滑动平均等数理统计方法,分析了1971-2010年内蒙古地区干湿指数的变化趋势及空间分布规律并划分出5 种干湿地区类型,探讨了干湿指数与降水量、日照时数、相对湿度等气象因子之间的关系。结果表明：近40a内蒙古地区年干湿指数呈略下降趋势,其变化倾向率为-0.003·（10a）-1,20世纪90年代中期以来年干湿指数呈减少趋势。在地理分布上年干湿指数存在较大的差异性,自东向西逐渐递减,高值中心位于内蒙古大兴安岭东北部,低值中心在内蒙古巴丹吉林沙漠北部。在全球气候变暖的背景下,90年代后干湿指数下降明显,尤其是在内蒙古东部地区,干湿类型明显由湿向干转变,降水减少、区域增温是该地区干旱化的主要原因。内蒙古地区干湿变化主要的气候影响因子是降水量,相关系数在0.9以上,其次是日照时数、相对湿度、潜在蒸散量,相关系数在0.6~0.7之间。近10a来内蒙古地区水资源总量急剧下降,与近些年来地表干湿状况的变化有一定的关系。 相似文献
5.
V Prasanna 《Journal of Earth System Science》2014,123(5):1129-1145
The study focuses on understanding the variations of precipitation during summer monsoon season and its impact on Kharif and Rabi foodgrain yield over India. Total foodgrain yield over India during Kharif (summer) season is directly affected by variations in the summer monsoon precipitation (June–September). An increase (decrease) in rainfall is generally associated with an increase (decrease) in foodgrain yield. A similar correspondence during the Rabi (winter) foodgrain yield is not evident. The Rabi crop is not directly affected by variations in the post-monsoon precipitation (October–December) alone, also the summer season precipitation influences the Rabi crop through water and soil moisture availability over many parts of India. Though the reduction of rainfall activity during the entire summer monsoon season leads to reduction in crop yields, the occurrence of prolonged rainfall breaks also causes adverse effect on the crop growth resulting in reduced crop yields. 相似文献
6.
By comparing simultaneously observed data of humidity and precipitation in Shanghai Urban area with those in its suburbs, we first deal with the urban influences on humidity. We find that both the average absolute humidity and relative humidity (diurnal, monthly and annual) are lower in the city than those in the surrounding 10 counties but night-time absolute humidity excess in the city exhibits a moisture island similar to that of temperature. The example is shown from a summer night at 5 h on Aug. 10, 1959.When 20-year's records of isohyets of annual average precipitation, average precipitation of rainy seasons (May–September), and that of other seasons (October–April) are analyzed, the urban influences on the distribution of annual precipitation and the rainy season precipitation become obvious, but it seems that the other seasons are not affected.Some rain events that illustrate the main contributing causes are also discussed, namely, heat island, obstacle effects and pollution products, for the modification and augmentation of precipitation in urban area and in the lee of the city. 相似文献
7.
基于长期原位监测对高寒阴湿区边坡土体温湿响应规律研究存在的不足,选取甘肃双达高速公路沿线土-岩二元结构边坡为研究对象,构建远程监测系统对边坡浅层土体温温度及大气降雨开展了为期2年多的现场监测,结合傅里叶模型与Pearson相关性分析方法,揭示了边坡土体水热迁移及降雨入渗规律,分析了边坡土体温湿度相互作用效应。研究结果表明:(1)边坡浅层土体温湿度随时间呈简谐式周期变化,且变化幅度随埋深逐渐减小,2 m深度处土体月平均温度变化具有一定滞后性,滞后时间约为30 d。(2)年内3月与9月,土体月平均温度曲线出现“纽结”现象,使边坡呈现出由春夏季表热而内凉向秋冬季表寒而内温转变的趋势。(3)春季降雨期,土体含水率增长仅发生在50 cm深度以内;夏季降雨期,降雨引起更深层土体含水率变化,因雨水持续性补充,浅层土体湿度长时间保持在35%以上。(4)土体温湿度存在较高的正相关关系,随土体埋深增加温湿度相关性增强,不同时期温湿度相互影响程度不同,年内温湿度相关性表现出“循环圈”效应。研究成果可为进一步认识边坡土体水文响应规律、水-热相关性与坡面侵蚀机理提供一定参考。 相似文献
8.
