Comparing mixing-length models of the diabatic wind profile over homogeneous terrain

Models of the diabatic wind profile over homogeneous terrain for the entire atmospheric boundary layer are developed using mixing-length theory and are compared to wind speed observations up to 300 m at the National Test Station for Wind Turbines at Høvsøre, Denmark. The measurements are performed within a wide range of atmospheric stability conditions, which allows a comparison of the models with the average wind profile computed in seven stability classes, showing a better agreement than compared to the traditional surface-layer wind profile. The wind profile is measured by combining cup anemometer and lidar observations, showing good agreement at the overlapping heights. The height of the boundary layer, a parameter required for the wind profile models, is estimated under neutral and stable conditions using surface-layer turbulence measurements, and under unstable conditions based on the aerosol backscatter profile from ceilometer observations.     

AMO’s structure and climate footprint in observations and IPCC AR5 climate simulations

This study aims to characterize the spatiotemporal features of the low frequency Atlantic Multidecadal Oscillation (AMO), its oceanic and atmospheric footprint and its associated hydroclimate impact. To accomplish this, we compare and evaluate the representation of AMO-related features both in observations and in historical simulations of the twentieth century climate from models participating in the IPCC’s CMIP5 project. Climate models from international leading research institutions are chosen: CCSM4, GFDL-CM3, UKMO-HadCM3 and ECHAM6/MPI-ESM-LR. Each model employed includes at least three and as many as nine ensemble members. Our analysis suggests that the four models underestimate the characteristic period of the AMO, as well as its temporal variability; this is associated with an underestimation/overestimation of spectral peaks in the 70–80 year/10–20 year range. The four models manifest the mid-latitude focus of the AMO-related SST anomalies, as well as certain features of its subsurface heat content signal. However, they are limited when it comes to simulating some of the key oceanic and atmospheric footprints of the phenomenon, such as its signature on subsurface salinity, oceanic heat content and geopotential height anomalies. Thus, it is not surprising that the models are unable to capture the majority of the associated hydroclimate impact on the neighboring continents, including underestimation of the surface warming that is linked to the positive phase of the AMO and is critical for the models to be trusted on projections of future climate and decadal predictions.     

Data analysis and adjustment of the first geodetic surveys in the Caldera of Teide, Tenerife, Canary Islands

To detect possible superficial deformations in the volcanic Caldera of Teide area (Canary Islands), we have set up a network composed by 17 points which we shall observe successively. In this paper, we present the analysis and reduction of data and the free tridimensional adjustment of the network for the first observation campaign.     

Zur Stratigraphie des Altpaläozoikums in Argentinien

At the beginning of the Paleozoic era three geotectonic units were already constitued in the argentine territory: 1. central cratonic region; 2. ortogeosynclinal belt in the West, and 3. intracratonic region in the East. On the basis of the morphostructural units that emerge out of the development of the geotectonic pattern, the regional distribution and stratigraphy of the Lower Paleozoic rocks are described (Cambrian to Silurian). In the Northern Argentina (Subandine ranges, Eastern Cordillera and Puna) the stratigraphical sequence is complete with a thickness of 9.100 meters. In the Transpampean Ranges only the Ordovician (Tremadoc-Llanvirn) is represented with a minimum thickness of 3.850 meters. In the Precordillera of Western Argentina the sequence is complete with a minimum thickness of 6.000 meters, the Ordovician being the most developed. In the San Rafael ranges (Mendoza), the Northern and Southern ranges of the Buenos Aires province, the Northpatagonian nesocraton and the Chaco-Parana basin, the succession is incomplete or little known. In each case the recognized lithological units are described and their respective stratigraphical relations are indicated.     

