CRRES in review: space weather and its effects on technology     

《Journal of Atmospheric and Solar》2002,64(16):1709-1721

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Transport of atmospheric impurities over the Qinghai–Xizang (Tibetan) Plateau as shown by snow chemistry     

《Journal of Asian Earth Sciences》2002,20(3):231-239

Chemical records were recovered from samples collected from snow pits over two transects (S–N and SE–NW) across the Qinghai–Xizang (Tibetan) Plateau. The records show that the flux of major ions in the regions to the north of Mt Tanggula is, on the average, 6–30 times higher than that of the regions to the south, and 0.6–5 times higher than regions to the southeast. It appears that Mt Tanggula provides a barrier to continental dust transported across the plateau from the north and to marine aerosols transported from the southeast. The spatial patterns of snow chemistry as well as the total suspended particle (TSP) distribution along the northern Qinghai–Xizang Highway demonstrate that continental dust originates mainly from the deserts to the north, while monsoon sources of moisture exert greater influence on snow chemistry on the southern part of the plateau.Seasonal variations of the major ions were also examined in a firn core drilled at a height of 7000 m on the Dasuopu Glacier and in a snow pit from the Meikuang Glacier (eastern Kunlun). The choice of a high altitude site at Dasuopu, and the sampling season (before snowmelt) at Meikuang, avoided post-depositional modification processes (mainly the elution effect of meltwater), thus guaranteeing the reliable recovery of the distribution of impurities in different seasons. The peak of the impurities appear at Dasuopu during the spring and at Meikuang in the winter/spring, coinciding with the Asian dust season. However, the amplitude of the seasonal variations at Meikuang is much higher than at Dasuopu.pH values at the Dongkemadi Glacier are greater than 6, but at the Dasuopu Glacier (Himalayas) they range between 4 and 7.5. The liquid conductivity (LC) from Dongkemadi is positively correlated with the pH, while at Dasuopu, LC is positively correlated with pH when pH is below 6 and negatively correlated with pH when it is greater than 6. This implies that during August to September the Himalayan range is a transition zone between the transportation of continental dust and marine aerosols.  相似文献   

江淮流域强暴雨过程对阻高和副高逐日变化的响应关系   总被引：3，自引：1，他引：2       下载免费PDF全文

陈菊英  冷春香  程华琼 《地球物理学进展》2006,21(3):1012-1022

江淮流域是我国暴雨频发的地区之一,而乌拉尔山阻塞高压和西太平洋副热带高压是北半球两个主要的大气环流系统.本文统计分析了1971~2003年期间乌山阻塞高压和西太平洋副高的逐日强度变化特征,研究了乌山阻塞高压和西太平洋副高对江淮流域强暴雨过程的响应关系.结果表明,江淮流域多数强暴雨过程发生在乌山阻高的减弱期,在乌山阻高的建立和加强期较少有持续性暴雨发生.乌山阻高的突然减弱是江淮流域强暴雨过程发生的强信号之一.同时,西太平洋副热带高压的加强西伸登陆是江淮流域强暴雨过程发生的必要条件之一.  相似文献   

基于DERF2.0的华南前汛期降水订正          下载免费PDF全文

王娟怀  李清泉  汪方  杨守懋  胡娅敏 《应用气象学报》2021,32(1):115-128

针对我国华南前汛期(4-6月)降水,基于国家气候中心第2代月动力延伸模式(DERF2.0)结果,利用非参数百分位映射方法将模式预测结果转化为概率预报,并进行概率订正.分别选用交叉建模与独立样本建模两种订正方法,并利用偏差、偏差百分率、时间相关系数、均方根误差等统计方法检验订正效果.结果表明:订正方法对预报技巧的改善与起...  相似文献   

Multivariate probabilistic estimates of heat stress for rice across China     

Lei?Zhang  Bingyun?Yang  Anhong?Guo  Dapeng?Huang  Zhiguo?HuoEmail author 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(11):3137-3150