空气湿度是重要的气象要素，与气温和降水密切相关，其长期变化特征是气候系统变化的重要表征。2003年前后全国自动站与人工站的更替使得相对湿度资料存在不能满足均一性的要求，亟需加强空气湿度变化特征方面研究。利用1961—2010年中国824个气象站订正后均一性较好的逐日气温、降水量和相对湿度数据，剔除缺测多的站点，采用线性回归分析、Mann-Kendall趋势检验和偏相关分析方法，综合分析中国水汽压和相对湿度的长期变化特征及其与气温和降水量的相关特征。结果表明:①全国各地年均水汽压呈增大趋势的站点占全部站点的90.3%；除春夏两季的黄土高原至云贵高原一带和长江下游地区、秋季的华南地区有所减小外，各季节全国水汽压普遍呈增大趋势。②全国年均相对湿度呈减小趋势的站点占64.1%；除河北北部至辽宁北部、陕西南部至黄淮地区、江南北部、青藏高原和四川西部地区以及西北大部呈增大趋势外，其余地区普遍减小；季节差异明显，春、夏和秋季，中东部大部分地区相对湿度以减小趋势为主；冬季除东北地区和云南减小外，其余大部分地区相对湿度增大。③全国各地水汽压与气温、降水量普遍以正相关为主，与气温的相关性强于与降水量的相关性；相对湿度与气温普遍呈显著的负相关，与降水量普遍以正相关为主。 相似文献
9.
通过分析我国东北、华北、西北地区东部、西南以及黄淮、江淮和江汉5个区域不同时间尺度气象干旱指数与20 cm土壤相对湿度的相关关系, 探讨了前期气象干旱对后期土壤湿度的影响, 并利用多元线性回归方法分区域、分季节建立了土壤湿度预测模型.结果表明: 春季, 东北地区土壤湿度主要受前5~6个月, 尤其是上年秋末冬初的降水的影响, 而其他4个区域土壤湿度主要受前1~2个月大气水分的影响;各区域夏季土壤湿度与前1~2个月时间尺度上的大气水分相关最密切;秋季, 东北地区20 cm土壤湿度主要受前2~4个月的气象干旱的影响, 其余区域土壤湿度仍与前1~2个月尺度的大气水分相关最密切.基于前期气象干旱指数建立的各区域、各季节的土壤湿度回归模型对当地土壤湿度具有一定的拟合能力, 平均估计偏差在10.1%~13.9%之间, 其中, 西北地区东部和华北地区春、夏季偏差较大, 2008-2011年间干旱等级拟合准确率在65%~74.9%之间;东北、西南、黄淮、江淮和江汉区域拟合较好, 拟合准确率在88%以上. 相似文献
10.
空气湿度是重要的气象要素，与气温和降水密切相关，其长期变化特征是气候系统变化的重要表征。2003年前后全国自动站与人工站的更替使得相对湿度资料存在不能满足均一性的要求，亟需加强空气湿度变化特征方面研究。利用1961—2010年中国824个气象站订正后均一性较好的逐日气温、降水量和相对湿度数据，剔除缺测多的站点，采用线性回归分析、Mann-Kendall趋势检验和偏相关分析方法，综合分析中国水汽压和相对湿度的长期变化特征及其与气温和降水量的相关特征。结果表明：①全国各地年均水汽压呈增大趋势的站点占全部站点的90.3%；除春夏两季的黄土高原至云贵高原一带和长江下游地区、秋季的华南地区有所减小外，各季节全国水汽压普遍呈增大趋势。②全国年均相对湿度呈减小趋势的站点占64.1%；除河北北部至辽宁北部、陕西南部至黄淮地区、江南北部、青藏高原和四川西部地区以及西北大部呈增大趋势外，其余地区普遍减小；季节差异明显，春、夏和秋季，中东部大部分地区相对湿度以减小趋势为主；冬季除东北地区和云南减小外，其余大部分地区相对湿度增大。③全国各地水汽压与气温、降水量普遍以正相关为主，与气温的相关性强于与降水量的相关性；相对湿度与气温普遍呈显著的负相关，与降水量普遍以正相关为主。 相似文献
11.
