Effect of climatic change on surface environments in the typical region of Horqin Sandy Land

The town of Agura,a typical region in Horqin Sandy Land,was selected as the study area in this paper.Using 12 remote sensing images and climatic data from the past 20 years,the effects of climate change on surface environments were analyzed.The impact indices of climatic factors,along with their corresponding ranks,were used to characterize the responses of different types of surface environments to climate change.Results show that in the past 20 years,the surface environments of the study area have been deteriorating.Furthermore,there is a positive relationship between the changes in surface environments and those in climatic factors.Various climatic factors influence surface environments in different ways and at different levels.The most sensitive factor is relative humidity,followed by precipitation and evaporation.Overall,moisture is the key factor that affects the changes in surface environments of arid and semi-arid areas.     

Characteristics of plant calcium fractions for 25 species in Tengger Desert

Little attention has been paid to plant calcium fractions in the desert.To address the characteristic of the calcium fractions of desert plants,we collected 25 plant species in Tengger Desert,observed the calcium crystals using an optical microscope and determined water soluble calcium,acetic acid soluble calcium,and hydrochloric acid soluble calcium.To do so,we used sequential fractionation procedures to probe the relationships among different functional groups,different growth forms,or different successional stages.The results showed that the psammophyte,the late successional plants,and the drought-resistant shrub and semi-shrub all held considerable calcium oxalate crystal compared to the grassland plants,the early successional plants,and the perennial herb.With the proceeding succession,the acetic acid soluble calcium decreased gradually,and the hydrochloric acid soluble calcium increased gradually.The perennial herb had more water soluble calcium,while shrub held greater hydrochloric acid soluble calcium.The grassland plants held more water soluble calcium,while psammophyte had greater hydrochloric acid soluble calcium.This implies that the plants that are relatively sensitive to drought hold more calcium ion,while the drought-resistance plants hold more calcium oxalate.Thus,the plant calcium components are in close relation to plant drought-resistance,and of important significance in plant physiology of the desert.     

Stable isotope techniques in plant water sources：a review

The stable hydrogen and oxygen isotopes widely exist in various kinds of natural water.Plants have to cope with various water sources:rainwater,soil water,groundwater,sea water,and mixtures.These are usually characterized by different isotopic signatures (18O/16O and D/H ratios).Because there are relative abundance variations in water,and plant roots do not discriminate against specific water isotopes during water uptake,hydrogen and oxygen stable isotope ratios of water within plants provide new information on water sources,interactions between plant species and water use patterns under natural conditions.At present,the measurement of δD,δ18O composition of various potential water sources and stem water has become significant means to identify plant water sources.Based on previous studies,this review highlights recent advances such as theory basis,methodology,as well as different spatial and temporal scales,and existed questions and prospects.Stable isotope techniques for estimating plant water sources have provided valuable tools for conducting basic and applied research.Future studies emphasize the modification of preparing methods,isotope technique combined with other measurements,and aerial organs of plant water source should be en-couraged.     

Consensus maps of cloned plant cuticle genes

Plant cuticle,which covers the plant surface,consists of waxes and cutins,and is associated with plant drought,cold,and salt resistance.Hitherto,at least 47 genes participating in the formation of plant cuticle have been cloned from Arabidopsis thaliana,Oryza sativa,Zea mays,Ricinus communis,Brassica napus,and Medicago truncatula;and about 85% of them encode proteins sharing above 50% identities with their rice homologous sequences.These cloned cuticle genes were mapped in silico on different chromosomes of rice and Arabidopsis,respectively.The mapping results revealed that plant cuticle genes were not evenly distributed in both genomes.About 40% of the mapped cuticle genes were located on chromosome 1 in Arabidopsis,while 20% of the mapped cuticle genes were located on chromosome 2 but none on chromosome 12 in rice.Some cloned plant cuticle genes have several rice homologous sequences,which might be produced by chromosomal segment duplication.The consensus map of cloned plant cuticle genes will provide important clues for the selection of candidate genes in a positional cloning of an unknown cuticle gene in plants.     

Time-scale effects in human-nature interactions,regionally and globally

Spatial-temporal scales effects are general among human-nature interactions.However, the laws and mechanisms of the interaction between humans and the environment at different spatial-temporal scales remain to be identified. The Hexi Corridor in Northwest China is located in the eastern section of the Silk Road and is one of the world’s first long-distance cultural exchange centers. Here we present a comprehensive dataset of the Hexi Corridor, including changes in environments, population, wars,...     

