Near-surface wind environment in the Yarlung Zangbo River basin,southern Tibetan Plateau

Aeolian processes have been studied extensively at low elevations, but have been relatively little studied at high elevations. Aeolian sediments are widely distributed in the Yarlung Zangbo River basin, southern Tibetan Plateau, which is characterized by low pressure and low temperature. Here, we comprehensively analyzed the wind regime using data since 1980 from 11 meteorological stations in the study area, and examined the interaction between the near-surface wind and aeolian environment. The wind environment exhibited significant spatial and temporal variation, and mean wind speed has generally decreased on both annual and seasonal bases since 1980, at an average of 0.181 m/(s·10a). This decrease resulted from the reduced contribution of maximum wind speed, and depended strongly on variations of the frequency of sand-driving winds. The drift potential and related parameters also showed obvious spatial and temporal variation, with similar driving forces for the wind environment. The strength of the wind regime affected the formation and development of the aeolian geomorphological pattern, but with variation caused by local topography and sediment sources. The drift potential and resultant drift direction were two key parameters, as they quantify the dynamic conditions and depositional orientation of the aeolian sediments. Wind affected the spatial variation in sediment grain size, but the source material and complex topographic effects on the near-surface wind were the underlying causes for the grain size distribution of aeolian sands. These results will support efforts to control aeolian desertification in the basin and improve our understanding of aeolian processes in high-elevation environments.     

我国北方强风蚀区空间分布格局及特征分析

我国北方强风蚀区是形成沙尘天气的主要区域,本文依据各风蚀区风速的大小、走向,自然地理条件,沙化土地现状及分布特点,将我国北方沙区分为古尔班通古特沙漠西北缘、天山东段—塔克拉玛干沙漠南缘、柴达木盆地西段、河西走廊—阿拉善、鄂尔多斯—乌拉特、浑善达克沙地东北部、内蒙古东部七个强风蚀区。同时从沙化土地、降水量、风速及大风日数、沙尘天气的发生等方面对强风蚀区空间分布格局及特征进行了分析。     

莫高窟顶输沙势研究

本文以1992-1994、1998-2001年莫高窟顶自动气象观测站2m高度,时距15min记录的风资料为基础,通过对风况的统计分析和输沙势的计算,从风沙环境特征阐明该区主要受西北、东北和偏南风三组风向共同作用。三组风况出现频率和输沙势明显不同。该区风向变率指数较小,风况复杂,属于中风能环境。通过对风况的分析及输沙势的理论计算,以期对莫高窟的风沙危害防治提供科学理论依据。     

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.     

青藏高原全新世风沙活动历史与环境变化

风沙活动记录的研究对于人们了解气候环境变迁有着重要意义。风成砂层的稳定出露可以作为风沙活动及沙漠形成的最直接证据,因而通过对风成砂-黄土-古土壤序列地层剖面进行对比分析,即可还原地质历史时期风沙活动历史与环境演化。通过对比青藏高原南部、柴达木盆地、共和盆地、青海湖盆地等地区风成沉积剖面的岩性变化,结合14C测年、热释光和光释光测年结果,建立了青藏高原地区全新世以来风沙活动演化历史。青藏高原全新世在11.0kaBP左右开始进入全新世,环境逐渐转向暖湿;9.0kaBP左右出现了一次强烈的风沙活动事件;7.7～4.6ka BP14C大部分地区为暖湿环境,而藏南地区有较大范围风成砂沉积,风沙活动强烈。全新世晚期区域性差异较大,但整体环境恶化,风沙活动增强。     