南水北调对北方干旱化趋势可能影响的初步分析 总被引：2，自引：0，他引：2
使用地表土壤水量平衡模式和大气能量平衡模式，对南水北调中线工程对华北地区的可能局地气候效应进行了虚拟模拟试验，得出了在不同调水方案和气候情景假定下华北地区可能出现的局地土壤水分、蒸发、温度和降水的变化。结果表明，不同调水量在不同时间、不同气候条件下的气候效应是有差别的，并与降水的季节变化有关。总体而言，在给定气候背景下调入水可以改变土壤水含量和径流，并使局地夏半年温度降低、冬半年温度有所升高；夏半年局地降水量和蒸发量有所增加，而冬半年变化不大。因此，在目前情况下南水北调中线工程的实施不仅可以减缓华北地区水资源紧缺的矛盾，而且有可能在一定程度上改善当地的局地干旱气候环境，进而有利于生态环境的良性循环和有序人类活动的可持续发展。 相似文献
12.
Tree-ring-width index chronologies of teak (Tectona grandis L.F.) from three sites in central India have been studied for their dendroclimatic potential. The existence of good correlation
among the three site chronologies indicates the influence of common forcing factor to the tree growth of the region. Tree
growth and climate relationship based on correlation analysis revealed the important contribution of moisture index and rainfall
rather than the direct influence of the temperature on tree growth during different seasons. Significant positive relationship
of moisture index and rainfall during the monsoon months as well as on the annual scale with tree-ring width variations over
the region indicates the important role of moisture availability at the root zone. The results suggest that the teak tree-ring
chronologies can be used as high resolution proxy for past precipitation and moisture level in the environment. 相似文献
13.
基于山西阳泉市莲花洞石笋8个230Th年代和109个δ13C数据,获取了末次冰期54.5~41.1 ka BP期间平均分辨率为120年的δ13C记录。综合对比亚洲季风区29°~41°N之间5条独立定年的、高分辨率石笋δ13C记录表明:不同洞穴石笋δ13C记录在相同生长时段具有较好的重现性,δ13C指标能够有效指示洞穴上覆地区土壤CO2产率,从而反映洞穴外部环境与季风气候的变化。δ13C记录的5个千年尺度亚洲夏季风增强事件在定年误差范围内响应于格陵兰冰芯记录的Dansgaard-Oeschger（DO）10~14事件,而2个弱季风过程与北大西洋钻孔记录Heinrich 5和Heinrich 5a事件密切联系。这种石笋δ13C记录的空间一致性表明亚洲夏季风及其控制下的区域生态环境波动在千年尺度上通过海－气耦合响应于北高纬气候变化。 相似文献
14.
通过念青唐古拉峰拉弄冰川垭口处(30°24'30″N, 90°34'12″E;海拔5850m)长度为29.5m的冰芯记录,恢复了1952~1998年间大气降水δD和净积累量的时间变化序列。上述两组序列与NCEP/NCAR气候资料的相关分析表明:δD和净积累量与中亚冬季的气压、南亚和青藏高原冬季、夏季的位势高度关系密切。中亚地区冬季气压的升高以及冬、夏季南亚和青藏高原位势高度的异常增强了印度夏季风,导致了念青唐古拉峰地区20世纪80年代以来降水量的增多和降水中δD值的降低。根据念青唐古拉冰芯δD和净积累量记录及其与亚洲地区大气环流的关系,可以通过青藏高原南部较长的冰芯记录来恢复过去该地区大气环流变化的历史。 相似文献
15.