历史时期中国重大自然灾害时空分异特征(英文)

Based on historical documents and records this paper analyzes the characteristics of frequency and distribution of major disasters that took place in the history of China. The findings show that occurrences of different types of disasters varied and spatial pattern at provincial level are significantly different as well. The results also indicate that there is a strong relationship between type of disasters and spatial distribution and that the spatial pattern of losses was not the same as that of the frequency. The reasons are: (1) the hazard-formative environments which, to a large extent, determine the spatial pattern of the disasters are significantly different; (2) the losses caused by natural disasters were closely related to the concentration of economy and population. Number of deaths was usually large in areas where agriculture, culture and business were relatively developed. The spatial pattern of disaster losses is an evitable result of uneven economic development in the history of China.     

塔里木河下游植被生态需水量(英文)

We have appraised the relationships between soil moisture,groundwater depth, and plant species diversity in the lower reaches of the Tarim River in western China,by analyzing field data from 25 monitoring wells across eight study sites and 25 permanent vegetation survey plots.It is noted that groundwater depth,soil moisture and plant species diversity are closely related.It has been proven that the critical phreatic water depth is five meters in the lower reaches of the Tarim River.We acquired the mean phreatic evaporation of different groundwater levels every month by averaging the two results of phreatic evaporation using the Qunk and Averyanov formulas.Based on different vegetation types and acreage with different groundwater depth,the total ecological water demand(EWD)of natural vegetation in 2005 was 2.4×108m 3in the lower reaches of the Tarim River.Analyzing the monthly EWD,we found that the EWD in the growth season(from April to September)is 81%of the year's total EWD.The EWD in May,June and July was 47%of the year's total EWD,which indicates the best time for dispensing artificial water.This research aims at realizing the sustainable development of water resources and provides a scientific basis for water resource management and sound collocation of the Tarim River Basin.     

INTERPRETATION OF COPPER AND ZINC CONTAMINATION IN THE AQUATIC ENVIRONMENT OF PENINSULAR MALAYSIA WITH SPECIAL REFERENCE TO A POLLUTED RIVER, SEPANG RIVER

Three different aquatic ecosystems(an urban pond,Kelana Jaya Pond;a polluted river,Sepang River;and the intertidal and offshore areas of the west coast of Peninsular Malaysia)with different sets of ecological backgrounds and human activities were reviewed and assessed for the levels of Cu and Zn contamination with special reference to those found in polluted sediments collected from the Sepang River.The discussion on the contamination levels of Cu and Zn in the aquatic environment of Peninsular Malaysia was based on a comparison of the metal contamination of 4 kinds of aquatic environments.The comparison of 4 different areas was based on ① total concentrations of 2 metals;② the concentrations and percentages of the nonresistant(EFLE,acid-reducible and oxidisable-organic)and resistant geochemical fractions;and ③ correlation coefficients(R-values)based on data of 4 areas separately and a combination of 4 areas.The Sepang River recorded nonresistant fractions of 63.1% for Zn and 55.8% for Cu in addition to slightly lower metal concentrations when compared to those(60%-70%)reported before the shutting down of the piggery activities in that area.These nonresistant metal percentages(55%-63%)indicated that the metal concentrations were still dominated by anthropogenic sources since nonresistant fraction of metals were mostly contributed by anthropogenic sources.The positive results from the four different aquatic environments assessed here provided strong evidence to show that Malaysia's aquatic environment had received anthropogenic Cu and Zn.The present study also showed that the percentage of the nonresistant fraction and the R-values based on correlation analysis of Cu and Zn could be used as indicators of Cu and Zn pollution in the Malaysian aquatic ecosystem.Based on the present data,the correlation coefficients(R-values)are potential indicators of EFLE Cu and acid-reducible Cu of the sediments.The use of R-values as indicators of metal pollution is suggested and it is applicable to other heavy metal data although it should be improved in future studies.     

