塔克拉玛干沙漠塔中地区春夏季风蚀起沙研究

利用塔克拉玛干沙漠腹地塔中地区的观测资料,对塔中地区春夏季地表土壤风蚀起沙的临界摩擦速度及其变化特征和起沙风速进行了分析研究,并计算了2008年4月19日和7月19日两次沙尘暴天气过程沙漠地表的风蚀起沙量。结果表明:塔中地区春夏季地表起沙的临界摩擦速度为0.26 m·s-1;2 m高度的临界起沙风速约为4.1 m·s-1;两次沙尘暴过程的顺风向沙粒通量和垂直尘粒通量的平均值分别为17.44×10-4 kg·m-1·s-1 、13.8×10-8 kg·m-2·s-1、164.69×10-4 kg·m-1·s-1和799.77×10-8 kg·m-2·s-1;沙尘通量的变化与风速及摩擦速度的变化具有一致性。     

塔克拉玛干沙漠肖塘地区空气动力学粗糙度分析

利用塔克拉玛干沙漠北部肖塘地区梯度自动站2007年1月1日至2007年5月31日的观测数据,计算出该区域中性条件下粗糙度范围是1.00×10-11~1.65×10-3 m,平均粗糙度为6.05×10-5 m,接近沙粒粒径的1/30,与平坦沙面粗糙度相似。摩擦速度的范围是0.14~2.33 m·s-1,平均值1.24 m·s-1。粗糙度随下垫面性质变化明显,与稳定度呈正相关,与风速呈负相关,摩擦速度随粗糙度增大而减小。     

阿拉尔——和田沙漠公路风沙运动若干规律监测研究

以塔克拉玛干沙漠为研究区域,将覆盖塔克拉玛干沙漠的17个气象站近50 a(1961-2010年)历史资料与沙漠公路沿线近3 a(2007年4月~2010年4月)5层梯度风短期监测资料,以及沙漠公路7种防风阻沙体系下典型横断面5层梯度风监测资料进行信息化整编和规范化计算,对阿和沙漠公路风沙运动若干规律进行了系统研究。结果表明:(1)阿和沙漠公路沿线气象站10 m高度最大瞬时风速与沿线梯度风监测站及短期监测站距路面4 m高度最大瞬时风速具有空间相关性,平原路段空间代表性为20~40 km;特殊路段空间代表性为5~10 km;(2)沙漠公路沿线迎风侧最大瞬时风速比背风侧偏大1.15~1.30;(3)沙漠公路沿线2 a一遇最大瞬时风速水平分布规律是以沙漠公路中部向南北递减,最大值出现在k66.7~k326区间;(4)沙漠公路北部强风主风向WNW和N风,次强风主风向ENE和NE风;沙漠公路中部全年强风主风向ENE和NE风,次强风主风向为NNW风;沙漠公路南部全年强风主风向W风,次强风主风向为WNW风;(5)沙漠公路沿线起沙风是随7种防风阻沙体系的作用存在明显差异,以芦苇、草帘子方格防风阻沙体系下2 m高度的起沙风速和沙粒过路临界风速为最大,分别为8.0~9.0 m/s和10.0~11.0 m/s,对输沙贡献最大的有效瞬间风速在8.0~15.0 m/s之间;黑土工袋方格防风阻沙体系下起沙风速为4.0~5.0 m/s,沙粒过路临界风速为5.0~6.0 m/s,防风阻沙效应最差,建议更换。     

基于ASCAT散射计数据的2012年南极周边海面风场特征分析

利用2012年全年的ASCAT散射计风场数据,对55°S以南的南极周边海域海面风场开展了时空分布特性统计分析。结果表明:对于南极周边海域,7月平均风速最大,为12 m·s-1,12月平均风速最小,为8 m·s-1,冬季大于夏季;该区域平均风速主要在9—12 m·s-1之间,全年出现的天数280天,约占全年的77%;风速10 m·s-1所占比例也是冬季大于夏季。从全年来看,南极周边海域在冬季(4—6月)和春季(7—9月)风速普遍较大。该区域0°W—60°W海域内风速明显比其他海域要小。     

