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1979～2004年中国大陆南方地区春季降水的年代际变化特征及其与欧亚大陆积雪的联系 总被引：1，自引：0，他引：1
本文研究了中国南方春季降水在1979～2004年期间的年代际变化特征,结果表明无论在年际还是在年代际时间尺度上,中国南方东南和西南地区降水都具有反相变化的特征,并分别呈现出显著的减少趋势和增加趋势.中国南方春季降水在20世纪80年代末出现了一次明显的年代际气候转型.东南地区的春季降水明显减少,降水量在80年代末以后比80年代末之前减少了30%;而西南地区的春季降水则明显增加,80年代末之后的降水量是80年代末之前的两倍.伴随着这次年代际转型,欧亚大陆西伯利亚上空对流层中低层位势高度增强,对流层低层中国东部北风增强,造成中国东部西南风减弱,使得降水在东南地区减少,西南地区增多.中国南方春季降水在20世纪80年代末出现的年代际气候转型与欧亚大陆春季积雪的年代际转型有密切联系.从20世纪80年代末开始欧亚大陆春季积雪明显减少,与欧亚大陆春季积雪变化所伴随的大气环流变化,是造成春季我国东南地区降水减少和西南地区降水增多的一个重要原因. 相似文献
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利用相关、合成、奇异值分解等统计诊断和数值模拟方法,分析了前冬(12—2月)南半球环状模(SAM)对春季(3—5月)中国华南降水的可能影响及其机理.诊断分析的结果表明,前冬南半球环状模与春季华南降水存在显著的负相关关系,也即前冬SAM偏强(弱),对应春季华南降水偏少(多).为了探讨这种南半球中高纬信号影响滞后一个季节的华南降水的物理机制,需要考虑下垫面海洋的桥梁作用.诊断分析的结果表明,当前冬SAM偏强时,南半球中高纬海洋的潜热释放受到海表风速影响发生变化,导致30°S—45°S海温偏高, 45°S—70°S海温偏低,并且异常的海温信号可以持续到次年春季.这种前冬SAM偏强时的春季海温异常信号,对应着春季西北太平洋副热带高压位置偏东且强度偏弱,西北太平洋上盛行异常气旋式环流,华南地区上空对流层低层有异常东北风和风场辐散,西南水汽输送较常年减弱,为春季降水偏少提供了有利的条件.前冬SAM偏弱时,南半球中高纬的海温异常及其引起的华南区域大气环流异常相反,有利于华南降水偏多.利用CAM3进行海温敏感性试验,也证明了上述南半球中高纬海温异常对应的环流异常.模拟结果表明,SAM偏强时的海温异常,对应着华南上空对流层低层的东北风异常、风场辐散、以及下沉运动,不利于华南降水生成;SAM偏弱时的海温异常,对应的环流异常相反,有利于华南降水增多,验证了资料诊断的结论.综上,在前冬SAM影响春季华南降水的过程中,体现了海气耦合桥的作用,即:海洋储存了冬季SAM的异常信号并在春季释放,通过影响春季大气环流,进一步影响华南春季降水.因此,前冬SAM为华南春季降水预测提供了一个有意义的前期信号. 相似文献
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观测事实揭示,春季Hadley环流在年际时间尺度上与东亚夏季风环流和降水具有密切联系.在未来全球变暖背景下,春季Hadley环流与东亚夏季风环流和降水的这种年际关系是否会发生变化？针对该问题,本文在评估的基础上选取五个气候模式,分析了A1B排放情景下春季北半球Hadley环流年际变率的未来变化及其与东亚夏季风环流和降水的年际关系.多模式集合(MME)预估结果表明,在全球变暖背景下,与20世纪末期(1970—1999年)相比,到21世纪末期(2070—2099年),春季北半球Hadley环流的年际变率强度将减弱,减弱幅度达32%.随着春季Hadley环流年际变率的减弱,其与夏季西太平洋副热带高压和东亚夏季风强度的联系将变弱.MME模拟结果还显示,春季Hadley环流与夏季东亚西风急流和降水的关系也降低,但各单个模式间存在较大差异. 相似文献
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利用美国国家环境预报中心和美国国家大气科学研究中 心（NCEP/NCAR）再分析月平均气候资料以及Xie和Arkin分析的月平均降水资料（1968～199 8年），针对索马里低空急流（SMJ）的年际变化及其对东亚夏季降水的影响问题展开了分析 研究. 结果揭示，SMJ作为最主要的越赤道气流，对两个半球间水汽输送起最关键的作用， 它把水汽从冬半球输送到夏半球. 夏季SMJ的年际变化有全球范围内的环流异常与之相联系 ，特别是东亚沿岸的波列状异常分布、南亚高压以及澳大利亚以南的偶极型异常分布；它 也同春季的北印度洋等海区的海温异常有密切关系. 研究还表明，春季SMJ的年际变化对东 亚夏季降水和大气环流有显著影响，由于SMJ影响的超前性，因此它在东亚夏季气候预测上 有重要意义. 相似文献
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东亚副热带夏季风建立与中国汛期开始时间 总被引：3，自引：0，他引：3
采用谐波等分析方法,讨论了季节转化过程中东亚大陆降水和对流层风场时空分布特征、海-陆热力差异以及大气加热与风场和降水之间的季节变化关系,确定了春季中国江南降水的副热带夏季风性质.分析认为,3月份中国江南春雨是东亚副热带夏季风降水的孕育阶段,4月初东西向海陆热力差异在东亚副热带地区最早完成冬夏的季节性反转,时间早于南海夏季风爆发并对应华南前汛期的开始,标志着东亚副热带夏季风的建立和中国汛期降水的开始.东亚副热带夏季风主要活动在东亚100°E以东、20°N以北地区,春季（3~4月份）中南半岛和江南地区大气加热的持续作用可能导致了东亚东西向海陆热力差异在副热带地区完成反转.其中,江南上空大气热源是导致该地区对流层低层西南风、上升运动和降水增强的主要原因. 相似文献
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1990s长江流域降水趋势分析 总被引：2，自引：0，他引：2
依据国家气象局提供的实测月降水和日降水资料,运用Mann-Kendall(M-K)非参数检验法验证了降水趋势,并通过空间插补法,由点扩展到面,分析了1990s长江流域降水变化特征,发现1990s长江流域降水变化以降水在时间和空间分布上的集中度的增加为主要特点:时间上,年降水的增加趋势以冬季1月和夏季6月降水的集中增加为主;一日降水量大于等于50mm的暴雨日数和暴雨量在1990s也有了较明显的增加.空间上,年降水、夏季降水、冬季降水的增加都以中下游区的增加为主,尤其以鄱阳湖水系、洞庭湖水系的降水增加为主.1990s长江流域春季和秋季降水的减少以5月和9月两个汛期月份的降水减少为主,除金沙江水系和洞庭湖水系等少数地区外,流域大部分地区降水呈减少趋势.上述1990s出现的降水趋势明显与近年来全球变暖背景下长江流域各地区不同的温度及水循环变异有关. 相似文献
