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71.
Abstract We use results from a primitive-equation ocean numerical model (SCRUM) to test a theoretical 'string function' formulation put forward by Tyler and Käse in another article in this issue. The string function acts as a stream function for the large-scale potential energy flow under the combined beta and topographic effects. The model results verify that large-scale anomalies propagate along the string function contours with a speed correctly given by the cross-string gradient. For anomalies having a scale similar to the Rossby radius, material rates of change in the layer mass following the string velocity are balanced by material rates of change in relative vorticity following the flow velocity. It is shown that large-amplitude anomalies can be generated when wind stress is resonant with the string function configuration. 相似文献
72.
Stephen D. Sebestyen Nina K. Lany Daniel Tyler Roman Jacob M. Burdick Richard L. Kyllander Elon Sandy Verry Randall K. Kolka 《水文研究》2021,35(3):e14092
The Marcell Experimental Forest (MEF) in northern Minnesota, USA, with hydrological research and monitoring of peatland catchments in a low-topographic relief landscape, contrasts with the mountainous terrain that typifies most research catchments. Six research catchments were instrumented and hydrological and meteorological monitoring was initiated during 1960. Paired-catchment studies, which started during 1969, have been used to assess land management and environmental change effects on forests, water availability, and biogeochemistry. Over the decades, the research and collaborations have proliferated to include new monitoring and ecosystem experiments. We provide an overview of available datasets and access information for hydrological and meteorological data. Data on streamflow, water table elevation, precipitation, snow, ground frost, air temperature, soil moisture, upland runoff, and water chemistry are discoverable with associated metadata and are archived through several Web-based, community repositories. The research programme is ongoing and we anticipate updates on an annual or more frequent basis. Additionally, we aim to release other physical, chemical, and isotopic measurements associated with long-term catchment monitoring and studies at the MEF. 相似文献
73.
Lateral inflows control the spatial distribution of river discharge, and understanding their patterns is fundamental for accurately modelling instream flows and travel time distributions necessary for evaluating impacts of climate change on aquatic habitat suitability, river energy budgets, and fate of dissolved organic carbon. Yet, little is known about the spatial distribution of lateral inflows in Arctic rivers given the lack of gauging stations. With a network of stream gauging and meteorological stations within the Kuparuk River watershed in northern Alaska, we estimated precipitation and lateral inflows for nine subcatchments from 1 July to 4 August,2013, 2014, and 2015. Total precipitation, lateral inflows, runoff ratios (area-normalized lateral inflow divided by precipitation), percent contribution to total basin discharge, and lateral inflow per river kilometre were estimated for each watershed for relatively dry, moderate, or wet summers. The results show substantial variability between years and subcatchments. Total basin lateral inflow depths ranged 24-fold in response to a threefold change in rainfall between dry and wet years, whereas within-basin lateral inflows varied fivefold from the coastal plain to the foothills. General spatial trends in lateral inflows were consistent with previous studies and mean summer precipitation patterns. However, the spatially distributed nature of these estimates revealed that reaches in the vicinity of a spring-fed surficial ice feature do not follow general spatial trends and that the coastal plain, which is typically considered to produce minimal runoff, showed potential to contribute to total river discharge. These findings are used to provide a spatially distributed understanding of lateral inflows and identify watershed characteristics that influence hydrologic responses. 相似文献
74.
Benjamin W. Abbott Kevin Bishop Jay P. Zarnetske David M. Hannah Rebecca J. Frei Camille Minaudo F.Stuart Chapin Stefan Krause Lafe Conner David Ellison Sarah E. Godsey Stephen Plont Jean Marais Tamara Kolbe Amanda Huebner Tyler Hampton Sen Gu Madeline Buhman Sayedeh Sara Sayedi Ovidiu Ursache Melissa Chapin Kathryn D. Henderson Gilles Pinay 《水文研究》2019,33(23):3046-3052
75.
76.
Greg G. Sass Stephen R. Carpenter Jereme W. Gaeta James F. Kitchell Tyler D. Ahrenstorff 《Aquatic Sciences - Research Across Boundaries》2012,74(2):255-266
Lakeshore residential development (LRD) reduces coarse woody habitat (CWH) in lakes resulting in negative effects on fishes.
We tested whether the addition of CWH could reverse those effects. We added CWH to Camp Lake, a lake with CWH abundances similar
to developed lakes, following 2 years of study of the fish populations in the reference and treatment basins. Both basins
were monitored for 4 years following the manipulation. Specifically, we tested for changes in the population dynamics (densities,
size-structure, growth), diet, and behavior (habitat use) of bluegill (Lepomis macrochirus) and largemouth bass (Micropterus salmoides). CWH addition had no discernible effect on fish population dynamics. Diet and behavioral responses were more pronounced
in the treatment basin. Prey diversity and availability increased. Piscivory increased, with decreased reliance upon terrestrial
prey, for largemouth bass. Habitat use was positively correlated with CWH branching complexity and abundance. Our study suggests
that negative effects observed in fish populations through CWH reductions cannot be reversed in the short-term by adding CWH.
We recommend that regulations governing the LRD process be protective of CWH. 相似文献
77.
Very Large Array (VLA) observations at wavelengths of 20 and 91 cm have been combined with data from the SOHO and RHESSI solar
missions to study the evolution of transequatorial loops connecting active regions on the solar surface. The radio observations
provide information about the acceleration and propagation of energetic electrons in these large-scale coronal magnetic structures
where energy release and transport take place. On one day, a long-lasting Type I noise storm at 91 cm was seen to intensify
and shift position above the northern hemisphere region following an impulsive hard X-ray burst in the southern hemisphere
footpoint region. VLA 20-cm observations as well as SOHO EIT EUV images showed evolving coronal plasma that appeared to move
across the solar equator during this time period. This suggests that the transequatorial loop acted as a conduit for energetic
particles or fields that may have triggered magnetic changes in the corona where the northern noise storm region was seen.
On another day, a hard X-ray burst detected at the limb was accompanied by impulsive 20- and 91-cm burst emission along a
loop connecting to an active region in the same hemisphere but about 5′ away, again suggesting particle propagation and remote
flare triggering across interconnecting loops. 相似文献
78.
79.
Successful adaptation assumes the availability of appropriate information for groups potentially impacted by climate change. This research examines information available to help farmers in the Canadian Prairies to adapt, with focus on information related to soil and water conservation practices, such as preserving wetlands and maintaining shelterbelts and groundcover, considered particularly important for this region. Results of 28 semi-structured interviews carried out with producers in two Prairie provinces, Alberta and Manitoba, revealed that information regarding soil and water conservation practices comes from a variety of sources. These included industry, government, producer and conservation organizations, social sources of information and personal experience, and media. Producers were more open to new practices when they could learn them through observation, trials, and two-way dialogue. There appears to be a general lack of producer organization involvement, and dearth of government information, direction, and coordination for climate change adaptation. Information from government and producer organizations can be important for the co-production of knowledge that can lead to successful adaptation. 相似文献
80.
Natural Hazards - This study systematically reviews the diverse body of research on community flood risk management in the USA to identify knowledge gaps and develop innovative and practical... 相似文献