太湖流域地表水资源分质评价及水质型缺水形势分析

太湖流域水资源供需矛盾主要体现为"水质型缺水"问题,如何对"水质型缺水"进行定量描述,在太湖流域是一个难题.本文提出了"分质水资源量"的概念,以流域水资源四级分区为单元,以分区水质监测资料结合水资源量进行分析,分别统计分区分质水资源量.分析表明:太湖流域142×10⁸ m³的地表水资源量中,Ⅲ类以上的适合于饮用水源和一般工业用水的优质水为35.8×10⁸ m³,占25.2%;适合于电力冷却用水、农业灌溉的Ⅳ-Ⅴ类水为46.4×10⁸ m³,占32.6%;不可利用的劣Ⅴ类水有59.9×10⁸ m³,占42.2%.流域内优于Ⅴ类(含Ⅴ类)的地表水资源量为82.2×10⁸ m³,占地表水总资源量的57.8%.而浅层地下水己基本被污染.需要指出,Ⅰ-Ⅲ类优质水虽仍有35.8×10⁸ m³,但目前流域内对Ⅰ-Ⅲ类水的需求量己达60.6×10⁸ m³,如将此两数对比,则优质水缺额为24.8×10⁸ m³,但实际上,优质水的需求主要集中在流域中下游,而可供优质水水源则主要集中在流域上游地区山区水库和中游太湖湖心区、东部湖区和太浦河,供需两者的空间分布有较大出入,因此优质水资源缺额将更大,由此可见太湖流域水质型缺水形势十分严峻.     

2022年第5期封面

抚仙湖,位于云南省中部,为构造断陷湖. 面积214.7 km², 平均水深89m, 最大水深155m,蓄水量204×10⁸8 m³（水位1722.5m时）, 是我国第二深水湖泊和蓄水量最大的淡水湖.     

The Volume Calculation Method of Rock Collapses and Loess Landslides Triggered by the 1556 AD Huaxian M8 1/2 Earthquake in Shaanxi Province, China

Accurate volume calculation of each individual landslide triggered by strong historical earthquakes can help understand the characteristics of the typical earthquake-induced landslides, thus providing significant information for the modification of the focal parameters of historical earthquakes. In this study, we select one rock fall and three loess landslides triggered by the 1556 AD Huaxian M8 1/2 earthquake, compute their volumes using the low-altitude high-precision Unmanned Aerial Vehicle (UAV) photogrammetry and landslide profile restoration methods. The results show that:① the whole influencing area of the Huangjiagou Rock Fall is approximately 3.03×10⁵ m² and the area of the collapsed rock accumulated at the slope foot is 3.33×10⁴ m², accounting for approximately 10% of the entire influencing range. However, the estimated volume of the collapsed rock is only 0.699×10⁶ m³, indicating a rock fall with large influencing range but limited collapsed rock; ② the geological form of thethree loess landslides are preserved intactly, with volumes of 0.283×10⁸ m³, 0.074×10⁸ m³, and 0.377×10⁸ m³. These important geological hazard relics reflect the strong vibrations and severe casualties in the meizoseismal area; ③ loess landslides are the key reason of the serious death toll in the hilly-gully loess area. Our new method can be used to estimate the influencing area and the actual volume of each individual landslide, and rationally evaluate the role of earthquake landslides in the disaster. In addition, quantitative research on secondary disasters triggered by strong historical earthquakes is beneficial for understanding the surface process and focal parameters of the earthquakes.     

