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大气环流因子对北半球气温变化影响的研究 总被引：22，自引：0，他引：22
首先分析了北大西洋涛动(NAO)、北太平洋涛动(NPO)和南方涛动(SO)对北半球气温影响的空间分布特征。冬季大气涛动对温度方差贡献主要是在低纬和中高纬大陆地区及北太平洋部分区域,40°N以北大部分陆地总的贡献率达30%以上,热带3/4地区也在30%以上。近百年气温和大气涛动关系表明,三个涛动对北半球冬季、夏季和年平均气温的变化贡献分别达31.8%、2.6%和12.8%,也是以冬季影响最大。用大气涛动可以解释近20多年来气温上升的很大一部分方差,这说明可能在原有气温上升的趋势上,由于叠加了近期大气环流引起的气温变化,所以才形成了70年代末以来的加速变暖现象。 相似文献
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在系统梳理国内外海洋热浪相关研究文献的基础上,本文综述了海洋热浪季节、年际和年代际变化特征与长期变化趋势及其形成机理的主要研究进展。已有的研究表明：(1)由于夏季海洋混合层深度较浅,海表温度对海面加热过程更敏感,导致海洋热浪多发生于夏季且强度最强,冬季则相反。复杂的局地海洋与大气强迫也使得海洋热浪的季节变化具有显著的区域性特征。(2)海洋热浪的年际变化主要受厄尔尼诺-南方涛动（ENSO）和印度洋偶极子（IOD）等年际尺度海气耦合模态的影响,其中ENSO对海洋热浪的影响最为显著,其影响范围覆盖了全球大部分海域,IOD的影响主要集中在热带印度洋和热带太平洋,北大西洋涛动和大西洋纬向模态主要影响区域分别位于北大西洋和非洲西岸近海。(3)年代际太平洋涛动、太平洋十年涛动等低频气候波动对太平洋、热带大西洋以及东南印度洋海洋热浪的年代际变化具有重要作用。(4)海洋热浪长期变化趋势主要受人类活动的影响。全球气候模式的结果表明,在RCP8.5情景下,到2100年海洋热浪的强度将是RCP4.5的2倍,并且全球大部分海洋将陷入“永久性”的海洋热浪状态。最后,本文讨论了海洋热浪研究一些亟待解决的重要科学问题... 相似文献
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北极涛动异常对西北地区东部沙尘暴频次的影响 总被引：7，自引：4，他引：3
利用西北地区东部沙尘暴日数资料、北极涛动指数资料、东亚高低空大气环流形势场资料,分析了沙尘暴日数与北极涛动的关系,进而研究了北极涛动异常年东亚大气环流分布特征,探讨了北极涛动影响西北地区东部沙尘暴的可能途径。结果表明：西北地区东部沙尘暴频次呈波动减少之势,20世纪80年代中期发生气候突变;北极涛动指数与西北地区东部沙尘暴频次显著负相关,二者年际、年代际变化都有较好的应关系,北极涛动正位相年,西北地区东部沙尘暴偏少,反之亦然。究其原因：北极涛动异常对东亚冬季风强度、东亚高低空气压场、风场分布形势有重要影响：北极涛动正位相年,东亚冬季风、蒙古高压均偏弱;500 hPa高度场上,春季西风带纬向环流占优势,极涡面积偏小,强度偏弱,贝加尔湖阻塞高压异常强盛,蒙古国及我国华北和西北地区位于贝加尔湖阻塞高压底部的暖区里,地面至高空西北风偏弱;在这种形势下,整个中高纬度冷空气势力较弱,活动次数偏少,不利于大风、寒潮天气的发生,因此沙尘暴频次也偏少。而北极涛动负位相年基本相反。 相似文献
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以湖南湘西莲花洞LH2石笋为研究对象,在高精度铀系定年的基础上,构建了湘西地区中晚全新世文石石笋灰度序列。中晚全新世,LH2石笋灰度值与δ18O值呈负相关同步变化,与旋回沉积速率呈正相关关系。LH2石笋的剖面灰度与文石的结晶形态有关,受降雨量和温度的控制。LH2石笋灰度显示,中晚全新世（8.6—0.03 ka B.P.）湘西地区气候变化可以划分为3个阶段：8.6—5.7 ka B.P.期间,夏季风强盛,气候暖湿,灰度值整体偏高;5.7—2.8 ka B.P.期间,灰度值逐渐降低,指示夏季风持续减弱,气候从暖湿向冷干过渡;2.8—0.03 ka B.P.期间,灰度值整体偏低,且存在较大幅度的波动,表明该时段气候整体偏冷干,但其间存在明显的温湿波动。在轨道尺度上,LH2石笋灰度值主要受北半球夏季太阳辐射量和热带辐合带（ITCZ）位置的控制。在百年尺度上LH2石笋灰度值的突变可能与北大西洋冰筏事件存在关联;年代际尺度上,LH2石笋灰度的变化受太阳活动和太平洋年代际涛动（PDO）的调控。在年际尺度上LH2石笋灰度的波动可能受厄尔尼诺—南方涛动（ENSO）活动驱动。 相似文献
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以Fire_CCI51为主要数据源,应用GIS空间分析技术对呼伦贝尔地区2001—2019年草原火的时空分布进行了研究,结果发现：呼伦贝尔草原火时间上具有年际波动较大、循环周期不定和春、秋两季双峰式集中的特点;空间上集中分布在东部森林草原、边境线附近,呈现出东多西少、北多南少的格局。利用相关分析方法对主要气象因子（平均降水量、最高气温、最小相对湿度、最大风速）与草原火之间的关系进行了深入分析,发现气象因子与草原火之间不存在显著相关;通过对呼伦贝尔市1981—2015年的草原起火原因统计数据分析发现,人类活动是导致草原火发生的主要因素。应用空间分析方法对边境线20 km缓冲区内的草原火进行了提取,发现境外过火面积远高于境内而且俄罗斯的过火面积远高于蒙古和中国。 相似文献
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《山地学报》2016,(6)
依据天山地区40个气象站点的实测气温资料和同期的全球气候指数,运用线性倾向估计和相关分析等方法,分析近63年来天山地区气温变化特征及其对全球气候变化的响应。初步得到以下结论:天山地区平均升温幅度为0.306℃/10a;南亚季风季风指数(SASMI)是影响天山地区气温变化的主要气候指数,春季SASMI与四季的气温均呈现正相关;夏季SASMI与春季气温呈现负相关,而与夏季气温呈现正、负两种相关;冬季SASMI与夏、秋、冬季气温均呈现正相关,说明春、冬SASMI对四季的升温均有一定影响。太平洋10年涛动(PDO)是影响天山气温变化的另一较为主要气候指数,夏季PDO与夏季气温呈现负相关,与冬季气温呈现正相关;秋季PDO与夏秋季气温均呈现负相关。夏季北大西洋涛动NAO与春季气温呈现负相关,与夏季气温呈现正负两种相关;夏冬季太平洋北美涛动(PNAO)与冬季气温呈现正相关,秋季印度洋偶极子(IOD)与春季气温呈现正相关。此外,上述气候指数对气温变化的影响,在空间上存在一定的差异性。 相似文献
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《中国沙漠》2019,(3)
利用亚洲季风区帕默尔干旱指数(PDSI)重建格点数据集(Monsoon Asia Drought Atlas,MADA)中长江源及附近地区的5个格点序列,通过PDSI与长江源区径流量的相关分析,发现5个格点的第一主成分(PC1)与长江源区夏季(6—8月)平均径流量的相关性最大(r=0.609,N=50,α0.001)。由此,重建了1300—2005年长江源区夏季径流量变化,并运用独立验证法对重建结果的可靠性进行了检验,运用小波分析方法对重建径流序列进行周期分析。结果表明:近706 a,长江源区经历了显著的丰水期13个、枯水期15个,其中持续时间最长的丰水期为1513—1573年,持续时间最长的枯水期为1389—1414年;重建序列主要存在2～6、10～13、20～26、30～50、50～70 a的显著周期振荡。重建序列与海表温度的相关性表明,长江源区径流变化可能与厄尔尼诺-南方涛动(ENSO)、大西洋年际振荡(AMO)、北大西洋涛动(NAO)、太平洋年代际振荡(PDO)等有关。 相似文献
