基于高分六号WFV数据的冬小麦种植面积提取

冬小麦是我国重要的粮食作物之一,准确获取冬小麦种植面积具有重要的现实意义。为探究高分六号卫星影像进行冬小麦遥感监测的可行性和精确性,本文选取甘肃省崆峒区为研究区,运用红边波段+监督分类中的支持向量机法,提取了2019年崆峒区冬小麦种植面积,并利用混淆矩阵对分类结果进行精度验证。结果表明:提取崆峒区冬小麦种植面积为15045 hm 2,与实际种植面积相比,误差率为1.02%;该模型能有效地提取崆峒区冬小麦,总体精度为98.88%,Kappa系数为0.97;红边波段能有效地提取干扰地物,提取精度比直接使用监督分类高7.88个百分点;GF6影像在提取冬小麦种植面积上具有明显优势。     

Estimating Sea-Level Allowances for Atlantic Canada using the Fifth Assessment Report of the IPCC

Abstract

Sea-level allowances at 22 tide-gauge sites along the east coast of Canada are determined based on projections of regional sea-level rise for the Representative Concentration Pathway 8.5 (RCP8.5) from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5) and on the statistics of historical tides and storm surges (storm tides). The allowances, which may be used for coastal infrastructure planning, increase with time during the twenty-first century through a combination of mean sea-level rise and the increased uncertainty of future projections with time. The allowances show significant spatial variation, mainly a consequence of strong regionally varying relative sea-level change as a result of glacial isostatic adjustment (GIA). A methodology is described for replacement of the GIA component of the AR5 projection with global positioning system (GPS) measurements of vertical crustal motion; this significantly decreases allowances in regions where the uncertainty of the GIA models is large. For RCP8.5 with GPS data incorporated and for the 1995–2100 period, the sea-level allowances range from about 0.5?m along the north shore of the Gulf of St. Lawrence to more than 1?m along the coast of Nova Scotia and southern Newfoundland.     

卡尔曼滤波器在卫星遥感影像大地校正中的应用

在卫星遥感图像的预处理中,通过系统校正可以基本上消除影像内部的变形误差。然而,整幅影像的大地定位误差仍然是很大的,甚至几百米至1公里的数量级。本文介绍利用少量的地面控制点,采用递归算法而不是批处理算法,大大地提高大地定位精度。在单幅影像处理中,可以重新对卫星的轨道参数与姿态参数进行估值,从而提高影像的大地定位精度。在一条轨道上连续的多幅影像中,可以预报下一幅影像的大地位置,从而对那些不具有地面控制点的影像的大地校正中,实现外推计算。文中介绍并推导了卡尔曼滤波器方程中的转移矩阵和测量矩阵的系数,并推荐用数值回归的办法求得其数值解。文中最后介绍模拟试验及算法计算结果,并讨论其优缺点。     

鄂尔多斯盆地直罗油田长6油层组成岩作用及孔隙演化研究

位于鄂尔多斯盆地的直罗油田三叠系延长组长6油层组为近年来新开发的一个主力油气产层。岩石学和成岩作用特征研究表明,直罗油田长6油层组以细粒长石砂岩和岩屑长石砂岩为主,砂岩经历了机械压实作用、胶结作用、交代作用和溶蚀作用等成岩作用,成岩作用处于晚成岩阶段A期。成岩作用控制了储层砂岩孔隙发育特征,其中压实作用与胶结作用是导致储层超低渗的主导因素,而次生溶蚀孔隙的形成对储层砂岩物性具有一定改造作用,并控制了该区长6油层组相对高孔高渗储层的展布特征。     

Late Ordovician climbing‐dune cross‐stratification: a signature of outburst floods in proglacial outwash environments?

Climbing dune‐scale cross‐statification is described from Late Ordovician paraglacial successions of the Murzuq Basin (SW Libya). This depositional facies is comprised of medium‐grained to coarse‐grained sandstones that typically involve 0·3 to 1 m high, 3 to 5 m in wavelength, asymmetrical laminations. Most often stoss‐depositional structures have been generated, with preservation of the topographies of formative bedforms. Climbing‐dune cross‐stratification related to the migration of lower‐flow regime dune trains is thus identified. Related architecture and facies sequences are described from two case studies: (i) erosion‐based sandstone sheets; and (ii) a deeply incised channel. The former characterized the distal outwash plain and the fluvial/subaqueous transition of related deltaic wedges, while the latter formed in an ice‐proximal segment of the outwash plain. In erosion‐based sand sheets, climbing‐dune cross‐stratification results from unconfined mouth‐bar deposition related to expanding, sediment‐laden flows entering a water body. Within incised channels, climbing‐dune cross‐stratification formed over eddy‐related side bars reflecting deposition under recirculating flow conditions generated at channel bends. Associated facies sequences record glacier outburst floods that occurred during early stages of deglaciation and were temporally and spatially linked with subglacial drainage events involving tunnel valleys. The primary control on the formation of climbing‐dune cross‐stratification is a combination between high‐magnitude flows and sediment supply limitations, which lead to the generation of sediment‐charged stream flows characterized by a significant, relatively coarse‐grained, sand‐sized suspension‐load concentration, with a virtual absence of very coarse to gravelly bedload. The high rate of coarse‐grained sand fallout in sediment‐laden flows following flow expansion throughout mouth bars or in eddy‐related side bars resulted in high rates of transfer of sands from suspension to the bed, net deposition on bedform stoss‐sides and generation of widespread climbing‐dune cross‐stratification. The later structure has no equivalent in the glacial record, either in the ancient or in the Quaternary literature, but analogues are recognized in some flood‐dominated depositional systems of foreland basins.     

