三峡库区范家坪滑坡地表形变InSAR监测与综合分析

位于湖北省秭归县的范家坪滑坡是长江三峡库区干流上的大型岩质滑坡之一。阐述了高分辨率合成孔径雷达干涉测量技术(InSAR)监测滑坡地表形变的工作方法与技术体系,采用22景3m空间分辨率的TerraSAR-X数据,辅以人工反射体布设和GPS测量,对范家坪滑坡变形进行监测,发现滑坡处在缓慢匀速变形状态,其谭家河滑坡体的形变比木鱼包滑坡体更为强烈,形变最大处的雷达视线向形变速率达到300mm/a。通过综合分析滑坡区2012年大气降雨和长江水位资料,发现年度内范家坪滑坡变形受水位变化和大气降雨影响微弱。     

疏勒河径流量与绿洲面积、农业产值及生态效益的关系

基于1954-2010 年疏勒河干流出山径流量、2000-2010年流域内灌区水资源供应量、灌区农作物种植类型、农作物及林草地面积等资料,通过建立系统动力学模型,探讨了气候变化背景下疏勒河径流量对绿洲的影响。结果表明:绿洲受径流量变化影响显著,若出山径流量按1954-2010 年变化趋势增加,绿洲面积、农业产值、生态效益将有不同程度增加; 若出山径流量减小,绿洲面积、农业产值、生态效益亦相应减小。2020年出山径流量较2010年分别减少5%、10%、15%时,绿洲面积和农业产值相应减小4.5%、8.9%、13.4%。在径流量不变情况下,若普及常规节水,林、草地面积均增加16%以上; 若普及高效节水,林、草地面积均扩大54.7%; 若提高渠系利用率到0.70,林草地面积扩大5%以上,总产值增加5.4%; 若提高渠系利用率到0.75,林草地面积增加12%以上,总产值增加12.2%。     

民勤荒漠绿洲过渡带灌丛沙堆形态特征及分布格局

以民勤荒漠绿洲过渡带为研究区,通过样方调查,研究了荒漠区、荒漠绿洲过渡区到绿洲内不同梯度生境中灌丛沙堆的形态特征及分布格局。结果表明:(1)3种生境中灌丛沙堆的形态呈极显著性差异(p<0.01);绿洲区灌丛沙堆的平均高度、底面积、纵横断面积和体积均最大,其次为荒漠区,过渡区最小。(2)过渡带3种生境灌丛沙堆的长、短轴之间均呈二次函数关系,但相关程度不同,过渡区相关性最高,相关系数达0.78;绿洲区相关性最低,相关系数为0.57;高度与底面积、体积与高度间均呈幂函数关系,相关系数均在0.59以上;(3)过渡区灌丛沙堆分布密度较大,呈聚集分布,而荒漠区及绿洲区沙堆分布密度较小,均呈随机分布。     

Use of Machine Learning Methods to Reduce Predictive Error of Groundwater Models

Quantitative analyses of groundwater flow and transport typically rely on a physically‐based model, which is inherently subject to error. Errors in model structure, parameter and data lead to both random and systematic error even in the output of a calibrated model. We develop complementary data‐driven models (DDMs) to reduce the predictive error of physically‐based groundwater models. Two machine learning techniques, the instance‐based weighting and support vector regression, are used to build the DDMs. This approach is illustrated using two real‐world case studies of the Republican River Compact Administration model and the Spokane Valley‐Rathdrum Prairie model. The two groundwater models have different hydrogeologic settings, parameterization, and calibration methods. In the first case study, cluster analysis is introduced for data preprocessing to make the DDMs more robust and computationally efficient. The DDMs reduce the root‐mean‐square error (RMSE) of the temporal, spatial, and spatiotemporal prediction of piezometric head of the groundwater model by 82%, 60%, and 48%, respectively. In the second case study, the DDMs reduce the RMSE of the temporal prediction of piezometric head of the groundwater model by 77%. It is further demonstrated that the effectiveness of the DDMs depends on the existence and extent of the structure in the error of the physically‐based model.     

Distribution and bioaccumulation of polychlorinated biphenyls and organochlorine pesticides residues in sediments and Manila clams (Ruditapes philippinarum) from along the Mid-Western coast of Korea

The distribution and bioaccumulation features of PCBs, DDTs, and HCHs were investigated in the sediments and Manila clams collected from along the Mid-Western coast of Korea. The measured concentrations of ΣPCBs, ΣDDTs and ΣHCHs were 1.08–3.5, 0.12–0.35 and 0.090–0.30 ng g⁻¹ dw in sediment, and 33–390, 7.4–46 and 6.3–27 ng g⁻¹ lipid in Manila clam, respectively. Their levels were found to be relatively lower than those of other contaminated areas and the consumption of Manila clam from these areas seems to be safe for human health according to calculated lifetime cancer risk and hazard indices. The ΣPCBs and ΣDDTs concentrations in sediments showed a significant relationship to those in clams. The significant correlation was observed between BSAF in clams and K_ow for each PCB congeners and DDT metabolites. These findings support that the PCBs and DDTs levels, which are highly hydrophobic chemicals, in clam reflect the sediment pollution through bioaccumulation.     