夏季强沙尘暴内部热力动力特征的个例研究

根据对流体在热低压条件下激发强沙尘暴的机理,并应用Rennó和Ingersoll于1996年提出的热机自然对流理论,对2004年7月12日甘肃省酒泉基准站发生的强沙尘暴内部动力热力结构进行了探讨。结果表明:①在沙尘暴发生前的一小时大气底层处于干热状态,垂直方向巨大的温度梯度有利于干对流发展。②激发强沙尘暴的对流体的切向旋转速度和垂直运动速度的大小,很大程度上决定了沙尘暴的强弱。③利用酒泉站探空资料计算出的沙尘暴对流体的最大切向旋转速度为11.4 m·s-1,垂直运动速度为14.0 m·s-1;地面沙尘暴观测系统记录的平均环境风速仅为5.5 m·s-1,瞬间最大风速只9.3 m·s-1。     

柴达木盆地东北部哈勒腾河流域风况特征及其对风沙地貌发育的影响

风况是影响风沙地貌发育的重要因子,在一定程度上决定了沙丘类型.为探究区域风沙地貌发育与风况之间的关系,对哈勒腾河流域不同区域一个完整年度的风况进行分析.结果表明:流域年平均风速为2.78 m·s-1,起沙风集中在春夏季,平均风速为7.78 m· s-1,起沙风事件平均持续时间为4.1 h;流域输沙势122-254 VU...     

1961~2010年河西地区平均风速时空变化趋势分析

利用河西地区15个气象站点1961~2010年月平均风速和最大风速日值资料,采用M-K突变检验、ArcGIS中的IDW插值和小波分析等方法分析河西地区平均风速的时空变化趋势。结果表明：近50 a来,河西地区年平均风速呈明显下降趋势,其递减速率为0.14 m/( s?10 a)(α=0.001);该地区四季平均风速均呈减少趋势且减少趋势相同;平均风速的变化在空间分布上存在差异,具体表现为年平均风速的递减趋势是自西向东逐渐减小,瓜州和玉门是该地区减幅最大的区域,而乌鞘岭却呈现出微增的趋势;风速的长期变化具有一定的突变性,其年平均风速在1985年发生突变;该地区平均风速存在存在多尺度的周期结构特性,其变化周期为6、19和25 a。     

广西地形分布与前汛期降水时空变化关系

采用广西88个测站1959-2006年4-6月月平均降水资料,运用小波分析、EOF、REOF、新型区域旱涝指数等方法,研究了广西前汛期不同区域降水的长期变化特征。结果表明:(1)广西前汛期降水异常可分为8个地形空间分布型:桂东南、桂东北、桂东、桂西、桂西南、桂西北、桂南及桂中;(2)各异常区代表站降水的时间演变特征、不同年代盛行的主要周期均有所差异,但大部分区都存在2～4 a的短周期和12～14 a的长周期变化;(3)上世纪60年代全区性大涝大旱,70年代除桂西、桂西北外的其它地区平均气候态均以湿润状态为主,而80年代除桂西南、桂南外其它区以干旱状态为主要特征,进入90年代后出现局地敏感气候区。     

半干旱区冬春季黑碳气溶胶吸收特性的观测研究

利用2006年4月和12月锡林浩特观象台黑碳灰度仪的观测资料,分析了半干旱地区黑碳气溶胶浓度的变化特征,讨论了引起这些变化特征的影响因子。结果表明,黑碳气溶胶浓度冬季远大于春季,日变化呈明显的双峰型;讨论了风速对黑碳气溶胶浓度不同影响的范围,可知风速在较小的情况下（小于3.5 m·s-1）,黑碳气溶胶浓度值随风速的增大而减小;在3.5~4.5 m·s-1之间,风速增大,黑碳气溶胶浓度值也增大;风速较大（大于4.5 m·s-1）后,黑碳气溶胶浓度与风速之间没有明显的相关性。冬季12月由于黑碳气溶胶吸收作用造成的消光占总气溶胶消光的25%。     

