地电井下观测装置技术指标的测试与认定讨论——井下观测设施构建与测试技术

观测技术系统的设施构建技术指标认定是观测技术的核心所在,本文结合地电井下观测设施构建工程^[1],着重讨论针对观测装置测试的需求、技术指标测试的方法以及认定的过程。文中以具体工程参数为例,给出4项测试结果,讨论了认定依据和认定过程,希望本讨论能对地电井下观测设施建设、指标的认定起到参考作用。     

基于ENVI／IDL的AVHRR1B数据格式读取与预处理软件模块开发

NOAAAVHRR提供的1B数据,是以一个文件存储图像数据和相关的辅助数据,目前的商用遥感图像处理软件大多无法直接读取与图像有关的定标、定位、太阳与传感器位置等数据,对图像的后续定量化处理与应用带来了困难。本文在深入分析1B数据格式的基础上,实现了基于ENV~IDL平台的1B格式数据读取与预处理模块开发,这对于AVHRR图像数据的应用具有重要的现实意义。     

Mechanisms of tropical precipitation biases in climate models

Climate Dynamics - We investigate the possible causes for inter-model spread in tropical zonal-mean precipitation pattern, which is divided into hemispherically symmetric and anti-symmetric modes...     

基底滑脱层分布对褶皱冲断带变形影响的物理模拟研究：以塔西南西昆仑山前褶皱冲断带为例

针对塔西南西昆仑山前基底寒武系膏盐层的分布情况, 采用物理模拟研究方法,设计了研究基底滑脱层的分布对褶皱
冲断带影响的两组实验。实验结果表明：基底滑脱层的分布对构造变形样式的发育及变形前锋的传播有重要的控制作用。
具体表现为在基底寒武系膏盐层分布靠近山前的苏盖特地区变形整体表现为滑脱式的宽缓箱状褶皱的发育;寒武系膏盐层
分布较远离山前的柯东地区在缺失寒武系膏盐层的山前地区,表现为叠瓦状逆冲断层的发育,形成断层相关的紧闭褶皱,
往北有寒武系膏盐层发育的固满地区才发育较大型的箱状背斜。实验过程中苏盖特地区的变形前锋往前陆方向传播得更快
更远,而柯东地区变形前锋往前陆方向传播得较慢较近,从而在变形过程中二者的变形前锋容易出现一个“Z”字形转折。     

Determining the active region model parameter from dye staining experiments for characterizing the preferential flow heterogeneity in unsaturated soils

The active region model (ARM) has been developed as a practical and effective approach for characterizing and representing preferential flow patterns in unsaturated soils. However, studies on methods to determine the ARM parameter (γ) are very limited. The major objective of this work was to refine the methods for determining the ARM parameter (γ) using the data from field-scale dye staining experiments. For this purpose, 13 field-scale dye staining experiments were conducted in silty clay, loam and sand with various initial and boundary conditions. The distributions of soil water content and fraction of stained region were measured to determine the ARM parameter (γ). Three determination methods of ARM parameter (γ) were presented according to the different distribution patterns of the soil water content of stained region. The efficiency of these approaches was demonstrated with the results from 13 field-scale dye staining tests that were directly related to preferential flow patterns. Impacts of soil texture on soil water redistribution, and effects of initial soil water content and infiltration amount on the preferential flow heterogeneity were also discussed in this research.     

Comparative studies of glacier mass balance and their climatic implications in Svalbard, Northern Scandinavia, and Southern Norway

