不同沙丘部位和不同结皮类型对土壤种子库的影响

采用萌发法对古尔班通古特沙漠沙垄不同部位生物结皮类型的种子库进行研究,发现不同沙丘部位和结皮类型种子分布特征有一定的规律性:藻类结皮的种子数量、丰富度和多样性均显著高于地衣和苔藓结皮。生物结皮从藻类到地衣和苔藓的演替,有降低种子数量和种子多样性的现象。在不同沙丘部位,沙丘顶部流沙的种子数量和多样性较低,与丘顶流沙相比沙丘底部的藻类结皮显示出较高的丰富度和多样性,但沙丘底部的地衣和苔藓结皮与丘顶流沙相比未表现出明显的差异。背风坡中部的藻类结皮种子多样性较高,显著高于迎风坡中部的藻类结皮。     

新疆两大沙漠风沙土土壤理化特性对比分析

本文对塔克拉玛干沙漠和古尔班通古特沙漠的风沙土土壤理化特性进行了对比分析，结果表明：两大沙漠风沙土土壤肥力无明显差异，土壤有机质很低；塔克拉玛干沙漠风沙土在全盐、ＣａＣＯ３含量上高于古尔班通古特沙漠；塔克拉玛干沙漠风沙土分选好，颗粒组成以细沙为主，而古尔班通古特沙漠风沙土分选较差；两大沙漠风沙土在２４种化学元素含量上多数存在明显差异。     

新疆两大沙漠风沙土壤理化特性对比分析

本文对塔克拉玛干沙漠和古尔班通古特沙漠的风沙土土壤理化特性进行对比分比分析，结果表明：两大沙漠风沙土土壤肥力无明显差异，土壤有机质很低；塔克拉玛干沙漠风沙土在全盐、ＣａＣＯ３含量上高于古尔班通古特沙漠；塔克拉玛干沙漠风沙土分选好，颗粒组成以细沙为主，而古尔班通古特沙漠风沙土分选较差，两大沙漠风沙土在２４种化学元素含量上多数存在明显差异。     

塔里木沙漠公路风沙危害形成研究

塔里木沙漠公路南北横贯塔里木盆地 ,全长 5 6 2km ,其中近 80 %的路段穿行于塔克拉玛干沙漠之中 ,是世界上穿越流动沙漠最长的等级公路 ,因而风沙危害是制约沙漠公路正常运行的主要病害。研究表明 ,1)沙漠公路沿线风力强劲 ,沙丘形态各异 ,地表组成物质松散 ,为风沙危害形成提供了动力条件和奠定了物质基础 ;作为风沙危害的受灾对象 ,沙漠公路防沙体系结构以及公路纵横断面也直接作用于风沙危害形成过程 ;2 )沙漠公路风沙危害主要源于防沙体系沙物质的侵入和防沙体系内部因近地面气流变异而产生的风蚀与堆积 ;目前沙漠公路风沙危害的主体是防沙体系 ,危害的形式包括风蚀、风沙流滞留积沙和沙丘前移压埋。     

新月形沙丘及新月形沙丘链存在的环境条件——以甘肃河西沙区为例

新月形沙丘是一种主要的沙丘类型,一般存在于沙漠边缘亦即绿洲边缘.环境是新月形沙丘形成和存在的基础,不同环境的风沙活动规律不同.为了揭示新月形沙丘形成和存在的环境条件,文中在对甘肃河西沙区新月形沙丘和新月形沙丘链的分布状况调查的基础上,详细调查了甘肃河西沙区新月形沙丘和新月形沙丘链的形态特征和分布的环境条件,用方差检验了样本之间的差异显著性和指标之间的相关显著性.结果表明:甘肃河西沙区的新月形沙丘及新月形沙丘链均分布在沙漠边缘的下风向,一般为斑块状分布.分布区域为平坦的沙粘质或沙砾质滩地,丘间较为开阔,新月形沙丘上风向平均有246.4m的平坦沙砾质滩地或平坦粘砾质滩地,沙丘下风向平均有374.4m的平坦沙砾质滩地或平均粘砾质滩地;新月形沙丘链的上风向平均有236.6m的平坦粘砾质滩地或平坦的沙砾质滩地,下风向平均有958.1m的平坦粘砾质滩地或平坦的沙砾质滩地.新月形沙丘及新月形沙丘链的分布区都具有明显的主风向,其他方向的风速较小或偶尔有大风但频率较低;甘肃河西地区沙漠边缘的新月形沙丘相对较为高大,新月形沙丘链较新月形沙丘更高更大.分析结果认为,沙丘最高点与沙脊线重合或分离可能与主导风向与反向风的分布频率以及观测的季节有关.     