Development of an operational rainfall data quality-control scheme based on radar-raingauge co-kriging analysis

Abstract

Automatic raingauge data often serve as an important input to hydrological and weather warning operations. They are not only fundamental in quantitative rainfall analysis, but also act as the ground truth in warning operation and forecast validation. Quality control is required before the data can be used quantitatively due to systematic and random errors. Extremely large random errors and unreasonably small or false zero values can hamper effective monitoring of heavy rain. Yet both are difficult to detect in real-time by objective means. In an attempt to address these problems, a rainfall data quality-control scheme based on radar-raingauge co-kriging analysis was developed. The important threshold values required in the data quality control of 60-min raingauge rainfall were determined from a detailed analysis of the distributions of rainfall residuals defined as the arithmetic difference and the logarithm of the ratio between a raingauge measurement and its co-kriging estimate. The scheme has been developed and is in real-time use in Hong Kong, a coastal city of about 1100 km² area with more than 150 raingauges installed. Geographically, it is located in the subtropics and dominated by heavy convective rainfall in the summer. As a basis of the quality-control scheme, the co-kriging rainfall analysis was shown through a verification exercise to be superior to those obtained by the Barnes analysis and ordinary kriging of raingauge data. The performance of the quality-control algorithm was assessed using selected cases and controlled tests, and was found to be satisfactory, with a high error detection rate for the two targeted types of error. Limitations and operational issues identified during a real-time trial of the quality-control scheme are also discussed.

Citation Yeung, H.Y., Man, C., Chan, S.T., and Seed, A., 2014. Development of an operational rainfall data quality-control scheme based on radar-raingauge co-kriging analysis. Hydrological Sciences Journal, 59 (7), 1285–1299. http://dx.doi.org/10.1080/02626667.2013.839873     

Aftershock sequence simulations using synthetic earthquakes and rate-state seismicity formulation

We use an efficient earthquake simulator that incorporates rate-state constitutive properties and uses boundary element method to discretize the fault surfaces, to generate the synthetic earthquakes in the fault system. Rate-and-state seismicity equation is subsequently employed to calculate the seismicity rate in a region of interest using the Coulomb stress transfer from the main shocks in the fault system. The Coulomb stress transfer is obtained by resolving the induced stresses due to the fault patch slips onto the optimal-oriented fault planes. The example results show that immediately after a main shock the aftershocks are concentrated in the vicinity of the rupture area due to positive stress transfers and then disperse away into the surrounding region toward the background rate distribution. The number of aftershocks near the rupture region is found to decay with time as Omori aftershock decay law predicts. The example results demonstrate that the rate-and-state fault system earthquake simulator and the seismicity equations based on the rate-state friction nucleation of earthquake are well posited to characterize the aftershock distribution in regional assessments of earthquake probabilities.     

SCI-E干旱区研究重要期刊与投稿指南

应用文献计量学方法,在对1997--2005年SCI-E收录的世界干旱区研究论文进行统计、分析、研究的基础上,通过期刊发义量指标（V1）、论文被引次数指标（V2）和期刊影响因子（V3）三项指标的加权综合评判分析,评选出世界范围内干旱区研究领域的28种重要期刊。介绍了世界干旱区研究重要期刊的相关投稿信息。     

气候系统模式FGOALS_gI模拟的小冰期气候

利用1650～1750年逐年变化的太阳辐照度等外强迫资料,驱动中国科学院大气物理研究所LASG发展的快速气候系统模式FGOALS_gl,模拟了小冰期(LIA)气候.把模拟的LIA表面温度变化与重建资料进行对比,结果表明FGOALS_gl对LIA气候具有较强的模拟能力,说明太阳辐照度的自然变化是导致小冰期气候的重要成因.模拟结果显示,LIA时期纬向平均温度变化表现为整个对流层降温,低纬度地Ⅸ的降温中心位于对流层中层,北半球降温幅度大于南半球,高纬地区的降温幅度大于低纬地区.分析发现,中高纬地区的局地温度变化主要与环流异常相对应的冷暖平流有关;低纬地区的降温主要与赤道东风加强有关,东风增强通过增大蒸发和引起次表层冷海水上翻而令表层温度降低.LIA时期的降水变化丰要位于中低纬地区,表现为日界线东(西)侧降水的负(正)异常.与降水异常相对应.Walker环流加强,东太平洋对流活动减弱,它与低纬地区对流层中层冷异常相联系.与大气层顶净短波辐射异常的季节变化相对应,南、北半球夏季平均表面温度异常较之冬季低0.28℃左右.     

Description of a small goby, Trimma grammistes (Perciformes: Gobiidae), from Jeju Island, Korea

A small goby, Trimma grammistes, was described in detail as the first reliable record from Korea based on 10 specimens (27.8～34.0 mm SL) collected from the coastal waters of Jeju Island. The species is easily differentiated from congeners by having no scales on the predorsal region, VI-I, 10 dorsal fin rays modally, I, 10 anal fin rays, 18 pectoral fin rays, 27～30 longitudinal scales as well as two dark longitudinal bands on the body.