A Precipitation Detection Method for MWTS-Ⅱ Radiance Assimilation in Typhoon Simulation

FY-3C Microwave Temperature Sounder Ⅱ(MWTS-Ⅱ) lacks observations at 23.8 GHz, 31 GHz and 89 GHz,making it difficult to remove the data contaminated by precipitation in assimilation. In this paper, a fast forward operator based on the Community Radiative Transfer Model(CRTM) was used to analyze the relationship between the observation minus background simulation(O-B) and the cloud fractions in different MWTS-Ⅱ channels. In addition,based on the community Gridpoint Statistical Interpolation(GSI) system, the radiation brightness temperature of the MWTS-Ⅱ was assimilated in the regional Numerical Weather Prediction(NWP) model. In the process of assimilation,Visible and Infrared Radiometer(VIRR) cloud detection products were matched to MWTS-Ⅱ pixels for precipitation detection. For typhoon No. 18 in 2014, impact tests of MWTS-Ⅱ data assimilation was carried out. The results show that,though the bias observation minus analysis(O-A) of assimilated data can be reduced by quality control only with | O-B| 3 K; however, the O-A becomes much smaller while the precipitation detection is performed with F_(virr) 0.9(VIRR cloud fraction threshold of 0.9). Besides, the change of the environmental field around the typhoon is more conducive to make the simulated track closer to the observation. The 72-hour typhoon track simulation error also shows that, after the precipitation detection, the error of simulated typhoon track is significantly reduced, which reflects the validity of a precipitation detection method based on a double criterion of | O-B | 3 K and F_(virr) 0.9.     

《巴黎协定》实施细则评估与全球气候治理展望

《巴黎协定》在确立2020年后应对气候变化框架性制度安排的同时也给出了一系列留待解决的后续任务,包括制定《巴黎协定》实施细则,细化相应规则、制度和指南等。经过3年的谈判,2018年年底在卡托维兹举行的第24次缔约方会议对《巴黎协定》涉及的除市场机制外的众多议题做出了一揽子安排,建立了一系列指导和帮助各方在2020年后落实和履行《巴黎协定》的实施细则,为全面有效实施《巴黎协定》提供了更明确的指导。本研究致力对《巴黎协定》实施细则的内容和特点、对中国的潜在影响和要求、后续谈判走向以及中国的对策等进行全面深入的梳理和分析。评估发现,实施细则继续保持了《巴黎协定》的“精妙平衡”,严格恪守并充分体现了“自下而上”的《巴黎协定》模式,在为发展中国家保留一定灵活性的基础上统一了报告和审评的“度量衡”,并进一步明确了以五年为周期提高行动和支持力度的序贯决策机制。细则可能给中国引领全球气候治理和国内履约带来新的机遇和挑战。中国需要从观念认识、责任担当、业务协调上做好新的布局,根据国内外新趋势、新特点构建中国特色的气候治理新体系。     

储层构型研究进展与展望

本文从储层构型概念出发,概括了国内学者对河流相、冲积扇、三角洲等不同沉积领域的储层构型研究方法和取得的成果,并在此基础上了归纳总结了现阶段储层构型研究所遇到问题,最后针对目前的研究现状和存在的问题,指出了储层构型研究的发展趋势,这将对研究储层非均质性、剩余油分布及提高油气采收率等具有十分重要意义。     

流体包裹体的研究进展

前人对流体包裹体进行了大量研究,本文在此基础上,系统阐述了流体包裹体的各种分类方案和主要的研究方法,重点介绍了包裹体在研究油气藏烃源岩排烃史、油气形成时物化条件、油气运移演化、成藏期次和时间等方面的应用,以及在矿床类型、成矿流体来源、成矿条件、成矿物质搬运及成矿机制研究中的应用新进展。大量的研究表明,流体包裹体在理论、原理和方法等各个方面都取得了很大的发展,并逐渐在地质领域发挥其重要作用,已经成为解决某些地质问题的重要手段。     

Natural disasters in China: 1900–2011

China is a country prone to high frequency of natural catastrophic events. According to the natural disaster data from 1900 to 2011, the major disaster types include drought, earthquake, epidemic, extreme temperature, flood, mass movement wet and storm. The occurrence of natural disaster and economic loss is increased during the studied period. However, the death toll induced by natural disaster is decreased significantly. A new frame of social development and natural disaster is proposed to discuss the impact of population and GDP on the influence of disaster through the recording and reduction efforts. The results indicated that economic development contributes to the reduction in the impact of natural disaster on the people lives and society. New comprehensive integrated management, including international cooperation, should be established.