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《中国科学:地球科学》2020,(1)
利用中国气象科学研究院气候系统模式CAMS-CSM中大气和陆面的耦合版本进行了土壤湿度和热带太平洋海温异常影响东亚夏季风的数值模拟,探讨了中国东部从长江中下游到华北(YRNC)春季土壤湿度和厄尔尼诺(El Ni?o)在影响夏季东亚环流和中国东部降水中的作用及其机理.结果表明,中国东部春季土壤湿度和El Ni?o海温异常均对东亚夏季风有显著的影响,其中土壤湿度对中国东部夏季降水的影响略大于海温的作用,然而两者对东亚夏季风环流和中国夏季降水的作用显著不同. YRNC土壤偏湿(干)引起的降水异常模态为中国北部和东南降水偏少(多),而长江流域和东北降水偏多(少),环流上YRNC土壤偏湿(干)能引起西太平洋副热带高压显著偏强(弱)偏西(东)和东亚大槽偏深(浅),表现为弱(强)夏季风形态. El Ni?o对降水的影响显著不同于土壤湿度的作用,在El Ni?o发展期的夏季,中国东北和华北地区为异常反气旋,长江中下游和华南地区为异常气旋,西太平洋副热带高压偏弱,引起长江下游、华南降水偏多,华北降水偏少.在El Ni?o衰减期的夏季,中国东北地区存在一个异常气旋,华南有一个异常反气旋,异常反气旋西部的偏南气流和异常气旋西部的偏北气流在中国中部和北部地区汇合,使得夏季华北和长江中游地区降水增多,其余地区降水偏少. 相似文献
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利用RAMS数值模式,研究了巨凝结核数浓度改变对半干旱地区春季冰雹云降水特征的影响,研究显示巨核浓度改变对冰雹云中微物理过程及地面降水都有重要影响.累积带对冰雹生成有重要贡献.巨核数浓度增加时,冰雹云中冰雹混合比含量及其云中水平覆盖面积增加;云中过冷雨水和大云滴生成的过冷云水增加,冻结作用增强;地面降雨量增加但降雹量减少;总的地面累积降水量增加但累积冰相降水量减小.对降水的作用在污染云中要比清洁云中明显.地面流场分布随着巨核数浓度的改变而不同.在不同背景气溶胶下,春季冰雹云的判别指标不同于夏季冰雹云. 相似文献
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《中国科学:地球科学》2015,(5)
利用JTWC提供的1981~2011年孟加拉湾热带风暴最佳路径资料,研究春季、初夏(AMJ)及秋冬季节(SOND)孟加拉湾风暴对青藏高原降水及土壤湿度的影响特征.研究表明:每年平均约1.35个孟加拉湾风暴能够影响青藏高原,5和10月是孟加拉湾风暴影响青藏高原的两个主要时期,且在AMJ生成的风暴比SOND影响范围更大,影响的纬度更偏北;孟加拉湾风暴引起的降水最大可超过当地当月降水量的50%,同时也能够占到整个季节的20%.资料分析还表明春季风暴降水引起的青藏高原表层土壤湿度异常大概能维持20~25 d,秋冬季节孟加拉湾风暴引起的高原积雪也仅能维持20 d左右便基本消融殆尽.数值试验表明青藏高原表层土壤湿度异常仅持续20 d左右,次表层异常则大概可以持续2个月,而更深层次土壤湿度异常则可维持数个月甚至更久.最后,统计关系还表明前期风暴引起的高原积雪及土壤湿度异常并不足以影响到东亚夏季降水,其与中国东部夏季降水异常无直接联系.近30年来孟加拉湾风暴强度增强,使得20世纪90年代中期以后孟加拉湾风暴对青藏高原春季降水的影响有所增强. 相似文献
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应用日本东京大学气候系统研究中心(CCSR)发展起来的一个全球大气环流谱模式(T42L200版本),对l998年夏季气候异常和大气环流的预测问题进行了研究,定量地检查了该模式对夏季降水和大气环流异常的预测准确度.说明该模式对1998年的预测水平是比较高的;并证实大气环流在春季的初始异常对北半球夏季大气环流和降水异常起了很重要的作用,而对南半球的作用则小得多.就中国长江流域1998年的降水异常而言,初始环流的作用约占50%. 相似文献
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The spatial and temporal variations of precipitation and runoff for 139 basins in South Korea were investigated for 34 years (1968–2001). The Precipitation‐Runoff Modelling System (PRMS) was selected for the assessment of basin hydrologic response to varying climates and physiology. A non‐parametric Mann–Kendall's test and regression analysis are used to detect trends in annual, seasonal, and monthly precipitation and runoff, while Moran's I is adapted to determine the degree of spatial dependence in runoff trend among the basins. The results indicated that the long‐term trends in annual precipitation and runoff were increased in northern regions and decreased in south‐western regions of the study area during the study period. The non‐parametric Mann–Kendall test showed that spring streamflow was decreasing, while summer streamflow was increasing. April precipitation decreased between 15% and 74% for basins located in south‐western part of the Korean peninsula. June precipitation increased between 18% and 180% for the majority of the basins. Trends in seasonal and