Diurnal variations of cosmic rays during a solar magnetic cycle

We have used data from five neutron monitor stations with primary rigidity (Rm) ranging from 16 GeV to 33 GeV to study the diurnal variations of cosmic rays over the period: 1965–1986 covering one 22-year solar magnetic cycle. The heliosphere interplanetary magnetic field (IMF) and plasma hourly measurements taken near Earth orbit, by a variety of spacecraft, are also used to compare with the results of solar diurnal variation. The local time of maximum of solar diurnal diurnal variations displays a 22-year cycle due to the solar polar magnetic field polarities. In general, the annual mean of solar diurnal amplitudes, magnitude of IMF and plasma parameters are found to show separte solar cycle variations. Moreover, during the declining period of the twenty and twenty-ne solar cycles, large solar diurnal amplitudes are observed which associated with high values of solar wind speed, plasma temperature and interplanetary magnetic field magnitude B3.     

西北干旱区石羊河流域末次冰期晚期气候不稳定性记录

通过对我国西北干旱区石羊河流域三角城末次冰期最盛期晚期-晚冰期地层剖面沉积物中有机质碳同位素分析,表明在季风边缘带的沉积地层中较详细地记录了这一时期气候快速颤动,发生千年至百年尺度的冷干-温湿变化,高分辨的有机质碳同位素组成与GRIP氧同位素组成有较好的可比性,表明与全球古气候变化有明显的联系,也反映在末次冰期最盛期与晚冰期过渡期气候温湿,陆地植被比较发育,可能与东亚季风有关。有机质碳同位素这一指标对气候记录较敏感,是重建干旱区高分辨古气候演化模式十分有效的手段,在季风交汇带能灵敏地记录到气候快速变化。     

Proxy Record of a Firn-Core From an Alpine Glacier and Its Implication to Recent Glacio-Climatic Varia tions on Mt. Yulong, Southeastern Part of Tibetan Plateau

PROXY RECORD OF A FIRN-CORE FROM AN ALPINE GLACIER AND ITS IMPLICATION TO RECENT GLACIO-CLIMATIC VARIATIONS ON MT. YULONG, SOUTHEASTERN PART OF TIBETAN PLATEAU     

Large-scale flow and transport of magnetic flux in the solar convection zone

Horizontal large-scale velocity field describes horizontal displacement of the photospheric magnetic flux in zonal and meridian directions. The flow systems of solar plasma, constructed according to the velocity field, create the large-scale cellular-like patterns with up-flow in the center and the down-flow on the boundaries. Distribution of the largescale horizontal eddies (with characteristic scale length from 350 to 490 Mm) was found in the broad equatorial zone, limited by 60‡ latitude circles on both hemispheres. The zonal averages of the zonal and meridian velocities, and the total horizontal velocity for each Carrington rotation during the activity cycles no. 21 and 22 varies during the 11-yr activity cycle. Plot of RMS values of total horizontal velocity is shifted about 1.6 years before the similarly shaped variation of the magnetic flux.     

秦岭-黄淮平原交界带地表径流与其时间变化的关系分析

根据秦岭-黄淮平原交界带及其邻近地区42个径流站1962~1999年的观测资料,分析了地表径流量及其时间变化(年内分配和年际变化)的空间分布规律,得出二者之间存在正相关关系的结论,并探讨了这种反常现象的成因。     

太湖越冬蓝藻空间分布的初步研究

为确定2007-2008年冬季蓝藻在太湖各个湖区的分布及其变化规律,在冬季逐月对太湖主要湖区14个位点采集底泥和水样,应用荧光分析法测定样品中藻蓝素含量,以确定冬季太湖各个湖区的藻蓝素分布状况,比较冬季太湖各个湖区水体和底泥中蓝藻的分布差异.实验结果说明与夏季情况不同,相对于西南太湖水域,2007-2008年冬季北太湖水体和底泥中的蓝藻含量均较低,而西南湖区部分区域12月仍出现了蓝藻的聚集,底泥表面的藻蓝素含量也较高,说明调查期间,冬季越冬蓝藻主要分布于西太湖和南太湖.     

福建三沙湾游泳动物种类和数量的季节变化

根据2019年1月、4月、7月和10月四个季度10个站位定置张网调查资料, 对福建三沙湾游泳动物的种类组成及季节变化进行分析研究。结果表明: 调查共获得游泳动物209种, 隶属于3门4纲19目73科144属, 其中鱼类154种, 甲壳类48种, 头足类7种。游泳动物种类数以秋季出现最多, 四个季节共同出现的种类有42种。鲈形目种类最多, 其次是十足目。鱼类适温性以暖水性种类居多, 占71.43%, 暖温性种类次之(27.92%); 生态类型以底层、近底层鱼类居多, 两者合占75.97%。鹰爪虾(Trachypenaeus curvirostris)、大黄鱼(Larimichthys crocea)、棘头梅童鱼(Collichthys lucidus)、红星梭子蟹(Portunus sanguinolentus)和日本蟳(Charybdis japonica)等14个种类是三沙湾游泳动物的优势种类, 季节性优势种居多。三沙湾定置张网调查渔业资源质量密度为111.09 kg/km², 尾数密度为13.72×10³ ind./km², 均以夏季最高, 春季最低。应该进一步加强对三沙湾渔业资源的合理利用和有效保护, 同时重视对外来物种的监测。     

GNSS测站坐标非线性变化影响机制的研究

对影响地球参考框架稳定度与精确度的地球动力学因素进行深入研究,能更好地促进毫米级地球参考架的建立.而研究GNSS测站坐标的非线性变化及其相关机制,是实现毫米级地球参考框架的前提,也为提升GNSS坐标精度、研究地球物理因素等提供参考.首先研究了GNSS测站坐标非线性变化的影响机制与理论改正模型,给出了季节性温度效应、地表物质负荷效应、GNSS周年性系统误差和高阶电离层延迟这四种因素的研究进展,并提出了在机制和模型研究方面一些改进的方向.然后通过以高阶电离层延迟对GNSS测站坐标时间序列的影响为例,进行分组实验,研究了高阶电离层延迟对GNSS测站坐标非线性变化的影响,并进一步将影响进行了量化.研究结果有助于对测站坐标非线性变化的机制做出更精确合理的解释,同时也有助于削弱与限制高阶电离层延迟对建立高精度地球参考框架的影响;为我国北斗地球参考框架的建立与维持提供了可靠的理论基础,具有一定的参考价值.     

The seasonal variation of undercurrent and temperature in the equatorial Pacific jointly derived from buoy measurement and assimilation analysis

Based on the TOGA-TAO buoy chain observed data in the equatorial Pacific and the assimilation analysis results from SODA(simple ocean data assimilation analysis), the role of the meridional cells in the subsurface of the tropical Pacific was discussed. It was found that, the seasonal varying direction of EUC (the quatorial Undercurrent)in the Peacific is westwards beginning from the eastern equatorial Pacific in the boreal spring. The meridional cell south of the equator plays important role on this seasonal change of EUC.On the other hand, although the varying direction is westwards,the seasonal variation of temperature in the same region gets its minimum values in the boreal autumn beginning from the eastern equatorial Pacific.The meridional cell north of the equator is most responsible for the seasonal temperature variation in the eastern equatorial Pacific while the meridional cell south of the equator mainly controls the seasonal temperature change in the central Pacific. It is probably true that the asymmetry by the equator is an important factor influencing the seasonal cycle of EUC and temperature in the tropical Pacific.