Experience in CCD Spectrocolorimetry of Lunar-Surface Regions

Panoramic scans of two lunar regions (Aristarchus–Herodotus and Plato craters) were obtained with a CCD camera and spectrograph to determine a range of actual color differences. The color differences expressed in color–excess (CE) units and determined as the intensity ratios for lunar features at 440 and 550 nm are mainly less than 0.1^m. The color–albedo dependence is revealed only in separate clusters and is not the same in different parts of each region under consideration. This special feature of crater Aristarchus is confirmed; that is, in spite of its high albedo, the color in the crater is intermediate within the general range of color differences.     

Lang Trang Cave (Northern Vietnam): Pleistocene Mammalian Locality with Gigantopithecus Finds

Doklady Earth Sciences - Speleological, geological and paleontological characteristics of the Lang Trang cave in northern Vietnam are presented. Primates Gigantopithecus blacki von Koenigswald,...     

Variations of Seismicity in the Avachinsky Gulf (Kamchatka, Russia)

Variations of seismic mode in the region of the Avachinsky Gulf (Kamchatka, Russia) are considered. Observed anomalies (seismic quiescence, the ring seismicity, reduction of the slope of the earthquake recurrence diagram) provide a basis to consider this region as a place of strong earthquake preparation. The Kamchatka regional catalogues of earthquakes between 1962–1995 were used in the analysis. A reduced seismicity rate is observed during 10 years in an area of 150 km × 60 km in size. During the last five years, in the vicinity of the area considered, earthquakes with M > 5 occurred three times more often than the average over thirty years. It is interpreted as ring seismicity. The block of 220 km × 220~km in size, including the quiescence zone, is characterized by a continuous decrease of the recurrence diagram slope, which has reached a minimum value for the last 33 years in this region.     

Reconstruction of the harmonic component of the magnetic field modulus anomalies

An algorithm is proposed for calculating a harmonic function equal to the projection of the anomalous magnetic field vector onto the normal field direction from in situ measurements of the anomalous magnetic field modulus (the scalar magnetic anomaly) ΔT, which is a nonharmonic function and is nonlinearly related to the magnetization of anomaly sources. It is shown that the inferred estimates tend to the desired harmonic function if the iterative algorithm converges. The convergence conditions and stability of the process are studied numerically in a wide range of amplitudes of the anomalous field. The results of the modeling simulation demonstrate the efficiency of the proposed algorithm in solving magnetic field interpretation problems often encountered in practice.     

Similarity of rivers and their systems

Similarity criteria of rivers and river systems are studied. Zonal and azonal indicators of their similarity are established. The role of river system patterns in the changes of hydrographic and hydrologic characteristic of rivers in the passage from river heads to mouths is considered. The efficiency of applying fractal and indication analyses to river systems is examined. The extent and the scale effect of changes in various characteristics of the flow-channel systems are shown to depend on changes in river orders. The fractal dimension and the scale effects of their changes are correlated. A universal relationship between river orders, on the one hand, and river drainage area and river network density, on the other hand, was established. The root-mean-square error of the obtained formula, evaluated based on data on 274 watersheds, was 0.27, enabling it to be used in hydrological calculations under various landscape conditions.     

Modeling Iceberg Drift in the Barents Sea from Field Data

The iceberg drift model is developed and used for simulating the iceberg drift trajectory in the Barents Sea. The model is forced by hydrometeorological characteristics obtained from ship observations. Original techniques for retrieving the sea-level slope gradient and surface velocity of currents are proposed, implemented, and validated using independent data. Thus, additional data were calculated from field data in order to use the iceberg drift model with the full set of external forces. This allowed improving the iceberg trajectory simulation and assessing the contribution of all forces that affect the iceberg drift. The iceberg drift calculations demonstrate that the drift characteristics are extremely sensitive to all external effects and the model parameters; therefore, the quality of input hydrometeorological data essentially affects the simulation of real iceberg trajectories.