Geomorphological analysis of the morphometric characteristics that determine the volume of sediment yield of Wadi Al-Arja,South Jordan

This study addresses the morphometric variables that determine the sediment yield in Wadi Al-Arja through the analysis of the impact of different morphometric characteristics along the course of the valley on its sediment yield, as well as the analysis of spatial and formal dimensions and morphologies of the basin and its relationship to the sediment yield. The study also addresses the size of variation in the volume of sediment yield of the river tributaries that make up the water network of the valley under the differences of its morphometric and hydrological characteristics. The study found several results, most notably: The classification of Wadi Al-Arja basin according to the hypsometric integral value (72.1%) within an uneven topography, which increases the force of the erosive activity and the size of the sediment yield if the basin was exposed to moist climatic periods. The study also showed the presence of convergence in the intra-spaces between the river tributaries in the water network. This increases the volume of water flows when these tributaries meet with each other and thus increasing their erosive ability and sediment yield.The study also showed the presence of marked variation in the sediment yield of the river tributaries depending on the differences in its morphometric characteristics. The results of the step-wise regression analysis confirmed the importance of the morphometric and hydrological variables, and plant coverage in interpreting the variation in the size of the sediment yield of the river tributaries of different stream order in Wadi Al-Arja basin, where these variables interpreted 43% of the total variation, with statistical significance less than 0.05.     

盐胁迫对红砂(Reaumuria soongorica)种子吸胀过程中生理特性的影响

以0%、0.5%、1.0%、1.5%、2.0%、2.5%、3.0%的NaCl和CaCl2溶液处理红砂(Reaumuria soongorica)种子,探讨了两种盐胁迫对种子吸胀过程中生理特性的影响及对种子的伤害程度。结果表明:红砂种子发芽率随两种盐胁迫的加剧极显著下降。种子丙二醛(MDA)含量在NaCl溶液胁迫后先下降后上升,在盐溶液浓度为1.0%时达到最小值,在2.5%处达到最大值;经不同浓度的CaCl2溶液胁迫后,MDA含量呈上升趋势,且均高于对照,最大值出现在3.0%处;种子内可溶性糖含量随NaCl和CaCl2溶液浓度的增大先下降后上升,分别在盐溶液浓度为1.0%和2.0%时达到最小值;种子过氧化氢酶(CAT)活性的变化较小;过氧化物酶(POD)活性随两种盐浓度的增加显著降低;超氧化物歧化酶(SOD)的活性随两种盐溶液浓度的增加先下降再上升又下降,但总体低于对照。经综合分析得出,CaCl2对红砂种子的伤害程度大于NaCl。     

蒙古韭(Allium mongolicum)的分布和结实特性

为掌握蒙古韭(Allium mongolicum)在中国的分布现状和种群发展趋势,采用野外踏查和栽培实验相结合的方法,对其地理分布范围进行了界定;以结实量调查数据为基础,分析了不同分布区域蒙古韭的结实特点以及影响因素。结果显示:(1)蒙古韭在中国的分布区约在36°28′—46°14′N、88°39′—116°05′E之间,包括陕西、甘肃、宁夏、内蒙古、新疆、青海6省(区)。(2)由于生境差异,蒙古韭不同群落中物种组成差异很大,蒙古韭多为伴生种或偶见种,很少为优势种。(3)不同生境条件下蒙古韭的结实特性差异较大,多数地区没有结实或结实率很小,主要是因为干旱导致其生殖生长受阻,加之人为因素干扰,使蒙古韭不能正常完成其生活史。     

基于RTK-GPS技术的干热河谷冲沟沟头形态特征

采用高精度实时动态差分GPS(以下简称RTK-GPS)技术对干热河谷冲沟进行野外调查,获取36个不同活跃度类型沟头的形态参数,研究不同活跃度类型之间沟头的形态特征差异,并分析集水区、沟床植被盖度与形态特征之间的关系。结果表明:1.沟头不同活跃度类型之间,其跌坎高差、沟床比降差异最为显著,可作为沟头活跃度类型野外判别的主要参考指标;沟壁坡度、宽-深比等的差异较为显著,亦可在一定程度上表征沟头活跃程度。2.沟床植被盖度与各形态特征参数的相关性显著,表明沟床植被盖度可作为形态参数的综合替代性指标。同一活跃度类型的沟头,其跌坎高差、沟床比降等与沟床植被盖度呈极显著负相关关系,说明随着沟床植被盖度的增加(或减小),跌坎高差、沟床比降均呈减小(或增加)趋势。3.集水区植被盖度与各形态特征参数的关系不显著,表明干热河谷集水区植被盖度对沟头发育的贡献有限。     

菏泽市紫外线辐射变化特征及月预报方程

利用2008年4月至2012年12月菏泽市紫外线观测资料以及地面常规气象观测资料和空气质量资料,分析了该地区太阳紫外线辐射的变化特征及其与各因子的相关关系,并建立逐月预报方程。结果表明:菏泽紫外线辐射年总量达到187.98 W/m2,春夏两季明显高于秋冬两季,5月达到全年的最大值,1月为全年的最小值;3~9月紫外线辐射极大值均可达到5级,其他月份均可达到4级。不同天气条件下紫外线辐射强度存在明显差异,其中晴天紫外线辐射强且稳定,呈抛物线变化;多云天紫外线辐射波动较大,时强时弱;阴天紫外线辐射相对较弱。紫外线辐射强度与风速、能见度、气温呈正相关,与总云量、低云量、相对湿度呈负相关,与SO2、PM10、NO2、PM2.5多呈负相关。基于多元线性回归分析向后剔除变量方法得出的逐月预报方程,经检验总体预报效果较好,对当地紫外线等级预报工作具有参考意义。     

