激光测高卫星波形饱和识别与测高误差改正初步研究

激光测高仪回波波形饱和现象客观存在,为增加可用激光点数目、提高饱和波形测高精度,本文提出了一种波形饱和识别与测高误差改正方法,首先,利用回波波形峰度系数对饱和波形进行识别,然后,针对饱和现象对波形高斯拟合的影响,计算高斯拟合波形与原始波形相交区域的形心位置,以形心位置差异确定因波形饱和导致的测高误差并改正。最后,采用ICESat/GLAS（Ice,Cloud and land Elevation Satellite/Geo-science Laser Altimeter System）在青海湖、纳木错、色林错采集的波形数据进行实验。结果表明,经本文算法改正后数据误差均值为0.03 m,大型湖泊区域可实现约0.05 m的测高精度,结合峰度的饱和识别方法可以对波形进行有效筛选,可发现GLAS遗漏的饱和波形,饱和改正算法可以有效改正波形饱和引起的测高误差,改正后精度明显优于GLAS提供的饱和改正结果,相关结论对高分七号卫星激光波形处理有一定参考价值。     

渤南洼陷北带沙四上亚段储层成岩流体演化

渤南洼陷北带沙四上亚段在埋藏过程中经历了多期酸碱流体演化,同时经历了多期油气充注作用,导致储层物性经历了复杂的演化过程。对渤南洼陷北带沙四上亚段埋藏演化史、有机质热演化、膏盐层脱水等综合研究,结合各种烃类和盐水包裹体特征分析,确定了渤南洼陷北带沙四上亚段成岩流体演化序列：(1)沙四上亚段沉积时期气候干旱,原始地层水呈弱碱性。(2)开始沉积至距今42.5 Ma,有机质尚未成熟,地层流体仍保持弱碱性,成岩作用主要为压实排水作用,形成早期球粒状黄铁矿胶结物。(3)距今42.5~30 Ma,为有机酸控制下的酸性环境,发生长石溶解、石英加大。(4)距今30~24.6 Ma,有机酸发生脱羧,同时沙四上亚段顶部膏盐层脱出大量碱性水,使地层水pH值呈碱性,发生碳酸盐胶结和石英溶解,其中距今28.8~24.6 Ma,发生第一期油气充注;距今24.6~6 Ma,地层经历抬升及再沉降,在抬升过程中有机质再次生成有机酸,使地层水pH值呈酸性,发生第二期酸性溶解、石英加大,其中距今10~6 Ma,发生第二期油气充注。(5)距今6 Ma至现今,沙四上亚段膏盐层发生脱水,地层流体呈碱性,发育少量晚期黄铁矿胶结等。     

Application of Spectral Decomposition to Detection of Fracture-Cavity Carbonate Reservoir Beds in the Tahe Oilfield, Tarim Basin, NW China

Ordovician fracture-cavity carbonate reservoir beds are the major type of producing formations in the Tahe oilfieid, Tarim Basin. The seismic responses of these beds clearly changes depending on the different distance of the fracture-cavity reservoir bed from the top of the section. The seismic reflection becomes weak or is absent when the fracture-cavity reservoir beds are less than 20 ms below the top Ordovician. The effect on top Ordovician reflection became weaker with deeper burial of fracture-cavity reservoir beds but the developed deep fracture-cavity reservoir beds caused stronger reflection in the interior of the Ordovician. This interior reflection can be divided into strong long-axis, irregular and bead string reflections, and was present 80 ms below the top Ordovician. Aimed at understanding reflection characteristics, the spectral decomposition technique, which uses frequency to "tune-in" bed thickness, was used to predict Ordovician fracture-cavity carbonate formations in the Tahe oilfield. Through finely adjusting the processing parameters of spectral decomposition, it was found that the slice at 30 Hz of the tuned data cube can best represent reservoir bed development. Two large N-S-trending strong reflection belts in the mid-western part of the study area along wells TK440- TK427-TK417B and in the eastern part along wells TK404-TK409 were observed distinctly on the 30 Hz slice and 4-D time-frequency data cube carving. A small N-S trending reflection belt in the southern part along wells T403-TK446B was also clearly identified. The predicted reservoir bed development area coincides with the fracture-cavities connection area confirmed by drilling pressure testing results. Deep karst cavities occur basically in three reservoir bed-development belts identified by the Ordovician interior strong reflection. Spectral decomposition proved to be a useful technique in identifying fracture-cavity reservoir beds.     

基于多源数据的近50 a玛纳斯河流域冰川变化分析

我国新疆玛纳斯河流域的冰川变化极大影响流域内及其周边地区的经济社会发展.使用国产高分一号(GF-1)遥感影像和Landsat8数据,分别通过基于多源数据的冰川识别方法和波段比值法获取了2013年玛纳斯河流域冰川信息,结合玛纳斯河流域第一次(1964年)、第二次(2009年)冰川编目数据与1998年、2003年TM影像冰川目视解译结果等四期的冰川边界矢量数据,对玛纳斯河流域1964-2013年50 a来的冰川变化特征进行了综合分析.研究结果显示:玛纳斯河流域冰川自2009年以来有略微增加的趋势,2013年冰川面积比2009年增加了10.25 km²,这在一定程度上抑制了长期以来冰川的快速消融;1964-2013年,玛纳斯河流域的冰川总体呈减少趋势;冰川面积从1964年的673.61 km²减少到2013年的512.07 km²,面积减少161.54 km²,减少23.98%;近50 a来,流域内冰川面积在海拔4500 m及以上呈净增加趋势,而在海拔4500 m以下呈净减少趋势,冰川在海拔(4000±100) m左右退缩的速率最大,高达0.5 km²·a^-1;冰川面积的减少主要体现为大量的冰舌后退和小面积冰川的快速消融,超过85%的冰川冰舌后退距离在200 m以上;该流域的冰川变化主要集中在南、北两个坡向,在南坡向上出现明显的先减少和后增加的变化趋势;1964-2013年,玛纳斯河流域的气温和降水量呈较明显的增加趋势,线性增加率分别为0.26℃·(10a)^-1和16.07 mm·(10a)^-1.研究结果表明气温的持续升高和降水量的增加分别是导致玛纳斯河流域冰川减少期和增加期形成的主要原因.     

