A Cloud Detection Scheme for the Chinese Carbon Dioxide Observation Satellite(TANSAT)

Cloud detection is an essential preprocessing step for retrieving carbon dioxide from satellite observations of reflected sunlight.During the pre-launch study of the Chinese Carbon Dioxide Observation Satellite(TANSAT),a cloud-screening scheme was presented for the Cloud and Aerosol Polarization Imager(CAPI),which only performs measurements in five channels located in the visible to near-infrared regions of the spectrum.The scheme for CAPI,based on previous cloudscreening algorithms,defines a method to regroup individual threshold tests for each pixel in a scene according to the derived clear confidence level.This scheme is proven to be more effective for sensors with few channels.The work relies upon the radiance data from the Visible and Infrared Radiometer(VIRR)onboard the Chinese Feng Yun-3A Polar-orbiting Meteorological Satellite(FY-3A),which uses four wavebands similar to that of CAPI and can serve as a proxy for its measurements.The scheme has been applied to a number of the VIRR scenes over four target areas(desert,snow,ocean,forest)for all seasons.To assess the screening results,comparisons against the cloud-screening product from MODIS are made.The evaluation suggests that the proposed scheme inherits the advantages of schemes described in previous publications and shows improved cloud-screening results.A seasonal analysis reveals that this scheme provides better performance during warmer seasons,except for observations over oceans,where results are much better in colder seasons.     

持续光照下光强对北极海域芬迪亚历山大藻生长及产毒的影响

以格陵兰岛西部、冰岛沿海和楚科奇海的芬迪亚历山大藻为受试对象,并以缅因湾的芬迪亚历山大藻藻株做为参照,从沉积物或海水中的休眠孢囊或营养细胞中分离到12株目标藻种,并在实验室建立纯培养系。然后对这些地域的藻种在不同光照下生长特性的比较、对毒素含量进行研究,发现芬迪亚历山大藻在持续光照条件下最适的生长光强范围是38—91μmol×m~(–2)×s~(–1)。另外,在所有分离到的12株藻细胞中均未检测到脱氨甲酰基膝沟藻毒素2(dc GTX2),大部分藻细胞都在光强较强时,即生长速率低时表现出更高的细胞毒素含量和毒性。     

农户耕地保护意愿影响因素研究

以福建厦门、福州、南平为例,通过对627户农户的问卷调查,全面比较分析不同经济发展水平地区农户耕地保护意愿的影响因素,结果表明:(1)家庭特征是影响各地区农户耕地保护意愿的基础与普遍性因素;(2)经济价值认知是影响经济欠发达地区农户耕地保护意愿的核心因素;(3)用途转换收益是影响经济发达地区农户耕地保护意愿的关键因素;(4)政策相关特征是农户耕地保护意愿的导向性因素。为提升农户耕地保护意愿、守住耕地资源红线,建议结合地方经济水平,制定出符合当地实际的耕地保护政策;尊重农户意愿,合理调整耕地保护政策执行方式;建立符合市场经济要求的农村土地流转机制,推进耕地集中经营。     

Modelling the integrated effects of land use and climate change scenarios on forest ecosystem aboveground biomass,a case study in Taihe County of China

Global and regional environmental changes such as land use and climate change have significantly integrated and interactive effects on forest. These integrated effects will undoubtedly alter the distribution, function and succession processes of forest ecosystems. In order to adapt to these changes, it is necessary to understand their individual and integrated effects. In this study, we proposed a framework by using coupling models to gain a better understanding of the complex ecological processes. We combined an agent-based model for land use and land cover change (ABM/LUCC), an ecosystem process model (PnET-II), and a forest dynamic landscape model (LANDIS-II) to simulate the change of forest aboveground biomass (AGB) which was driven by land use and climate change factors for the period of 2010–2050 in Taihe County of southern China, where subtropical coniferous plantations dominate. We conducted a series of land use and climate change scenarios to compare the differences in forest AGB. The results show that: (1) land use, including town expansion, deforestation and forest conversion and climate change are likely to influence forest AGB in the near future in Taihe County. (2) Though climate change will make a good contribution to an increase in forest AGB, land use change can result in a rapid decrease in the forest AGB and play a vital role in the integrated simulation. The forest AGB under the integrated scenario decreased by 53.7% (RCP2.6 + land use), 57.2% (RCP4.5 + land use), and 56.9% (RCP8.5 + land use) by 2050, which is in comparison to the results under separate RCPs without land use disturbance. (3) The framework can offer a coupled method to better understand the complex and interactive ecological processes, which may provide some supports for adapting to land use and climate change, improving and optimizing plantation structure and function, and developing measures for sustainable forest management.     

