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1.
青海沙利克山祁连圆柏千年树轮宽度序列的变化特征 总被引：6，自引：1，他引：5
利用功率谱、奇异谱和小波分析等方法对在青海沙利克山建立的两条祁连圆柏 (Sabi naprzewalskiiKom )千年树轮宽度序列进行了变化特征的分析 ,发现在低频变化上都存在2 0 0年的最显著周期和百年左右的显著周期 ;各种周期存在不同的演变特征 ,2 0 0年周期在15～ 17世纪最为盛行 ,百年左右的周期变化自 18世纪初以来较为突出。 15世纪下半叶是轮宽序列千年来最突出的低值期 ,它主要体现了 2 0 0年周期的变化 ,而 2 0世纪后期的高值区则主要是百年左右周期变化的作用。轮宽序列的低频变化与太阳活动的长期变化之间存在较好的对应关系 ,说明祁连圆柏年轮宽度序列所指示的气候低频变化可能受太阳活动的影响。 相似文献
2.
利用英国东英格兰大学气候研究中心CRU最新发布的1901-2012年的月平均气候资料,分析陕西近百年降水、气温的时空分布特征。结果表明:(1)年平均降水南北差异较大,陕南降水多且年际变化最大,西安为年际变化的第二高值中心。(2)陕西降水具有明显的年代际变化周期,20世纪40年代之前降水变化较平缓,40年代后降水变化幅度变大,异常偏多或偏少的年份较多。(3)降水的EOF1表现为整体的正异常,体现了陕西年平均降水的一致变化,EOF2主要表现为陕西南部和陕西东北部的反相位振荡,且具有显著年际变化周期。(4)陕西气温近112年有两个偏冷期:20世纪20年代之前和50年代到90年中期,20世纪20年代到50年代和90年代后期以来为偏暖期。与全国气温变化不同,第二个暖期是从90年代开始迅速升温,滞后于全国气温变化,且气温的最高值出现在90年代而不是40年代。(5)气温的第一模态解释了总模态的88.4%,且表现为陕西一致的正异常,表明陕西平均气温空间变化的一致性,Morlet小波分析显示其有2~4年的周期震荡和16年左右的年代际变化周期。 相似文献
3.
John M. Harlin 《The Professional geographer》1979,31(1):25-33
Computer maps of the association between annual precipitation and the solar cycle illustrate strong regional response, supporting the notion of rhythmic changes in circulation concomitant with the elevenyear sun cycle. The strength and sign of correlation coefficients between annual precipitation and sunspot frequency indicate that the solar-terrestrial relationship may be a function of geographical location and solar amplitude. 相似文献
4.
通过在祁连山东部互助地区采集的油松样本,建立标准树轮（STD）年表,重建该地区近188 a上年8月到当年6月的降水,解释方差为48.8%。根据重建结果,历史上的湿润时期有1850s—1860s、1930s末—1950s、1970s—1990s以及2000s;干旱时期有1830s—1840s、1900s、1920s,其中1920s的干旱在北方大范围内普遍存在。根据本文重建结果与周围地区降水和PDSI重建比较,发现该地区降水变化与贺兰山地区干湿变化最为相近,尤其是1940s以前,在1940s之后与青海省德令哈和祁连山中西部地区的重建结果更为相似。因此推测,祁连山东部地区在1940s前后受不同的气候类型主导。 相似文献
5.
DOUGLAS J. Cant 《Basin Research》1989,2(2):73-81
Abstract An equation to relate the thickness of sediment deposited (ΔSed), eustatic sea-level change (ΔE), and subsidence (ΔSub), to changes in depth of water (ΔD) is: ΔSub +ΔE-ΔSed =ΔD.
Using existing sea-level curves, the equation shows that some transgressive-regressive sequences in a foreland basin and a composite seismic facies sequence on a passive margin cannot result solely from eustatic variation. In each case, the space created by subsidence is greater than that provided by eustatic rise. However, eustatic variation could have triggered sequence development if superimposed on a basin with relatively constant values of the other parameters. Short-period sea-level fluctuations with high rates of change, exceeding 70–100 m Myr-1 for periods less than 2–3 Myr, affect the stratigraphy and sedimentology more than longer period, higher amplitude variations.
