The simulation of runoff from small catchments in the permafrost zone by the SWAP model

The ability of a new version of SWAP physically based model, which describes the heat and water exchange processes in the soil-vegetation (snow cover)-near-surface atmosphere system and has been adapted to the permafrost conditions, to reproduce runoff formation at small watersheds in the permafrost zone. The procedure for the preparation of missing input data for model simulations is described. Model simulations were performed based on observational data collected within a decade (1969–1978) by the Kolyma Water Balance Station, located in a high-land continuous permafrost zone. The results of comparison of the modelled daily and annual runoff with data of appropriate measurements in a number of experimental watersheds in the basin of the Kontaktovyi Creek (Upper Kolyma) are analyzed.     

Parameterization of Heat and Moisture Exchange on Land Surface in Areas with Moderate Continental Climate

A technique is proposed for parameterization of the process of heat and moisture exchange between the underlying surface and the atmosphere at a regional scale under moderate continental climate, which implies a long cold period with stable snow cover and seasonally frozen soil. The technique allows the heterogeneity of the area under consideration to be explicitly accounted for in the model through properly selecting the model grid. The details at a scale below the grid size, such as the presence of field or forest ecosystems in any grid cell, also can be incorporated in the model. The proposed technique has been tested against unique observational data along with published scientific generalization for the Polomet River basin (Valdai Hills), which is 1215 km² in area.     

Kinematics of the Local cosmic void

Available data on the distances and radial velocities of galaxies are systematized in order to study the distribution of peculiar velocities in neighborhoods of the Local cosmic void lying in the direction of the Aquila and Hercules constellations. A sample of 1056 galaxies is used, with distances measured in terms of the luminosity of the tip of the red giant branch (TRGB), the luminosity of the cepheids, the luminosity of type 1a supernovae, surface brightness fluctuations (SBF), and the Tully-Fisher relation. The amplitude of the outflow velocity of the galaxies is found to be ∼300 km/s. The average number density of galaxies inside the void is roughly a factor of five lower than the average outside it. The Local void population is characterized by lower luminosities and later morphological types, with medians of M _B = − 15^m.7 and T=8 (Sdm), respectively.     

Runoff evaluation for ungauged watersheds by SWAP model. 1. Application of artificial neural networks

The potentialities of artificial neural networks are studied as applied to estimating key model parameters required for calculating river runoff by SWAP model in the case of ungauged watersheds. The examined geographic objects were 323 experimental watersheds of MOPEX project. The quality of model parameter estimates based on ANNs with different architecture was analyzed.     

The Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) phase 2(c) Red-Arkansas River basin experiment:: 2. Spatial and temporal analysis of energy fluxes

The energy components of sixteen Soil-Vegetation Atmospheric Transfer (SVAT) schemes were analyzed and intercompared using 10 years of surface meteorological and radiative forcing data from the Red-Arkansas River basin in the Southern Great Plains of the United States. Comparisons of simulated surface energy fluxes among models showed that the net radiation and surface temperature generally had the best agreement among the schemes. On an average (annual and monthly) basis, the estimated latent heat fluxes agreed (to within approximate estimation errors) with the latent heat fluxes derived from a radiosonde-based atmospheric budget method for slightly more than half of the schemes. The sensible heat fluxes had larger differences among the schemes than did the latent heat fluxes, and the model-simulated ground heat fluxes had large variations among the schemes. The spatial patterns of the model-computed net radiation and surface temperature were generally similar among the schemes, and appear reasonable and consistent with observations of related variables, such as surface air temperature. The spatial mean patterns of latent and sensible heat fluxes were less similar than for net radiation, and the spatial patterns of the ground heat flux vary greatly among the 16 schemes. Generally, there is less similarity among the models in the temporal (interannual) variability of surface fluxes and temperature than there is in the mean fields, even for schemes with similar mean fields.     

The Lagrange-Jacobi equation in the finite-size many-body problem

We determine the values of the barycentric energy constant that necessarily result in collisions between bodies. The standard Hill stability regions in the problem of four or more bodies are shown to be located inside the regions where collisions are inevitable. Only in the problem of three finite bodies is part of the Hill stability region preserved where the bodies can move without colliding with one another. We point out possible astronomical applications of our results.     

Blueshifted galaxies in the virgo cluster

We examine a sample of 65 galaxies in the Virgo cluster with negative radial velocities relative to the Local Group. Some features of this sample are pointed out. All of these objects are positioned compactly within a virial zone of radius 6o in the cluster, but their centroid is displaced relative to the dynamic center of the cluster, M87, by 1o.1 to the northwest. The dwarf galaxies in this sample are clumped on a scale of ∼10' (50 kpc). The observed asymmetry in the distribution of the blueshifted galaxies may be caused by infall of a group of galaxies around M86 onto the main body of the cluster. We offer another attempt to explain this phenomenon, assuming a mutual tangential velocity of ∼300 km/s^-1 between the Local Group and the Virgo cluster owing to their being repelled from the local cosmological void.     

Hill stability in the many-body problem

We established a criterion for the Hill stability of motions in the problem of many spherical bodies with a spherical density distribution. The region of Hill stability was determined. The sizes of this region are comparable to the total volume of all of the bodies in the system, which sharply increases the probability of mutual collisions. This result may be considered as a confirmation that a supermassive core can be formed at the center of a globular star cluster. The motions in the n-body problem are shown to be unstable according to Hill.     

Physically Based Modeling of the Long-Term Dynamics of Water Balance and Snow Water Storage Components in the Ob–Irtysh River Basin

Water Resources - The applicability of the previously developed technique for simulating the runoff hydrographs of northern rivers to the Ob River, which has largest basin area among Russian rivers...     

Physically based modeling of many-year dynamics of daily streamflow and snow water equivalent in the Lena R. basin

The applicability of a procedure, developed previously for evaluating runoff hydrographs of northern rivers, to the largest Russian river—the Lena—which flows under severe conditions of the Northeastern Siberia, is examined. The procedure is based on the land surface model SWAP in combination with input data derived from global databases of land surface parameters and meteorological forcing data derived from observations at meteorological stations located in the basins of the rivers or near them. Also studied was the ability of the model SWAP to reproduce the many-year dynamics of the values of snow water equivalent averaged over the Lena basin and their distribution over the basin area.