青海不同地形下蒸发皿蒸发量变化及其影响因子分析

利用青海省不同地形（河谷、盆地、高原）中36个台站1961-2003年观测的蒸发皿蒸发量及其他气象因子资料,分析蒸发皿蒸发量的变化趋势,探讨其变化形成的原因。结果表明：蒸发量在青海大部分观测站表现为下降趋势。盆地、河谷中的观测站下降较为显著,而青南高原中的观测站变化趋势并不一致,且下降趋势不显著。河谷中由于山脉的影响,大气污染物不易扩散,气溶胶粒子增加,减弱了太阳的直接辐射,使河谷中湿度增加、山谷风环流减弱、日照减小、气温日较差减小,导致蒸发皿蒸发量的下降。柴达木盆地在全球温室气体以及气溶胶浓度增加的背景下,云量增多、降水增加使该区域风速减小、日照减小、气温日较差减小,从而使蒸发皿蒸发量出现下降趋势,并呈现出盆地西部下降趋势大,盆地中东部下降趋势小的分布特征。青南高原位于青藏高原主体,各气象观测站蒸发量的变化并不是一致性的下降或上升。     

Effects of aeolian processes on nutrient loss from surface soils and their significance for sandy desertification in Mu Us Desert,China: a wind tunnel approach

Mu Us Desert, a region with high aeolian activity, is at extremely high risk of sandy desertification. Using surface soil samples collected from Mu Us Desert of northern China, we evaluated the effects of aeolian processes on nutrient loss from surface soils by employing wind tunnel experiments. The experiments were conducted using free-stream wind velocities of 14, 16, 18 and 22 m/s. Our results showed that the fine particles(50 μm in diameter; 12.28% of all transported materials) carrying large nutrient loadings were exported outside the study area by aeolian processes. After the erodible fine particles were transported away from the soil surfaces at low wind velocity(i.e. 14 m/s), the following relatively high wind velocity(i.e. 22 m/s) did not have any significant effect on nutrient export, because the coefficients of variation for soil organic matter, total phosphorus, total nitrogen and available potassium were usually 5%. Our experimental results confirmed that aeolian processes result in a large amount of nutrient export, and consequently increase the risk of sandy desertification in arid and semi-arid ecosystems.     

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.     

罗布泊盐湖沉积物磁性特征及其环境意义

以罗布泊盐湖沉积物为研究对象,以环境磁学为主要研究方法,探讨罗布泊盐湖沉积物磁性特征的影响因素和环境意义.根据磁性特征可将罗布泊LOP1剖面沉积物分为两类:磁铁矿主导和铁硫化物(胶黄铁矿和黄铁矿)主导.磁铁矿主要来源于物源区塔里木盆地.胶黄铁矿和黄铁矿是早期还原成岩作用的产物,对磁性特征产生显著影响,胶黄铁矿主导层具有...     

准葛尔盆地南缘沙尘暴、大风气候特征分析

选取1953~2006年准葛尔盆地南缘石河子垦区3个地面观测站的资料,对比分析了沙尘暴、大风的时空分布特征,探讨沙尘暴和大风之间的关系及沙尘暴发生时的最多风向和最小风速指标。结果表明:准葛尔盆地南缘石河子垦区沙尘暴与大风的地理分布刚好相反,沙尘暴多的地方大风较少,北部莫索湾沙漠边缘一带为沙尘暴高发区;但有着基本一致的气候变化趋势。沙尘暴发生时的最多风向为西北风,引起沙尘暴的最小风速指标大于10m/s。     

高寒温带干旱区农牧业生态系统的能值分析——以柴达木盆地为例

能值理论是综合分析生态经济系统的各种能量流的转换机理,并定量研究生态效益与经济效益及其相互关系的重要理论。本文以柴达木盆地(青海海西州)的农牧生态经济系统为例,通过一系列的能值指标的建立和能值的投入产出分析,定量分析海西州农牧业生态系统的特点,并发现该地区农牧业生产中存在的问题,从而为本地区和相似区域农牧业的可持续发展提供科学依据。     

柴达木盆地土被的旱生演替过程

柴达木盆地是一个以干旱盐质荒漠为主要特征的封闭型内陆高原盆地。在以荒漠化为背景的环境演化过程中,土被演替过程依次经历了水成阶段、半水成阶段、荒漠化和盐渍化阶段。随着气候变干,土壤类型不断向旱化和盐渍化的更高阶段发展。在土被演替中,干旱化和盐渍化两种机制的同时存在导致了自我型和盐成型两种顶极土壤的出现,土被演替表现为二元顶极特征。柴达木盆地以荒漠化为特征的自然地理过程和人为因素的不合理干预,对土壤发育和土被演替具有深刻的影响。     