monthly streamflow show similar patterns compared to trends in precipitation. Decreases in spring runoff are associated with decreases in spring precipitation which, accompanied by rising temperatures, are responsible for reducing soil moisture. The regional patterns of precipitation and runoff changes show a strong to moderate positive spatial autocorrelation, suggesting that there is a high potential for severe spring drought and summer flooding in some parts of Korea if these trends continue in the future. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Yonghong Hao Guoliang Liu Huamin Li Zhongtang Li Jiaojuan Zhao Tian‐Chyi J. Yeh 《水文研究》2012,26(20):3062-3069
Niangziguan Spring complex is the largest karst spring in North China. We investigate the karst hydrological processes by using Morlet wavelet transform analysis and cross wavelet analysis based on monthly precipitation from 1958 to 2010 and spring discharge from 1958 to 2009. From Morlet wavelet transform coefficients of precipitation and the spring discharge in Niangziguan Springs Basin, we find that the precipitation and discharge are characterized by the multi‐scale features in the time domain, and the energy distribution of the signal is highly irregular across scales. Although precipitation eventually becomes spring discharge by infiltrating and propagating through karst formations, the signals are attenuated. The results also show that the precipitation of Niangziguan Springs Basin has the main periodic components of 1‐, 5‐, 12‐, and 17‐year periods with alternating wet–drought cycle. Similarly, the spring discharge of Niangziguan Springs has the main components of 17‐year periods, but the 1‐, 5‐, and 12‐year periodicity of precipitation are not reflected in spring discharge, which is filtered by the aquifers. The results of cross wavelet analysis reveal that the precipitation and spring discharge share the common periodicity of 17 years. This means that those signals with high energy and long timescales can penetrate through the aquifer and be reflected in spring discharge, whereas other signals are filtered and modified. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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应用 １００ｈＰａ、５００ｈＰａ月平均高度资料、海温、射出长波辐射（ＯＬＲ）及武汉的气温 和降水资料,对１９９８年长江中游特大洪涝的成因作了总结分析．结果表明,冬春厄尔尼诺、副 热带高压和从春到初夏期间,印度洋－西太平洋赤道辐合带（ＩＴＣＺ）南侧积云对流的异常较 强,以及冬季雨雪异常偏多等气候特点,是有利于洪涝发生的强信号． 相似文献
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Changes in seasonality and timing of peak streamflow in snow and semi‐arid climates of the north‐central United States, 1910–2012 
