Reporting negative results to stimulate experimental hydrology: discussion of “The role of experimental work in hydrological sciences – insights from a community survey”*

ABSTRACT

Experimental work in hydrology is in decline. Based on a community survey, Blume et al. showed that the hydrological community associates experimental work with greater risks. One of the main issues with experimental work is the higher chance of negative results (defined here as when the expected or wanted result was not observed despite careful experimental design, planning and execution), resulting in a longer and more difficult publishing process. Reporting on negative results would avoid putting time and resources into repeating experiments that lead to negative results, and give experimental hydrologists the scientific recognition they deserve. With this commentary, we propose four potential solutions to encourage reporting on negative results, which might contribute to a stimulation of experimental hydrology.     

MJO对2018年华北夏季降水的影响

本文基于华北夏季降水资料和热带大气季节内振荡（Madden–Julian Oscillation，简称MJO）指数、NCEP/NCAR（美国国家环境预报中心/美国国家大气研究中心）再分析环流资料，采用多种统计方法分析MJO与2018年华北夏季降水的关系及影响机制。结果表明:（1）MJO与华北夏季降水有密切的联系。虽然MJO不能移到较高纬度直接影响华北夏季降水，但MJO对流区的气旋会在其北侧激发出反气旋环流，这对“气旋—反气旋对”在缓慢东移过程中，处于较高纬度的反气旋会直接影响华北夏季降水。即MJO会间接影响华北夏季降水，表现为当夏季MJO进入5、6位相时，华北地区夏季会出现明显降水过程，但降水强弱与MJO振幅大小有关。（2）影响机制方面。在850 hPa，伴随MJO的“气旋—反气旋对”的东移，它会造成华北夏季偏南风水汽输送加强（对应RMM1）或东南风水汽输送加强（对应RMM2），从而有利于降水过程发生。在500 hPa层，MJO通过中层扰动向中高纬的传播，诱导副热带高压移到朝鲜半岛附近并加强，对西来高空槽形成阻挡作用，有利于华北地区产生上升运动，从而有利于华北夏季降水过程发生。（3）可以用MJO制作华北夏季延伸期降水过程预报。     

Activity–composition relations for phases in petrological calculations: an asymmetric multicomponent formulation

For petrological calculations, including geothermobarometry and the calculation of phase diagrams (for example, P–T petrogenetic grids and pseudosections), it is necessary to be able to express the activity–composition (a–x) relations of minerals, melt and fluid in multicomponent systems. Although the symmetric formalism—a macroscopic regular model approach to a–x relations—is an easy-to-formulate, general way of doing this, the energetic relationships are a symmetric function of composition. We allow asymmetric energetics to be accommodated via a simple extension to the symmetric formalism which turns it into a macroscopic van Laar formulation. We term this the asymmetric formalism (ASF). In the symmetric formalism, the a–x relations are specified by an interaction energy for each of the constituent binaries amongst the independent set of end members used to represent the phase. In the asymmetric formalism, there is additionally a "size parameter" for each of the end members in the independent set, with size parameter differences between end members accounting for asymmetry. In the case of fluid mixtures, for example, H₂O–CO₂, the volumes of the end members as a function of pressure and temperature serve as the size parameters, providing an excellent fit to the a–x relations. In the case of minerals and silicate liquid, the size parameters are empirical parameters to be determined along with the interaction energies as part of the calibration of the a–x relations. In this way, we determine the a–x relations for feldspars in the systems KAlSi₃O₈–NaAlSi₃O₈ and KAlSi₃O₈–NaAlSi₃O₈–CaAl₂Si₂O₈, for carbonates in the system CaCO₃–MgCO₃, for melt in the melting relationships involving forsterite, protoenstatite and cristobalite in the system Mg₂SiO₄–SiO₂, as well as for fluids in the system H₂O–CO₂. In each case the a–x relations allow the corresponding, experimentally determined phase diagrams to be reproduced faithfully. The asymmetric formalism provides a powerful and flexible way of handling a–x relations of complex phases in multicomponent systems for petrological calculations.     

