最近十多年来冰冻圈加速萎缩——IPCC第六次评估报告之冰冻圈变化解读

政府间气候变化专门委员会（IPCC）于2021年8月发布了第六次评估报告第一工作组报告《气候变化2021：自然科学基础》。该报告基于最新的观测和模拟研究,评估了冰冻圈变化的现状,并采用CMIP6模式对未来变化进行了预估。报告明确指出,近十多年来冰冻圈呈现加速萎缩状态：北极海冰面积显著减小、厚度减薄、冰量迅速减少;格陵兰冰盖、南极冰盖和全球山地冰川物质亏损加剧;多年冻土温度升高、活动层增厚,海底多年冻土范围减少;北半球积雪范围也在明显变小,但积雪量有较大空间差异。冰冻圈的快速萎缩加速海平面的上升。未来人类活动对冰冻圈萎缩的影响将愈加显著,从而导致北极海冰面积继续减少乃至消失,冰盖和冰川物质将持续亏损,多年冻土和积雪的范围继续缩减。报告也提出,目前冰冻圈研究仍存在观测资料稀缺、模型对各影响因素的敏感性参数和过程描述亟需提升、对吸光性杂质的变化机制认知不足等问题,从而影响了对冰冻圈变化预估的准确性,未来需要重点关注。     

BCC模式及其开展的CMIP6试验介绍

世界气候研究计划（WCRP）正在组织实施第六次国际耦合模式比较计划（CMIP6),国家气候中心作为参与单位之一,通过近几年的模式研发,推出3个最新模式版本参与该计划,包括含有气溶胶化学模块的地球系统模式BCC-ESM1.0、中等分辨率气候模式BCC-CSM2-MR和高分辨率气候模式BCC-CSM2-HR。除了CMIP6中的气候诊断、评估和描述试验（DECK）和历史气候模拟试验（Historical),这3个模式共将参与CMIP6中的10个模式比较子计划。文中主要介绍这3个模式的基本情况以及所开展的CMIP试验,并对BCC-CSM2-MR模式的Historical试验结果进行简要评估,为试验数据使用者提供参考。     

Analysis of the Decadal and Interdecadal Variations of the East Asian Winter Monsoon as Simulated by 20 Coupled Models in IPCC AR4

Using the output data of 20 coupled climate models used in IPCC AR4 and observational data from NCEP, the capability of the models to simulate the boreal winter climatology of the East Asian sea level pressure, 850-hPa wind, and surface air temperature; the decadal variations of the East Asian winter mon- soon (EAWM) intensity and EAWM-related circulation, and the interdecadal variations of EAWM-related circulation are systematically evaluated. The results indicate that 16 models can weakly simulate the declin- ing trend of the EAWM in the 1980s. More than half of the models produce relatively reasonable decadal variations of the EAWM-related circulation and the interdecadal di?erences of EAWM-related circulation between the boreal winters of 1960-1985 and 1986-1998, including the weakened Siberian high, Aleutian low, and East Asian trough, the enhanced Arctic oscillation and North Pacific oscillation, and a deepened polar vortex. It is found that the performance of the multi-selected-model ensemble in reproducing the spatial dis- tribution of the variations is encouraging, although the variational amplitudes are generally smaller than the observations. In addition, it is found that BCCR_BCM2.0, CGCM3.1_T63, CNRM_CM3, CSIRO_MK3.0, GISS-ER, INM_CM3.0, and MRI_CGCM2.3.2 perform well in every aspect     

性类固醇激素及其受体在半滑舌鳎性腺分化发育过程中的表达与生理功能

首次用17β-雌二醇(E_2)及其受体(ERα)、睾酮受体(AR)的多克隆抗体在半滑舌鳎(Cynoglossus semilaevisG(u|¨)nther)性腺分化发育过程中进行免疫细胞化学定位研究。结果表明:在半滑舌鳎原始性腺中已有E_2、ERα和AR的分布和表达;卵原细胞、初级卵母细胞、精原细胞、初级精母细胞、次级精母细胞对E_2及ERα、AR抗体均呈现不同程度的阳性反应,在精细胞和精子中对E_2和ERα呈免疫阴性反应,而AR则一直保持较强表达,揭示了半滑舌鳎性腺中类固醇激素可能通过旁分泌调控机制刺激卵子和精子发育和成熟。性类固醇激素及其受体免疫阳性物定位在生殖细胞的胞质、胞膜和核膜等广泛部位并有表达,在性腺分化和不同发育时期的表达强度有所不同,表明其在性腺分化发育过程各阶段所起生理功能不同。这些结果为证明性类固醇激素及受体参与调节半滑舌鳎性腺分化发育提供了重要形态学新证据。     

Geophysical surveys of the sediments of Loch Ness,Scotland: implications for the deglaciation of the Moray Firth Ice Stream,British–Irish Ice Sheet

