The long-term statistical forecast of geomagnetic pulsations of type Pc 1 activity

The forecast of geophysical phenomena from pulsation data is one of the problems of hydromagnetic diagnostics. Long-term forecast is made by extrapolating into the future data accumulated in the past. We attempt a preliminary forecast of Pc 1 (pearls) activity for some years to come, and we predict that during 1972–1974 there will be a large amount of activity. This information is very useful since it enables us to choose favourable times for carrying out synoptical observations on a global scale, as, for instance, finding pearls in the magnetosphere by means of satellites.     

Hydromagnetic “whistles” at the dayside cusps: IPRP events

The current status of the morphological properties of the variation of the earth's magnetic field known as Intervals of Pulsations with Rising Periods (IPRP) observed at the polar cusp stations Casey, Mirny and Heiss throughout 1978 is presented. They have the characteristic of a “whistle” with steadily falling tone. Comprehensive observational and dynamical morphological accounts of the IPRP phenomenon are presented including new analyses of polarisation, power spectra and digital sonograms. Simultaneously occurring IPRP at the two widely spaced stations Casey and Mirny are examined. In an accompanying paper (Cole et al., 1982) a theory which accounts for the properties of the phenomenon is presented.     

Diurnal latitude variation of the location of the dayside cusp

The properties of specific high-latitude pulsations (ipcl) reveal the existence of a significant diurnal variation in latitude of the position of the day side cusp (Δφ 6°). This systematic change of the position of the cusp during 24 hr must be taken into account when the rapid shirtings of the cusp connected with the changes of magnetic activity are studied.

A method of determination of the position of the cusp, using a limited number of ground stations is suggested.     

Where do solar wind-controlled micropulsations originate?

An analysis of micropulsation data, recorded at Borok during upstream wave events observed by the HEOS satellite in the solar wind, clearly demonstrates that pulsation activity was present at Borok only when the solar wind velocity was sufficiently large compared with the sunward component of the Alfvén velocity along the interplanetary magnetic field. We show that the form of this relationship is consistent with the generation of the Borok pulsations by the Kelvin-Helmholtz mechanism at the magnetopause. The experimentally determined threshold for this wave excitation agrees best with theory when the latter represents a magnetosheath flow of finite thickness and nonlinear effects of the interaction are included. The modified theoretical treatment is given in the appendix.     

The analysis of results of remote sensing monitoring of the temperature profile in lower atmosphere in Bergen (Norway)

Considered is the application of MTP-5 meteorological temperature profiler used for the remote sensing of vertical profiles of the air temperature in the planetary boundary layer and the lower one-kilometer layer of the atmosphere. The measurements were carried out in Bergen (Norway) in 2011–2012. The obtained dataset of temperature profiles has temporal resolution of five minutes and vertical resolution of 50 m. The MTP-5 data are complemented with the measurements of the air temperature and the wind taken at two automatic weather stations and with the measurements of the rain intensity made with the rain radar. Studied is the impact of meteorological conditions and precipitation on the MTP-5 readings. It is revealed that formation of a thin water film (of ice or, to a smaller degree, of sleet) on the surface of the sensor cover of MTP-5 has a significant impact on the data of the temperature monitoring. The removal of intensive precipitation (the precipitation rate is >0.2 mm/hour) improved the reliability and quality of the temperature profile monitoring. In particular, it is demonstrated that significant air pollution and stably stratified atmospheric conditions which lead to low temperatures are reliably monitored with this instrument.     

Fragmentation of the “bag-breakup” type as a mechanism of the generation of sea spray at strong and hurricane winds

Experiments on generation mechanisms of sea water spray under hurricane wind were performed using shadow illumination high-speed video recording from several camera positions. Classification of fragmentation mechanism leading to generation of spray was conducted. Statistics of the events causing generation of spray was studied. A phenomenological model was developed based on the methods of statistical physics to describe the “bag-breakup” generation mechanism. The function of spray generation was conducted on this basis, which describes well the experimental data obtained under hurricane winds in the natural and laboratory conditions.