Heat stress, a major threat to rice (Oryza sativa) production across China, would tend to increase in frequency and intensity under warming climate. Unlike probabilistic analysis via a univariate character, heat stress events, characterized by three variables (i.e., duration, peak and accumulated detrimental intensity), were identified in the past years. Nine distribution functions (i.e., Beta, Cauchy, Logistic, Normal, Exponential, Gamma, Lognormal, Weibull and Generalized Extreme Value) were firstly introduced and compared to select the best-fit marginal distribution of univariable by using Kolmogorov–Smirnov test, and seven copula functions (i.e., Normal and t, Gumbel–Hougaard, Clayton, Frank, Joe, Ali-Mikhail-Haq) were applied in the distributions of multivariables by Akaike Information Criterion statistics. It was obvious that higher magnitude was in the eastern parts in the context of heat stress frequency and characteristic variables. Critical values of heat stress variables corresponding to the certain return periods (i.e. 5, 10, 20 and 50 years) successively expanded in intensity and spatial scope. Inter-correlations of heat stress variables were significant, enlightening the importance of copula in connecting heat stress variables. The combined and co-occurrence bivariate and trivariate return period at certain univariate value corresponding to the given return periods, were consistent at the spatial scale. Accordingly, it was highlighted that eastern parts, especially Zhejiang, central-northern Fujian and eastern Jiangxi, were prone to heat stress, as a consequence of not only univariate but also multivariate probabilistic analysis. These results can be helpful in quantitatively assessing the vulnerability of rice to heat stress and provide us desired information of prevention strategies for heat stress.  相似文献   

A high-accuracy method for simulating the XCO<Subscript>2</Subscript> global distribution using GOSAT retrieval data     

MingWei Zhao  XingYing Zhang  TianXiang Yue  Chun Wang  Ling Jiang  JingLu Sun 《中国科学:地球科学(英文版)》2017,60(1):143-155

A high-accuracy surface modeling (HASM) method based on the fundamental theorem of surfaces, is developed to simulate XCO₂ surfaces using the GOSAT retrieval XCO₂ data. Two tests are designed to investigate the simulation accuracy. The first test divides the existing satellite retrieval XCO₂ data into training points and testing points, and simulates the XCO₂ surface using the training points while computing the simulation error using the testing points. The absolute mean error (MAE) of the testing points is 1.189 ppmv, and the corresponding values of the comparison methods, Ordinary Kriging, IDW, and Spline are 1.203, 1.301, and 1.355 ppmv, respectively. The second test simulates the XCO₂ surface using all the satellite retrieval points and uses the TCCON (Total Carbon Column Observing Network) site observation values as the ture values. For the six typical TCCON sites, the HASM simulation MAE is 1.688 ppmv, and the satellite retrieval MAE at the same sites is 2.147 ppmv. These results indicate that HASM can successfully simulate XCO₂ surfaces based on satellite retrieval data.  相似文献   

影响中国北方强降雪事件年际变化的典型环流背景和水汽收支特征分析   总被引：1，自引：0，他引：1       下载免费PDF全文

王遵娅  周波涛 《地球物理学报》2018,61(7):2654-2666

基于1961-2014年中国台站观测资料和NECP/NCAR再分析资料,对影响中国北方强降雪事件（日降雪量5 mm及以上,包括大到暴雪）年际变化的典型大尺度环流特征和水汽条件进行了综合分析.结果表明：中国北方强降雪事件主要集中在新疆北部和东北两个地区,而且强降雪日数和降雪量具有高度一致的年际变化特征.中国北方强降雪事件偏多时,对应北大西洋涛动（NAO）和北极涛动（AO）负位相;贝加尔湖上空维持异常低槽区,有利于冷空气的爆发南下;热带印度洋至热带西太平洋上空维持一条异常反气旋带,有利于暖湿气流向北输送;中国北方及以北区域高空为异常西风气流,提供有利的动力抬升条件,使得强降雪易于在中国北方发生;反之亦然.水汽收支分析显示,中国北方西边界和南边界水汽入流增强在强降雪偏多中起着主要贡献.异常西风水汽输送利于新疆北部大到暴雪偏多,异常西南风水汽输送则利于东北地区大到暴雪的发生.进一步研究揭示：与小雪相比,影响中国北方大到暴雪年际偏多的中高纬环流特征相类似,但环流经向度更大;而且大到暴雪与NAO和AO的关系更密切,并更多的受到来自中低纬地区的水汽输送影响.  相似文献   

