Remote determination of momentum-flux profiles in the lower atmospheric boundary layer

An acoustic locator—a sodar—is a unique instrument for getting the objective characteristics of the current state of the atmospheric boundary layer (ABL) owing to a combination of such properties as remoteness, mobility, resolution, and information content. This study demonstrates the capabilities of a sodar to obtain data on the second moments of the field of wind-velocity fluctuations, in particular, the profiles of momentum flux in the lower ABL, which are very important in practical applications. A corresponding method is described, and the results of its experimental verification and some examples of its application under the conditions of different ABL stratification are presented.     

Lagrangian fronts in the ocean

We introduce the concept of Lagrangian fronts (LFs) in the ocean and describe their importance for analyzing water mixing and transport and the specific features and differences from hydrological fronts. A method of calculating LFs in a given velocity field is proposed. Based on altimeter velocity fields from AVISO data in the northwestern Pacific, we calculate the Lagrangian synoptic maps and identify LFs of different spatial and temporal scales. Using statistical analysis of saury catches in different years according to the Goskomrybolovstvo (State Fisheries Committee of the Russian Federation), we show that LFs can serve as good indicators of places that are favorable for fishing.     

Geoelectric section of the Central Tien Shan: Sequential inversion of the magnetovariational and magnetotelluric data along the Naryn Line

The paper presents the results of 2D inversion of deep magnetotelluric (MT) and magnetovariational (MV) soundings along the Naryn Line. The method of partial (sequential) inversions is used. According to this method, at the first stage, magnetovariation responses are used for the localization of deep anomalies of electrical conductivity, and then the magnetotelluric sounding data are invoked to refine the structure of the host medium and the structural details in the upper part of the section. It is shown that this approach enables one to estimate the informativeness of separate components of the electromagnetic field, to reduce the distorting influence of the near-surface geoelectric inhomogeneities, and to increase the stability of the final solution of the inverse problem.     

Accuracy estimates for some global analytical models of the Earth’s main magnetic field on the basis of data on gradient magnetic surveys at stratospheric balloons

Two global analytical models of the main magnetic field of the Earth (MFE) have been used to determine their potential in deriving an anomalous MFE from balloon magnetic surveys conducted at altitudes of ～30 km. The daily mean spherical harmonic model (DMSHM) constructed from satellite data on the day of balloon magnetic surveys was analyzed. This model for the day of magnetic surveys was shown to be almost free of errors associated with secular variations and can be recommended for deriving an anomalous MFE. The error of the enhanced magnetic model (EMM) was estimated depending on the number of harmonics used in the model. The model limited by the first 13 harmonics was shown to be able to lead to errors in the main MFE of around 15 nT. The EMM developed to n = m = 720 and constructed on the basis of satellite and ground-based magnetic data fails to adequately simulate the anomalous MFE at altitudes of 30 km. To construct a representative model developed to m = n = 720, ground-based magnetic data should be replaced by data of balloon magnetic surveys for altitudes of ～30 km. The results of investigations were confirmed by a balloon experiment conducted by Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation of the Russian Academy of Sciences and the Moscow Aviation Institute.     

Near-vertical seismic reflection image using a novel acquisition technique across the Vrancea Zone and Foscani Basin, south-eastern Carpathians (Romania)