Comparing the Correlative Holdridge Model to Mechanistic Biogeographical Models for Assessing Vegetation Distribution Response to Climatic Change

A well-established and widely used correlative climate-vegetation model (Holdridge Life Zone model) was compared to three mechanistic simulation models (BIOME2, Dynamic Global Phytogeography Model (DOLY), and Mapped Atmosphere-Plant-Soil System (MAPSS)) for the conterminous United States under contemporary climate and a set of future climates prescribed by three Global Circulation Model experiments. Output from the mechanistic models were from the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP) intercomparison. Holdridge modeling approaches, using a Simple implementation (vegetation distribution based on biotemperature and precipitation alone) or a Full implementation (vegetation distribution based on biotemperature, precipitation, altitudinal region, latitudinal belt, and transitional vegetation zones), represented current potential natural U.S. vegetation poor to fair, respectively. The more sophisticated mechanistic models were superior at reproducing potential vegetation under current climate compared to Holdridge, although there was significant variability among these models. The Holdridge implementations generally showed similar or greater climate sensitivity with respect to spatial redistribution of vegetation compared to the mechanistic models run both with and without doubled CO₂ levels; however, the sensitivity of the Holdridge model depended on the implementation. Reduced sensitivity of the mechanistic models arises from direct (physiological) CO₂ effects and other compensating feedbacks not captured by the Holdridge model. The greater degree of physical realism in the mechanistic models makes them the model class of choice for climate impact assessment. However, under circumstances of limited data availability, computation resources, and access to mechanistic models and model expertise, simple correlational models such as Holdridge may be the only method that can be applied. The paper makes some recommendations on the use of the Holdridge model for impact assessment if it is the only available model.     

井间断层的计算机分析方法

井间断层分析的研究,是油气储层地质研究的一项重要基础性工作,对油气的运移和聚集其中重要的控制作用。它是利用测井资料,以地层分层为基础,采用计算机技术实现井间断层分析的一种井间断层自动分析方法。动态波形匹配算法是本次研究采用的主要算法,它能够很好地建立井间地层之间的对比关系,通过曲线拟合、特征提取、匹配代价计算等步骤,自动绘制井间地层对比的路径图解。本文在对各种构造的路径图分析的基础上,总结出正断层、逆断层、不整合、同沉积断层、犁式断层和地层尖灭等30种情况下的路径图模式,提出路径图模式及相关概念。在大港油田的实例分析中取得了很好的效果。     

青藏高原东部全新世冬夏季风变化的高分辨率泥炭记录

在建立了全新世泥炭沉积物高分辨率冬夏季风代用指标时间序列的基础上, 发现青藏高原若尔盖地区全新世冬夏季风的变化具有此消彼长和同时消长两种基本的模式, 冬季风与夏季风在不同时间尺度上两种模式又相互嵌套. 由冬夏季风指标叠加效应合成的气候状况却有与全球同步的规律性, 表现出千年-百年尺度的不稳定性, 6.2 ka的季风突然减弱事件要比8.0 ka的事件更显著, 反映了亚洲季风的区域特点或它本身就是全球气候的一个窗口.     

The effect of organic materials on the mobility and toxicity of metals in contaminated soils

Organic materials such as compost are often proposed as suitable materials for the remediation of contaminated brownfield sites intended for soft end-use. In addition to vitalising the soil, they are also believed to immobilise metals thereby breaking contaminant-receptor pathways and reducing the ecotoxicity of the contaminants. However, some research has demonstrated contradictory effects between composts on metal immobilisation. In the present study, four different composts and a liming product containing organic matter (LimeX70) were tested to examine both their metal retention and toxicity reduction capabilities on three different metal contaminated soils. Leaching tests, a plant growth test with Greek cress (Lepidium sativum), an earthworm (Eisenia fetida) survival and condition test and a bacterial toxicity test using Vibrio fischeri were carried out. The leaching test results showed that spent mushroom compost caused an increase in metal concentration in the leachates, while LimeX70 caused a decrease. The variation in behaviour between different amendments for each soil was high, so a generic conclusion could not be drawn. Toxicity tests showed significant reduction of metal bioavailability and toxicity for Greek cress, earthworms and bacteria. The results also suggest that more research should be undertaken to understand the mechanisms involved in metal complexation using different types of organic matter, in order to optimise the use of organic materials like compost for soil remediation.