塔里木沙漠公路风沙危害研究

通过分析沙漠公路不同时段和地段风沙危害的特点 ,找出了从北向南风沙危害强度趋于减弱 ,公路及防沙体系受害程度逐渐降低的规律。注意到防沙体系所受风沙危害类型和程度在公路东西两侧和不同地貌部位差异明显。并且查明随着时间推移 ,公路受害面积扩大 ,重型沙害所占比例明显增长的公路沙害发展状况。     

古尔班通古特沙漠工程沙害形成的环境分析

通过对风动力与下垫面，包括地形地貌、沙丘高度、植被盖度以及沙物质颗粒等的相互作用和影响的分析，将古尔班通古特沙漠从北到南划分为6个风沙危害形成的环境区：Ⅰ．北部边缘区；Ⅱ．北部区；Ⅲ．中部区；Ⅳ．中部偏南区；Ⅴ．南部区；Ⅵ．南部边缘区。综合考虑各因素，依据沙源条件，将风沙危害形成环境的6个区划分为3个级别：一级为潜在风沙危害严重区（Ⅲ区）；二级为潜在风沙危害较重区（Ⅳ，Ⅴ，Ⅵ区）；三级为潜在风沙危害较轻区（Ⅰ，Ⅱ区）。     

古尔班通古特沙漠边缘春秋季沙丘水分状况初步研究

古尔班通古特沙漠边缘植被破坏严重,沙丘活化明显,是新疆干旱区植被恢复的重点地区之一,当地降水稀少,其沙丘的水分状况便成为植被生存和恢复过程的关键条件,为掌握古尔班通古特沙漠边缘流动沙丘和固定沙丘不同部位的水分状况,从2003年3月到10月植物生长期内利用中子仪进行连续监测的结果表明:沙丘含水量月变化与月降水量分布相一致;流动沙丘0-30cm的含水量低于固定沙丘,而其它各层都高于固定沙丘;流动沙丘含水量从上部到下部依次升高,而固定沙丘则并无此规律;流动沙丘中部和下部稳定湿沙层处在距沙丘表面60cm以下,且厚度超过100cm,固定沙丘稳定湿沙层只存在于沙丘中部距沙丘表面60~150cm深度范围内,其厚度不超过100cm。     

古尔班通古特沙漠不同类型生物结皮对草本植物多样性影响

选择古尔班通古特沙漠的北部(一号点)、中部(二号点)、南部(三号点)3个不同样点的裸沙和藻结皮、地衣结皮与苔藓结皮3种生物结皮类型,对比研究了草本植物多样性的差异性及其主要环境影响因素。结果表明:(1)不同生物结皮类型的土壤理化性质有明显差异,土壤有机质、全氮、全磷、全钾含量以及黏粒、粉粒和细沙的含量随生物结皮演替显著上升,而中沙和粗沙的含量呈显著下降趋势,在沙漠不同区域呈现明显的空间异质性,二号样点中裸沙和藻结皮的养分含量和pH明显低于一号点和三号点。(2)草本植物的物种丰富度和Shannon-Wiener指数随生物结皮发育呈明显上升趋势,草本植物的物种组成、群落结构在不同类型生物结皮和沙漠不同区域均具有显著差异。(3)在土壤理化特征中,有机质、速效P和全K含量,以及pH和粉粒含量是影响草本植物分布的关键因子。(4)不同类型生物结皮之间的微地形和种类组成差异、种子生物学特性以及生物结皮在不同尺度下的土壤环境异质性共同影响草本植物在生物结皮中的物种组成和丰度,最终导致草本植物群落结构在生物结皮中的演替变化。     