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下载免费PDF全文 Changes in the seasonality and timing of annual peak streamflow in the north‐central USA are likely because of changes in precipitation and temperature regimes. A source of long‐term information about flood events across the study area is the U.S. Geological Survey peak streamflow database. However, one challenge of answering climate‐related questions with this dataset is that even in snowmelt‐dominated areas, it is a mixed population of snowmelt/spring rain generated peaks and summer/fall rain generated peaks. Therefore, a process was developed to divide the annual peaks into two populations, or seasons, snowmelt/spring, and summer/fall. The two series were then tested for the hypotheses that because of changes in precipitation regimes, the odds of summer/fall peaks have increased and, because of temperature changes, snowmelt/spring peaks happen earlier. Over climatologically and geographically similar regions in the north‐central USA, logistic regression was used to model the odds of getting a summer/fall peak. When controlling for antecedent wet and dry conditions and geographical differences, the odds of summer/fall peaks occurring have increased across the study area. With respect to timing within the seasons, trend analysis showed that in northern portions of the study region, snowmelt/spring peaks are occurring earlier. The timing of snowmelt/spring peaks in three regions in the northern part of the study area is earlier by 8.7– 14.3 days. These changes have implications for water interests, such as potential changes in lead‐time for flood forecasting or changes in the operation of flood‐control dams. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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采集夏县中心地震台温泉水及周边水点样品进行水化学组分特征分析。利用矩形图、Na-K-Mg三角图等方法,初步分析温泉水的水质类型、水-岩平衡状态、热储温度以及循环深度等,并结合氢氧同位素组成特征,初步分析温泉水补给来源。研究表明,夏县中心地震台温泉水化类型属于Na-Cl·SO4型,水-岩反应属于部分成熟水,热储温度为148.8℃,循环深度为3.91 km,补给源主要为大气降水,温泉为断裂型温泉。以上结果可为该台流体异常分析提供基础研究资料,为夏县地区水化研究奠定基础。 相似文献
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Quantifying changes of effective springshed area and net recharge through recession analysis of spring flow 下载免费PDF全文
下载免费PDF全文 The average flow of Silver Springs, one of the largest magnitude springs in Central Florida, declined 32% from 2000 to 2012. The average groundwater head in the springshed declined 0.14 m, and the spring pool altitude increased 0.24 m during the same period. This paper presents a novel explanation of the spring flow recession curve for Silver Springs using the Torricelli model, which uses the groundwater head at a sentinel well, the spring pool altitude and the net recharge to groundwater. The effective springshed area and net recharge (defined as recharge minus groundwater pumping and evapotranspiration) were estimated based on the observed recession slopes for spring flow, groundwater head and spring pool altitude. The results indicate that the effective springshed area continuously declined since 1989 and the net recharge declined since the 1970s with a significant drop in 2002. Subsequent to 2002, the net recharge increased modestly but not to the levels prior to the 1990s. The reduction in net recharge was caused by changes in hydroclimatic conditions including precipitation and air temperature, along with groundwater withdrawals, which contributed to the declined spring flow. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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This work presents results from a nearly two-year monitoring of the hydrologic dynamics of the largest submarine spring system in Florida, Spring Creek Springs. During the summer of 2007 this spring system was observed to have significantly reduced flow due to persistent drought conditions. Our examination of the springs revealed that the salinity of the springs' waters had increased significantly, from 4 in 2004 to 33 in July 2007 with anomalous high radon (222Rn, t1/2=3.8 days) in surface water concentrations indicating substantial saltwater intrusion into the local aquifer. During our investigation from August 2007 to May 2009 we deployed on an almost monthly basis a continuous radon-in-water measurement system and monitored the salinity fluctuations in the discharge area. To evaluate the springs' freshwater flux we developed three different models: two of them are based on water velocity measurements and either salinity or 222Rn in the associated surface waters as groundwater tracers. The third approach used only salinity changes within the spring area. The three models showed good agreement and the results confirmed that the hydrologic regime of the system is strongly correlated to local precipitation and water table fluctuations with higher discharges after major rain events and very low, even reverse flow during prolong droughts. High flow spring conditions were observed twice during our study, in the early spring and mid-late summer of 2008. However the freshwater spring flux during our observation period never reached that reported from a 1970s value of 4.9×106 m3/day. The maximum spring flow was estimated at about 3.0×106 m3/day after heavy precipitation in February-March 2008. As a result of this storm (total of 173 mm) the salinity in the spring area dropped from about 27 to 2 in only two days. The radon-in-water concentrations dramatically increased in parallel, from about 330 Bq/m3 to about 6600 Bq/m3. Such a rapid response suggests a direct connection between the deep and the surficial aquifers. 相似文献
20.
利用水文地球化学数据建立温泉水文循环模型, 探讨温泉水文地球化学变化与地震的关系, 对中强地震短临流体异常判断具有重要的意义。 通过对石棉公益海温泉水常量元素、 微量元素和氢氧同位素以及锶同位素的测量, 探讨了该区域水文地球化学时空变化特征。 因此, 于2008年10月至2019年9月, 共对公益海温泉采集水样206个, 并对温泉水中离子组分和浓度, 温泉逸出气组分、 温泉气体同位素、 碳同位素和氢氧同位素含量进行测量。 分析结果表明: ① 公益海温泉主要为Na-HCO3·Cl型水, δD、 δ18O同位素测值分别为-14.19‰~-14.83‰和-108.67‰~-110.47‰, 分布于大气降水线附近, 说明温泉水主要源于大气降水; ② 据SiO2地温计计算热储温度约94.12℃, 循环深度约4.3 km, 表明大气降水入渗地下, 在热源加热后, 沿着断层和裂隙循环到地表, 形成温泉补给; 并且, 锶同位素和微量元素研究发现, 87Sr和86Sr主要来自硅酸盐类矿物, 微量元素含量较低, 水岩反应程度较弱; ③ 通过对研究区进行长时间连续观测发现, 在公益海周围300 km范围内的3个五级以上的地震使温泉水中常量元素的浓度, 分别出现了震前异常、 同震响应和震后效应。 推测这可能是因为公益海温泉位于公益海断裂和安宁河断裂的交会区, 推测周围的地震会触发公益海温泉水中的离子地球化学特征产生变化。 结合已有地质资料与公益海温泉水文地球化学数据, 建立公益海断裂带温泉水文循环模型, 这些对公益海断裂带周围未来中强地震短临流体异常判断具有重要的意义。 相似文献