Clinoforms are generated because of lateral variations in sedimentation rate compared to the rate of creation of accommodation space. These variations may result from differing sedimentation rates, subsidence rates, or rates of eustatic change, superimposed on a basin with lateral sediment supply. Clinoform slopes and curvatures are interpre table in terms of these variables as well as the type of sediment supplied and the energy distribution in the basin.
These equations put some well-known geological principles on a simple quantitative basis. They force precision in definition of variables, and may lead to further development of quantitative techniques in stratigraphy and sedimentology. 相似文献
Using existing sea-level curves, the equation shows that some transgressive-regressive sequences in a foreland basin and a composite seismic facies sequence on a passive margin cannot result solely from eustatic variation. In each case, the space created by subsidence is greater than that provided by eustatic rise. However, eustatic variation could have triggered sequence development if superimposed on a basin with relatively constant values of the other parameters. Short-period sea-level fluctuations with high rates of change, exceeding 70–100 m Myr
Clinoforms are generated because of lateral variations in sedimentation rate compared to the rate of creation of accommodation space. These variations may result from differing sedimentation rates, subsidence rates, or rates of eustatic change, superimposed on a basin with lateral sediment supply. Clinoform slopes and curvatures are interpre table in terms of these variables as well as the type of sediment supplied and the energy distribution in the basin.
These equations put some well-known geological principles on a simple quantitative basis. They force precision in definition of variables, and may lead to further development of quantitative techniques in stratigraphy and sedimentology. 相似文献
6.
廖要明 《地理学报(英文版)》2013,23(4):579-594
Parameters of weather generator BCC/RCG-WG for daily non-precipitation variables including maximum temperature, minimum temperature and sunshine hours at 669 stations in China are estimated using history daily records from 1951 to 1978 and from 1979 to 2007 respectively. The changes in the parameters for the two periods are revealed to explore the impact of climate change on these parameters. The results show that the parameters of the non-precipitation variables have experienced different changes. While the annual means and the amplitudes of the seasonal cycle show a clear change, the interannual variability, the timings of the seasonal cycles, and the temporal correlations for each variable remain practically unchanged. This indicates that climate changes in China over the last 57 years are mainly reflected in variations in the means and in the strength of the seasonal cycles. The changed parameters have implications for the stationary assumption implied in the parameter estimation and use of the weather generator for climate change studies. 相似文献
7.
Philip L. Woodworth 《Geophysical Journal International》1985,80(3):743-755
Summary. Tide gauge records from throughout the world have been examined for evidence of the 11-yr solar cycle in mean sea-level (MSL). In Europe an amplitude of 10–15mm is observed with a phase relative to the sunspot cycle similar to that expected as a response to forcing from previously reported solar cycles in sea-level air pressure and winds. At the highest European latitudes the MSL solar cycle is in antiphase to the sunspot cycle while at mid-latitudes it changes to being approximately in phase. Elsewhere in the world there is no convincing evidence for an 11-yr component in MSL records. 相似文献
8.
Dryness and wetness variations on different time scales in Shanghai were analyzed using the Standardized Precipitation Index (SPI) based on monthly precipitation data for 1873-2005. The SPI on scales of 3, 6, 12 and 24 months has been calculated. The SPI on 3, 6, 12 and 24 months present 4 wet periods prevailed during 1873-1885, 1904-1923, 1938-1960 and 1983-2005, and 3 dry episodes during 1888-1903, 1924-1937 and 1961-1982. Significant periods of higher wavelet power in the SPI-24 months occurred on the time scales of 2-7-year band in around 1880-1890, 1910-1950 and 1970-1990, and at 8-15-year band in 1920-1960 and 1965-2000 respectively. Periodicities in the SOI and ENSO indices are similar to those in SPI-24 months with little difference, namely, in the SPI-24 months, there are significant periods at the 2-7- and 8-15-year bands during 1930-1940. The periodicity components in individual SPI-24 months, SOI and ENSO indices are more complicated, showing the wetness and dryness variability in Shanghai is controlled by more than one physical factors. The research results indicate that the Shanghai area has experienced dryness and wetness variability on different time scales during the past 133 years. 相似文献
9.
