Thermal Remote Sensing of Near Surface Environmental Variables: Application Over the Oklahoma Mesonet

Many recent studies have applied satellite remote sensing data to large‐scale hydrologic and biospheric modeling. It is widely accepted that the thermal infrared observations from the Advanced Very High Resolution Radiometer (AVHRR) have the potential to estimate land surface conditions, such as surface temperature, near surface air temperature, and near surface water vapor. In this study, algorithms to estimate all three variables are presented and applied to an area covering the state of Oklahoma for a six day period in August, 1994. The results were validated using ground observations from the 111 station Oklahoma Mesonet. Validation of the remote sensing algorithms with Mesonet observations produced comparable results to previous validation studies. In addition, the validation process revealed inadequacies in thermal modeling that had not been detected in previous validation studies leading to the development of a new approach to estimate atmospheric water vapor.     

DTM resolution controls the accuracy of estimating surface runoff indicators in flat,lowland landscapes

Surface runoff plays an important role in contaminant transport, nutrient loss, soil erosion and peak discharges in streams and rivers. Because it is the result of a variety of complex hydrological processes, estimating surface runoff using physically based hydrological models is challenging. Upscaling of physical soil properties is necessary to cope with the limits of computational power in surface runoff modelling. In flat landscapes, the (micro)topographic surface controls the onset and progression of surface runoff on saturated soils during rain events. Therefore, its proper representation is crucial when attempting to model and predict surface runoff. In this study, the influence of microtopography (centimetre scale) on estimations of maximum depression storage (MDS), random roughness (RR) and the connectivity threshold (CT) is explored. These properties are selected because they often serve as surface runoff indicators in hydrological modelling. To characterize microtopography, a terrestrial laser scanner (TLS) is used to generate a digital terrain model (DTM) of the study site with a horizontal spatial resolution of 5 cm. MDS, RR and CT are then calculated and compared to the values generated from the publicly available Dutch national DTM dataset with a resolution of 50 cm. Our results show considerable differences in MDS, RR and CT when calculated for the different input resolution datasets. Using DTMs that do not sufficiently capture microtopography leads to underestimation of MDS and RR, and to overestimation of CT. Our findings indicate that surface runoff indicators, and thereby the surface runoff response of a saturated surface to rainfall events, are defined at scales smaller than the scales of typically available DTMs. Understanding surface runoff through modelling studies therefore requires a framework that accounts for this lack of information arising from using coarser resolution DTMs. We demonstrate a linear relationship between MDS values generated from the different resolution DTMs. This opens the possibility of using empirical scaling relationships between high- and lower-resolution DTMs to account for microtopography. Repetition of our measurements on similar surfaces would contribute to establishing such empirical scaling relationships. Our results should be seen as indicative of flat landscapes and surfaces where centimetre scale microtopography is relevant.     

脆弱环境平原绿色工程增源研究

根据大量的资料，从环境水文学的角度分析了林带的水文效应，论证了脆弱环境平原绿色工程增源的必要性、可能性和现实性，并提出了实施意见及存在问题。结论对平原区水资源合理开发利用、当地工农业生产持续发展及环境保护具有重要的参考价值。     

山西水文下垫面分类探讨

水文下垫面分析是水文分析计算、水文测验、水文预报、水资源评价等的基础性工作。本文试图通过对水文下垫面性质及组成水文下垫面各要素的分析，探讨水六下垫面的分类原则，分类标准，并从山西的具体情况出发，讨论了山西水文下垫面分类的具体问题。     

线性矩法的特点评析和应用问题

介绍了线性矩法的无偏估计与直接计算的关系，讨论了在概率权重矩计算过程中各系列之间的高度相关性及其对结果的影响，建立了直接计算线性矩法的Cv和Cs近似公式，叙述了适线问题和相应的经验频率公式。文中认为，水文频率计算时，由于资料的随机性和处理方法上的概化性，故用任何计算方法得到的结果，具有不同程度的不确定性，只能作为估计的初值，需通过时空上综合平衡，再经合理性分析和调整后，才能取用。     

自动报汛技术相关标准体系适应性初探

2005年7月1日,长江委水文局118个中央报汛站全部实现了防洪报汛自动化,从满足洪水风险管理对水情信息采集、传输的实时性、准确性、时效性新的要求来说,无疑是长江水文现代化发展的重要技术突破。本文从长江水文防洪报汛自动化实践技术标准方面的问题入手,对目前水文行业规范中有关自动报汛标准条款的适应性进行了初步探讨,并力求提出相应的解决办法与措施。     

石羊河流域水文要素变化特征分析

选取石羊河流域永昌、肃南、天祝、古浪、武威、民勤6个气象站1961～2000年的降水、蒸发资料及黄羊河水库、杂木寺、南营、四沟嘴、古浪、沙沟寺、插剑门、大靖峡水库、红崖山水库9个水文站1961～2000年的径流资料,运用距平分析法和Kendall秩次相关法对流域水文要素的时程变化特征进行了分析。研究结果表明:石羊河流域降水、蒸发年内分配不均,但年际变化不大;降水集中于6～9月份,占全年的65%以上,蒸发集中于5～8月份,占全年的54%。径流的年内分配与降水一致,集中于6～9月,占全年的58%。径流的年际变化呈明显减少趋势,尤以红崖山水库入库流量减少最为显著。     

水文数据库随机检索实用模型

随机检索是水文数据库重要的检索功能之一，由于检索要求的不确定性给软件开发带来一定的困难。以数据库SQL语言为基础，通过对语言的简化和提示性的模式化操作，建立了一种实用的随机检索模型。     

ALEXANDER THE GREAT'S MOUNTAIN*

ABSTRACT. The metaphorical power of natural landscapes and geographical objects has attracted an increasing amount of critical interest. The myth of Dinocrates planning to carve Mount Athos into the figure of Alexander the Great epitomizes the complex relationship between the insistent materiality of prominent geographical features such as mountains and imagination. Through an iconographic reading of different renderings of the Dinocratic myth in western Europe, this article explores the way Mount Athos turned into a powerful emblem circulating across space and time. While considering the continuity of a Classical vision projected on rock, the article focuses on its constant reappropriations and transformations in different historical and geographical contexts. Dinocratic Athos becomes a metaphor of egotism, power, and desire but also a free‐floating referent, reflecting a shifting relationship between the microcosm of the human body and the natural macrocosm.     

Imagining Strawberry Fields as a place of pilgrimage

This paper examines the significance of Strawberry Fields, the memorial to John Lennon in Central Park, New York City, as a place of secular pilgrimage. Situated within postmodern conceptualizations of secular pilgrimage, Strawberry Fields is shown to be the spatial focus of a variety of discourses related to John Lennon's life and music. Furthermore, this paper illustrates how autobiography as a qualitative research method can reveal the sentiments that motivate particular pilgrims to places associated with major figures in popular music.