考虑自相关影响的设计年径流适线法估计的统计试验研究

当前设计年径流的计算,一般都采用适线法做参数估计.考虑到适线法是以水文序列独立性为前提.而实际的年径流序列存在一定的相关关系,对此,应用适线法估计到底精度如何?本文采用AR(1)模型生成符合P-Ⅲ分布的非独立样本,以参数、设计值的无偏性和有效性为评价标准,通过大量蒙特卡罗试验,对以上问题进行了研究.结果表明,在总体参数值Cv、Cs较小的地区,自相关系数即使达到0.5,对估计效果的影响也很小,但对于Cv、Cs较大的地区,自相关系数的增大会使估计效果趋于负偏.本文同时也对Cv、Cs、点据比例、序列长以及保证率等的变化对设计值无偏性、有效性存在的综合影响趋势进行了分析.希望对实际生产实践有一定的指导意义.     

FIO-ESM v2.0 CORE2-forced experiment for the CMIP6 Ocean Model Intercomparison Project

We introduced the Coupled Model Intercomparison Project Phase 6 (CMIP6) Ocean Model Intercomparison Project CORE2-forced (OMIP-1) experiment by using the First Institute of Oceanography Earth System Model version 2.0 (FIO-ESM v2.0), and comprehensively evaluated the simulation results. Unlike other OMIP models, FIO-ESM v2.0 includes a coupled ocean surface wave component model that takes into account non-breaking surface wave-induced vertical mixing in the ocean and effect of surface wave Stokes drift on air-sea momentum and heat fluxes in the climate system. A sub-layer sea surface temperature (SST) diurnal cycle parameterization was also employed to take into account effect of SST diurnal cycle on air-sea heat ?uxes to improve simulations of air-sea interactions. Evaluations show that mean values and long-term trends of significant wave height were adequately reproduced in the FIO-ESM v2.0 OMIP-1 simulations, and there is a reasonable fit between the SST diurnal cycle obtained from in situ observations and that parameterized by FIO-ESM v2.0. Evaluations of model drift, temperature, salinity, mixed layer depth, and the Atlantic Meridional Overturning Circulation show that the model performs well in the FIO-ESM v2.0 OMIP-1 simulation. However, the summer sea ice extent of the Arctic and Antarctic is underestimated.     

Comparison of coupled and uncoupled models in simulating Monsoon Intraseasonal Oscillation from CMIP6

The monsoon intraseasonal oscillation (MISO) is the dominant variability over the Indian Ocean during the Indian summer monsoon (ISM) season and is characterized by pronounced northward propagation. Previous studies have shown that general circulation models (GCMs) still have difficulty in simulating the northward-propagating MISO, and that the role of air-sea interaction in MISO is unclear. In this study, 14 atmosphere-ocean coupled GCMs (CGCMs) and the corresponding atmosphere-only GCMs (AGCMs) are selected from Phase 6 of the Coupled Model Intercomparison Project (CMIP6) to assess their performance in reproducing MISO and the associated vortex tilting mechanism. The results show that both CGCMs and AGCMs are able to well simulate the significant relationship between MISO and vortex tilting. However, 80% of CGCMs show better simulation skills for MISO than AGCMs in CMIP6. In AGCMs, the poor model fidelity in MISO is due to the failure simulation of vortex tilting. Moreover, it is found that failure to simulate the downward motion to the north of convection is responsible for the poor simulation of vortex tilting in AGCMs. In addition, it is observed that there is a significant relationship between the simulated sea surface temperature gradient and simulated vertical velocity shear in the meridional direction. These findings indicate that air-sea interaction may play a vital role in simulating vertical motions in tilting and MISO processes. This work offers us a specific target to improve the MISO simulation and further studies are needed to elucidate the physical processes of this air-sea interaction coupling with vortex tilting.     

鄂尔多斯盆地子北地区长6段油藏成藏条件及主控因素

分析了鄂尔多斯盆地子北地区延长组长6段油层构造特征、沉积相分布及砂体展布特征,从烃源岩、储层、盖层等方面对长6段油藏成藏条件进行了探讨,并就油藏类型、主控因素及成藏期次进行了讨论。结果表明:子北地区长6段油藏具有较好的生、储、盖配置关系,主要受沉积微相及储层物性控制;长6段油气主要储存在长61、62、63段河道砂体内,油藏类型主要为岩性圈闭;长6段油藏主控因素有主分流河道、储层物性及其非均质性、原油分布;长6段油层中,油气包裹体均一温度分布呈双峰状,主要在100℃~110℃和130℃~140℃;利用热演化史与流体包裹体均一温度法对油气成藏期次进行判断,长7段烃源岩生成的油气在早白垩世运移并大量聚集至长6段油层组,形成长6段油藏。     

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