对流层气溶胶的直接气候效应对平流层的影响

通过WACCM-3模式中气溶胶光学厚度与卫星资料的对比发现,模式可以很好地再现全球气溶胶的主要分布特征,但在一些区域还存在数值上的差异。利用数值试验研究对流层气溶胶的直接气候效应对平流层气候的影响,结果表明:对流层气溶胶对平流层气候有明显影响,平流层化学过程在这一影响中起重要作用,而对流层气溶胶对平流层辐射的影响不是其直接气候效应对平流层影响的主要原因。其机制可能是对流层气溶胶改变对流层的辐射平衡,影响对流层的温度和大气环流,进而影响行星波的上传,使得平流层气候发生变化;影响区域主要位于高纬度和极地地区,南半球的变化比北半球大,温度变化最大达10 K,纬向风变化最大可达12 m/s,臭氧体积分数最多减少0.8×10-6。     

Impact of Anthropogenic Heat Release on Regional Climate in Three Vast Urban Agglomerations in China简

We simulated the impact of anthropogenic heat release （AHR） on the regional climate in three vast city agglomerations in China using the Weather Research and Forecasting model with nested high-resolution modeling.Based on energy consumption and high-quality land use data,we designed two scenarios to represent no-AHR and current-AHR conditions.By comparing the results of the two numerical experiments,changes of surface air temperature and precipitation due to AHR were quantified and analyzed.We concluded that AHR increases the temperature in these urbanized areas by about 0.5℃-1℃,and this increase is more pronounced in winter than in other seasons.The inclusion of AHR enhances the convergence of water vapor over urbanized areas.Together with the warming of the lower troposphere and the enhancement of ascending motions caused by AHR,the average convective available potential energy in urbanized areas is increased.Rainfall amounts in summer over urbanized areas are likely to increase and regional precipitation patterns to be altered to some extent.     

The Interdecadal Changes of South Pacific Sea Surface Temperature in the Mid-1990s and Their Connections with ENSO简

The characteristic changes of South Pacific sea surface temperature anomalies （SSTAs） for the period January 1979 to December 2011, during which the 1990s Pacific pan-decadal variability （PDV） interdecadal regime shifts occurred, were examined. Empirical Orthogonal Function （EOF） analysis was applied to the monthly mean SSTA for two sub-periods： January 1979 to December 1994 （P 1） and January 1996 to December 2011 （P2）. Both the spatial and temporal features of the leading EOF mode for P1 and P2 showed a remarkable difference. The spatial structure of the leading EOF changed from a tripolar pattern for P 1 （EOF-P 1） to a dipole-like pattern for P2 （EOF-P2）. Besides, EOF-P 1 （EOF-P2） had significant spectral peaks at 4.6 yr （2.7 yr）. EOF-P2 not only had a closer association with E1 Nifio-Southern Oscillation （ENSO）, but also showed a faster response to ENSO than EOF-P1 based on their lead-lag relationships with ENSO. During the development of ENSO, the South Pacific SSTA associated with ENSO for both PI and P2 showed a significant eastward propagation. However, after the peak of ENSO, EOF-P1 showed a stronger persistence than EOF-P2, which still showed eastward propagation. The variability of the SSTA associated with the whole process of ENSO evolution during P1 and the SSTA associated with the development of ENSO during P2 support the existence of ocean-to-atmosphere forcing, but the SSTA associated with the decay of ENSO shows the phenomenon of atmosphere-to-ocean forcing.     

Evidence from the Historical Record to Support Projection of Future Wind Regimes: An Application to Canada

In the field of climate change impact analysis, bidirectional changes in projections of future wind regimes varying among studies, locations, and models have been described in the literature, which is understandable from a global perspective. However, we should attempt to find evidence in the historical record to support these projections. This paper attempts to address this issue by analyzing historical wind gust observations for up to 57 years (1953–2009) over Canada. Two wind gust analysis techniques were used: the speed of daily wind gust events ≥50?km?h^?1 was compared with (1) the climatological daily temperature anomaly and (2) the climatological daily sea level air pressure anomaly. In addition, the frequency of daily wind gust events ≥90?km?h^?1 was compared with both daily temperature and pressure anomalies. The results indicate that during the past five decades gust wind speed over Canada increased significantly as the daily temperature anomaly increased and the daily pressure anomaly decreased. About 50–60% of daily wind gust events ≥90?km?h^?1 occurred with positive daily temperature anomalies and negative daily pressure anomalies. One major conclusion is that the methods used in and results derived from this study might be applied to climate change impact analysis to support projections of future wind regimes.     