On the basis of the data of glacier mass balance during 1946?C2005 over Svalbard, Northern Scandinavia, and Southern Norway, the characteristics of glacier mass-balance are analyzed, and its sensitivity to climate change is calculated using a simple degree-day model. The mass balance of glaciers in these three regions reached maximum or comparatively high values in the late 1980s or the early 1990s. After that there was an accelerating negative tendency. A glacier with more positive mass balance has a higher sensitivity to equilibrium-line altitude (or climate) change and vice versa. On average, the mass loss during the entire period in these three regions was equivalent to the result of an air temperature rise of 0.32°C relative to zero net balance state. The highest temperature increase is found in Svalbard, and is 0.55°C; however, a rise of only 0.12°C is found in Southern Norway. The net balance sensitivity to a hypothetical air temperature increase of +1°C ranges from ?0.31 to ?1.03?m?w.e.?a^?1, and the net balance sensitivity to an assumed increase in snow precipitation of +10% varies from +0.05 to +0.37?m?w.e.?a^?1; thus, a 31% increase in snow precipitation is needed to compensate for the net mass loss induced by an air temperature increase of +1°C. The summer balance sensitivity to a hypothetical air temperature increase of +1°C varies from ?0.39 to ?0.95?m?w.e.?a^?1, and the winter balance sensitivity to an assumed increase in snow precipitation of +10% ranges from +0.02 to +0.38?m?w.e.?a^?1. This study confirms early findings that maritime glaciers have comparatively higher mass balance sensitivity than continental glaciers.     

A semi-continuous measurement of gaseous ammonia and particulate ammonium concentrations in PM<Subscript>2.5</Subscript> in the ambient atmosphere

Ammonia has a short residence time in the atmosphere and rapidly neutralizes acid gases that occur near its source, requiring a rapid measurement system for ammonia and particulate ammonium concentrations to better understand their sources, temporal variation of ammonia emissions, and the formation of secondary ammonium aerosols. A semi-continuous measurement system, consisting of a diffusion scrubber, a particle growth chamber, an air-liquid separator, and a fluorescent detector, was developed to determine both gaseous ammonia (NH₃) and particulate ammonium (NH ₄ ⁺ ) in PM_2.5 in the ambient atmosphere of Gwangju, South Korea, during the months of March, April, July, and September of 2007. During the sampling periods, the average concentrations of ammonia and ammonium were found to be 2.33?±?1.29 μg/m³ and 1.89?±?0.99 μg/m³, respectively. Although the average gaseous ammonia concentration was highest in March, the particulate ammonium concentration was higher during the warmer season, reaching 2.08?±?1.07 μg/m³ and 2.32?±?0.94 μg/m³ in April and July, respectively, while only 1.68?±?0.61 μg/m³ in March and 1.24?±?0.99 μg/m³ in September. It is proposed that the higher availability of acid species during the warmer months produced a significant amount of particulate ammonium sulfate. Diurnal fluctuation of ammonia and ammonium during the warmer months showed that their peak time occurred at approximately 10:00 am. Both ammonia and ammonium concentrations were better correlated during the warmer months than during the cooler months. Further, the data suggest that the ammonia and ammonium were measured under well dispersed conditions, and multiple sources contributed to the ammonia at the sampling site.     

Simulation of the anthropogenic aerosols over South Asia and their effects on Indian summer monsoon

A regional climate model coupled with a chemistry-aerosol model is employed to simulate the anthropogenic aerosols including sulfate, black carbon and organic carbon and their direct effect on climate over South Asia. The model is driven by the NCAR/NCEP re-analysis data. Multi-year simulations with half, normal and double emission fluxes are conducted. Results show that the model performs well in reproducing present climate over the region. Simulations of the aerosol optical depth and surface concentration of aerosols are also reasonable although to a less extent. The negative radiative forcing is found at the top of atmosphere and largely depended on emission concentration. Surface air temperature decreases by 0.1?C0.5°C both in pre-monsoon and monsoon seasons. The range and intensity of cooling areas enlarge while aerosol emission increases. Changes in precipitation are between ?25 and 25%. Different diversifications of rainfall are showed with three emission scenarios. The changes of precipitation are consistent with varieties of monsoon onset dates in pre-monsoon season. In the regions of increasing precipitation, monsoon onset is advanced and vice versa. In northeast India and Myanmar, aerosols lead the India summer monsoon onset advancing 1?C2 pentads, and delaying by 1?C2 pentads in central and southeast India. These changes are mainly caused by the anomaly of local Hadley circulations and enhancive precipitation. Tibetan Plateau played a crucial role in the circulation changes.