《Quaternary Science Reviews》2004,23(1-2):137-143
Peatland surface wetness records provide long Holocene palaeoclimate reconstructions at 101–102 year resolution. They reflect changes in water balance but the relative strength of precipitation and temperature signals are not known. In common with other non-annually resolved records, there has been no testing of the reconstructions against instrumental climate data. In this paper high-resolution records of palaeohydrological change reconstructed from testate amoebae analysis are used to examine critically the relationships between reconstructed water table change, instrumental water table and climate data. A 200-year record of reconstructed water table from northern England shows that the strongest control on reconstructed mean annual water table change is summer precipitation, with summer temperature becoming more important over longer time periods. A 50-year record from Estonia shows that both measured and reconstructed water table records are strongly correlated with summer precipitation. Summer temperature is also correlated with reconstructed water table. We conclude that peatland surface wetness records should be interpreted as primarily reflecting summer precipitation variability, with summer temperature increasingly important in more continental settings. 相似文献
16.
气候变化对巴音布鲁克高寒湿地地表水的影响 总被引：7，自引：0，他引：7
通过对巴音布鲁克高寒湿地各特征气候要素的变化分析,研究了近50a来巴音布鲁克高寒湿地地表水环境和气候变化的变化趋势和年际分布特征.结果表明:巴音布鲁克湿地不论冬季还是年平均气温都没有明显的升高趋势,极端最高、最低气温也没有明显变化,但夏季增温幅度高于新疆平均水平;夏季降水量占了全年降水量的68.4%,是巴音布鲁克湿地水体的主要来源.20世纪80年代中期是降水量最少的时期,此后开始逐步增加;开都河的径流量自1987年后呈现逐步增加趋势,并与巴音布鲁克年降水量和年均气温存在良好的响应关系.气候变化对湿地水环境的影响直接关系到湿地的生态系统. 相似文献
17.
《Quaternary Science Reviews》2007,26(7-8):941-953
Pollen analysis shed light on vegetation community structure over the last 23,000 year in the western Cape. The pollen from dated hyrax faecal accumulations (hyraceum) relates to the evolution of climate and contributes to proxy records in southern Africa. Principal components analyses of the pollen data and δ13C values of the hyrax dung samples show millennial and shorter scale temperature, moisture and seasonality variations in the winter rain region. The moisture availability at times do not parallel that in previously studied proxy records in the summer rain region showing an asynchronous moist event in the early Holocene and drier conditions in the Middle Holocene. Anomalies in climate between the two regions may depend on the degree of northward or southward shifting of winter- and summer-rain circulation systems. Scenarios with winter-rain or cool growing seasons mostly typify the dung sequence but do not exclude the possibility of southward displacement of the westerly belt under precessional strength with slight summer rain increases during the Last Glacial Maximum. Limited southward displacement is also possible during the Mid Holocene. 相似文献
18.
Mid to late holocene climate evolution of the lake telmen basin, north central mongolia, based on palynological data 总被引：2，自引：0，他引：2
Sarah J. Fowell Barbara C. S. Hansen John A. Peck P. Khosbayar Enebish Ganbold 《Quaternary Research》2003,59(3):353-363
Palynological and sedimentological data from Lake Telmen, in north-central Mongolia, permit qualitative reconstruction of relative changes in moisture balance throughout the mid to late Holocene. The climate of the Atlantic period (7500–4500 yr ago) was relatively arid, indicating that Lake Telmen lay beyond the region of enhanced precipitation delivered by the expanded Asian monsoon. Maximum humidity is recorded between 4500 and 1600 cal yr B.P., during the Subboreal (4500–2500 yr ago) and early Subatlantic (2500 yr–present) periods. Additional humid intervals during the Medieval Warm Epoch (1000–1300 A.D. or 950–650 ago) and the Little Ice Age (1500– 1900 A.D. or 450–50 yr B.P.) demonstrate the lack of long-term correlation between temperature and moisture availability in this region. A brief aridification centered around 1410 cal yr B.P. encompasses a decade of cold temperatures and summer frost between A.D. 536 and 545 (1414–1405 yr B.P.) inferred from records of Mongolian tree-ring widths. These data suggest that steppe vegetation of the Lake Telmen region is sensitive to centennial- and decadal-scale climatic perturbations. 相似文献
19.