新疆沙漠空间分布格局与类型结构

在对新疆沙漠区域环境特点分析的基础上,基于新疆1[JP18]∶[JP]1 000 000数字地貌图和TM影像数据及Google Earth等资料,利用GIS技术,编制了新疆沙漠分片图与沙漠类型分布图,对新疆沙漠空间分布与类型结构进行了分析。结果表明：① 新疆共有577块沙漠,可以划分为35片区。按照区域可分为塔里木盆地沙漠区、准噶尔盆地沙漠区、阿尔泰山沙漠区、准噶尔西部山沙漠区、昆仑山-阿尔金山沙漠区、天山沙漠区6个区;② 新疆沙漠面积达428 977.14 km²,占新疆总面积的26.12%;沙漠分布广泛,平原、丘陵和山地均有分布,但各区域的沙漠面积相差悬殊;沙漠在空间上呈聚集分布,主要分布在塔里木盆地和准噶尔盆地;沙漠景观破碎化程度具有很大空间差异性,在塔里木盆地和准噶尔盆地中面积较大沙漠的破碎化程度低,而在山地与两大盆地的过渡地带面积较小的沙漠破碎化程度较高。③ 新疆沙漠具有独特的地貌类型、稳定性和类型丰富度等类型结构,地貌类型以沙丘和沙垄为主,沙漠植被覆盖度差,以流动性沙丘和流动性沙垄为主,多数沙漠的类型丰富度贫乏,只有少数沙漠类型数量可以达到中等乃至极丰富。     

策勒绿洲-荒漠过渡带风沙前沿近地面不同方向的输沙特征

利用策勒绿洲-荒漠过渡带风沙前沿输沙资料及风速风向资料,分析这一区域近地面输沙的方向分布特征。结果表明：① 风沙前沿起沙风风向以W、WNW为主,风向变化比较单一;② 观测点输沙量集中于NW、WNW、W、SW、WSW 5个方位,合计占总输沙量的68.3%;0～40 cm高度年输沙量为96.0 kg,年合成输沙量为45.9 kg,合成输沙方向为102.5°;③ 观测点年输沙势为43.2 VU,年合成输沙势为31.04 VU,输沙势的方向分布与实测输沙量存在较大差异。     

古尔班通古特沙漠腹地输沙风能及地貌学意义

根据古尔班通古特沙漠腹地2个气象台站2003-2006年气象资料,分析起沙风况和输沙势,并对其地貌学意义进行探讨。结果表明：沙漠中部全年起沙风出现频率为0.25%,以东北风和西北风为主;南部起沙风出现频率为0.11%,以西北风和西南风为主。沙漠中部和南部均属于低风能环境,中部地区的总输沙势（DP）为66.7VU,合成输...     

Estimation of the quantity of aeolian saltation sediments blown into the Yellow River from the Ulanbuh Desert,China

The Ulanbuh Desert borders the upper reach of the Yellow River.Every year,a mass of aeolian sand is blown into the Yellow River by the prevailing wind and the coarse aeolian sand results in serious silting in the Yellow River.To estimate the quantity of aeolian sediments from the Ulanbuh Desert blown into the Yellow River,we simulated the saltation processes of aeolian sediments in the Ulanbuh Desert.Then we used a saltation submodel of the IWEMS(Integrated Wind-Erosion Modeling System)and its accompanying RS(Remote Sensing)and GIS(Geographic Information System)modules to estimate the quantity of saltation sediments blown into the Yellow River from the Ulanbuh Desert.We calibrated the saltation submodel by the synchronous observation to wind velocity and saltation sediments on several points with different vegetation cover.The vegetation cover,frontal area of vegetation,roughness length,and threshold friction velocity in various regions of the Ulanbuh Desert were obtained using NDVI(Normalized Difference Vegetation Index)data,measured sand-particle sizes,and empirical relationships among vegetation cover,sand-particle diameters,and wind velocity.Using these variables along with the observed wind velocities and saltation sediments for the observed points,the saltation model was validated.The model results were shown to be satisfactory(RMSE less than 0.05 and|Re|less than 17%).In this study,a subdaily wind-velocity program,WINDGEN,was developed using this model to simulate hourly wind velocities around the Ulanbuh Desert.By incorporating simulated hourly wind-velocity and wind-direction data,the quantity of saltation sediments blown into the Yellow River was calculated with the saltation submodel.The annual quantity of aeolian sediments blown into the Yellow River from the Ulanbuh Desert was 5.56×106t from 2001 to 2010,most of which occurred in spring(from March to May);for example,6.54×105tons of aeolian sand were blown into the Yellow River on 25 April,2010.However,in summer and winter,the saltation process occasionally occurred.This research has supplied some references to prevent blown sand hazards and silting in the Yellow River.     

