对台风麦莎(2005)的熵流特征初步分析

根据热力学第二定律推导出熵平衡方程,并在数值模拟输出结果的基础上利用熵平衡方程中的熵流项来分析2005年台风"麦莎"发生、发展和消亡各阶段的熵流特征.(1) 从对流层的低层到对流层的高层,台风中心附近的熵流分布会逐渐由负熵流占优势互补趋向于以正熵流为主;(2) 对流层中层500 hPa的负熵流分布显示出,随着台风的强度加强(减弱),台风中心附近的负熵流强度也会随之加强(减弱);(3) 台风中心附近的负熵流分布和强度特征对于台风强度和未来移动路径有一定的指示意义.     

热脉冲技术测定树干液流研究进展

热脉冲技术是生态生理学和森林水文学研究树木耗水最为常用的技术之一,该技术具有在树木自然生长状态基本不变的情况下实时测量树干木质部上升液流速度及流量,可以简捷准确地确定树冠蒸腾耗水量,同时具有经济可行,测定准确的优点.综述了热脉冲技术的发展历程,对热脉冲方法测定树干液流理论研究、树干液流时空变异性与环境因子的关系研究以及单株耗水向林分水平的尺度转换研究等方面作了较为详细的总结,据此,对热脉冲技术的发展做了展望.     

西部省会城市新型城镇化水平综合测度研究

新型城镇化是中国经济社会健康、稳定、可持续发展的根本途径,也是消除中国城乡社会经济"二元结构"的根本出路。根据新型城镇化的内涵,从人口、经济发展、生活质量、基础设施、资源环境、城乡统筹6个方面,构建了包含24项指标的新型城镇化水平综合测度指标体系,运用熵值法,对西部11个省会城市2005—2015年的城镇化发展水平进行综合测度。研究表明:西部省会城市的新型城镇化发展水平存在显著差异,总体上可分为"高等水平"、"中等水平"、"低等水平"3个级别,基础设施建设是造成差异的主要驱动力。各城市不同年间的城镇化单项水平影响因素呈现多元化,在今后的发展中应有所侧重,同时兼顾城镇化质量,推动城乡协调发展。     

Quantitative Assessment of the Ecological Vulnerability of Baiyangdian Wetlands in the North China Plain

Quantitative assessment of vulnerability is a core aspect of wetland vulnerability research. Taking Baiyangdian (BYD) wetlands in the North China Plain as a study area and using the ‘cause-result’ model, 23 representative indicators from natural, social, sci-tech and economic elements were selected to construct an indicator system. A weight matrix was obtained by using the entropy weight method to calculate the weight value for each indicator. Based on the membership function in the fuzzy evaluation model, the membership degrees were determined to form a fuzzy relation matrix. Finally, the ecological vulnerability was quantitatively assessed based on the comprehensive evaluation index calculated by using a composite operator to combine the entropy weight matrix with the fuzzy relation matrix. The results showed that the ecological vulnerability levels of the BYD wetlands were comprehensively evaluated as Grade II, Grade Ⅲ, Grade IV, and Grade Ⅲ in 2010, 2011-2013, 2014, and 2015-2017, respectively. The ecological vulnerability of the BYD wetlands increased from low fragility in 2010 to general fragility in 2011-2013, and to high fragility in 2014, reflecting the fact that the wetland ecological condition was degenerating from 2010 to 2014. The ecological vulnerability status then turned back into general fragility during 2015-2017, indicating that the ecological situation of the BYD wetlands was starting to improve. However, the ecological status of the BYD wetlands on the whole is relatively less optimistic. The major factors affecting the ecological vulnerability of the BYD wetlands were found to be industrial smoke and dust emission, wetland water area, ammonia nitrogen, total phosphorus, rate of industrial solid wastes disposed, GDP per capita, etc. This illustrates that it is a systematic project to regulate wetland vulnerability and to protect regional ecological security, which may offer researchers and policy-makers specific clues for concrete interventions.     