《Quaternary Science Reviews》2007,26(17-18):2042-2066
A review of seven outstanding issues on Mediterranean palaeoenvironments is presented. These are related to the dominant orbital pacing of climate variability, the length of the interglacial vegetation succession, the influence of the African summer monsoon, the seasonality of precipitation during boreal insolation maxima, the moisture balance during glacial maxima and the appearance of the mediterranean-type climate rhythm and evolution of mediterranean sclerophyllous plants. What emerges is that (1) marine δ18Oplanktonic and SST records show that precession has been a fundamental tempo of Mediterranean climate change, representing both a low-latitude signal (runoff from North Africa) and the direct influence of insolation at Mediterranean latitudes, but high-latitude glacial effects (41-kyr and 100-kyr cycles) became superimposed after 2.8 Ma. Sapropel and dust deposition patterns in marine cores reveal that obliquity also has an effect on Mediterranean climate through dry–wet oscillations, which are independent of glacial–interglacial variability. (2) The temperate part of interglacial vegetation succession has a duration of approximately half a precession cycle. This persisted during the interval of obliquity-dominated glacial cycles (∼2.8–1 Ma), with distinct forest successions following the precessional cycles. However, these are not always separated by an open vegetation phase because of minimal ice growth, producing an impression of a prolonged interglacial forest interval. (3) The effect of an enhanced African monsoon during summer insolation maxima has been mainly indirect, in terms of Nile discharge and runoff along the North African coast, leading to increased freshwater input into the Mediterranean Sea, reduced deep-water ventilation and sapropel deposition. (4) The notion of an accentuated summer rain regime in the northern Mediterranean borderlands also contributing to a freshening of the Mediterranean Sea during boreal insolation maxima is not supported by the available evidence, which suggests increased summer aridity. (5) Recent improvements in chronological precision and data resolution point to an increase in aridity and decreased temperatures during the Last Glacial Maximum (21±2 ka), but suggest an increase in effective moisture during the immediately preceding interval of 24–27 ka. (6) The mediterranean-type climate is not exclusively a post-3.6 Ma phenomenon, but may have appeared intermittently during the course of the Tertiary (or before). (7) If that is the case, then the paradigm that the sclerophyllous evergreen habit represents a pre-adaptation to summer drought may need re-evaluation. 相似文献
20.
陆生蜗牛壳体碳氧同位素组成记录了环境气候信息,是地质历史时期古环境和古气候重建的一个良好指标。文章在前人对现生蜗牛壳体碳氧同位素的环境意义研究基础上,通过增加对不同气候条件下的新疆地区（受西风带控制）、川西地区（受印度季风控制）以及东北地区（东亚季风北端）的现生蜗牛碳氧同位素组成进行测试分析,结合中国其他地区已有数据,总结探讨所有研究区已有蜗牛壳体碳氧同位素组成的分布规律及影响因子,回归分析蜗牛壳体碳氧同位素组成与降水量、温度、湿度、蒸发量及干燥度等5个气候因子之间的关系。得出以下研究结果：全国范围内的蜗牛壳体碳同位素组成与年均降水量、年均相对湿度具有明显负相关关系,与年均蒸发量及干燥度具明显正相关关系,年均温度大于9.5℃采样点的蜗牛壳体碳同位素与温度呈负相关关系;蜗牛壳体氧同位素组成与各种气候因子之间的关系比较复杂而显示无明显的相关性,可能由于不同区域蜗牛壳体氧同位素对不同气候因子的响应程度不同,也可能是由于蜗牛壳体氧同位素与温度的关系在不同区域存在差异导致。总之,蜗牛壳体碳同位素较为忠实地记录了有效降水引起C3植被同位素变化的信息,而对蜗牛壳体氧同位素记录的信息的解读还不明晰,仍需更多研究。 相似文献