Robert G. Currle 《Geophysical Journal International》1981,67(3):547-556
Summary. The 11-yr solar cycle term in sea-level is further elucidated by single-and two-channel high resolution signal processing techniques applied to 37 European height H of sea-level records. In agreement with earlier analysis the period and amplitude are 10.6 ± 0.3 yr and 10.3 ± 4.8 mm. New results are as follows: in view of the recently detected 11-yr term in Earth rotation Δ T = ET — UT, cross-spectra of the H records with Δ T were computed. At the solar cycle period H lags Δ T by 0.7 ± 0.5 yr; since AT lags the change in length of day Δ(10 d) by 2.7 yr the result is that H lags Δ(10 d) by 3.4 ± 0.5 yr. The continuum spectrum of H and Δ T has a high coherency and zero phase from the solar cycle down to a period of 40 yr, although this relation cannot be causal. We propose that the circumpolar vortex of westerly winds is the common forcing function for the H and Δ T discrete solar cycle signal and a significant portion of the long-period continuum in European waters. 相似文献
10.
近50年气候变化背景下青藏高原冰川和湖泊变化(英文) 总被引：2，自引：0，他引：2
李治国 《资源与生态学报(英文版)》2014,(2):123-131
本文综述了近年来青藏高原冰川和湖泊变化研究取得的成果,并特别着重于冰川和湖泊变化的相互关系论述。在全球变暖背景下,近几十年青藏高原冰川以退缩为主,湖泊水量以增加为主。本文一方面对青藏高原冰川末端退缩、冰川面积和冰川储量变化方面的研究成果进行了综合分析,探讨了冰川变化的时空特征;另一方面从湖泊面积和水位与水量变化探讨了湖泊变化的时空规律。结果表明青藏高原冰川退缩的幅度总体上呈从青藏高原外缘向内陆呈减小的变化态势,受冰川融水补给比较大的湖泊近期面积扩张、水位上升明显。最后指出了青藏高原冰川、湖泊变化研究中存在的问题及今后的发展趋势。 相似文献
11.
利用1973-2010年12个站点的年平均气温、降水量、风向、风速数据,对38 a来毛里塔尼亚气候变化和风况特征作了初步分析。结果表明:毛里塔尼亚沿海区域38 a来呈变暖趋势,北部荒漠区域和南部热带草原区域则呈现冷暖交替变化的趋势。20世纪60年代降雨量最多,70年代和80年代降雨量偏少,总体上降雨量略有减少。除沿海区域外,南部热带草原区域和北部荒漠区域少雨期和降温期相对应,多雨期与升温期相对应,降雨滞后于温度。1973-2010年月平均风速均呈现下降趋势,南部热带草原区域下降趋势较为明显,北部荒漠区域下降趋势不明显。月平均风速为春季、夏季较大,冬季次之,秋季最小。季节风热条件存在明显差异,北部风热同步,南部先同步后异步,沿海则完全不同步。各站点的年风向频率,沿海区域以北风为主,而北部荒漠区域及南部热带草原区域风向则介于东、北向之间。 相似文献
12.
塔克拉玛干沙漠腹地地表辐射收支特征研究 总被引：4，自引：4，他引：0
利用塔克拉玛干沙漠大气环境观测试验站探测的辐射数据,分析了流动沙漠区近地层辐射收支特征以及云和沙尘对其的影响。总辐射在夏季某些特定的天气条件下接近太阳常数。不同天气条件下,辐射收支特征存在较大差异;总辐射受云和沙尘的影响最明显,变幅最大,夏季沙尘暴天气时比晴天减少了80%以上;反射辐射的日变化趋势在各个季节内、各种天气条件下与总辐射非常一致;大气长波辐射所受影响较小,且云和沙尘会使其略微增加;地面长波辐射的变化幅度最小,均在10%以下;净辐射在阴天时略微降低,沙尘天气时明显降低,为负值。观测期间的平均辐射特征与晴天比较接近,平均的总辐射、净辐射与晴天的比值白天基本在0.7左右,说明云和沙尘对塔中的辐射能量有较大的强迫作用。 相似文献
13.
