河南省棉花气候适宜度变化趋势分析

结合前人的研究确立河南省棉花气候适宜度模型, 对所选46个站点1961—2000年的适宜度进行计算, 分析1961—2000年全省及各站点适宜度的变化趋势, 表明1981—2000年适宜度变化趋势显著。对1981—2000年各站点适宜度的变化趋势根据变化的方向和强度进行分类, 将河南省划分为适宜度强增长型、弱增长型、减弱型。分析结果表明:河南省棉花气候适宜度总体呈下降的变化趋势, 各地的变化趋势依据热量带和地形地貌的不同有明显的地域差异。结合各地1981—2000年的气候资料对各类型的气候适宜度变化原因进行了初步分析。     

Petrogenesis and tectonic setting of the peralkaline Pine Canyon caldera, Trans-Pecos Texas, USA

The Pine Canyon caldera is a small (6–7 km diameter) ash-flow caldera that erupted peralkaline quartz trachyte, rhyolite, and high-silica rhyolite lavas and ash-flow tuffs about 33–32 Ma. The Pine Canyon caldera is located in Big Bend National Park, Texas, USA, in the southern part of the Trans-Pecos Magmatic Province (TPMP). The eruptive products of the Pine Canyon caldera are assigned to the South Rim Formation, which represents the silicic end member of a bimodal suite (with a “Daly Gap” between 57 and 62 wt.% SiO₂); the mafic end member consists primarily of alkali basalt to mugearite lavas of the 34–30 Ma Bee Mountain Basalt. Approximately 60–70% crystallization of plagioclase, clinopyroxene, olivine, magnetite, and apatite from alkali basalt coupled with assimilation of shale wall rock (M_a/M_c = 0.3–0.4) produced the quartz trachyte magma. Variation within the quartz trachyte–rhyolite suite was the result of 70% fractional crystallization of an assemblage dominated by alkali feldspar with subordinate clinopyroxene, fayalite, ilmenite, and apatite. High-silica rhyolite is not cogenetic with the quartz trachyte–rhyolite suite, and can be best explained as the result of  5% partial melting of a mafic granulite in the deep crust under the fluxing influence of fluorine. Variation within the high-silica rhyolite is most likely due to fractional crystallization of alkali feldspar, quartz, magnetite, biotite, and monazite. Lavas and tuffs of the South Rim Formation form A-type rhyolite suites, and are broadly similar to rock series described in anorogenic settings both in terms of petrology and petrogenesis. The Pine Canyon caldera is interpreted to have developed in a post-orogenic tectonic setting, or an early stage of continental rifting, and represents the earliest evidence for continental extension in the TPMP.     

A modified Richards equation, its adjoint, and a new perspective on land data assimilation

Summary Richards equation, which is the key relationship for addressing basic soil hydrological processes within the rhizosphere and constitutes the basis for multiple-layer soil hydrology models for meteorological studies, is modified to include two vegetation processes: the transpiration (daytime) and hydraulic lift (nighttime). The analytical form of the adjoint system is derived and can serve as the guideline for discrete forms, as implemented in a variety of multiple layer land surface models. The modified equation and its adjoint model may be used to address at least two types of inverse problems: estimation of the initial soil moisture contents from sparse observations of related quantities; and retrieval of critical soil/vegetation parameters with observations of soil moisture contents (or other related quantities) distributed over a certain period of time. The former may be of more interest for numerical weather prediction studies, whereas the latter may be more valuable for longer time integration of climate models.     

黄河的输沙量：过去、现在和将来——距今15万年以来的黄河泥沙收支表

黄河于150 ka BP切穿三门峡，东流入海。黄河泥沙90%来自黄土高原。黄土高原土地利用和植被的变化对黄河输沙有决定性的影响。15万年以来，黄河进入华北平原的泥沙约70 000×108 t，其中10 ka BP以前占80%。10 ka BP以后的输沙量中，最后1040年黄土高原滥垦时期占60%。黄河泥沙的归宿，建造华北大平原占73%，流入海洋占26%。现在，黄河每年流入北黄海的泥沙不足0.2×108  t，其输运主要受海洋环流系统的影响。现在黄海每年向东海输运悬浮沉积物0.2×108~0.3×108 t，主要为废黄河三角洲及水下三角洲受侵蚀再悬浮的黄河泥沙。1996—2000年黄河下游连年断流，利津站的年径流量和输沙量只有1950—1979年30年平均的19%左右。今后20~30年内，由于气候变暖、工业、城市等引黄水量增加，黄河的入海泥沙量仍将偏少。     

海潮对高精度GPS网的影响初探

本文叙述了海洋负荷潮改正的基本原理，结合算例分析了海潮对GPS网的影响，结果显示：对于近海地区较短时段的GPS观测，考虑海潮负荷改正可以明显地提高解算精度，特别对改善高程方向的精度贡献明显。影响可达数厘米，这种影响的量级对水平方向不明显；对于远离海洋地区，海潮负荷改正的影响已不明显，可以不与考虑。     

太原新一代多普勒天气雷达故障浅谈

太原新一代天气雷达C IN RA D/CC投入使用以来,经过3年多的实际运行,从中发现了一些常见故障,我们对这些故障进行了分析总结,并给出了相应的处理办法,得到了一些经验。1故障类型1.1虚假故障虚假故障是指雷达终端有故障报警,但是还处于正常工作状态。这类故障对于雷达运行没有影     

地下流体短临地震信息的特殊意义

根据华南地区１０次５级以上震例分析结果,得到了与理论分析一致的认识,即地下流体能灵敏地显示短临地震信息,特别是地震发生的时间信息,但不能较好地显示震中方位信息。然而,短临地震时间信息对于地震短临综合预报及防震减灾决策具有重要意义。     

GIS中缓冲区自动生成问题研究

缓冲区分析(Buffer Analysis)是地理信息系统(GIS)重要的空间分析功能之一。地理信息系统中的缓冲区生成分点、线、面三种,其中线状目标缓冲区生成是关键和基础。本文将线状目标缓冲区的生成分为每个线状目标缓冲区多边形独立生成过程和所有线状目标缓冲区多边形重叠合并过程两个阶段,并分别给出了相应的矢量算法。     

二维介质柱的电磁成像研究

从体等效原理出发得到用介质柱介电参数表示的体等效电流,并得到一个积分方程组求解散射问题．利用变分原理,对此方程组求变分,并化为矩阵方程组,消去含介质柱内总场变化的项,得到散射场变化与介质柱介电参数变化之间关系的矩阵方程．即反演方程．用算例检验此法的反演精度、收敛性能、多目标反演能力、抗噪声性能及利用不完备测量散射信息反演目标的能力．结果表明,此法是一种实用性很强的二维介质柱电磁成像方法．     

华南地震区地震带划分的新研究

对华南地区地震带的划分提出了一个新方案。认为北东东向断裂是控制华南地震区地震活动的主要断裂,同时东部有北西向巴士系裂交汇,迭加。