一次川东暴雨的雷达资料同化试验与诊断分析

为了对大尺度暴雨天气过程的雷达资料四维变分同化效果进行验证,选取2013年6月29日至7月2日发生在川东遂宁地区的一次暴雨天气过程,使用WRF中尺度模式进行雷达资料的同化模拟试验,并使用模式输出进行诊断分析。结果表明,高时空分辨率的雷达资料使短时间窗口的四维变分同化成为可能。同化结果能很好地改善由地形和初始场误差等因素带来的模拟缺陷,模拟输出场能完整再现整个暴雨的发生发展过程。副高西南侧低空急流带来的海上水汽与南亚季风自南向北带来的水汽共同构成了本次过程稳定的水汽供应通道。中β尺度涡旋的不断生消交替形成了该次暴雨过程的3次降水阶段。垂直方向不稳定能量的快速累积,缓慢释放以及垂直方向强的水汽输送交换,是造成该次过程降水时间长,量级大的主要原因。     

The thermal behaviour of γ-CaSO<Subscript>4</Subscript>

Thermal behaviour of γ-anhydrite (γ-CaSO₄, soluble anhydrite) has been investigated in situ real-time using laboratory parallel-beam X-ray powder diffraction data. Thermal expansion has been analysed from 303 to 569 K with temperature steps of 4 K. Lattice parameters and volume were fitted with a second-order polynomial to calculate thermal expansion coefficients. Thermal expansion of γ-anhydrite is anisotropic being larger along the c axis. Within the 343–383 K thermal range, γ-anhydrite has been found to partially re-hydrate to bassanite CaSO₄·0.5H₂O. At 455 K the transformation γ-CaSO₄ → β-CaSO₄, insoluble anhydrite, starts reaching completion at 653 K.     

三峡澎溪河水域CO2与CH4年总通量估算

以2010年6月~2011年5月三峡澎溪河回水区CO₂与CH₄通量监测数据为基础,参考澎溪河高阳平湖水域全年4次的24 h昼夜连续跟踪观测结果,对每月各采样点的日通量值进行估算。提出了水下地形划分法和环境因素控制法,将各采样点日通量数据外延至整个回水区水域,并估算了澎溪河回水区水域CO₂与CH₄年总通量值。研究期间,澎溪河回水区全年各采样点CO₂通量均值为(3.05±0.46)mmol/(m2·h);CH₄为(0.050 1±0.009 6)mmol/(m2·h)。以水下地形法为基础,该水域全年CO₂和CH₄总通量分别为40 060.5 t和540.9 t;以环境因素控制法为基础,全年CO₂与CH₄总通量分别为39 073.0 t和467.2 t。以环境要素控制法为参考,该水域CO₂全年平均释放强度为43.26 mmol/(m2·d),在全球水库数据序列中处于中等略偏高水平,CH₄全年平均释放强度为1.42 mmol/(m2·d),在全球水库序列中处于中等水平。     

Analysis of the decadal and interdecadal variations of the east asian winter monsoon as simulated by 20 coupled models in IPCC AR4

Using the output data of 20 coupled climate models used in IPCC AR4 and observational data from NCEP, the capability of the models to simulate the boreal winter climatology of the East Asian sea level pressure, 850-hPa wind, and surface air temperature; the decadal variations of the East Asian winter monsoon (EAWM) intensity and EAWM-related circulation, and the interdecadal variations of EAWM-related circulation are systematically evaluated. The results indicate that 16 models can weakly simulate the declining trend of the EAWM in the 1980s. More than half of the models produce relatively reasonable decadal variations of the EAWM-related circulation and the interdecadal differences of EAWM-related circulation between the boreal winters of 1960-1985 and 1986-1998, including the weakened Siberian high, Aleutian low, and East Asian trough, the enhanced Arctic oscillation and North Pacific oscillation, and a deepened polar vortex. It is found that the performance of the multi-selected-model ensemble in reproducing the spatial distribution of the variations is encouraging, although the variational amplitudes are generally smaller than the observations. In addition, it is found that BCCR-BCM2.0, CGCM3.1-T63, CNRM-CM3, CSIRO-MK3.0, GISS-ER, INM-CM3.0, and MRI-CGCM2.3.2 perform well in every aspect.     

降水云团移动速度对风云四号A星降水反演误差的影响

针对FY-4A卫星降水反演产品GPM-SCaMPR中的误差,提出台风区域降水云团移动速度的计算方法并用于误差改进,以全球降水观测计划(Global Precipitation Mission,GPM)的IMERG(the Integrated Multi-satellite Retrievals for GPM)降水产...