基于行星会合指数运动学方程,推演出太阳质心到太阳系质心距离变化的计算公式,并利用该公式重建太阳质心相对于太阳系质心的距离变化时间序列,作为太阳轨道运动的替代性指标,使用聚合经验模态分解(Ensemble empirical mode decomposition,EEMD)方法分析0~25.0 ka BP太阳质心到太阳系质心的距离与Δ^14C时间序列。结果显示:两者均存在蕴含~2300 a周期(Hall?statt cycle)的IMF分量;互相关分析证实两者蕴含的Hallstatt周期分量间具有相关性,0~13.9 ka BP与13.9~25.0 ka BP年代相关系数分别可达0.52、0.44,并且太阳质心到太阳系质心距离的变化超前于太阳活动指标Δ14C的变化。表明太阳质心远离太阳系质心时,大气14C含量增加,对应于太阳活动较弱的时期;太阳质心靠近太阳系质心时,大气14C含量减小,对应于太阳活动较强的时期。这一认识对于进一步探究太阳活动Hallstatt周期的成因机制提供了新的依据和思路。 相似文献
14.
利用通用地球系统模式CESM过去1500年气候模拟试验结果,对比分析中世纪暖期南、北半球气候变化特征及成因,对认识南、北半球暖期气候变化规律及其与外强迫变化的关系有重要科学意义。结果表明：中世纪暖期全球及南、北半球总体是变暖的,但仍存在峰谷变化,高纬地区增温幅度大于低纬地区,北半球中世纪暖期比南半球更为明显,其距平变幅也大于南半球。全球降水距平基本为正,南、北半球降水变幅基本相当,降水变化显著区域集中于低纬地区。太阳辐射是影响中世纪暖期全球及半球气温变化最显著的因素,火山活动对北半球气温变化也有较显著的影响。从全球尺度来看,降水由太阳辐射和火山活动共同影响,其中太阳辐射影响最为显著,但从半球尺度来看,火山活动是影响半球降水的重要因素。 相似文献
15.
G. K. Rangarajan 《Geophysical Journal International》1980,61(2):451-455
Summary. Using an index derived from the observations of horizontal intensity at two stations in the Indian equatorial region, the characteristics of the lunar semi-monthly tide in the equatorial electrojet strength are studied. It is shown that a contamination of the lunar signal by recurrent geomagnetic disturbance is largely eliminated and that the strength of the signal vanes systematically with solar time. Comparison of amplitude between conditions of low and high solar activity indicates a difference in local time progression, while the phase change is independent of the solar activity and season. Results of seasonal subdivision of data indicate that the largest amplitude is associated with the d-season. With increased solar activity there is an increase in the d- and e-seasons and a marginal decrease in the j-season. For all the seasons, the phase progression is fairly consistent with the theoretical considerations of Stening. 相似文献
16.
Observed climatic changes in Shanghai during 1873-2002 总被引：2，自引：0，他引：2
Variation characteristics of temperature and precipitation in January and July and annual mean temperature and annual precipitation are analyzed with the help of cumulative anomalies, Mann-Kendall analysis and wavelet analysis. The research results indicate that January precipitation presents an increasing trend after 1990, wavelet analysis result suggests that this increasing trend will continue in the near future. The changes of July precipitation present different features. During 1900-1960, July precipitation is in a rising trend, but is in a declining trend after 1960. Wavelet analysis shows that this declining trend will go on in the near future. Temperature variations in Shanghai are in fluctuations with 2 to 3 temperature rising periods. Mann-Kendall analysis indicates that temperature variations have the obvious abrupt change time when compared with precipitation changes in Shanghai during the past 100 years. The abrupt change time of January temperature lies in 1985, and that of July temperature lies in 1931-1933 and annual mean temperature has the abrupt change time in 1923-1930. Except July precipitation, the precipitation in January, temperature in January, July and annual mean temperature, and annual precipitation are also in a rising trend in the near future. The research results in this paper may be meaningful for future further climatic changes of Shanghai and social mitigation of climatic disasters in the future. 相似文献
17.