     

北部湾盆地北部坳陷古近纪原型结构分析

北部湾盆地北部坳陷古近纪受多期次构造运动的影响,后期改造强烈.从现今构造格局出发,通过剥蚀量恢复并结合断裂活动特征,进行了北部湾盆地北部坳陷古近纪原型结构重建及成凹机制探讨.认为北部湾盆地北部坳陷古近系沉积沉降中心在时空上呈现由西向东和由北向南的迁移特征;始新世流沙港组沉积时期涠西南凹陷D次凹与海中凹陷的西洼为同一沉积单元;断裂和隆起联合控制了洼陷的基本形态,特别是涠西南低凸起的活动对北部坳陷古近纪统一湖盆的分割起关键作用.     

Response of artificial grassland carbon stock to management in mountain region of Southern Ningxia,China

Grassland is a major carbon sink in the terrestrial ecosystem. The dynamics of grassland carbon stock profoundly influence the global carbon cycle. In the published literatures so far, however, there are limited studies on the long-term dynamics and influential factors of grassland carbon stock, including soil organic carbon. In this study, spatial-temporal substitution method was applied to explore the characteristics of Medicago sativa L.(alfalfa) grassland biomass carbon and soil organic carbon density(SOCD) in a loess hilly region with different growing years and management patterns. The results demonstrated that alfalfa was the mono-dominant community during the cutting period(viz. 0–10 year). Community succession began after the abandonment of alfalfa grassland and then the important value of alfalfa in the community declined. The artificial alfalfa community abandoned for 30 years was replaced by the S. bungeana community. Accordingly, the biomass carbon density of the clipped alfalfa showed a significant increase over the time during 0–10 year. During 0–30 year, the SOCD from 0–100 cm of the soil layer of all 5 management patterns increased over time with a range between 5.300 ± 0.981 kg/m2 and 12.578 ± 0.863 kg/m2. The sloping croplands had the lowest SOCD at 5.300 ± 0.981 kg/m2 which was quite different from the abandoned grasslands growing for 30 years which exhibited the highest SOCD with 12.578 ± 0.863 kg/m2. The ecosystem carbon density of the grassland clipped for 2 years increased 0.1 kg/m2 compared with the sloping cropland, while that of the grassland clipped for 10 years substantially increased to 10.30 ± 1.26 kg/m2. Moreover, the ecosystem carbon density for abandoned grassland became 12.62 ± 0.50 kg/m2 at 30 years. The carbon density of the grassland undisturbed for 10 years was similar to that of the sloping cropland and the grassland clipped for 2 years. Different management patterns imposed great different effects on the accumulation of biomass carbon on artificial grasslands, whereas the ecosystem carbon density of the grassland showed a slight increase from the clipping to abandonment of grassland in general.     

基于选权迭代估计与非监督分类的多光谱图像变化检测

针对多光谱图像的变化检测问题,提出了一种基于选权迭代估计(iterative estimation with weight selection,IEWS)与非监督分类(unsupervised classification,UC)的多光谱图像变化检测方法。借鉴IEWS的思想,并以类似于迭代加权多元变化检测(iteratively reweighted multivariate alteration detection,IRMAD)的迭代模式进行回归估计,得到初步的变化检测结果;并通过对初始变化信息的UC处理,以及对不同类别的IEWS,得到最终的变化检测结果。利用该方法对TM图像进行了实验,结果表明:所得到的变化信息在空间位置上同该区域相应时间段内土地利用/覆盖的变化情况具有很好的一致性;同时与多元变化检测及IRMAD方法变化检测的结果相比较,表明该方法对相对较小的变化信息具有更好的变化检测能力。