Ambient TSP concentration and dustfall variation in Urumqi,China

Total suspended particulate(TSP, particle diameter≤100 μm) was the dominant air pollutant and significantly influenced local air quality. In this paper, we investigated the interannual and seasonal variations of TSP and dustfall of the atmosphere over Urumqi, the capital city of Xinjiang Uygur autonomous region, northwestern China, basing on environmental monitoring records and meteorological data from 1986–2012. The results showed that during the study period, annual average TSP concentration decreased from 716 to 260 μg/m3, with an average level of 422.9 μg/m3, while dustfall intensity reduced from 350.4 to 166.6 t/(km2?a), with an average level of 259 t/(km2?a). Over 50% of the annual pollution days were induced mainly by TSP. Spring and winter had relatively higher dustfall intensities, and dense traffic and residential areas had the highest dustfall intensities in the Urumqi metropolitan area. With an annual average precipitation of less than 300 mm, atmospheric particulates in Urumqi could be hardly removed through wet deposition. During spring and summertime prevailing winds from northwest and northeast could carry aeolian dust particles from sandy deserts to Urumqi. Aeolian dusts from deserts would remain to be a priority regarding air pollution control in arid oasis cities.     

沙漠地区风沙活动特征——以中国科学院风沙观测场为例

运用中国科学院风沙科学观测场的实测资料,对腾格里沙漠风沙环境特征进行初步分析,内容包括起沙风、风沙活动强度、风沙流结构和沙漠边界层的风速廓线.该地区的起沙风以6～8 m/s为主,占总起沙风的71.63%,其次为8～10 m/s,占19.24%,两者之和占90.87%;大风日数为4天;风向以W-N组风向为主;占全年的53.14%.年输沙势为36.56VU,风能属于低风能环境,单一主风向和单风态风环境.风沙流主要集中在地表的0.1 m,占总输沙量的95.46%.观测场近地层厚度大于50 m.     

柴达木盆地水资源与合理开发利用研究

本文通过对柴达木盆地水资源量、农业水资源开发利用现状分析,结合盆地水土资源匹配情况与经济发展方向,提出了实现盆地水资源合理开发利用的基本途径,并指出在实施水资源开发利用中所要注意的具体问题,为盆地可持续发展提供依据。     

柴达木盆地土地资源可持续利用问题与对策

本文讨论了柴达木盆地土地资源的特点、土地利用中存在的问题,提出了农业可持续发展的对策     

全新世科尔沁沙地环境演变的初步研究

本文通过科尔沁沙地沙丘剖面及孢粉组合特征的分析研究,建立了该地区风沙活动期和风沙稳定期节律,恢复了风沙稳定期原始自然景观为疏林草原。     

Grain-size characteristics of linear dunes on the northern margin of Qarhan Salt Lake,northwestern China

In order to clarify the formation mechanism of linear dunes on the northern margin of Qarhan Salt Lake, northwestern China, we analyzed the grain-size and sorting parameters of the dune and interdune sands. The surface sands(0–30 mm) from the dune base to the crest of both flanks and interdune corridors were sampled along transects from upwind to downwind through the dune field. The results indicated that the grain-size distribution differed at different positions between and within the dunes. The frequency curve for dune sands mainly showed a bimodal distribution, while the interdune sediments showed a trimodal distribution. The grain size distribution of the linear dunes showed a finer crest pattern, i.e. the crests were composed of sands that were generally finer, better sorted than those of base sands. In addition, at the dune field scale, the dune crest sands were tending to become much finer but sorting became worse along the downwind transects. However, the grain-size parameters of sediments in the interdune corridors showed no clear pattern. The results demonstrated that the grain size and sorting parameters exhibited a systematic change not only at the individual scale but also at the dune field scale. Our results quantitatively estimate the limited role of cohesive sediments on the formation of linear dune under unidirectional wind regime. More attention should be paid to a long-term wind regime observation, internal sedimentary structures and their formation ages.     