基于生态系统恢复力的干旱区植被生态需水阈值计算方法与应用

本文以石羊河流域中下游为研究区,采用考虑生态系统恢复力(latitude of ecosystem resilience, LER)的月尺度生态需水评估方法计算1982-2020年植被月适宜生态需水量、最小生态需水量以及相应的生态缺水量,并与土壤水分特征值法(characteristic value of soil water, CVSW)进行比较,分析不同类型植被生长期的水分盈亏关系。结果表明:LER法和CVSW法计算结果相近,但LER法具有更大的生态需水阈值区间;天然降水基本可以满足植被的基本生存,但无法满足正常生长需求;LER法的适宜需水条件下,各植被生长期总体处于缺水状态,缺水严重程度排序为灌木林＞其他林地＞疏林地＞高覆盖度草地＞中覆盖度草地＞有林地,全部植被生长期总适宜生态需水量为3.7×10⁸ m³,亏缺水量为1.2×10⁸ m³,同一植被亏缺水量基本符合春秋多、夏季少的规律;最小需水条件下,只有其他林地存在生长期缺水情况,全部植被生长期总最小生态需水量为0.8×10⁸ m³;在缺乏土壤水分数据的干旱地区,LER法具有良好的适用性。研究结果可为石羊河流域水资源高效利用和干旱区生态系统的恢复与重建提供理论参考。     

全球变暖对长江洪水的可能影响及其前景预测

要长江流域近150a间发生的1870、1931、1935、1954与1998年特大洪水灾害损失严重;长江洪水是我国的心腹之患.1990年以来,长江大洪水高频发生,达6次.长江洪水的发生,除湖泊蓄洪功能减弱等因素外,与全球变暖有关.20世纪90年代为近千年中全球最暖的年代,水循环加快,长江中下游夏季降水量为近120a最多的十年,高出1961-1990平均值112mm;而降雨集中和大暴雨降水事件的增加是洪水增加的主要原因.区域气候模式模拟在CO₂倍增时,长江流域温度升高2.2℃,夏季降水增加10%-20%,气溶胶的增加可能使此值降低一些.考虑气候变暖可能促进潜在蒸发增加9%-15%的假定情景,计算在降水增加10%,蒸发增加9%条件下,最大洪峰流量在大通站将会达到8.4×10⁴ m³/s左右,己超过1998年洪峰流量;汉口站7.9×10⁴ m³/s,超过有记录以来所有的洪峰流量;而在宜昌站高达6.94×10⁴ m³/s,超过自有实测记录以来的除1896年和1981年以外所有的洪峰流量.假定情景的最高值出现在降水增加20%,蒸发增加15%时,大通站流量将达到9.45×10⁴ m³/s,超过该站近百年最大值,1954年的9.26×10⁴ m³/s;宜昌站将出现7.82×10⁴ m³/s流量,超过1882年以来所有实测记录值,但比1870年据洪痕推算的10.5×10⁴ m³/s仍有逊色.未来气候若继续变暖,降水量增加将给长江洪水防御带来巨大的压力.但上述估算是粗糙的,有一定的不确定性,需在以后的研究中进一步改进.     

生态环境需水量评估方法与例证

首先评价了生态环境需水量概念内涵, 包括概念的界定、生态环境水的组成结构和需水特点. 在此基础上, 提出了生态环境需水量分级和计算方法. 以黄淮海地区为研究实例, 估算了研究区生态环境现状用水量、最小需水量、适宜需水量, 并计算了相应的缺水量. 然后根据相关的规划, 对未来的水平年2010年, 2030年和2050年生态环境需水量进行了预测. 结果显示, 随着功能设定的不同, 水资源参照平台的差异, 最小和适宜生态环境需水量不同, 相应的缺水量也会产生差异. 研究表明, 黄淮海地区最小生态环境需水范围在2.84×10¹⁰~1.02×10¹¹ m³, 适宜需水量范围在6.45×10¹⁰~1.78×10¹¹ m³, 最小需水时的缺水量范围为9.1×10⁹~2.16×10¹⁰ m³之间, 适宜需水时的缺水量范围为3.07×10¹⁰~7.53×10¹⁰ m³之间. 通过不同的缺水量数值, 可以安排配水的优先性. 三个预测年的生态环境需水量范围分别为4.49×10¹⁰~1.73×10¹¹ m³, 5.99×10¹⁰~2.09×10¹¹ m³和7.44×10¹⁰~2.52×10¹¹ m³.     