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欧亚秋季雪盖与北半球冬季大气环流的联系 总被引：1，自引：0，他引：1
利用NOAA 提供的1973-2004 年32 年欧亚雪盖面积资料和NCEP/NCAR 再分析资料, 采用相关和合成方法对比分析了欧亚秋、冬季雪盖与北半球冬季大气环流的关系,得到了一个观测事实: 欧亚秋季雪盖与后期冬季北半球中高纬大气环流存在显著的相关关系, 尤其是与北半球冬季大气环流的最主要模态北极涛动(AO) 或北大西洋涛动(NAO) 呈显著的负相关关系, 而且欧亚秋季雪盖面积与后期冬季北半球大气环流的关系比欧亚冬季雪盖与同期大气环流的关系更好。最后提出了一个联系欧亚秋季雪盖与冬季大气环流的可能原因: 欧亚秋季雪盖异常可能是导致后期冬季北半球大气环流变化的一个主要强迫因子。 相似文献
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利用开都河流域中段采集的雪岭云杉树芯样本,采用研究区域森林上下限2个采样点的树轮宽度年表,分析该地区两个树轮宽度年表的基本特征,建立与气象因子的关系模型,探讨树轮宽度生长与北大西洋涛动的关系。结果表明：（1）森林上限树木生长的一致性要强于森林下限,并且上限树轮宽度年表可能含有更多的气候信息;（2）森林上、下限树轮宽度年表在全频域、高频域及低频域上均存在显著正相关;（3）森林上、下限树轮宽度年表的气候响应结果基本一致,均表现出对上年9月至当年3月的逐月平均气温呈显著正相关,且均与上年12月的平均气温相关最高。树轮宽度年表与气象因子关系的模拟结果也证明了上年9、12月份和当年2、3、4月份的月平均气温与研究区树轮宽度生长间的密切关系;（4）研究区域树轮宽度生长与冬季北大西洋涛动指数的变化趋势较为一致。 相似文献
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Wildfires have long been an important environmental concern in Florida. Recent wildfires along the urban-rural interface of large cities in Florida have pointed to the need for an increased understanding of the physical and biological mechanisms that govern wildfire occurrence. Increased awareness of the relationships between global climate changes occurring in the tropics and their teleconnections outside the tropics dictate a reevaluation of the role of phenomena such as El Niño-Southern Oscillation on the risk of wildfire. One simple way of illustrating the relationship between ENSO and wildfire occurrence is the use of an Analysis of Variance (ANOVA) on wildfire data that has been categorized according to ENSO status (El Niño, La Niña, and neutral years). This research shows that a statistically significant relationship exists between ENSO conditions and annual wildfire occurrence in Florida when ENSO conditions are treated as a potential precursor to wildfire conditions. In particular, a statistically significant relationship exists between both acreage burned and average fire size, when the data are separated into El Niño and La Niña categories according to the previous year's ENSO status. This supports the idea that the climate from previous years has a measurable effect upon fire statistics in the years following the climate measurements, and that it may be possible to create a regional fire prediction model that incorporates ENSO information. [Key words: wildfire, natural hazards, ANOVA, Florida, ENSO.] 相似文献
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北疆西部近50 a来气候、水文变化趋势及其与北大西洋/北极涛动的关系 总被引：6，自引：2，他引：4
根据北疆西部11个气象站点1957—2007气象资料,主要代表性河流1960—2006年流量数据以及1957—2007年NAO和AO时间序列数据,采用趋势分析,Mann-Kendall检验以及相关分析等方法,研究了北疆西部地区近50 a来气候、水文的变化趋势,分析了气候变化对径流的影响,初步探讨了NAO和AO对区域气候变化的影响。研究结果表明,近50 a来,北疆西部地区增温、增湿显著,但二者变化幅度存在季节差异。受气候变化的影响,奎屯河年径流量表现出显著增加趋势。进一步分析发现,奎屯河、四棵树河年径流量的变化主要受温度因子控制,卡琅古尔河、精河和博尔塔拉河的年径流量则主要受降水因子控制。研究表明,艾比湖水域面积同样受气候变化的影响,尤其是与年降水量增加紧密相关,二者相关系数为0.584。相关分析证实NAO和AO确实对北疆西部地区的气候变化具有显著影响。具体体现在,NAO和AO显著的影响研究区冬季温度和全年的温度变化;NAO对整个区域年降水具有显著影响。温度比降水对NAO和AO的响应更敏感。 相似文献
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BY FIDEL A. ROIG DAVID BARRIOPEDRO RICARDO GARCÍA HERRERA DANIEL PATÓN DOMINGUEZ SUSANA MONGE 《Geografiska Annaler: Series A, Physical Geography》2009,91(2):141-157
