Understanding and modeling basin hydrology: interpreting the hydrogeological signature

Basin landscapes possess an identifiable spatial structure, fashioned by climate, geology and land use, that affects their hydrologic response. This structure defines a basin's hydrogeological signature and corresponding patterns of runoff and stream chemistry. Interpreting this signature expresses a fundamental understanding of basin hydrology in terms of the dominant hydrologic components: surface, interflow and groundwater runoff. Using spatial analysis techniques, spatially distributed watershed characteristics and measurements of rainfall and runoff, we present an approach for modelling basin hydrology that integrates hydrogeological interpretation and hydrologic response unit concepts, applicable to both new and existing rainfall‐runoff models. The benefits of our modelling approach are a clearly defined distribution of dominant runoff form and behaviour, which is useful for interpreting functions of runoff in the recruitment and transport of sediment and other contaminants, and limited over‐parameterization. Our methods are illustrated in a case study focused on four watersheds (24 to 50 km²) draining the southern coast of California for the period October 1988 though to September 2002. Based on our hydrogeological interpretation, we present a new rainfall‐runoff model developed to simulate both surface and subsurface runoff, where surface runoff is from either urban or rural surfaces and subsurface runoff is either interflow from steep shallow soils or groundwater from bedrock and coarse‐textured fan deposits. Our assertions and model results are supported using streamflow data from seven US Geological Survey stream gauges and measured stream silica concentrations from two Santa Barbara Channel–Long Term Ecological Research Project sampling sites. Copyright © 2004 John Wiley & Sons, Ltd.     

Seismic stratigraphy of Chinese loess

A loess section near Lanzhou, China, has been investigated using the seismic refraction technique. The results show that the method is able to discriminate four distinct seismic boundaries within the section as well as indicating that the loess-bedrock contact occurs at a depth of more than 200 m. A 30 m deep pit was subsequently dug and revealed that the first two seismic boundaries correspond to soil units Sa (an intermediate soil within loess unit L1) and S1 (the last interglacial soil at the base of L1). These results, though preliminary, indicate the potential of the technique not only for mapping loess-bedrock contacts but also for determining the finer subsurface detail of the loess-palaeosol stratigraphy.     

国际古植物学1989年研究进展

古植物学是一个日新月异发展着的学科。每年,都有一些新的方法问世,它们结合地质学和生物学方法来研究地史时期植物的生活。其研究广度可以从1989年7月在美国首都华盛顿召开的第28届国际地质大会上明显看出。古植物学家们报告了他们关于“古气候”、“前寒武纪/寒武纪的过渡”、“泥炭和煤的来源”、“适应辐射”、“埋藏过程”、“特异埋藏”及南极地质等方面的研究成果;关于晚石炭世植物群的生物地理方面的文章也很多。 由Gastaldo(1989)编辑的《植物埋藏学——有机沉积过程》论文专辑是将更多的地质     

A rapid-response 2-D drag anemometer for atmospheric turbulence measurements

A rapid response drag anemometer for measuring streamwise and lateral components of horizontal windspeed is described. Theory of operation, design and calibration are discussed with emphasis on the electronic preconditioning of signals and problems associated with using a mechanically resonant system as a sensor. Field comparisons showed half-hourly means and standard deviations of the streamwise component to be within 8% and 5% of respective values obtained from a 3-dimensional sonic anemometer. The lateral component from the drag anemometer was significantly more noisy than that from the 3-D sonic due to induced oscillations arising from vortex shedding. After mechanical and electronic filtering, half-hourly standard deviation comparisons agreed to within 6% for this component. Friction velocities obtained from the drag anemometer in combination with a 1-D sonic, agreed with measurements from the 3-D sonic anemometer to within 4% over a measured range of 0.05 to 1.2 m s^-1     

A water column sampler for invertebrates in salt-marsh tidal pools

A column sampler for use in shallow (1 m) pools is described. The apparatus is a 10-cm diameter PVC pipe mounted on a base plate. A sliding trap on the base plate is attached to a cable which runs over a pulley to the upper part of the sampler. A whole water column of 78 cm² is sampled and 1–2 cm of substrate can be included as desired. The sampler has been used successfully in salt marsh pools to census gastropods, amphipods, and copepods.