Geoeffectiveness and efficiency of CIR, Sheath and ICME in generation of magnetic storms

We investigate relative role of various types of solar wind streams in generation of magnetic storms. On the basis of the OMNI data of interplanetary measurements for the period of 1976-2000 we analyze 798 geomagnetic storms with Dst < -50 nT and their interplanetary sources: corotating interaction regions (CIR), interplanetary CME (ICME) including magnetic clouds (MC) and Ejecta and compression regions Sheath before both types of ICME. For various types of solar wind we study following relative characteristics: occurrence rate; mass, momentum, energy and magnetic fluxes; probability of generation of magnetic storm (geoeffectiveness) and efficiency of process of this generation. Obtained results show that despite magnetic clouds have lower occurrence rate and lower efficiency than CIR and Sheath they play an essential role in generation of magnetic storms due to higher geoeffectiveness of storm generation (i.e higher probability to contain large and long-term southward IMF Bz component).Comment: 23 pages, 4 figures, 3 tables, submitted to JGR special issue "Response of Geospace to High-Speed Streams

Recovery phase of magnetic storms induced by different interplanetary drivers

Statistical analysis of Dst behaviour during recovery phase of magnetic storms induced by different types of interplanetary drivers is made on the basis of OMNI data in period 1976-2000. We study storms induced by ICMEs (including magnetic clouds (MC) and Ejecta) and both types of compressed regions: corotating interaction regions (CIR) and Sheaths. The shortest, moderate and longest durations of recovery phase are observed in ICME-, CIR-, and Sheath-induced storms, respectively. Recovery phases of strong ($Dst_{min} < -100$ nT) magnetic storms are well approximated by hyperbolic functions $Dst(t)= a/(1+t/\tau_h)$ with constant $\tau_h$ times for all types of drivers while for moderate ($-100 < Dst_{min} < -50$ nT) storms $Dst$ profile can not be approximated by hyperbolic function with constant $\tau_h$ because hyperbolic time $\tau_h$ increases with increasing time of recovery phase. Relation between duration and value $Dst_{min}$ for storms induced by ICME and Sheath has 2 parts: $Dst_{min}$ and duration correlate at small durations while they anticorrelate at large durations.Comment: 18 pages, 4 figures, 2 tables, submitted to JGR special issue "Response of Geospace to High-Speed Streams

Interball-tail observations of vertical plasma motions in the magnetotail

International audienceThe Interball spacecraft configuration favors, in contrast to previous experiments, investigation of vertical ion flows (GSM Vz ). We use measurements of the CORALL instrument for the statistical study of Vz and Vy plasma flows in the mid-tail plasma sheet. In agreement with the previous observations, the mean Vy was positive on the dusk side and negative on the dawn side. When IMF was southward, the mean Vz consisted of the convection flow towards the equatorial plane ~ 7 km/s and the northward flow ~ 8 km/s. When IMF was northward, both components nearly vanished. The velocity variance was much larger than the mean values. The Vz variance maximized on the dawn flank and was always 15?20% smaller than the Vy one. The Vy variance maximized in the pre-midnight sector closer to the neutral sheet. We conclude that velocity fluctuations are composed with the inherent high-beta plasma turbulence contributing to all components, and the BBF-related activity contributing mainly to Vy in the pre-midnight plasma sheet

Comment on "Are periodic solar wind number density structures formed in the solar corona?" by N. M. Viall et al., 2009, Geophys. Res. Lett., 36, L23102, doi:10.1029/2009GL041191

Location of formation of periodic solar wind number density structures is discussed. Observation of proton and alpha anticorrelation in these structures [Viall et al., 2009] indicates that taking into account that bulk velocity of aplha-particles is higher than that of proton the place of formation for these structures should be located at distance less 0.002 AU from place of observation.Comment: 6 pages, submitted in GR

The floor in the interplanetary magnetic field: Estimation on the basis of relative duration of ICME observations in solar wind during 1976-2000