Exactly dated ring-width chronologies derived from Pyrenean oak and sweet chestnut trees growing in northern Extremadura, Spain, were evaluated for their potential as proxies for regional precipitation and North Atlantic Oscillation variability. The relationships among tree-rings, instrumental climatic records, and three versions of the NAO index were computed for different time subperiods over the last century. The results indicate that tree-ring records reflect, with variable intensity, both short-term and long-term variations in climate. Multiple correlation and regression analysis revealed that summer precipitation appeared to be the major factor affecting tree growth at inter-annual timescales. Moreover, since fluctuations in accumulated variability in annual rainfall over southwest Iberia are controlled by winter precipitation, the accumulated rainfall (August of the year n -1 to July of year n ) and winter NAO indices are also strongly correlated with tree-ring records at interdecadal timescales. This relationship appears to be especially strong during the second half of the 20th century, which is consistent with an increase of the NAO signal in the annual precipitation during the later part of the century. These results indicate that tree-rings from western Iberia are potential proxies of the NAO variability, useful to be included in palaeoclimatic model studies. 相似文献
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《Singapore journal of tropical geography》2018,39(2):281-299
This paper examines spatial and temporal patterns of large to medium‐sized fires across the Indonesian Archipelago using remote sensing, particularly the MODIS fire products, over a 14 years period (2000–13 inclusive) in conjunction with climatic and land data in a GIS. Results showed fires (burned area and number of fires) were detected the most in year 2002 and least in 2010. The extent of burning was correlated with the annual Southern Oscillation Index with most burning occurring during times of sustained negative SOI values, which generally means drier conditions across the region. Most of the detected fires occurred in the middle of the dry season and in drier eastern Indonesia. Across Indonesia, approximately 1.5 per cent of available open vegetation area burned, whereas only 0.5 per cent of forest area burned. Most open vegetation burning was detected in the savanna with an area equivalent to 11.1 per cent of its extent being burned over the 14 years. On Sumba Island, where the pronounced dry season extends for at least four months, open vegetation is the most common land cover type, of which 99 per cent burned by area over the study period making it the island with the most burned areas in the Indonesian Archipelago. 相似文献
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阿克苏河径流变化与北大西洋涛动的关系 总被引：6，自引：0，他引：6
使用小波、交叉小波多尺度分析、相关和突变检验以及线性趋势等方法研究了阿克苏河天然径流与北大西洋涛动的关系。结论如下：（1）对NAO与阿克苏河径流的年代际变化、周期、相关等分析表明两者关系密切;（2）交叉小波谱表明：阿克苏河径流与NAO在年、冬季和夏季各周期尺度上的20世纪90年代相关性高,相关显著区多集中在90年代;（3）阿克苏河径流与NAO年代趋势强弱变化具有一致性;（4）NAO突变影响阿克苏河径流突变;（5）NAO通过大气环流变化来影响阿克苏河流域温度和降水,进而影响其径流。 相似文献
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The relationship between North Atlantic Oscillations (NAO) and Aksu River Runoff (ARR) was investigated by using the wavelet transform (WT), cross wavelet transform (CWT), correlation and linear trend analyses, and abrupt change test. The main results are as follows: the interannual/decadal variation and period analyses of ARR and NAO reveal that the both were close correlated each other; the CWT indicates that the correlation was good between ARR and NAO at all periods in the 1990s, because the significant correlation areas mainly concentrated in the 1990s; the variations in the trend strength of ARR and NAO were consistent; the abrupt change of NAO was also temporally consistent with that of ARR, which exerted impact on the Aksu River Basin (ARB) climate and then the ARR through atmospheric circulation variation. 相似文献