额济纳荒漠绿洲植被生态需水量研究

荒漠绿洲的生态需水量主要指维持荒漠绿洲植被正常生长所需要消耗的水量.采用3S技术与野外生产力测定相结合的方法, 通过建立植被归一化指数(NDVI)、生产力、蒸腾系数之间的关系方程, 计算了额济纳荒漠绿洲的植被生态需水量.结果表明, 维持额济纳绿洲现状的需水量为1.53×10⁸ m³, 若使现有的植被恢复到目前最高生产力水平的生态需水量为3.49×10⁸ m³. 考虑到城镇居民生活用水、河道输水损失、绿洲植被耗水、绿洲内农田用水和降水补充等, 额济纳旗绿洲维持现状需要黑河下泄水量(狼心山)为1.93~2.23×10⁸ m³之间, 若使现有的植被恢复到目前最高生产力水平, 需要黑河下泄水量(狼心山)为4.28~5.17×10⁸ m³之间.     

强人类活动下半干旱地区湖泊水资源损失过程重建——以岱海为例

湖泊水资源持续损失已经成为影响半干旱地区经济社会发展的主要问题之一.然而,由于缺少长期连续的湖泊动态监测数据,该地区湖泊水资源损失过程及其与气候变化和经济社会发展之间的关系没有得到详细的评估.针对此问题,本文以位于半干旱地区的岱海为研究对象,利用改进型归一化差异水体指数从1986—2020年258景Landsat遥感影像中提取湖泊水体边界,结合湖泊水位数据,重建了近60 a岱海水资源量动态变化过程.结果表明：1961—2019年期间,岱海急剧萎缩,湖泊水量共减少9.88×10⁸ m³.同时水量变化趋势分段函数拟合结果表明,岱海水量变化可分为3个阶段：1961—1978年,水量损失速率为0.726×10⁷ m³/a的缓慢损失阶段;1979—2004年,水量损失速率为2.10×10⁷ m³/a的快速损失阶段;2005—2019年,水量损失速率为3.39×10⁷ m³/a的加速损失阶段.相关分析表明：岱海水量损失与流域经济社会发展密切相关.其中,改革开放后流域农业开发利用规模和强度的提高是导致岱海水量损失的主要原因;“西部大开发”战略实施后工业经济的兴起则加速了岱海水量的损失.据此,本研究建议干旱半干旱地区湖泊流域经济社会的发展应与其水资源承载力相协调.     

黄土高原水土保持生态建设耗水量宏观分析

黄土高原水土保持现状减水约10亿m³,但大规模综合治理后耗水量是多少?本文通过多种方法分析,2010年、2030年和2050年水土保持生态建设需耗水约20亿m³,40 亿m³和50亿m³.     

基于随机森林模型的GRACE数据3种空间降尺度对比

陆地水储量是赋存在陆地上各种形式水的综合体现,研究其时空变化对认识区域水循环过程和水资源调控等具有重要意义。然而现有陆地水储量变化数据实际分辨率较低,限制了其在中小流域或地区中的应用。针对这一问题,本文基于GRACE重力卫星和其后续卫星GRACE-FO反演的陆地水储量变化数据,首先采用随机森林模型,分别基于格点、区域(流域)和区域(全国)3种空间降尺度思路将GRACE数据降尺度至0.25°×0.25°,后结合GLDAS模型数据,基于水量平衡原理计算得到地下水储量变化数据,最后基于降尺度模型模拟效果和实测地下水位数据评估3种降尺度思路在全国的适用性。结果表明:随机森林模型能够较好地模拟驱动数据(降水、气温、植被条件指数和土壤水储量)与GRACE数据的统计关系,验证期格点降尺度思路的平均相关系数总体在0.6左右,区域降尺度思路的平均纳什效率系数、相关系数和均方根误差分别>0.5、>0.75和<6.6 cm,3种空间降尺度思路的模拟精度均满足基本要求;2003—2021年间,GRACE数据、格点降尺度、区域降尺度(流域)和区域降尺度(全国)得到的我国陆地水储量亏缺量分别约为119.5×10⁸、62.4×10⁸、121.1×10⁸和121.8×10⁸ m³/a,地下水储量亏缺量分别约为230.0×10⁸、171.8×10⁸、235.6×10⁸和236.4×10⁸ m³/a,受制于样本数较少等原因,格点降尺度结果精度较差;两种区域降尺度思路得到的水储量变化速率均和原始GRACE数据基本一致,模拟结果均优于格点降尺度,且细化到流域的区域降尺度对地下水储量变化验证精度有一定的改善。区域降尺度具有适用性强、模拟精度高、计算效率高的优势,研究结果可为流域水资源可持续利用以及水资源规划等提供精细化的水储量变化数据。     