气象上寒潮天气两种不同统计方法的探讨

文章使用多伦县2001—2010年寒潮天气统计资料,分析了当地寒潮变化特征,通过对寒潮统计两种不同方法从降温特征、大气环流特征及地表覆盖几个方面进行分析,得出如下结论:按日最低气温降温幅度统计寒潮天气出现次数明显多于按日平均气温降温幅度统计寒潮天气出现的次数,尤其在初冬和冬末季节日最低气温变化比日平均气温变化幅度更加剧烈。     

佛山市龙卷风活动的特征及环流背景分析

利用常规气象观测资料和NCEP再分析资料,分析了多年来佛山龙卷风的活动特点及其产生的环流背景和环境条件。结果表明:佛山龙卷风集中出现在4—8月;发生时间主要集中在08:00—14:00;发生地域以南海区最多,其次是三水区;16次龙卷风过程可归纳为4种诱生形势:台风外围型、锋面暖区型、地面辐合线型和热带扰动型。分析还发现:佛山龙卷风发生于偏南暖湿气流中,中低层通常有西南或偏南急流叠加配置,并存在强的垂直风切变和中干冷、下暖湿的强不稳定层结及较低的抬升凝结高度。另外,佛山龙卷风的发生还与地形因素关系密切。     

STATISTICAL ANALYSIS ON THE INFLUENCE OF THE LANDFALLING STRONG TROPICAL CYCLONES IN THE CATASTROPHIC MIGRATIONS OF NILAPARVATA LUGENS(STL) IN CHINA

In order to clarify the statistical pattern by which landfalling strong tropical cyclones(LSTCs)influenced the catastrophic migrations of rice brown planthopper(BPH),Nilaparvata lugens(stl)in China,the data of the LSTCs in China and the lighting catches of BPH that covered the main Chinese rice-growing regions from 1979 to 2008 were collected and analyzed in this work with the assistance of ArcGIS9.3,a software of geographic information system.The results were as follows:(1)In China,there were 220 strong tropical cyclones that passed the main rice-growing regions and 466 great events of BPH’s immigration in the 30 years from 1979 to 2008.73 of them resulted in the occurrence of BPH’s catastrphic migration(CM)events directly and 147 of them produced indirect effect on the migrations.(2)The number of the LSTCs was variable in different years during 1979 to 2008 and their influence was not the same in the BPH’s northward and southward migrations in the years.In the 30 years,the LSTCs brought more obvious influence on the migrations in 1980,1981,2005,2006 and 2007.The influence was the most obvious in2007 and all of the 7 LSTCs produced remarkable impact on the CMs of BPH’s populations.The effect of the LSTCs on the northward immigration of BPH’s populations was the most serious in 2006 and the influence on the southward immigration was the most remarkable in 2005.(3)In these years,the most of LSTCs occurred in July,August and September and great events of BPH's immigration occurred most frequently in the same months.The LSTCs played a more important role on the CM of BPH’s populations in the three months than in other months.(4)The analysis on the spatial distribution of the LSTCs and BPH’s immigration events for the different provinces showed that the BPH’s migrations in the main rice-growing regions of the Southeastern China were influenced by the LSTCs and the impact was different with the change of their spatial probability distribution during their passages.The most serious influence of the LSTCs on the BPH’s migrations occurred in Guangdong and Fujian provinces.(5)The statistical results indicated that a suitable insect source is an indispensable condition of the CMs of BPH when a LSTC influenced a rice-growing region.     

基于TRMM卫星的近10a甘肃临夏降水变化特征

基于2001~2010年TRMM 3B43降水资料和数字高程模型（DEM）数据,采用回归模型＋残差的方法,对甘肃临夏回族自治州近10 a的TRMM 3B43降水数据进行降尺度运算,并结合研究区6个雨量站的观测值,对TRMM 3B43降尺度结果进行精度检验,在此基础上定量研究了临夏回族自治州近10 a的降水量时空变化特征。结果表明：TRMM 3B43降尺度降水量数据整体上具有一定的可信度,但比地面台站的观测值偏小;甘肃临夏州年降水量呈现出由西南向东北递减的趋势,且降水量随着海拔高度的升高而逐渐增加,两者相关系数为0.82;年内降水主要集中在5~9月,基本占全年降水量的70%以上,其中6月降水量最大,12月降水量最小。     

西北太平洋海域风浪、涌浪、混合浪波浪能资源特征

用ECMWF的ERA-40海浪再分析资料,应用波浪能流密度计算方法,对西北太平洋海域的风浪能、涌浪能、混合浪能展开研究。结果表明:(1)波浪能流密度呈现出显著季节性差异。混合浪能流密度表现为冬高夏低;春、夏、秋季的涌浪能流密度明显大于风浪能流密度,冬季相反;(2)混合浪能流密度的大值区主要分布于阿留申群岛附近海域,高值中心可达60 kW/m以上;近海的大值区主要分布于琉球群岛—巴士海峡—传统的南海大风区一带,年平均值在4 kW/m以上,南海北部可达12 kW/m以上;(3)黄渤海的涌浪和混合浪能流密度峰值出现在8—9月,波谷出现在6月。风浪能流密度峰值出现在11月—次年3月,波谷出现在6—8月,均呈现双峰型月变化特征。东海、南海北部、南海中南部海域能流密度的月变化特征相似,都为双峰型,12月—次年4月的能流密度整体较高,波峰出现在12月,波谷出现在5—7月;(4)2 kW/m以上混合浪能流密度出现的频率较高,近海低于大洋;(5)0.5 m以上有效波高出现的频率都非常高,中国近海稍低于大洋;(6)涌浪能流密度的稳定性明显好于风浪能流密度;大洋的能流密度稳定性明显强于近岸。1月份能流密度的稳定性最好,4月和7月次之,10月的稳定性最差。