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Relationship between NAO and drought disasters in northwestern China in the last millennium 总被引：2，自引：0，他引：2
North Atlantic Oscillation (NAO) plays an important role in the Northern Hemisphere climate system. Although there is growing interest in the connection between NAO and precipitation change in China, there are few studies concerning that connection in northwestern China. Based on fine-grained historical drought disaster records and NAO proxies, we explored quantitatively their possible connection in northwestern China over the past millennium at the multi-decadal to centennial timescales. Statistical results show that NAO and drought disaster were negatively correlated, as positive modes of NAO caused northward-displaced, stronger-than average mid-latitude Westerlies with an enhanced latitudinal water vapor gradient into the central Asian drylands, resulting in reduced drought frequency and intensity in northwestern China. But, their correlation was out-of-phase during the Little Ice Age because of the southward shifting of monsoon, Westerlies, and the East Asian Jet Stream brought by long-term land surface cooling. As it has been indicated that the precipitation in northwestern China is also determined by El Niño-Southern Oscillation and North Atlantic sea surface and air temperature aside from NAO, further studies are needed to evaluate their individual roles and combined impacts upon the drought disaster there. 相似文献
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Katarina Pavlek Filip Bišćević Petra Furčić Ana Grđan Vesna Gugić Nino Malešić 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2017,117(1):22-35
Wildfires are an important factor of landscape dynamics in fire-prone environments of the world. In the Mediterranean, one of the most fire-susceptible environments globally, between 45,000 and 50,000 wildfires are recorded every year, causing disturbances in forest and grassland ecosystems. As a Mediterranean country, Croatia faces these problems, averaging over 1000 registered wildfires annually, with the coastal areas dominated by forest fires and continental Croatia by fires on agricultural lands. This research combines various landscape and socio-economic factors in the analysis of fire occurrence in Croatia’s southernmost region of Dalmatia. Around 275 of the largest fires (encompassing 98% of the total burnt area) registered in 2013 were investigated using OLS, and different spatial indices were employed to analyse regional variability in fire distribution. The results revealed that areas more prone to fires are the northern inland areas of Dalmatia and its entire coastal zone. Altitude and vegetation type demonstrated a correlation with fire occurrence, but an increase in population in the study area was also correlated with wildfire occurrence. Regarding vegetation, the grasslands and Mediterranean shrubland (maquis) were found to be the most fire-prone vegetation types in the study region, the distribution of which can be linked to different socio-economic and demographic processes occurring in the Eastern Adriatic. 相似文献