The DACIA PLAN (Danube and Carpathian Integrated Action on Process in the Lithosphere and Neotectonics) deep seismic sounding survey was performed in August–September 2001 in south-eastern Romania, at the same time as the regional deep refraction seismic survey VRANCEA 2001. The main goal of the experiment was to obtain new information on the deep structure of the external Carpathians nappes and the architecture of Tertiary/Quaternary basins developed within and adjacent to the seismically-active Vrancea zone, including the Focsani Basin. The seismic reflection line had a WNW–ESE orientation, running from internal East Carpathians units, across the mountainous south-eastern Carpathians, and the foreland Focsani Basin towards the Danube Delta. There were 131 shot points along the profile, with about 1 km spacing, and data were recorded with stand-alone RefTek-125s (also known as “Texans”), supplied by the University Texas at El Paso and the PASSCAL Institute. The entire line was recorded in three deployments, using about 340 receivers in the first deployment and 640 receivers in each of the other two deployments. The resulting deep seismic reflection stacks, processed to 20 s along the entire profile and to 10 s in the eastern Focsani Basin, are presented here. The regional architecture of the latter, interpreted in the context of abundant independent constraint from exploration seismic and subsurface data, is well imaged. Image quality within and beneath the thrust belt is of much poorer quality. Nevertheless, there is good evidence to suggest that a thick (10 km) sedimentary basin having the structure of a graben and of indeterminate age underlies the westernmost part of the Focsani Basin, in the depth range 10–25 km. Most of the crustal depth seismicity observed in the Vrancea zone (as opposed to the more intense upper mantle seismicity) appears to be associated with this sedimentary basin. The sedimentary successions within this basin and other horizons visible further to the west, beneath the Carpathian nappes, suggest that the geometry of the Neogene and recent uplift observed in the Vrancea zone, likely coupled with contemporaneous rapid subsidence in the foreland, is detached from deeper levels of the crust at about 10 km depth. The Moho lies at a depth of about 40 km along the profile, its poor expression in the reflection stack being strengthened by independent estimates from the refraction data. Given the apparent thickness of the (meta)sedimentary supracrustal units, the crystalline crust beneath this area is quite thin (< 20 km) supporting the hypothesis that there may have been delamination of (lower) continental crust in this area involved in the evolution of the seismic Vrancea zone.     

Paleoproterozoic quartz-pebble conglomerate type uranium mineralisation in Mankarhachua area,Angul district,Orissa

Ground Radiometric survey of Paleoproterozoic pyritiferous quartz-pebble conglomerate (QPC) occurring to the north of Pallahara area led to the discovery of a QPC type uranium mineralisation near Mankarhachua village. Significant radioactivity is recorded in three sub-parallel uraniferous QPC horizons with metamorphosed pebbly to medium grained recrystallised massive sandstones. Detrital grains of uranothorite, thorite, radioactive allanite, monazite, zircon, minute uraninite grains in carbonaceous matter and thucolite contributes to the radioactive phases present in QPC matrix. Adsorbed U on limonite and goethite, secondary uranyl minerals in matrix, along bedding planes and fractures are commonly observed. This discovery has opened up a new horizon for future exploration for QPC type uranium mineralization in the area. The paper presents observations on geology, radioactivity, petrological and geochemical nature of the uraniferous QPC horizons.     

The effect of low level supplementary heating on diving duration

The exothermic reaction which proceeds when small sachets containing particulate mixtures of iron and magnesium are flooded with sea water, has been used for thermal support of free divers. Initial application of such generators to heating of the hands (Burton and Chan, 1981), and later extension to heating of the torso, have been described previously (Chan and Burton, 1981, 1982). Of considerable interest during field trials of the torso heating system was a strong subjective impression among those taking part, that significant increases of dive duration and decreases of perceived discomfort could be obtained with relatively low levels of power generation, for example less than 50% of that required for thermal balance. In this paper, a simple mathematical model of human stored heat loss is used to rationalize this observation. Also it successfully predicts voluntary exposure times of unheated divers who become cold. When used to estimate body heat debt, the model enables documented dives by this laboratory and by others, including recent exposures in Antarctica using low level supplementary heating, to be analysed.     

The distribution of total and electrochemically available copper in the northwestern atlantic ocean

Copper in a series of samples from the northwestern Atlantic has been determined by anodic stripping voltammetry (ASV) and atomic absorption spectrometry after preconcentration by cobalt—APDC coprecipitation. Samples from a transect across the continental shelf directly off the New York Bight showed a linear relationship between total copper and salinity (31–34‰) and less than 5% of the total copper was detectable by ASV. A slope water station showed less than 9% of the total copper to be ASV detectable in the upper 780m, below which the ASV detectable copper increased to 70% at 3000 m. The Sargasso Sea profiles showed less than 7% ASV detectable copper in the upper 150 m; the fraction of the total copper detected by ASV increased to about 80% of the total copper at greater depths. The reduced availability of copper to the ASV measurement in coastal waters and open ocean surface waters appears to be related to recent contact with waters where biological productivity occurs.