To measure the floor in interplanetary magnetic field and estimate the time- invariant open magnetic flux of Sun, it is necessary to know a part of magnetic field of Sun carried away by CMEs. In contrast with previous papers, we did not use global solar parameters: we identified different large-scale types of solar wind for 1976-2000 interval, obtained a fraction of interplanetary CMEs (ICMEs) and calculated magnitude of interplanetary magnetic field B averaged over 2 Carrington rotations. The floor of magnetic field is estimated as B value at solar cycle minimum when the ICMEs were not observed and it was calculated to be 4,65 \pm 6,0 nT. Obtained value is in a good agreement with previous results.Comment: 10 pages, 2 figures, submitted in GR

Evaluation of siltation of rivers with intensive economic development of watersheds

In regions with a high degree of agricultural development with an active development of erosion processes and the critical level of degradation of the river network to which the Middle-Russian Upland belongs, the evaluation of sedimentation for various combinations of natural and economic conditions becomes an immediate proble

Geomorphometric analysis of river basins in east European Russia using SRTM and aster GDEM data

© 2016,International Journal of Pharmacy and Technology. All rights reserved.The spatial database of geomorphometric indices with the scale of 1:200 000 was created for the first time on the basis of a basin approach for the east of the Russian Plain European part. The basins built in a semiautomatic mode on the basis of SRTM DEM and Aster GDEM were used as OTE here. Using the abovementioned DEM the basic morphometric relief characteristics such as slope,slope length,vertical subdivision,river network density,LS factor were calculated. The mean values of these characteristics were calculated for basins. Using the vectorized map of geomorphological zoning,the belonging of basins to the geomorphological areas was determined. On the basis of the obtained geographic information database the main statistics of morphometric relief characteristics are calculated,and the results are interpreted using the existing scales and classifications. The dispersion analysis method revealed statistically significant associations for a number of characteristics with geomorphological regions. The regularities of spatial changes concerning considered geomorphometric characteristics were revealed. All studies were performed on the project Russian Science Foundation (RSF) «Geography and Geoecology of rivers and river basins of the European Russia: spatial analysis,estimation and modeling»

Geomorphometric analysis of river basins in East European Russia using SRTM and ASTER GDEM data

© Medwell Journals, 2016.The spatial database of geomorphometric indices with the scale of 1:200000 was created for the first time on the basis of a basin approach for the East of the Russian Plain European part. The basins built in a semiautomatic mode on the basis of SRTM DEM and Aster GDEM were used as OTE here. Using the abovementioned DEM the basic morphometric relief characteristics such as slope, slope length, vertical subdivision, river network density, LS factor were calculated. The mean values of these characteristics were calculated for basins. Using the vectorized map of geomorphological zoning, the belonging of basins to the was determined. On the basis of the obtained geographic information database the main statistics of morphometric relief characteristics are calculated and the results are interpreted using the existing scales and classifications. The dispersion analysis method revealed statistically significant associations for a number of characteristics with geomorphological regions. The regularities of spatial changes concerning considered geomorphometric characteristics were revealed. All studies were performed on the project Russian Science Foundation (RSF), geography and geoecology of rivers and river basins of the European Russia spatial analysis, estimation and modeling

Evaluation of Siltation of rivers with intensive economic development of watersheds

© Medwell Journals, 2016.In regions with a high degree of agricultural development with an active development of erosion processes and the critical level of degradation of the river network to which the Middle-Russian Upland belongs, the evaluation of sedimentation for various combinations of natural and economic conditions becomes an immediate problem. The evaluation of the silting-up of rivers, the catchment areas of which are undergoing an intensive economic development has been done at the regional and sub-continental level which allowed the adaptation of the GIS-analysis techniques for different scale levels. A possibility of assessing the risk of silting-up of rivers by calculating the sediment transport using hydraulic formulas and then comparing the sediment transporting capacity and sediment-production rate has been shown