Application of a hydrometeorological model chain to investigate the effect of global boundaries and downscaling on simulated river discharge

In the current study, two regional climate models (MM5 and REMO) driven by different global boundary conditions (the ERA40 reanalysis and the ECHAM5 model) are one-way coupled to the uncalibrated hydrological process model PROMET to analyze the impact of global boundary conditions, dynamical regionalization and subsequent statistical downscaling (bilinear interpolation, correction of subgrid-scale variability and combined correction of subgrid-scale variability and bias) on river discharge simulation. The results of 12 one-way coupled model runs, set up for the catchment of the Upper Danube (Central Europe) over the historical period 1971–2000, prove the expectation that the global boundaries applied to force the RCMs strongly influence the accuracy of simulated river discharge. It is, however, noteworthy that all efficiency criteria in case of bias corrected MM5 simulations indicate better performance under ERA40 boundaries, whereas REMO-driven hydrological simulations better correspond to measured discharge under ECHAM5 boundaries. Comparing the hydrological results achievable with MM5 and REMO, the application of bias-corrected MM5 simulations turned out to allow for a more accurate simulation of discharge, while the variance in simulated discharge in most cases was better reflected in case of REMO forcings. The correction of subgrid-scale variability within the downscaling of RCM simulations compared to a bilinear interpolation allows for a more accurate simulation of discharge for all model configurations and all discharge criteria considered (mean monthly discharge, mean monthly low-flow and peak-flow discharge). Further improvements in the hydrological simulations could be achieved by eliminating the biases (in terms of deviations from observed meteorological conditions) inherent in the driving RCM simulations, regardless of the global boundary conditions or the RCM applied. In spite of all downscaling and bias correction efforts described, the RCM-driven hydrological simulations remain less accurate than those achievable with spatially distributed meteorological observations.     

The Australia telescope 20 GHz survey: hardware, observing strategy, and scanning survey catalog

The Australia Telescope 20 GHz (AT20G) survey is a large area (2?? sr), sensitive (40 mJy), high frequency (20 GHz) survey of the southern sky. The survey was conducted in two parts: an initial fast scanning survey, and a series of more accurate follow-up observations. The follow-up survey catalog has been presented by Murphy et al. (MNRAS 402:2403, 2010). In this paper we discuss the hardware setup and scanning survey strategy as well as the production of the scanning survey catalog.     

Monica—A computer algorithm for solving boundary value problems using the double-hardening constitutive law Monot: II. Algorithm validation

The computer algorithm MONICA¹, which incorporates the double-hardening constitutive law Monot², has been tested on a large number of numerical examples. This paper summarizes the validation process, which has included consideration of both single element stress paths and multi-element boundary value problems. These results show MONICA to be effective for analysing practical problems using a soil model of the double-hardening type. They also demonstrate the ability of Monot to model a wide range of material responses. Problems involving pore pressure changes are identified as an area in which this form of analysis is of particular use^3,4.     

Environmental isotope study on hydrodynamics of Lake Naini,Uttar Pradesh,India

Environmental isotopes (δ¹⁸O, δD and ³H) were used to understand the hydrodynamics of Lake Naini in the State of Uttar Pradesh, India. The data was correlated with the in situ physico‐chemical parameters, namely temperature, electrical conductivity and dissolved oxygen. The analysis of the data shows that Lake Naini is a warm monomictic lake [i.e. in a year, the lake is stratified during the summer months (March/April to October/November) and well mixed during the remaining months]. The presence of a centrally submerged ridge inhibits the mixing of deeper waters of the lake's two sub‐basins, and they exhibit differential behaviour. The rates of change of isotopic composition of hypolimnion and epilimnion waters of the lake indicate that the water retention time of the lake is very short, and the two have independent inflow components. A few groundwater inflow points to the lake are inferred along the existing fractures, fault planes and dykes. In addition to poor vertical mixing of the lake due to the temperature‐induced seasonal stratification, the lake also shows poor horizontal mixing at certain locations of the lake. The lake–groundwater system appears to be a flow‐through type. Also, a tritium and water‐balance model was developed to estimate the water retention time of well‐mixed and hydrologically steady state lakes. The model assumes a piston flow of groundwater contributing to the lake. The developed model was verified for (a) Finger Lakes, New York; (b) Lake Neusiedlersee, Austria; and (c) Blue Lake, Australia based on literature data. The predicted water retention times of the lakes were close to those reported or calculated from the hydrological parameters given in the references. On application of this model to Lake Naini, a water retention time of ～2 years and age of groundwater contributing to the lake ～14 years is obtained. Copyright © 2001 John Wiley & Sons, Ltd.     