行星际磁场对极尖区位形变化的统计研究   总被引：1，自引：0，他引：1       下载免费PDF全文

徐佳莹  吕建永  王明  郭建广 《地球物理学报》2018,61(9):3526-3535

利用Cluster卫星数据,选取2001—2010年期间的616个极尖区穿越事件,研究了行星际磁场（IMF）的大小和方向对极尖区位形的影响.结果表明：当B_z为北向时,随着B_x负向的增大,极尖区的磁不变纬度向高纬方向（极区）移动;当B_z为南向时,随着B_x负向增大,极尖区的磁不变纬度略微向低纬度方向（赤道）移动.B_x正向增大时,极尖区并没有明显移动.B_x对极尖区影响在南半球较为显著,在北半球没有明显规律性变化.此外,随着行星际磁场锥角的增大（>90°）,极尖区也随之向高纬移动.当B_z南向时,随着B_y的负向增大,极尖区在北半球向晨侧移动,在南半球向昏侧移动.而当B_z南向增加时,南北半球两个极尖区的磁不变纬度都朝赤道方向移动;但北向B_z时几乎没有移动.  相似文献   

CMIP5模式对东亚冬季风指数变化及其与冬季大气环流和气温关系的模拟评估          下载免费PDF全文

王政琪  徐影  周波涛 《地球物理学报》2017,60(9):3315-3324

本文评估了44个CMIP5模式对东亚冬季风环流系统,特别是东亚冬季风指数及其对应的环流和气温特征的模拟能力.结果表明:CMIP5模式对地表气温和500 hPa位势高度场模拟效果最好,对200 hPa纬向风的模拟次之,而对海平面气压和850 hPa经向风的模拟相对较差.与单个模式相比,多模式集合(MME)的模拟能力要更优,其能够很好地再现西伯利亚高压、阿留申低压、东亚低层偏北风、中层东亚大槽、高层东亚西风急流以及地表气温的空间分布.不过,模拟的环流系统偏强,造成东亚地表气温总体偏低.对于东亚冬季风指数,分别选取基于300 hPa纬向风(I_(Jhun))、850 hPa风场(I_(Wang))、500 hPa位势高度(I_(Cui))、以及海平面气压(I_(Guo))定义的四个指数表征东亚冬季风强度.MME能很好地模拟I_(Cui)和I_(Wang)指数的长期变化,还能合理再现四个指数所指示的东亚冬季风环流和气温的变化特征:对应冬季风偏强年份,西伯利亚高压、阿留申低压、东亚沿岸低层北风、东亚大槽和高空西风急流加强,东亚大陆地表气温和极端低温降低,但变化的幅度比观测结果偏弱.  相似文献   

1901—2016年印太海域海表温度的偏差订正及数据集研制          下载免费PDF全文

陈丽凡  孙丞虎  张冬斌  曹丽娟  李维京 《地球物理学报》2019,62(6):2001-2015

海表温度系统性观测偏差的订正是开展长历史序列网格化海表温度气候数据产品研制的关键.本文在引入美国SR02海表温度偏差订正方法的基础上,结合国家气象信息中心自主研发的全球海表观测定时值数据集,进行了相关参数的优化改进,从而研制了1901-2016年印度洋-太平洋核心海域月平均2°×2°分辨率的海表温度偏差订正数据集.对海温偏差订正量的时空分布特征分析表明,基于自主研制的基础数据和优化改进的方法求解的偏差订正量能有效反映海表温度观测手段的历史变迁,以及海表温度系统性偏差随季节变化的规律.同时,与ERSST订正量的对比表明,由于优化改进后的方法其阈值计算随空间样本而变,因而其局地变化特征的表现能力更强,且其订正量在观测手段转型期的变化更为明显.相较订正前的海表温度距平(SSTA)场,订正后的SSTA资料与ERSSTv5SSTA间的偏差误差和均方根误差均有明显降低.其中,偏差误差的缩减比例在37.7%~87.9%之间,均方根误差可降低0.06℃.此外,与国际同类产品的对比表明,本文发展的SSTA订正数据集与国际同类SSTA产品序列的相关系数不低于0.97,且变化趋势类似.从差异对比上看,除中高纬东亚大陆近海区域外,本文的偏差订正数据集与国际上同类产品的SSTA差异基本在-0.2~0.2℃之间.  相似文献