Status of an endangered subspecies: the peninsular pronghorn at Baja California

During November 1993, we traversed by ground and by air the Vizcaíno Desert, the last redoubt of the peninsular pronghorn (Antilocapra americana peninsularis). A total of 29 h of aerial census was performed and a total of 1900 km²were covered by ground, totalling 400 man hours of survey. At present the peninsular pronghorn population consists of 175 individuals, and inhabits an area of approximately 5000 km². Because of the impossibility of controlling its activities over such an area and because of the present small population size, we propose to manage part of the population in semi-captivity at Mesa de la Choya island, with the objective of assuring the survival of this subspecies, the most endangered mammal in Mexico.     

Dynamics and seismic performance of rocking bridges accounting for the abutment-backfill contribution

The present study explores analytically the concept of rocking isolation in bridges considering for the first time the influence of the abutment-backfill system. The dynamic response of rocking bridges with free-standing piers of same height and same section is examined assuming negligible deformation for the substructure and the superstructure. New relationships for the prediction of the bridge rocking motion are derived, including the equation of motion and the restitution coefficient at each impact at the rocking interfaces. The bridge structure is found to be susceptible to a failure mode related to the failure of the abutment-backfill system, which can occur prior to the well-known overturning of the rocking piers. Thus, a new failure spectrum is proposed called Failure Minimum Acceleration Spectrum (FMAS) which extends the overturning spectrum put forward in previous studies, and it differs in principle from the latter. The comparison with the dynamic response of bridges modelled as rocking frames without abutments reveals not only that seat-type abutments and their backfill have a generally beneficial effect on the seismic performance of rocking pier bridges by suppressing the free rocking motion of the frame system, but also that the simple frame model cannot capture all salient features of the rocking bridge response as it misses potential failure modes, overestimating the rocking bridge's safety when these modes are critical.     

Spatial Analysis of Airborne Geophysical Data Applied to Geological Mapping and Mineral Prospecting in the Serra Leste Region, Carajás Mineral Province, Brazil

The Serra Leste region, located in the northeast portion of Carajás Mineral Province (PA), hosts important chrome-PGE, Au–Pd–Pt, Cu–Mo–Au, iron, and manganese deposits and occurrences related to different geological settings. We present a regional prospective model with focus on PGE mineralizations based on airborne geophysics (magnetometry, gamma-ray spectrometry and time domain electromagnetometry) and geological data. Geological and geophysics data analysis indicate a plausible correspondence between areas with meta-mafic–ultramafic rocks and low values in gamma spectrometry, mainly for the thorium channel. The meta-ultramafic units of the complexes, the main host rock of the PGE mineralization, are well defined by analytic signal from the anomalous magnetic field and by the apparent conductance anomalies derived from the GEOTEM system. The combination of the derivative products with updated geological data of the Serra Leste region and PGE-Luanga deposit enable to establish a regional prospective model for PGE and the identification of new targets within the studied area.     

Analysis of UVB values in the centre of the Iberian Peninsula

Records of UV data started in Madrid at the beginning of the 90's decade. After some quality control on the data a seven year period from 1996 to 2002 was selected to perform an analysis of daily and seasonal variability of solar ultraviolet B (UVB) values at the centre of the Iberian Peninsula. Instruments used are a Brewer MKIV spectrophotometer and a YES UVB-1 broadband pyranometer. Both instruments provided integrated daily values according with the Diffey spectrum although they have different measurement procedures. Data statistics from each instrument for the same period and statistical relationships between daily values from both instruments are shown. As broadband YES provided a record with fewer time gaps, analysis of UVI extreme values is performed using that instrument. The relationship between UVB values with ozone, cloudiness and visible radiation has been described in several papers for different places in the world. In this paper, those relationships are shown for Madrid. A discussion about specific problems found when trying to isolate every effective factor is also included. Some of those relationships could be helpful to retrieve UVB values from other ancillary data as visible radiation and cloudiness. Finally, a detailed study for 10 days in June 1997 when the maximum record of daily values from the present time series was obtained, highlight the close correlation between total ozone content and the daily variability of UVB for similar amounts of incoming radiation.