We present results from three geophysical campaigns using high‐resolution sub‐bottom profiling to image sediments deposited in Loch Ness, Scotland. Sonar profiles show distinct packages of sediment, providing insight into the loch's deglacial history. A recessional moraine complex in the north of the loch indicates initial punctuated retreat. Subsequent retreat was rapid before stabilisation at Foyers Rise formed a large stillstand moraine. Here, the calving margin produced significant volumes of laminated sediments in a proglacial fjord‐like environment. Subsequent to this, ice retreated rapidly to the southern end of the loch, where it again deposited a sequence of proglacial laminated sediments. Sediment sequences were then disturbed by the deposition of a thick gravel layer and a large turbidite deposit as a result of a jökulhlaup from the Spean/Roy ice‐dammed lake. These sediments are overlain by a Holocene sheet drape. Data indicate: (i) a former tributary of the Moray Firth Ice Stream migrated back into Loch Ness as a major outlet glacier with a calving margin in a fjord‐like setting; (ii) there was significant sediment supply to the terminus of this outlet glacier in Loch Ness; and (iii) that jökulhlaups are important for sediment supply into proglacial fjord/lake environments and may compose >20% of proglacial sedimentary sequences. Copyright © 2011 John Wiley & Sons, Ltd.     

PRINCIPES FONDAMENTAUX DE LA THEORIE DU MOUVEMENT DES EAUX SOUTERRAINES

ABSTRACT

In southeastern Arizona, almost all summer rainfall results from widely-scattered high-intensity afternoon or evening thunderstorms of limited areal extent. For eleven years of record on the Walnut Gulch Experimental Watershed, Tombstone, Arizona, about 70 percent of the annual rainfall of 11 1/2 inches and over 95 percent of the annual runoff occurred in July, August, and early September. In contrast, about 5 percent of the rainfall occurred in the previous 3 months, and about 25 percent in the remaining 6 1/2 months.

Therefore, summer rainfall, although highly variable, represented the most dependable source of water to the Walnut Gulch watershed. On the average, significant rainfall was recorded on some part of the watershed on 40 percent of the days in the critical July-August period. The maximum frequency was 3 out of every 4 days in 1955, and the minimum 3 out of every 10 days in 1960.

The wettest year was 1955, with a continuous rainy period of 47 days; whereas, the driest was 1960, with the longest rainy period lasting only 5 days. The longest summer drought during the period of record occurred in 1962, when no rain fell for 17 days in August, following a 14-day rainy period in late July.

As yet, there are not enough data to determine reliable expectancies for summer rainy or drought periods.     

Primary cracking of kerogens. Experimenting and modelling C1, C2–C5, C6–C15 and C15+ classes of hydrocarbons formed

Mathematical models of hydrocarbon formation can be used to simulate the natural evolution of different types of organic matter and to make an overall calculation of the amounts of oil and/or gas produced during this evolution. However, such models do not provide any information on the composition of the hydrocarbons formed or on how they evolve during catagenesis.From the kinetic standpoint, the composition of the hydrocarbons formed can be considered to result from the effect of “primary cracking” reactions having a direct effect on kerogen during its evolution as well as from the effect of “secondary cracking” acting on the hydrocarbons formed.This report gives experimental results concerning the “primary cracking” of Types II and III kerogens and their modelling. For this, the hydrocarbons produced have been grouped into four classes (C₁, C₂–C₅, C₆–C₁₅ and C₁₅₊). Experimental data corresponding to these different classes were obtained by the pyrolysis of kerogens with temperature programming of 4°C/min with continuous analysis, during heating, of the amount of hydrocarbons corresponding to each of these classes.The kinetic parameters of the model were optimized on the basis of the results obtained. This model represents the first step in the creation of a more sophisticated mathematical model to be capable of simulating the formation of different hydrocarbon classes during the thermal history of sediments. The second step being the adjustment of the kinetic parameters of “secondary cracking”.     

海城震区深地震测深资料A/D转换方法及其效果的研究

介绍深地震测深模拟磁带资料在CROMEMCO型微机上实现A/D转换的方法及其效果。在实现A/D转换研究中,进行了时标信号采集方式、六响信号处理、模拟回放电路改进等方法的试验,从而提高了A/D转换精度与效果。经对海城震区实际资料分析可知:该系统A/D转换精度达到了规范要求。     

钛-氨三乙酸-对氯苯基荧光酮-CTMAB四元配合物的分光光度法研究

本文研究Ti(Ⅳ)-氨三乙酸(NTA)-对氯苯基荧光酮(p-ClPF)-CTMAB四元配合物的显色条件。结果表明,在pH5.8—6.6形成了摩尔比为Ti(Ⅳ):NTA:p-ClPF:CTMAB=1:1:3:3的四元配合物,借此反应测定钛,灵敏度高,其ε_(573nm)=2.1×10~5L·mol~(-1)·cm~(-1)。Ti(Ⅳ)浓度在0—1.4μg/10ml范围服从比耳定律。已用本法直接测定了岩矿和铝合金中的Ti,结果满意。