中国公路自然区划的回顾与展望

1IntroductionHighway, as a kind of man-made structure, will become a part of the geographical environment and be impacted by all sorts of natural factors after it is finished. On the other hand, highway also brings some changes to the geographical environment. A highway often passes through different natural regions, so it must be adaptable to any geographical environments. On the basis of deep understanding of the geographical environment, service life and normal level of the highway can be e…     

The response of Caragana microphylla seedlings to water table changes in Horqin Sandy Land, China

This paper focuses on the growth response of Caragana microphylla seedlings to changes of artificially controlled water table in Horqin Sandy Land, China. Monitoring results of soil water content shows that soil moisture is closely correlated to groundwater depths. Soil volumetric water increased rapidly when close to water sources and finally stabilized in a saturated state. The soil moisture trend of CK(control) increased gradually at 0–50 cm of soil depth then decreased to 4% below 50 cm soil depth. C. microphylla can adapt to different soil environments by changes in ecological and physiological characteristics. By comparing the ecological characteristics of C. microphylla seedlings at various water tables, we found that a shallow water table of 40 cm depth inhibited seedling growth because of weak ecological characteristics. A groundwater depth of 120 cm was more advantageous for plant height and canopy growth of C. microphylla seedlings. During the first two years, the most suitable water depth for root biomass was 120 cm, and 180 cm for root length. The growth of vertical roots is positively correlated with groundwater depth, and root thickness is the determinate factor for root biomass while the fine root is the determinate factor for root length. A thick root would grow much more in a natural drought environment while access to ground water promotes the growth of fine roots.     

极端干旱地区绿洲小气候特征及其生态意义

运用微气象学方法对极端干旱区荒漠绿洲小气候进行了观测,分析我国极端干旱区荒漠绿洲的微气象特征并与林地外进行了对比。同时讨论晴天、阴天和沙尘暴天气的PAR的差异．分析了产生这些差异的原因。结果表明荒漠绿洲具有改变太阳辐射、调节近地层地表及地下温度、缩小温差、降低风速、提高土壤及大气湿度等重要生态作用。绿洲内部的太阳总辐射比林冠层顶部减少49．3％-49．83％：生长季胡杨和柽柳林内的气温均低于林地外．胡杨林平均比林外低1．62℃,柽柳林比林外低0．83℃,而且森林覆盖率越高降温作用越明显：群落上层气温高于群落下层,气温随高度增加而增加;林内大气相对湿度均高于林地外．生长期,胡杨林内比林地外高8．5％,柽柳林高4．2％;胡杨林地平均风速为0．33m／s．比林地外低2．7m／s：柽柳林平均风速为0．72m／s,比林地外低2_3lm／s。在沙尘暴日,PAR明显小于阴天日和晴天日下的值．而ηQ非常大,且变化不稳定,该结论对研究大气层的稳定性有极其重要的意义。     

夏季不同天气背景条件下黑河中游不同下垫面的辐射特征

 利用2005年“绿洲系统能量水分循环观测实验”（JTEX）获得的资料分析了夏季晴天和阴天西北干旱区金塔绿洲不同下垫面的辐射收支特征。结果表明:由于下垫面的水热特性不同,绿洲与沙漠、戈壁的辐射特征有很大差异,而沙漠和戈壁的差异则较小。相同天气背景条件下,不同下垫面的向下辐射基本一致,绿洲的向上辐射最小,净辐射最大。地表辐射特征会随天气状况有较大变化。     

新疆策勒沙漠-荒漠-绿洲典型下垫面小气候空间变化分析

利用从2010年8月1日至2011年6月30日新疆策勒绿洲-荒漠过渡带及绿洲内部4个观测点的风速、大气相对湿度（RH）、温度、太阳辐射能、光合有效辐射（PAR）同步观测资料,分析了小气候差异并初步探讨产生差异的原因。结果表明：不同空间的下垫面性质对小气候影响明显不同。在8月,半固定沙地、固定沙地和绿洲内部与流沙地前沿相比,日平均风速在2 m高处分别依次降低了42.69%、50.71%和94.32%,日平均风速在10 m高处分别依次降低了7.94%、13.66%和59.59%,这表明植被覆盖度越大,防风阻沙效果越好。夏季植被能够降温增湿,冬季12月份,绿洲内部在0.5 m高处日平均温度依次高于流沙地、半固定沙地、固定沙地1.47℃、1.20℃、2.74℃。4个下垫面的PAR与太阳辐射能变化趋势基本一致,绿洲内部的PAR值相对最小,太阳辐射能在6月达到最高值。夏季晴天在20:00~09:00左右近地表层会出现逆温现象。冬季晴天白天午后易出现大于起沙风的阵风,从流沙前沿到绿洲内部气温逐渐升高,大气相对湿度先逐渐降低后增大。     