The spatial organization of services in new land settlement: experiences and trends

Conclusion Despite its uniqueness, the vitality inherent in the rural structure of Israel is of particular interest to other developing regions with a predominant rural-agricultural population. Latin American countries, for example, are investing considerable resources in the development of new lands through construction of penetration roads and other infrastructure. Several countries have created regional development authorities; some have policies designed to attract private investments into virgin areas.¹³⁾ The general emphasis tends increasingly toward state-initiated and planned settlement, often in conjuction with agrarian reform programs — an approach dictated both by economic efficiency and welfare criteria.Past experience has shown that the rural population has to be organized in viable communities in order to become amenable to economic and cultural integration. Communities must likewise be spatially organized in an optimal way that will make it possible to provide them with amenities and so direct their production for the purpose of achieving economic status. At the same time, maximum flexibility must be preserved to fit varying developmental stages, since physical plans once carried into effect are extremely difficult to modify.In order to reduce the social and economic pull of existing urban centers it may be advisable to develop new settlement areas as self-sufficient enclaves, independent to some extent from the facilities existing in the region. The settlements would share the national infrastructure of communications and public services, but would gear their production to regional as well as extra-regional demand, bypassing the traditional local market place. Then, as the new communities consolidate as social and economic entities, the options for collaboration or competition with existing central places can be laid open on a more equitable basis.Admittedly such sheltered development may affect the role of the local intermediary and lessen the commercial activities of the urban sector, but it would also stimulate the development of an independent framework of handling, marketing, and an increasing degree of processing the settlements' produce. These complementary activities would help to retain part of the added value of the production and generate new sources of employment for successive village generations. The delay in the growth for the region's total output may well be worthwhile for achieving that social and economic transformation which in turn may lead to a more balance and sustained development of the entire region.¹⁴⁾     

Nickeliferous pyrite tracks pervasive hydrothermal alteration in Martian regolith breccia: A study in NWA 7533

Martian regolith breccia NWA 7533 (and the seven paired samples) is unique among Martian meteorites in showing accessory pyrite (up to 1% by weight). Pyrite is a late mineral, crystallized after the final assembly of the breccia. It is present in all of the lithologies, i.e., the fine‐grained matrix (ICM), clast‐laden impact melt rocks (CLIMR), melt spherules, microbasalts, lithic clasts, and mineral clasts, all lacking magmatic sulfides due to degassing. Pyrite crystals show combinations of cubes, truncated cubes, and octahedra. Polycrystalline clusters can reach 200 μm in maximum dimensions. Regardless of their shape, pyrite crystals display evidence of very weak shock metamorphism such as planar features, fracture networks, and disruption into subgrains. The late fracture systems acted as preferential pathways for partial replacement of pyrite by iron oxyhydroxides interpreted as resulting from hot desert terrestrial alteration. The distribution and shape of pyrite crystals argue for growth at moderate to low growth rate from just‐saturated near neutral (6 < pH<10), H₂S‐HS‐rich fluids at minimum log fO₂ of >FMQ + 2 log units. It is inferred from the maximum Ni contents (4.5 wt%) that pyrite started crystallizing at 400–500 °C, during or shortly after a short‐duration, relatively low temperature, thermal event that lithified and sintered the regolith breccias, 1.4 Ga ago as deduced from disturbance in several isotope systematics.     

Rainfall-induced shallow landslides caused by ex-Tropical Cyclone Debbie, 31st March 2017

Every year, Australia experiences tropical cyclones that bring large amounts of rainfall, causing flooding and damage to infrastructure and road closure due to landslips. In March 2017, tropical cyclone Debbie hit the Queensland coast dumping 747 mm of rainfall within 2 days to the Gold Coast region. As a result, multiple shallow landslides occurred in Gold Coast and northern New South Wales due to the increase in soil saturation. A field investigation was conducted from several sites between Gold Coast-Springbrook road and Tallebudgera creek road to identify geological settings and landslide characteristics. Key findings show that slides predominantly occurred in weathered meta-sediments of the Neranleigh-Fernvale Beds within a depth of 1–2 m. Furthermore, a series of shear box tests revealed that the shear strength of the soil significantly decreased when saturation occurred.