Interdecadal Change of the Northward Jump Time of the Western Pacific Subtropical High in Association with the Pacific Decadal Oscillation

In this paper, the northward jump time of the western Pacific subtropical high(WPSH) is defined and analyzed on the interdecadal timescale. The results show that under global warming, significant interdecadal changes have occurred in the time of the WPSH northward jumps. From 1951 to 2012, the time of the first northward jump of WPSH has changed from "continuously early" to "continuously late", with the transition occurring in 1980. The time of the second northward jump of WPSH shows a similar change, with the transition occurring in 1978. In this study, we offer a new perspective by using the time of the northward jump of WPSH to explain the eastern China summer rainfall pattern change from "north-abundant-southbelow-average" to "south-abundant-north-below-average" at the end of the 1970 s. The interdecadal change in the time of the northward jump of WPSH corresponds not only with the summer rainfall pattern, but also with the Pacific decadal oscillation(PDO). The WPSH northward jump time corresponding to the cold(warm) phase of the PDO is early(late). Although the PDO and the El Nino–Southern Oscillation(ENSO)both greatly influence the time of the two northward jumps of WPSH, the PDO’s effect is noticed before the ENSO’s by approximately 1–2 months. After excluding the ENSO influence, we derive composite vertical atmospheric circulation for different phases of the PDO. The results show that during the cold(warm)phase of the PDO, the atmospheric circulations at 200, 500, and 850 h Pa all contribute to an earlier(later)northward jump of the WPSH.     

河北北部四处温泉的水化学特征及成因分析

以河北北部承德地区的4处温泉,漠河沟温泉(A10)、三道营温泉(A11)、山湾子温泉(A12)和北大坝温泉(A13)为研究对象,根据2010年与2018年的温泉水样测试数据,分析温泉的水化学特征,并总结其成因模式。研究区出露地层主要有中新元古界、二叠系、三叠系、侏罗系、白垩系和新近系以及第四系,并伴随有大量侵入岩岩体。温泉的出露温度为36~75 ℃,pH值为7.2~8.2,TDS均小于1 g/L。研究区温泉阳离子均以Na⁺占绝对优势,毫克当量百分数在90%以上,阴离子主要以HC {\mathrm{O}}_3^{-}和S {\mathrm{O}}_4^{2-}为主,4处温泉的水化学类型分别为SO₄·HCO₃-Na型、HCO₃·SO₄-Na型、HCO₃-Na型和SO₄·HCO₃-Na型,且温泉的偏硅酸和F^-含量高。研究区温泉稀土元素总含量(∑REEs)为0.030~15.525 μg/L,主要以碳酸盐络合物和F的络合物形式存在;地下热水的稀土元素球粒陨石标准化配分模式较为平缓,轻稀土元素略显富集。研究区温泉水补给主要源于大气降水,利用 SiO₂ 温标估算的温泉地下热储温度为85~125 ℃,地下热水经深循环后通过接触带、破碎带或导水断裂上升出露地表。     

An assessment of uncertainties in VS profiles obtained from microtremor observations in the phased 2018 COSMOS blind trials

Journal of Seismology - Site response is a critical consideration when assessing earthquake hazards. Site characterization is key to understanding site effects as influenced by seismic site...     

浙江5个海湾鱼类分类多样性研究

本文基于2014年11月(秋季)和2015年5月(春季)在三门湾开展的渔业资源调查,结合杭州湾、象山湾、台州湾与乐清湾等4个相似的海湾的相关资料作为对照,依据《中国海洋生物名录》分别构建5个海湾的鱼种名录。以分类多样性指数、分类阶元包含指数、G-F多样性指数等进行多维度析。结果表明:平均分类差异指数(Δ+)象山湾最高(56.01),三门湾最低(48.79)。分类变异差异指数(Λ+)亦为象山湾最高(553.83),三门湾最低(313.63),由此可见象山湾鱼类在各分类阶元分布最不均匀,三门湾最均匀。关于分类阶元包含指数,三门湾鱼类的科、属、种的分类阶元包含指数值均较高;在目级水平上,杭州湾鱼类分类阶元包含指数最低,其余分类阶元上象山湾鱼类最低。G-F指数分析结果显示则显示:象山湾G-F指数最高(0.62),杭州湾最低(0.43)。由此得出,在目级水平上台州湾与乐清湾之间相似性最高(0.84),相似性最低的是三门湾与象山湾(0.5);在科级水平上台州湾与乐清湾之间相似性最高(0.71),相似性最低的是象山湾与台州湾(0.54)。综上,象山湾鱼类分类多样性最高,三门湾最低。本文通过揭示5个海湾鱼类多样性特征及差异,以期为鱼类资源的开发、利用、保护和管理等应用研究提供科学依据。     

Impact of FORMOSAT-3/COSMIC GPS radio occultation and dropwindsonde data on regional model predictions during the 2007 Mei-yu season