干旱区内陆湖盆沙尘水平通量及粒度特征——以青土湖地区为例

内陆季节性湖盆是干旱区重要的粉尘来源地,其沙尘的排放会通过一系列的陆地-大气相互作用对区域气候及生态环境产生重大影响。以青土湖、南湖和红沙岗为研究对象,利用BSNE型沙尘仪采集沙尘物质,探讨不同地区沙尘水平通量和粒度特征。结果表明：5个测点平均沙尘水平通量表现为青土湖北(612.1 kg·m^-2·a^-1)>青土湖南(84.6kg·m^-2·a^-1)>青土湖东(35.2 kg·m^-2·a^-1)>红沙岗(11.0 kg·m^-2·a^-1)>南湖(10.7 kg·m^-2·a^-1),随着高度增加,青土湖北和青土湖东沙尘水平通量快速降低,青土湖南和红沙岗的下降速度分别在0.5 m和1 m高度以上放缓,南湖先降后增;沙尘颗粒物主要为粉沙和极细沙,其次为细沙和黏土,除青土湖南外,其余测点随着高度的增加呈粉沙含量递增、细沙含量递减、平均粒径变细的趋势;5个测点总体表...     

Analysis of the characteristics of snow drop size distribution in the Qilian Mountains

Under the Watershed Allied Telemetry Experimental Research (WATER) project, a significant amount of snow size data was collected from March to April 2008. However, because of limited observation data for the Qinghai-Tibet Plateau, the modeling behavior was not satisfactory. This paper demonstrates characteristics of the snow drop size distribution (SSD) in this region. The experimental area is located in the northeastern part of the Qinghai-Tibet Plateau. The Heihe River Basin, which is the second largest interior river basin in China and is located on the northern slopes of the Qilian Mountains, was selected as the simulation region. This basin ranges from approximately 5,000 m to 1,000 m in elevation. A new generation Parsivel disdrometer, the OTT Parsivel, was used for measurements. Four data sets were compiled to determine the average distributions for four different snowfall rates. The characteristics of the snow particle size distribution in the mountainous area were analyzed. Similar to the raindrop distribution, there was a multi-peak structure. Most peaks appear in the D 2 mm region (D: diameter of the snow drop size). An M-P distribution and a Г distribution were developed based on the precipitation data observed in Qilian mountainous area. We found that the Г distribution has a better fit than the M-P distribution for the actual distribution. In addition, we observed that the intercept parameter (N0) and the slope parameter (Λ) correlate well with the shape parameter (μ). The disdrometer data can also be used to model the reflectivity factor (ZH) and differential reflectivity factor (ZDR). The radar reflectivity (ZHH, ZVV) and differential reflectivity (ZDR) were modeled in order to facilitate understanding of the connections between radar and ground measurements, and were used to support work for the improvement of rainfall estimates by polarimetric radar. Rain rate estimation using radar measurements was based on empirical models, such as the Z-R relationship and R(ZH, ZDR) in the Qilian mountainous areas. The relationship of R=0.017×100.079×ZH-0.022×ZDR is better than R=0.019×100.078×ZH for estimating R (melted snow). The normalized errors (NE) of R(ZH) and R(ZH, ZDR) are 13.22% and 5.20%, respectively.     

海南岛地域文化的空间分布研究

分析了海南岛地域文化的空间分布特点及其区域差异、南海岛文化景观的地理分异、人才及农业景观的区域分布等问题,指出海南岛地域文化的空间分布与地形条件和气候等地理要素密切相关,各种文化景观的分布总体上呈现沿海拔依次成圈层展布的特点。沿海平原地带城镇密布、人口众多、工业发展、交通设施齐备,整体文化水平处在最高层次。岛内丘陵、山地地区文化相对落后。另外,东部地区普遍先进于西部地区也是一个明显的特点     