Hurd C. Willett 《自然地理学》2013,34(2):95-107
In their broad synoptic features the basic hemispheric patterns of climate, on which the patterns of climatic change depend, fall into two distinctive categories, the zonal and meridional. Distinctive synoptic features of the primary zonal patterns are first described. Then statistically significant relationships are examined between the temporal changes in these patterns and the long secular cycles of sunspot and related variable solar activity. It is these relationships that lend them selves to the statistical prediction of long-term climatic trends. Possible physical linkage between disturbing solar impulses and atmospheric response is suggested. A significant relationship between zonal climatic patterns and shorter term (22 years) double sunspot cycles is noted. Distinctive syn optic features of the primary meridional patterns of climate and climatic change are then described. They are of short duration and relate significantly only to double sunspot (DSS) and shorter cycles, notably at higher latitudes and during the winter season. They are apparently responsive to solar corpuscular (solar wind) impulses in contrast to the apparent response of the zonal long-term trend patterns of change to solar electromagnetic (radiational) changes. The research approach best suited to investigate the physical mechanism of solar-climatic linkage is discussed as a necessary basis for the development of effective models for the solar prediction of climatic change. 相似文献
18.
G lobalw arm ing and its possible influences on hum an society have received increasing concernsfrom academ ic circles (Y ao et al.,1996; Chen, 1987; Zhang et al.,2004; Zhang et al.,2000).Som e scholars paid m uch m ore attention to clim atic changes duri… 相似文献
19.
云南千湖山第四纪冰川发育特点与环境变化 总被引：2，自引：0，他引：2
千湖山(4249 m) 是横断山脉中段保存确切第四纪冰川遗迹的山地,受西南季风影响强烈。对于研究青藏高原边缘山地冰川发育与气候和构造之间的耦合关系具有十分重要的科学意义。在千湖山海拔3500 m以上保存着古冰川侵蚀与堆积地貌,冰川发育依托海拔4000~4200 m的夷平面及其支谷地形。冰川形态类型为小型的冰帽以及由冰帽边缘溢流进入山谷的山谷冰川。应用相对地貌法,光释光(OSL) 年代测试,本文确定千湖山地区的冰进系列:末次冰盛期(LGM,22.2±1.9 ka BP)、末次冰期中期(MIS3b,37.3±3.7 ka BP、45.6±4.3 ka BP45.6±4.3 ka BP)、末次冰期早期(MIS4)。千湖山冰川前进规模是MIS3b 阶段大于末次冰盛期,主要原因是末次冰期中期(MIS3b) 时本区气候相对湿润,而在末次冰盛期(MIS2) 时气候条件比较干燥。在总体相似的气候背景下,与横断山其它存在多期次冰川作用的山地相比,千湖山只发育末次冰期的冰川作用,其差异性说明该地区冰川发育主要受山体构造抬升控制。 相似文献
20.
V. M. Fedorov R. V. Gorbunov T. Yu. Gorbunova N. K. Kononova 《Geography and Natural Resources》2017,38(1):86-92
A comparison is made of the calculated values of solar radiation incident on the upper atmospheric boundary with the measured values of surface temperature on the territory of the Crimean Peninsula. It is shown that the long-term temperature regime on the territory of the Crimean Peninsula is characterized by a stability. It is determined that the stability of the long-term regime of mean annual surface air temperatures is associated with the characteristics of the latitudinal distribution of solar radiation incident on the upper atmospheric boundary. The incident solar radiation increases in the regions of heat sources and decreases in the regions of heat sink. Stability of long-term mean annual values of surface air temperature is associated with the location of the Crimea on the boundary of the regions of heat sources and sinks. The study revealed the chronological structure of long-term changes in surface air temperature. The anomaly in the long-term surface air temperature variability is characterized by short-duration variations. An analysis is made of the chronological structure of interannual variability in surface air temperature on the territory of the peninsula. The dominant interannual and 2–3-year periodicities in the temperature regime variations are correlated with variations in incident solar radiation. In 62.7% of cases, the sign of interannual variability in surface air temperature corresponds to the sign of interannual variability in incident solar radiation. Thus it is shown that a small tendency in the long-term surface air temperature variability on the territory of the Crimean Peninsula, and the characteristics of its variations are determined largely by the specific character of the input and distribution of solar radiation incident on the upper atmospheric boundary. 相似文献