Wind regimes and associated sand dune types in the hinterland of the Badain Jaran Desert,China

Wind controls the formation and development of sand dunes. Therefore, understanding the wind regimes is necessary in sand dune research. In this study, we combined the wind data from 2017 to 2019 at four meteorological stations (Cherigele and Wuertabulage stations in the lake basins, and Yikeri and Sumujilin stations on the top of sand dunes) in the hinterland of the Badain Jaran Desert in China, with high resolution Google Earth images to analyze the correlation between the wind energy environments and dune morphology. The results of data analysis indicated that both the wind direction and sand drift intensity exhibited notable spatial and temporal variations. The highest level of wind activity was observed in spring. Northwesterly and northeasterly winds were the dominant in the Badain Jaran Desert. At the Cherigele, Wuertabulage, and Yikeri stations, the drift potential (DP) was below 200.00 vector units (VU). The wind energy environments in most areas could be classified as low-energy environments. The resultant drift direction differed at different stations and in different seasons, but the overall direction was mainly the southeast. The resultant drift potential (RDP)/DP ratio was greater than 0.30 in most parts of the study area, suggesting that the wind regimes mainly exhibited unimodal or bimodal characteristics. Differences between the thermodynamic properties and the unique landscape settings of lakes and sand dunes could alter the local circulation and intensify the complexity of the wind regimes. The wind regimes were weaker in the lake basins than on the top of sand dunes. Transverse dunes were the most dominant types of sand dunes in the study area, and the wind regimes at most stations were consistent with sand dune types. Wind was thus the main dynamic factor affecting the formation of sand dunes in the Badain Jaran Desert BJD. The results of this study are important for understanding the relationship between the wind regimes and aeolian landforms of the dune field in the deserts.     

Impact of utility-scale solar photovoltaic array on the aeolian sediment transport in Hobq Desert,China

Deserts are ideal places to develop ground-mounted large-scale solar photovoltaic (PV) powerstation. Unfortunately, solar energy production, operation, and maintenance are affected bygeomorphological changes caused by surface erosion that may occur after the construction of the solar PVpower station. In order to avoid damage to a solar PV power station in sandy areas, it is necessary toinvestigate the characteristics of wind-sand movement under the interference of solar PV array. The studywas undertaken by measuring sediment transport of different wind directions above shifting dunes andthree observation sites around the PV panels in the Hobq Desert, China. The results showed that the twoparameterexponential function provides better fit for the measured flux density profiles to the near-surfaceof solar PV array. However, the saltation height of sand particles changes with the intersection anglebetween the solar PV array and wind direction exceed 45°. The sediment transport rate above shifting duneswas always the greatest, while that around the test PV panels varied accordingly to the wind direction.Moreover, the aeolian sediment transport on the solar PV array was significantly affected by wind direction.The value of sand inhibition rate ranged from 35.46% to 88.51% at different wind directions. When theintersection angle exceeds 45°, the mean value of sediment transport rate above the solar PV array reducesto 82.58% compared with the shifting dunes. The results of our study expand our understanding of theformation and evolution of aeolian geomorphology at the solar PV footprint. This will facilitate the designand control engineering plans for solar PV array in sandy areas that operate according to the wind regime.     

Aeolian transport over a developing transverse dune

The spatial and temporal changes in aeolian transport over a dune are fundamental factors that control the morphology of the dune.In the present study,we obtained direct field observations of aeolian transport over a developing transverse dune at the Shapotou Aeolian Experiment Site in the southeastern part of China’s Tengger Desert.The transport rate versus wind speed relationship is complicated over a developing dune compared with the relationships over flat surfaces and over dunes that are in equilibrium with the wind.We obtained trend lines for transport rate over the transverse dune versus distance.The transport rate generally increased from the toe to the crest above the stoss slope,but the difference in transport rate between the crest and the toe was smaller than those that have been proposed for taller dunes.The crest/toe ratio for transport rates therefore seems to depend greatly on dune height.Flux density profiles for different points above the dune at different wind speeds were well described by the exponential decay law,as has been proposed for saltation flux density profiles.Coefficients in the flux density profile function can be defined in terms of the transport rate and wind speed.However,the dependence of relative decay rate with height and average saltation height on wind speed was weaker than that observed in a wind tunnel and above a flat surface.The preliminary results obtained in this study require more evidence from field observations to fully describe aeolian transport above developing dunes.     