气候变化与北疆北部2000年特大雪灾的必然性及预测

利用1960～2003年新疆阿勒泰地区7测站及塔城地区北部5测站当年11月至次年1月,44a气温、降水资料,研究了北疆北部冬季气候变化特征,解释了2000年该地区冬季特大雪灾极端气候事件出现的必然性,最后探讨了该地区冬季降水的预测问题;并得出一点很有意义的结论:在气候增暖、增湿背景下,特大雪灾也是可以预报的。     

The oxygen minimum zone (OMZ) off Chile as intense source of CO2 and N2O

The oxygen minimum zones (OMZs) are recognized as intense sources of N₂O greenhouse gas (GHG) and could also be potential sources of CO₂, the most important GHG for the present climate change. This study evaluates, for one of the most intense and shallow OMZ, the Chilean East South Pacific OMZ, the simultaneous N₂O and CO₂ fluxes at the air–sea interface. Four cruises (2000–2002) and 1 year of monitoring (21°–30°–36°S) off Chile allowed the determination of the CO₂ and N₂O concentrations at the sea surface and the analysis of fluxes variations associated with different OMZ configurations. The Chilean OMZ area can be an intense GHG oceanic local source of both N₂O and CO₂. The mean N₂O fluxes are 5–10 times higher than the maximal previous historical source in an OMZ open area as in the Pacific and Indian Oceans. For CO₂, the mean fluxes are also positive and correspond to very high oceanic sources. Even if different coupling and decoupling between N₂O and CO₂ are observed along the Chilean OMZ, 65% of the situations represent high CO₂ and/or N₂O sources. The high GHG sources are associated with coastal upwelling transport of OMZ waters rich in N₂O and probably also in CO₂, located at a shallow depth. The integrated OMZ role on GHG should be better considered to improve our understanding of the past and future atmospheric CO₂ and N₂O evolutions.     

中国水质站网规划中几个问题的探讨

在完成中国水质站网规划工作的基础上,对下列问题作了进一步探讨:(1)水质站网规划单元的划分;(2)聚类分析在水质站网规划中的应用;(3)站网密度与人口和经济发展的关系;(4)中国水质站网的分区特征。     

基于MaxEnt模型的薄壳山核桃气候适宜性区划

基于最大熵模型（MaxEnt）和GIS技术,提出一种薄壳山核桃气候适宜性区划方法。利用美国本土274个种植点,结合美国本土和中国云南省1981—2010年气候数据开展薄壳山核桃气候适宜性区划研究。结果表明：7月平均气温、年平均气温、30年极端最低气温、年降水量、3—5月降水量、年日照时数和4—5月日照时数为影响薄壳山核桃气候适宜性的主要气候因子。基于美国本土种植点构建的MaxEnt模型在该区域具有较高精度,但将模型直接外推用于中国云南省可靠性不足。因此,利用模拟区域和训练样本气候因子值域的偏离程度改进气候适宜性指数,并将云南省薄壳山核桃适宜性划分为最适宜、适宜、次适宜和不适宜4个等级。其中,最适宜区和适宜区分布于热量资源丰富、日照相对充足并具备较好冬季低温条件的亚热带地区和热带地区边缘。受云南省复杂地形和气候条件影响,区划结果呈现出破碎化分布。     

东亚地区天气吸引子特征的研究

利用东亚地区１１个有代表性测站（１９７９－１９８８年）连续１０年的５００ｈＰａ逐日位势高度时间序列，全面计算了它们的浑沌特征量。结果表明，各测站相应的关联维数都是分数；完整的Ｌｙａｐｕｎｏｖ指数谱中，不仅都有正值、零和负值，而且Ｌｙａｐｕｎｏｖ指数之和都小于零。因此，从整体来看，相应于东亚地区天气尺度的吸引子是由一个有限窨支撑起来的。东亚地区的天气吸引子所显示的系统平均Ｋｏｌｍｏｇｏｌｏｖ熵约为０