南极夏季普里兹湾磷虾幼体及纽鳃樽的丰度和分布特征

根据2002年及2006年南大洋普里兹湾浮游动物和环境调查资料,对普里兹湾磷虾幼体及被囊类纽鳃樽的分布和丰度进行了初步研究。结果表明,陆架以北深海水域（水深>1000 m）磷虾幼体主要由长臂樱磷虾Thysanoessa macrura和大磷虾Euphausia superba组成,其中长臂樱磷虾幼体的分布范围更广、丰度更高。2006年与2002年相比海冰回退时间早,测区海水的平均温度和叶绿素a浓度较高,大磷虾及长臂樱磷虾幼体的丰度相对更大,成熟度更高。近岸区域磷虾幼体主要由晶磷虾Euphausia crystallorophias组成,在2002年近岸冰情严重时丰度较小,仅为95.6尾/1000 m3,2006年近岸出现冰间湖时,晶磷虾幼体丰度高达43966.6尾/1000 m3,主要以无节幼体及原蚤状幼体CI期为主。测区纽鳃樽Salpa thompsoni丰度很低,2002年仅在最北部1个站位出现,密度为10个/1000 m3,2006年在陆坡及陆架坡折3个站位出现,平均丰度为146.7个/1000 m3。海冰消融时间、冰间湖、饵料浓度等环境因子对普里兹湾磷虾幼体及纽鳃樽的分布和丰度产生重要影响。     

Size distribution of urban blocks in the Tokyo Metropolitan Region: estimation by urban block density and road width on the basis of normative plane tessellation

The size distribution of urban blocks is important for the characterisation of urban block patterns and is known to follow several parametric statistical distributions. However, it has not previously been analysed on the basis of a normative plane tessellation and in terms of urban block density and mean road width. In this article, we formulate the size distribution of Voronoi cells using the gamma distribution estimated by urban block density and mean road width. We found that (1) both log-normal and gamma distributions can be good candidates for the size distribution of urban blocks at the scale of a region that consists of regular urban blocks and that has a uniform road width; and (2) the size distribution of urban blocks depends on the balance between pattern and width improvement effects. Based on one study region in Tokyo, if the pattern improvement effect is more prominent than the width improvement effect, the mode of urban block sizes tends to be larger than if it is not. These findings are expected to provide scientific support for urban planning (e.g. land readjustment projects).     

中国堵江滑坡发育分布特征

在我国已经发现和识别出160余个堵江滑坡,根据这些实际资料,绘制了我国滑坡堵江事件分布图,研究表明,堵江滑坡的发育与我国的降雨分区、地形地貌、断裂分布、地震活动和地层岩性的分布密切相关,从而堵江滑坡灾害在时间上、空间上的发育分布具有一定的规律。     

西北太平洋热带气旋活动的强度与频度分布规律初探

在结西北太平洋地区大量热带气旋观测资料的统计分析和数学似合分析的基础上,得出了热带气旋的强度一时间分布关系和频度一空间分布关系,并发现了两种分布关系具有相似的分布函数形式。     

Size and spatial distribution of loess slides on the Chinese Loess Plateau

ABSTRACT

The size and spatial distribution of loess slides are important for estimating the yield of eroded materials and determining the landslide risk. While previous studies have investigated landslide size distributions, the spatial distribution pattern of landslides at different spatial scales is poorly understood. The results indicate that the loess slide distribution exhibits a power-law scaling across a range of the size distribution. The mean landslide size and size distribution in the different geomorphic types are different. The double Pareto and inverse gamma functions can coincide well with the empirical probability distribution of the loess slide areas and can quantitatively reveal the rollover location, maximum probability, and scaling exponents. The frequency of loess slides increases with mean monthly precipitation. Moreover, point distance analysis showed that > 80% of landslides are located < 3 km from other loess slides. We found that the loess slides at the two study sites (Zhidan and Luochuan County) in northern Shaanxi Province, China show a significant clustered distribution. Furthermore, analysis results of the correlated fractal dimension show that the landslides exhibit a dispersed distribution at smaller spatial scales and a clustered distribution at larger spatial scales.     