梅雨锋云系内对流回波与层状回波的研究

本文利用1998年“淮河流域能量与水分循环试验（HUBEX）”所获得的大量雷达资料及遥测雨量计计资料，细致分析了淮河流域梅雨锋云系的结构，根据层状云和对流云在雷达回波图中的不同特征，本文提出用松散系数D（反映云系结构疏松程度）来区分大范围云带中的降水云类型，同529张PPI资料统计表明，若D＞0．17则说明该区结构松散，降水属于层状云降水，D≤0．17时，云区是对流性降水，由于梅雨锋水具有明显的不均匀结构特征，其中锋面对流云带和强下挂回波带是造成强降水的主要原因，在用地面雨量资料和雷达资料对地面降水进行短时（3小时以内）校正时，针对不同的降水类型采用不同的Z－R关系比用同一种Z－R关系的校正精度大约提高4％。     

GPS RTK技术在工程测量中的应用

本文以Trimble 470GPS接收机为例介绍了RTK作业仪器的配置及应用RTK技术进行生产作业的过程，通过实例分析可得到知：RTK技术可广泛应用于各项工程测量中。     

本世纪初我国大陆7级大震危险性研究

地震大形势研究结果表明，我国大陆地区（含边境）１９９９年已进入为期１２年的相对平静幕，幕内可能发生３次７级地震，最大震级不超过７．２级。首发７级地震为２０００年６月８日缅甸７级（位于中缅边境）。预计第二个７级地震危险时间在２００５±０．５年。第三个在２００８年前后。分析了我国主要地震区强震概率增益，给出了３个危险地点。未来３年即２００１～２００３年是相对安全时段，我国大陆不会发生７级以上破坏性地震。２０１１～２０２０年可能进入新世纪第一个７级大地震相对活跃幕，预计该幕持续１０年， 可发生１０次７～７.６级大震。     

区域水环境经济系统DSS的设计

从区域水环境与经济协调发展出发,建立了区域水环境的决策支持系统。介绍了区域水环境经济系统决策支持系统的设计原则、系统结构、系统组成及系统功能。系统由数据库、模型库及其管理系统三部分组成,具有预测、优化、模拟和管理等功能。模型库包括宏观经济模型、环境经济多目标优化模型、需水模型、水环境容量模型和水环境分析模型等5个基本模型。在求解水环境经济多目标优化模型时,使用了约束法,把多目标化为单目标进行求解。在决策过程中,使用逐步法,在迭代过程中输入经验与偏好获取满意的决策信息     

咸潮入侵对长江河口地区地下水质的影响

长江河口咸潮入侵对上海市自来水源水水质带来不良影响,从而殃及水厂产水质量而不利于生产和市民健康,这在上海市宝山区表现尤为显著。然而,宝山区地下承压含水层水质优良,资源丰富,且水质稳定,不受咸潮入侵影响。经研究,在不产生地面沉降危害等前提条件下,宝山区尚可扩采500万米~3/年优质地下水。     

一种飓风数值预报的初值化方法

本文使用具有Gallelean变换和详细动量、热量垂直输送通量描述的飓风动力方程组,由切向风速得到垂直运动场、加热场等,结果表明了垂直运动场和加热场具有明显的螺旋雨带特征,温度场有暖心结构及其位势高度场具有深低压特征,这些特征和实际观测结果相吻合。这个方法为飓风数值预报初始场提供了可行的方法。 用数值方法预报飓风的发生发展和路经及降水分布是飓风研究的一种主要方法。但是,对于数值预报飓风的初始场的确定仍是一个没有彻底解决的问题。在过去的初始场处理中,大致分几种,一种是初始场全部采用理想化的低压扰动,另一种则是用实际资料得到环境流场然后再加上一个理想化的