Age, geology, geophysics, and geochemistry of Mahukona Volcano, Hawai`i

The size, shape, and magmatic history of the most recently discovered shield volcano in the Hawaiian Islands, Mahukona, have been controversial. Mahukona corresponds to what was thought to be a gap in the paired sequence (Loa and Kea trends) of younger Hawaiian volcanoes (<4?Ma). Here, we present the results of marine expeditions to Mahukona where new bathymetry, sidescan sonar, gravity data, and lava samples were collected to address these controversies. Modeling of bathymetric and gravity data indicate that Mahukona is one of the smallest Hawaiian volcanoes (～6,000?km³) and that its magmatic system was not focused in a long-lived central reservoir like most other Hawaiian volcanoes. This lack of a long-lived magmatic reservoir is reflected by the absence of a central residual gravity high and the random distribution of cones on Mahukona Volcano. Our reconstructed subsidence history for Mahukona suggests it grew to at least ～270?m below sea level but probably did not form an island. New ⁴⁰Ar–³⁹Ar plateau ages range from 350 to 654?ka providing temporal constraints for Mahukona’s post-shield and shield stages of volcanism, which ended prematurely. Mahukona post-shield lavas have high ³He/⁴He ratios (16–21?Ra), which have not been observed in post-shield lavas from other Hawaiian volcanoes. Lava compositions range widely at Mahukona, including Pb isotopic values that straddle the boundary between Kea and Loa sequences of volcanoes. The compositional diversity of Mahukona lavas may be related to its relatively small size (less extensive melting) and the absence of a central magma reservoir where magmas would have been homogenized.     

The Yecheng,Xinjiang, China,earthquake of February 14, 1980

In this study, we have checked the location and focal depth of the Yecheng earthquake (m _b = 6.0, maximum intensity VII) of February 14, 1980. The result shows that this is an intermediate event with a focal depth of 90 km. The microepicenter is located at 36. 4°N, 76, 9°E, while the macroepicenter is at 37.3°N, 76.9°E, 90 km to the north of the microepicenter. This is the first destructive intermediate event in China which led to a damage as severe as of intensity VII. The focal mechanism of the event is determined to be of thrust type. Combined with the analysis of seismological and geological data in surrounding area, the possible relation between the event and plate movement has been discussed. The result in this paper indicates that in some particular place, the destructive effect of intermediate event should be considered in seismic hazard assessment.     

Podhale,Poland, earthquake of November 30, 2004

Earthquake of November 30, 2004, in Podhale region, southern Poland, was of unexpectedly big size in this area of weak seismicity. As Poland is considered a country of low seismicity, the earthquake has caused concern about seismic hazard in Poland, especially since it took place shortly after the even more unexpected Kaliningrad Region, Russia, earthquakes of September 21, 2004, that inflicted minor damage in northern Poland. The paper presents the findings on the Podhale earthquake which reached macroseismic intensity up to 7 and magnitude 4.7 (m _b ; ISC). The event was felt up to a distance of about 100 km and inflicted slight damage to buildings in its narrow epicentral area, thus evidencing its relatively shallow depth. The quake has been located near the village of Skrzypne, about 15 km west-southwest of the district capital Nowy Targ. The source mechanism has been found to be of dip slip normal fault type, although a problem remains of association of this mechanism with known tectonic dislocations in the region. The earthquake has been followed by a long series of aftershocks. Their distribution in time is also studied and the biggest aftershocks have been located.     