Morphological characteristics and dynamic changes of seif dunes in the eastern margin of the Kumtagh Desert,China

The seif dune field over the gravel desert surface in the eastern margin of the Kumtagh Desert is a valuable experimental site for the observation of dune formation and dynamics. We used high-resolution remote sensing and station observation approaches, combined with wind and grain size data, to study the characteristics of the aeolian environment and the morphologies of and dynamic changes in seif dunes. We observed the ratio of the resultant drift potential (RDP) to the drift potential (DP), which was 0.37, associated with an obtuse bimodal wind regime. The drift potentials in the west-northwest (WNW) and east-northeast (ENE) directions were dominant, and the angle between the two primary DP directions was 135.00°. The dune orientations ranged from 168.75°-213.75°, which were parallel to the resultant drift direction (186.15°). The dune lengths ranged from 51.68 to 1932.11 m with a mean value of 344.91 m. The spacings of the dunes ranged from 32.34 to 319.77 m with a mean value of 93.39 m. The mean grain size of the sediments became finer, and the sorting became better from upwind tail to downwind tip, which indicated that the sediment of the seif dunes in the study region may be transported from northward to southward. The rate of increase in the length, the mean longitudinal migration rate of the dune tail, and the mean longitudinal extension rate of the dune tip (also called elongation rate) were 4.93, 4.63, and 9.55 m/a, respectively. The mean lateral migration vector of the seif dunes was approximately 0.11 m/a towards the west (-0.11 m/a), while the mean amplitude of lateral migration was 0.53 m/a, ignoring the direction of lateral migration. We found that the seif dune field formed first beside seasonal rivers, which can provide sediment, and then expanded downwind.     

Wind-proof and sand-fixing effects of Artemisia ordosica with different coverages in the Mu Us Sandy Land,northern China

Wind erosion is a key global environmental problem and has many adverse effects. The Mu Us Sandy Land of northern China is characterized by an arid climate, where vegetation patches and bare sand patches are usually distributed mosaically, and aeolian activities occur frequently. Vegetation plays a significant role in controlling wind erosion. Artemisia ordosica is the most dominant native plant species in the Mu Us Sandy Land. It is urgent to study the wind-proof and sand-fixing effects of Artemisia ordosica in the Mu Us Sandy Land. This study analyzed the wind-proof and sand-fixing effects of Artemisia ordosica based on the field data of wind regimes, aeolian sediment transport, and surface change of Artemisia ordosica plots with four coverages (denoted as site A, site B, site C, and site D) in the Mu Us Sandy Land during the period from 1 June 2018 to 29 June 2019. The coverages of Artemisia ordosica at site A, site B, site C, and site D were 2%, 16%, 29%, and 69%, respectively. The annual average wind speeds at 2.0 m height above the ground for site A, site B, site C, and site D were 3.47, 2.77, 2.21, and 1.97 m/s, respectively. The annual drift potentials were 193.80, 69.72, 15.05, and 6.73 VU at site A, site B, site C, and site D, respectively. The total horizontal aeolian sediment fluxes during the period from 2-3 June 2018 to 6 June 2019 at site A, site B, site C, and site D were 4633.61, 896.80, 10.54, and 6.14 kg/m, respectively. Site A had the largest surface changes, and the surface changes at site B were significantly weaker than those at site A, whereas the surface changes at site C and site D were minimal. The results indicated that Artemisia ordosica significantly reduced the wind speed, drift potential, aeolian sediment transport, and surface changes. The higher the coverage of Artemisia ordosica is, the more obvious the effects of wind-proof and sand-fixing. Wind erosion would be effectively controlled in the Mu Us Sandy Land if the coverage of Artemisia ordosica is greater than 29%. These results provide a scientific basis for evaluating the ecosystem service function of Artemisia ordosica and the vegetation protection and construction projects in the Mu Us Sandy Land.