Chinese Contribution to CMIP5：An Overview of Five Chinese Models’Performances

An overview of Chinese contribution to Coupled Model Intercomparison Project-Phase 5 （CMIP5） is presented. The performances of five Chinese Climate/Earth System Models that participated in the CMIP5 pro ject are assessed in the context of climate mean states, seasonal cycle, intraseasonal oscillation, interan-nual variability, interdecadal variability, global monsoon, Asian-Australian monsoon, 20th-century historical climate simulation, climate change pro jection, and climate sensitivity. Both the strengths and weaknesses of the models are evaluated. The models generally show reasonable performances in simulating sea surface tem-perature （SST） mean state, seasonal cycle, spatial patterns of Madden-Julian oscillation （MJO） amplitude and tropical cyclone Genesis Potential Index （GPI）, global monsoon precipitation pattern, El Ni-no-Southern Oscillation （ENSO）, and Pacific Decadal Oscillation （PDO） related SST anomalies. However, the perfor-mances of the models in simulating the time periods, amplitude, and phase locking of ENSO, PDO time periods, GPI magnitude, MJO propagation, magnitude of SST seasonal cycle, northwestern Pacific mon-soon and North American monsoon domains, as well as the skill of large-scale Asian monsoon precipitation need to be improved. The model performances in simulating the time evolution and spatial pattern of the 20th-century global warming and the future change under representative concentration pathways pro jection are compared to the multimodel ensemble of CMIP5 models. The model discrepancies in terms of climate sensitivity are also discussed.     

宁夏地下水监测现状调查及对策

[目的]针对地下水监测存在问题,提出改进地下水监测工作的对策和建议。[方法]调查地下水监测历史沿革及现状,理出存在主要问题,研究应对策略。[结果]宁夏地下水监测范围小,监测层位浅,监测井标准低老化严重,井网布局和监测项目与面临任务不适应,难以满足地下水管理与开发保护要求,亟需完善地下水监测井网。[结论]做好宁夏地下水监测站网总体规划,建立稳定资金投入机制,加强与国土部门合作,逐年完善地下水监测站网,是做好地下水监测工作主要举措。     

王坡井田煤层气井部署方法研究

王坡煤矿是高瓦斯矿井,已有的井下瓦斯抽排不能满足矿井安全生产的要求,迫切需要通过地面抽采来缓解。在已有地质成果基础上,采用煤层气藏数值模拟方法,对王坡井田地面煤层气抽采工程部署方案进行优化。结果表明:A区块是井田煤层气开发试验首选区,以梅花形井网作为试验井网,井间距300m×250m,井网长轴方向60°。这种布井方式在工程实践中取得了较好效果,具有较大的推广价值。     

Contrasting geochemical signatures on land from the Middle and Late Permian extinction events

The end of the Palaeozoic is marked by two mass‐extinction events during the Middle Permian (Capitanian) and the Late Permian (Changhsingian). Given similarities between the two events in geochemical signatures, such as large magnitude negative δ¹³C anomalies, sedimentological signatures such as claystone breccias, and the approximate contemporaneous emplacement of large igneous provinces, many authors have sought a common causal mechanism. Here, a new high‐resolution continental record of the Capitanian event from Portal Mountain, Antarctica, is compared with previously published Changhsingian records of geochemical signatures of weathering intensity and palaeoclimatic change. Geochemical means of discriminating sedimentary provenance (Ti/Al, U/Th and La/Ce ratios) all indicate a common provenance for the Portal Mountain sediments and associated palaeosols, so changes spanning the Capitanian extinction represent changes in weathering intensity rather than sediment source. Proxies for weathering intensity chemical index of alteration, ?W and rare earth element accumulation all decline across the Capitanian extinction event at Portal Mountain, which is in contrast to the increased weathering recorded globally at the Late Permian extinction. Furthermore, palaeoclimatic proxies are consistent with unchanging or cooler climatic conditions throughout the Capitanian event, which contrasts with Changhsingian records that all indicate a significant syn‐extinction and post‐extinction series of greenhouse warming events. Although both the Capitanian and Changhsingian event records indicate significant redox shifts, palaeosol geochemistry of the Changhsingian event indicates more reducing conditions, whereas the new Capitanian record of reduced trace metal abundances (Cr, Cu, Ni and Ce) indicates more oxidizing conditions. Taken together, the differences in weathering intensity, redox and the lack of evidence for significant climatic change in the new record suggest that the Capitanian mass extinction was not triggered by dyke injection of coal‐beds, as in the Changhsingian extinction, and may instead have been triggered directly by the Emeishan large igneous province or by the interaction of Emeishan basalts with platform carbonates.     

A new methodology for building local climate change scenarios: A case study of monthly temperature projections for Mexico City

This paper proposes a new methodology for generating climate change scenarios at the local scale based on multivariate time series models and restricted forecasting techniques. This methodology offers considerable advantages over the current statistical downscaling techniques such as: (i) it provides a better representation of climate at the local scale; (ii) it avoids the occurrence of spurious relationships between the large and local scale variables; (iii) it offers a more appropriate representation of variability in the downscaled scenarios; and (iv) it allows for compatibility assessment and combination of the information contained in both observed and simulated climate variables. Furthermore, this methodology is useful for integrating scenarios of local scale factors that affect local climate. As such, the convenience of different public policies regarding, for example, land use change or atmospheric pollution control can be evaluated in terms of their effects for amplifying or reducing climate change impacts.