库布齐沙漠穿沙公路沙害综合防治技术

库布齐穿沙公路修建在库布齐沙漠高大的流动沙丘区 ,风沙流侵袭与沙丘整体前移埋压公路是主要沙害形式。现有防沙措施是沙障保护下的人工植被及天然植被相结合的综合防护体系 ,固沙及阻沙效益明显。目前要解决的是尽快形成公路两侧稳定的植被群落 ,以保证公路的长期畅通     

塔里木沙漠公路对近地表风沙运动过程的影响

通过对塔克拉玛干沙漠腹地野外试验数据的分析,探讨了塔里木沙漠公路对近地表风沙运动过程的影响.结果表明:①阻沙栅栏和草方格固沙带对近地表气流的速度和风速廓线形成很大影响,风速整体被削弱,而且越接近地表,削弱程度越大,风速廓线的垂直梯度增加;②在防沙体系内,地表输沙率急剧下降,风沙流结构发生很大变化,下层含沙量下降,而上层含沙量相对变化较少,在阻沙栅栏的积沙带和草方格固沙带内上层含沙量趋于均匀分布;(3) 阻沙栅栏和草方格固沙带也影响沙丘的移动.当主导输沙风向与栅栏相交呈小角度时,靠近栅栏的沙丘顺栅栏走向侧向移动相交呈大角度时,移动方向变化不大,草方格固沙带不影响沙丘的移动方向;阻沙栅栏和草方格固沙带能降低沙丘的移动速度,而在固沙带内部,由于沙丘的逆向演变,沙丘体积减小,移动速度较快.     

Morphology and formation mechanism of sand shadow dunes on the Qinghai-Tibet Plateau

The formation and development of dunes depend on wind-blown sand movement which is affected by the characteristics of sand material, topography, wind regimes and other factors. In this paper, we investigated two sand shadow dune groups in Shigatse and Za’gya Zangbo of Tibet and an individual dune in Da Qaidam of Qinghai, and analyzed their topographies and morphologies, and the physical characteristics of the sand, wind regime and sand transport. Formed under harsh conditions behind hills, these mature sand shadow dunes are hundreds of meters long, have significant ridges and crescent dunes downwind, and have a hill pass on one or both sides. Wind tunnel experiments revealed that the hill gap and wind velocity are important factors in the formation of these dunes. Sand shadow dunes formed only when the gap spacing is two-thirds of the hill height. When wind velocities are 20 m/s, the sand body is divided into two parts. The hill pass allows the transport of sand by wind, creating a "narrow-pipe effect", which causes the transported material to gradually accumulate in the center of the shadow zone. We observed that the following are needed for sand shadow dunes to form:(1) strong winds, sufficient sand, suitable obstacles and a dry climate;(2) one or both sides of the obstacle forming the shadow zone must have a hill pass; and(3) the windward side of the obstacle must have a wide, flat area, providing adequate spacing for wind flow and transport of material and the leeward side must have a sufficiently broad, flat area to allow the release of the transported material. Research results on these newly discovered dunes on the Qinghai-Tibet Plateau could contribute to the understanding of dune geomorphology.     

Effects of wind guide plates on wind velocity acceleration and dune leveling: a case study in Ulan Buh Desert,China

The areas used to be covered by shifting sand dunes have been reclaimed rapidly in recent years. However, it is a challenge to reclaim high sand dunes because it is rather costly to level the high dunes to gentle arable lands. In this study, a wind guide plate was used to change the characteristics of natural wind to level the sand dunes. The use of wind energy could significantly increase the efficiency of dune leveling and decrease the cost. Low wind velocity is a typical characteristic in Ulan Buh Desert of China where the average wind speed is much lower than the threshold velocity for sand movement. The experiment of this study was conducted to accelerate the wind velocity by a wind guide plate to level a sand dune. Results show that the threshold velocity for sand movement is 3.32 m/s at 10 cm above the sand surface in Ulan Buh Desert. A wind guide plate set at an angle less than 50° could significantly increase the wind velocity. The wind velocity could be accelerated up to the threshold velocity for sand movement behind a plate when the plate is at the angles of 20°, 25°, 35° and 40°. The most significant acceleration of wind velocity appears at 1.5 and 3.0 m behind the plate with an angle of 25°. An obvious wind velocity acceleration zone exists behind the wind guide plate when the angles are at 25°, 35°, 40° and 45°, with the most obvious zone under the angle of 45°. The results also show that the total amount of sand transferred over the experimental period increased by 6.1% under the effects of wind guide plates compared to the sand moved without wind guide plates. The results of the study will provide theoretical and practical supports for desert management in sand dune areas.