A study of the impact of FORMOSAT-3/COSMIC GPS radio occultation (RO) and dropwindsonde data on regional model simulations for a 11-day period during the 2007 Mei-yu season is presented. The Weather Research and Forecasting (WRF) model and its three-dimensional variation component, WRF-Var, are used for regional model predictions of heavy rainfall events in Taiwan. Without the use of GPS RO and dropwindsonde data, pressure and relative humidity are, in general, underestimated by the model; temperature predictions have a warm bias at the low level and a cold bias at the high level; and the east–west and north–south component winds have positive and negative biases, respectively. Incorporating GPS RO data tends to improve the prediction for longer integration. The assimilation of dropwindsonde data improves the forecast at the earlier time and at higher levels, and the improvement decreases over time. The reason the dropwindsonde data produce a positive impact earlier and the GPS RO data later is that there are few GPS RO observations in the fine domain. The large-scale simulation is first improved using the GPS RO observations, and the resulting changes can have a positive impact on the mesoscale at the later time. The dropwindsonde observations were taken inside the fine domain such that their impact can be detected early in the simulation. With both types of observation included, the prediction shows even greater improvement. At the earlier forecast time, there is nearly no impact from GPS and dropwindsonde data on rainfall forecasts. However, at the later integration time, the GPS data start to significantly improve the rainfall forecast. The dropwindsonde data also provide a positive impact on rainfall forecasts, but it is not as significant as that of the GPS data.     

京津唐地区的重力变化

我们重力测量组在1981年7月用三台 LCR 重力仪建立了重力测网.测量精度优于100nm/s2.文章描述了京,津,唐地区重力随时间的变化.结果表明在天津地区增加了约1000nm/s2,天津是沉降中心,每年平均沉降约7——8cm.在其它台站,如堂二里,霸县等地重力值也逐年增加,但其幅度小于天津.重力变化的空间分布由东南向西北逐渐减小.     

东北平原区地块尺度土地质量地球化学评价合理采样密度研究

选择吉林省公主岭市大岭地区作为东北平原区典型代表区域开展土壤元素空间变异性、经典统计学合理取样数及不同采用密度数据空间插值对比研究.结果表明:①受地形平坦及成土母质相对单一等因素影响,研究区土壤元素空间变异性总体较小,大部分以轻中度变异为主(变异系数<15%),受人为因素影响较大的Cd、Hg变异系数分别为35.3%、136.6%,属于高度变异.②经典统计学确定的研究区合理采样数为80,该样本量可在95%的置信区间及允许误差为30%的条件下反应区内土壤元素含量的均值与方差,但因未考虑样本的空间属性,不足以反应区内土壤元素空间变异特征,具有一定的局限性.③通过对均匀抽稀后4种不同采样密度数据与实测数据空间插值对比研究,在定量评估空间插值相对误差、地块预测值相对误差及预测等级与实测等级一致性的基础上,结合土地质量地球化学调查工作精度要求,提出研究区地块尺度地球化学评价工作合理采样密度为8个点/km2,该密度可在确保评价精度的前提下,大幅减少采样数量和工作成本.上述结论为东北平原及类似地区大面积开展地块尺度土地质量地球化学评价工作提供了关键的技术支撑,对进一步完善土地质量地球化学评价方法技术具有重要意义.     

油井流动成像束状探测电磁场

为了克服油井流动成像电磁探测的"软场"效应,提高成像质量,本文从测量物理模型出发,采用在轴向上屏蔽和径向上聚焦的方法构建束状探测场,通过有限元仿真计算电势分布以及测量敏感场,发现轴向上屏蔽后的电势分布均匀平坦,从而探测电磁场可以简化为二维场;径向上聚焦后敏感区域主要集中在发射电极和接收电极之间的束状区域内,敏感场呈马鞍状,其中间敏感性明显加强.模拟流动实验测量结果表明,束状探测电磁场的测量信号较强,成像质量明显提高.     

BCC_CSM模式夏季关键区海温回报评估

利用国家气候中心气候系统模式(Beijing Climate Center Climate System Model, BCC_CSM)的汛期回报试验数据集, 评估了夏季中低纬度海表面温度(Sea Surface Temperature, SST)的预测能力。结果表明:该模式对夏季中低纬海温具有一定的预测能力, 且在低纬地区的预测技巧尤为出色。对太平洋、热带印度洋和北大西洋这三个关键区进一步分析发现, 该模式对不同海区海温的预测能力有所不同。其中, 模式对夏季北太平洋海温及Ni?o 3.4指数表现出显著的预测技巧, 对热带印度洋、北大西洋海温及热带印度洋全区一致海温模态(Indian Ocean Basin-wide Warming, IOBW)也表现出一定的预测技巧, 而对北大西洋海温三极子模态(North Atlantic Tripole, NAT)的技巧相对较低。研究发现, 预测技巧与前冬的ENSO状态密切相关, 当前冬位于ENSO异常位相时, BCC_CSM模式对于三大海区夏季海温的预测技巧要高于前冬位于ENSO正常位相时, 且对NAT指数也具有更高的预测技巧。前冬ENSO所处的位相对于该模式对夏季Ni?o 3.4指数及IOBW指数的预测技巧影响不明显。此外, 该模式对夏季海温的预测技巧依赖于超前时间, 预测技巧在大部分情形下超前1个月的预测技巧相对更高。