策勒绿洲沙漠过渡带小气候的空间差异

对策勒2011年1—12月4个不同下垫面的风速、温度、湿度、光合有效辐射的月差异进行分析,同时选取夏季晴天天气作为背景,比较沙尘暴、扬沙、浮尘、阴雨天时4个下垫面气象要素的差异。结果标明:与流沙地相比,绿洲-沙漠过渡带半固定沙地、固定沙地、绿洲内部2.0 m高处的6月平均风速依次减少了25.22%、27.93%、65.27%,12月绿洲内部0.5 m高处平均气温分别高于流沙地、半固定沙地、固定沙地1.39 ℃、1.21 ℃、2.70 ℃。5—10月4个下垫面之间温、湿度差异较春、冬季显著,7月流沙前沿2.0 m高处平均气温分别比半固定沙地、固定沙地、绿洲内部高0.35 ℃、1.61 ℃、3.75 ℃。沙尘暴天气下4个下垫面之间的风速差值依次小于扬沙、浮尘、阴雨、晴天天气下;在浮尘和晴天天气下,气温从流沙前沿到绿洲内部逐渐减低,相对湿度逐渐增加;沙尘暴和阴雨天气下各下垫面的气温和相对湿度无明显差异,扬沙天气下各下垫面之间温、湿度差异大于阴天天气,但小于浮尘和晴天天气;4个下垫面之间的光合有效辐射（PAR）在沙尘暴天气下差异最为明显,浮尘和阴雨天气下4个下垫面之间的PAR接近,晴天天气下各点PAR明显大于扬沙天气下,且各下垫面之间差异大于扬沙天气下的差异。     

塔克拉玛干沙漠北缘辐射分量特征

利用塔克拉玛干沙漠北缘肖塘自动站2011年直接探测的辐射资料,对该地区辐射状况进行了初步分析。结果表明:短波辐射各个分量的月总量最大值均出现在7月,总辐射瞬时最大值为1 329.6 W·m-2,出现在6月。晴天天气下,辐射分量均为夏季最大,冬季最小,除大气长波辐射外,其他分量均呈现出标准的倒“U”型。大气长波辐射浮尘、扬沙天气时的日总量,均与晴天时一致;而地面长波辐射日总量则是晴天时最大,浮尘天气次之,阴天最小。肖塘地区地表反照率冬季较大,夏季较小,年均值为0.27,比塔克拉玛干沙漠腹地（0.3）低10%,但远高于绿洲和高原。     

中国陆地区域气象要素的空间插值

在区域农田生态系统生产力模拟模型研究中，空间插值可以提供每个计算栅格的气象要素资料。然而，在众多的气象要素空间插值方法中，并没有一种适合每一个气象要素的普适的最佳插值方法。本文以全国７２５站１９５１～１９９０年整编资料中的旬平均温度和计算得来的６７５站的月乎均光合有效辐射日总量（ＰＡＲ）为数据源，选用了距离平方反比法（ＩＤＳ）、梯度距离平方反比法（ＧＩＤＳ）和普通克立格法（ＯＫ）等３种插值方法，进行了方法选取的探讨。交叉验证结果表明：３种方法中，温度插值的平均绝对误差（ＭＡＥ）的排序为ＩＤＳ＞ＯＫ＞ＧＩＤＳ，其值分别为２．１５℃、１.９０℃和 ｌ．３２℃；在作物生长季节（４－１０月），ＭＡＥ分别 ２０℃、１．９℃和 １.２℃ ，表明ＧＩＤＳ在温度插值方面更具实用价值；对于ＰＡＲ，ＭＡＥ的排序为ＯＫ＞ＧＩＤＳ＞ＩＤＳ，其值分别为 ０．８３ＭＪ／ｍ２、０７１ＭＪ／ ｍ２和 ０．４６ＭＪ／ｍ２，说明复杂的方法并不必然具有更好的效果。对这２个气象要素的空间分布特征分析表明：温度和ＰＡＲ的经、纬向梯度和高度梯度均具有明显的季节性变化特征；温度的纬向梯度有近似正弦曲线的较强的季节变化，表现为夏季高，而冬、春季低；温度的高度梯度年     