Anorthite,andesine, wollastonite,diopside, cordierite and pyrope: thermodynamics of melting,glass transitions,and properties of the amorphous phases

Drop calorimetry measurements between 900 and 1850 K are reported for amorphous anorthite, andesine, wollastonite, diopside, cordierite and pyrope. The isobaric heat capacities of the glassy and liquid phases of these materials, and the enthalpies of fusion of the minerals have been derived. The calorimetric entropies of fusion of these substances and of other oxide minerals are generally consistent with the calculated volume changes on melting and with the observed pressure dependences of the melting points. The thermodynamics of mixing of liquid plagioclases have been examined, and it is concluded that their enthalpies of mixing are markedly different from the values derived directly from solution calorimetry measurements at 985 K.     

Physical properties,vitrinite reflectance,and microstructure of coal,Taiyuan Formation,Qinshui Basin,China

In this study, we experimentally established the relationship between physical properties, vitrinite reflectance, and microstructure of coal, Taiyuan Formation, Qinshui Basin, China using representative coal samples collected from three different mines via the rock mechanics testing system (MTS). We analyzed the organic macerals, vitrinite reflectance, and microstructure of 11 coal samples using petrography and scanning electron microscopy (SEM). The experimental results suggest that (1) the elastic parameters can be described by linear equations, (2) both P-and S-wave velocities display anisotropy, (3) the anisotropy negatively correlates with vitrinite reflectance, and (4) the acoustic velocities and Young’s modulus are negatively correlated with the volume of micropores. The derived empirical equations can be used in the forward modeling and seismic inversion of physical properties of coal for improving the coal-bed methane (CBM) reservoir characterization.     

太阳磁场磁性指数异常变化对南北半球中纬度气候的影响

本文参照太阳黑子相对数特征建立了太阳黑子磁场磁性指数时间序列. 大气温度场谱分析结果显示,南北半球中纬度平流层和对流层大气温度场普遍存在22年变化周期. 分析认为,大气温度场的22年变化周期是太阳活动22年磁性周期所激发.     

Comments on the use of Ti,Zr, Y,Sr, K,P and Nb in classification of basaltic magmas

The distribution of Ti, Zr, Y, Sr, K, P and Nb has been investigated at 55 sample sites within a single basaltic flow, the Cliefden Outcrop, which has adjusted to low-grade metamorphism of the prehnite-pumpellyite facies. The cluster of points in the plot of Ti, Zr and Y as proposed by Pearce and Cann shows that the ratio of these elements has remained relatively constant after metamorphism and would therefore have significance in attempts at classification of magma type. Likewise a plot involving Nb, Y, Zr and P as proposed by Floyd and Winchester shows only restricted scatter and appears useful. However, plots involving Sr or K show a scatter that is clearly related to metamorphic processes. Consequently, plots involving these two elements are likely to be of little use in classification in this case.Low-grade metamorphism is common, variable and not always recognized. The study concerned one style of alteration and revealed problems in the application of some classification schemes. Consequently it is apparent that much more rigorous testing is needed before classification schemes can be generally applied to sequences of basaltic rocks.     

The flocculation of dissolved Fe,Mn, Al,Cu, Ni,Co and Cd during estuarine mixing

A laboratory experiment was carried out in which the flocculation products, formed from the mixing of filtered (0.4 μm) river water and seawater, were analysed. This study established that Fe, Mn, Al, Cu, Ni, Cd and Co have resolvable and well-defined estuarine chemistries. Copper, Ni, Mn and Co have salinity dependences of removal which are similar to those of dissolved Fe and humic acids. The amount of removal of the above trace metals increases between 0 and 15–18‰, after which little additional removal occurs. The extents of removal from river water are very different: Fe, 95%; Al, 20%; Cu, Ni, 40%; Co, 10%; Cd, 5% and Mn, 25–45%. The basic removal mechanism appears to be the estuarine flocculation of trace metals which exist, in part, in river water as colloids in association with colloidal humic acids and hydrous iron oxides. A qualitative model, based on this mechanism, supports the observations of this flocculation study.The results of this study give the most complete and consistent set of data presently available, from which to postulate the most important processes controlling the estuarine chemistry of trace metals. The generality of their behaviours still needs to be determined by future investigations.