滇东喀斯特山地土壤种子及其分布特征

土壤种子是潜在的植物种群。在水洗土壤样品过粗细筛后,对云南东部3个不同岩溶地点的3种植被类型下的土壤中的种子进行了萌发实验研究,结果表明岩溶山地各植被类型的土壤中贮藏着丰富的种子,每个10cm×10cm×10cm土柱内储藏有40 9～149 3粒种子,高于贵州喀斯特山地和同纬度的广东森林。相对而言,次生林下的土壤中拥有相对较多的种子种类与数量,而退化草地内则较少,灌丛与二者之间的差异无明显规律。草本种子对密度值的贡献最大,灌木次之,乔木和藤本稀少。所有土壤的种子在水平方向上的分布差异巨大。种子密度随土层的深入而减小,次生林的减小趋势小于退化草地。垂直方向上的这种梯度差异可能与土壤的物理性质有关,次生林的土壤由于有机质含量高而使土壤的疏松程度高,有利于种子在土壤中的移动。     

Spatio-temporal Rainfall Distribution and Markov Chain Analogue Year Stochastic Daily Rainfall Model in Ethiopia

This paper aims at the spatiotemporal distribution of rainfall in Ethiopia and developing stochastic daily rainfall model. Particularly, in this study, we used a Markov Chain Analogue Year (MCAY) model that is, Markov Chain with Analogue year (AY) component is used to model the occurrence process of daily rainfall and the intensity or amount of rainfall on wet days is described using Weibull, Log normal, mixed exponential and Gamma distributions. The MCAY model best describes the occurrence process of daily rainfall, this is due to the AY component included in the MC to model the frequency of daily rainfall. Then, by combining the occurrence process model and amount process model, we developed Markov Chain Analogue Year Weibull model (MCAYWBM), Markov Chain Analogue Year Log normal model (MCAYLNM), Markov Chain Analogue Year mixed exponential model (MCAYMEM) and Markov Chain Analogue Year gamma model (MCAYGM). The performance of the models is assessed by taking daily rainfall data from 21 weather stations (ranging from 1 January 1984-31 December 2018). The data is obtained from Ethiopia National Meteorology Agency (ENMA). The result shows that MCAYWBM, MCAYMEM and MCAYGM performs very well in the simulation of daily rainfall process in Ethiopia and their performances are nearly the same with a slight difference between them compared to MCAYLNM. The mean absolute percentage error (MAPE) in the four models: MCAYGM, MCAYWBM, MAYMEM and MCAYLNM are 2.16%, 2.27%, 2.25% and 11.41% respectively. Hence, MCAYGM, MCAYWBM, MAYMEM models have shown an excellent performance compared to MCAYLNM. In general, the light tailed distributions: Weibull, gamma and mixed exponential distributions are appropriate probability distributions to model the intensity of daily rainfall in Ethiopia especially, when these distributions are combined with MCAYM.     

世界泥炭分布规律

全球地形复杂多样,泥炭资源分布也不均衡,根据泥炭的堆积强度,概括了全球泥炭的6个堆积带:①极地弱度泥炭堆积带;②中纬度弱度泥炭堆积带;③山地弱度泥炭堆积带;④热带和亚热带弱度泥炭堆积带;⑤温带强度泥炭堆积带;⑥潮湿热带强度泥炭堆积带.根据泥炭的地表形态,划分了以下主要泥炭地类型:苔原多边形泥炭地、冻结的丘状泥炭地、高低位镶嵌的泥炭地、毯状披盖式泥炭地、凸起的贫营养泥炭地和平坦的富营养泥炭地;论述了主要泥炭地类型的分布以及每类泥炭地的特点和赋存特征;总结了估算全球泥炭地面积的研究进展.针对全球气候变化和人类活动双重影响下的大尺度泥炭地面积及分布规律的研究,提出了未来精确估算泥炭地面积的方法及泥炭地在全球碳循环中的重要性.