额济纳绿洲地表土壤热通量特征及模拟估算

土壤热通量是地表能量平衡的重要分量,研究其变化特征对理解能量平衡过程具有十分重要的意义。利用中国科学院阿拉善荒漠生态水文试验研究站实际观测数据,分析了额济纳绿洲在不同天气条件（晴天和阴天）和时间尺度下地表土壤热通量变化特征,并采用强迫恢复法对地表土壤热通量进行了估算。结果表明：（1）晴天地表土壤热通量的日总量、平均值、最大值和振幅等都明显大于阴天。（2）在观测期内,地表土壤热通量总体呈先升高后降低的趋势,最大值出现在7月中旬,最小值出现在10月初,二者之间的日均值相差超过了900 W·m^-2。（3）不论晴天还是阴天,净辐射较地表土壤热通量在早晨和晚间都是先达到零值,且净辐射在正午前后先达到峰值。（4）对地表土壤热通量取绝对值可以看出,无论昼夜,均是晴天大于阴天。（5）一天内地表土壤热通量占净辐射的比例随着时间递减。（6）基于强迫恢复法估算的额济纳绿洲地表土壤热通量与实测值具有较好的一致性,可用于地表土壤热通量模拟。     

Trend analysis of major hydroclimatic variables in the Langat River basin,Malaysia

Trend analyses of monthly, seasonal and annual rainfall, air temperature, and streamflow were performed using Mann‐Kendall test within the Langat River basin to identify gradual trends and abrupt shifts for 1980 − 2010. Annual rainfall showed an increasing trend in upstream flow, a combination of decreasing and increasing trends in middle stream flow, and a decreasing trend in downstream flow. Monthly rainfall in most months displayed an insignificant increasing trend upstream. Stations with significant increasing trends showed larger trends in summer than those of other seasons. However, they were similar to the trends observed in annual rainfall. Annual minimum air temperature showed a significant decreasing trend upstream and significant increasing trends in the middle stream and downstream areas. Annual maximum air temperature portrayed increasing trends in both upstream and middle stream areas, and a decreasing trend for the downstream area. Both monthly and seasonal maximum air temperatures exhibited an increasing trend midstream, whereas they demonstrated trends of both decreasing and/or increasing temperatures at upstream and downstream areas. Annual streamflow in upper, middle and lower catchment areas exhibited significant increasing trend at the rates of 0.036, 0.023 and 0.001 × 10³ m³/y at α = 0.01, respectively. Seasonal streamflow in the upstream, midstream and downstream areas displayed an increasing trend for spring (0.55, 0.33 and 0.013 m³/y respectively) and summer (0.51, 0.37, 0.018 m³/y respectively). The greatest magnitude of increased streamflow occurred in the spring (0.54 m³/y). Significant increasing trends of monthly streamflow were noticed in January and August, but insignificant trends were found in May, September and November at all stations. Annual streamflow records at the outlet of the basin were positively correlated with the annual rainfall variable. This study concludes that the climate of the Langat River basin has been getting wetter and warmer during 1980‐2010.     

咸阳市三原县新庄不同植被土层含水量研究

通过测定咸阳市三原县新庄2005和2006年降雨正常年份人工林地土壤含水量得知,从地表向下土层含水量呈由高到低再到高的变化;2005年草地和玉米地土层含水量由上向下呈逐渐增高趋势,比同年12龄杨树林地和13龄中国梧桐林地平均含水量高约7%。2003年降水量达880 mm丰水年后,人工林土壤干层中水分完全恢复,人工林出现持续近4年茂盛生长期,预计2007年该区将会再次出现发育弱的土壤干层。     

民勤地区近地面沙尘监测系统的建立及其运行的初步评价

介绍了建于民勤地区的我国第一套近地面沙尘监测系统的组成、结构和功能。经1 a多运行,该系统取得了良好的沙尘监测效果。初步结果表明：2006年民勤19次沙尘暴平均气溶胶浓度的空间分布遵循幂函数关系,在沙漠和绿洲边缘区气溶胶浓度随着高度的增加显著下降,而在绿洲内部,则随高度增加而上升;在不同下垫面条件下,水平沙尘通量随高度变化也遵从幂函数关系,但在沙漠和绿洲边缘呈显著降低趋势,在绿洲呈平缓上升趋势。从沙漠区至绿洲内部,沙尘通量空间分布的规律一般是：沙漠>绿洲边缘>绿洲。2006年在民勤地区,绿洲边缘的沙尘通量比沙漠区减少了42.0%,至绿洲内部则减少74.42%,表明防风固沙林和农田防护林网对沙尘具有较强的防护功能和减灾作用。