Analysis Of The Disappearing Filament And Flare Of 7 May 1992

By using Yohkoh soft X-ray data, H filtergrams, and radio data, the activation of the disappearing filament and the flare eruption on 7 May 1992 have been studied. Main conclusions are as follows: (1) the emergence of new magnetic flux tends to affect the pre-existing X-ray loops, which usually appear in arcades spanning H filament, changing the magnetic environment of the filament, and then enhance the current in the filament. Therefore newly emerging flux plays a fundamental role in the destabilization of this filament. (2) According to the H data and the rising motion of the filament, the corresponding current variation in the filament has been calculated. It seems that the current interruption may be a possible trigger mechanism for this filament disappearance. (3) The magnetic field strength and the energy flux of energetic electrons in the source region of microwave bursts have been estimated by using the microwave spectrum. During the main phase, the mean magnetic strength and the energy flux of energetic electrons are about 300–400 G and 1×1011 erg cm–2 s –1, respectively. (4) The energy provided by reconnection of the current sheet and the total energy of the current filament are estimated and we show that there is enough energy stored in the filament to feed the 7 May, 1992 flare.     

Contribution of the demographic factor to the migration turnarounds in Japan,Sweden and Canada

"It is well known that similar changes of migration pattern occurred during recent decades in most developed countries; core regions recorded a greatly decreased net in-migration in the 1970s, but increased net in-migration in the 1980s. Based on shift-share analysis of the migration data of Japan, Sweden and Canada, this paper reveals that changing cohort size, especially related to the fertility fluctuation of baby boom and bust, has played an important role in the turnarounds. Furthermore, it is elucidated from a series of correlation analyses that this demographic factor was closely linked with labour-market restructuring in terms of industrial/occupational employment changes."     

Improvement of spatial interpolation accuracy of daily maximum air temperature in urban areas using a stacking ensemble technique

ABSTRACT

The reliable and robust monitoring of air temperature distribution is essential for urban thermal environmental analysis. In this study, a stacking ensemble model consisting of multi-linear regression (MLR), support vector regression (SVR), and random forest (RF) optimized by the SVR is proposed to interpolate the daily maximum air temperature (T_max) during summertime in a mega urban area. A total of 10 geographic variables, including the clear-sky averaged land surface temperature and the normalized difference vegetation index, were used as input variables. The stacking model was compared to Cokriging, three individual data-driven methods, and a simple average ensemble model, all through leave-one-station-out cross validation. The stacking model showed the best performance by improving the generalizability of the individual models and mitigating the sensitivity to the extreme daily T_max. This study demonstrates that the stacking ensemble method can improve the accuracy of spatial interpolation of environmental variables in various research fields.     

Authors' Reply

Abstract— Reimold et al. question our interpreted impact origin of the Fohn structure, Timor Sea, and criticise methodological aspects of the seismic reflection survey of Fohn structure and chemical analytical techniques. Our impact interpretation resulted from (1) remarkable analogies between the seismic structures of massive core‐annular trough structure of volcanic diatremes, and the syncline‐ringed central uplift of impact structures; (2) occurrence of Cretaceous microfossils in the drill chips, which suggested deep excavation; (3) lack of seismic evidence for volcanic feeders or conduits, and (4) the ultramafic chemistry of drill chips (Ni < 428 ppm; Co < 51 ppm; Cr < 518 ppm). Here we indicate that, since publication of our paper, we have uncovered in Fohn‐1 drill cuttings rare apatite‐rich lamproite mineral assemblages consisting of pseudomorphs of analcite after leucite, nontronite‐altered olivine, diopside, alkali pyroxene, Ti‐phlogopite, apatite, Mg‐ilmenite, priderite, rutile, and secondary barite. The new data explain the high gamma ray log anomalies in Fohn‐1 well and shed new light on the origin of the Fohn structure. Our error serves to clarify criteria for distinguishing between buried diatremes and impact structures.     

Short-term variability of Cyg X-1

The short-term X-ray variability distinguishes Cyg X-1, which is the most likely candidate for a black hole, from other X-ray sources. The present status of our knowledge on this short-term variation, mainly from the UHURU, the MIT and the GSFC observations, is reviewed. The nature of impulsive variations which compose the time variation exceeding the statistical fluctuation is discussed. There are indications that the energy spectrum of large pulses is harder than the average spectrum, or that the large pulses are the characteristics of the hard component of the spectrum if it is composed of two, soft and hard, components. Features of the variations may be partly simulated by the superposition of random shot-noise pulses with a fraction of a second duration. However, the autocorrelation analysis and the dynamic spectrum analysis indicate that the correlation lasts for several seconds and in the variation are buried some regularities which exhibit power concentrations in several frequency bands; 0.2–0.3, 0.4–0.5, 0.8, 1.2–1.5 Hz. There are several possible interpretations of these results in terms of; e.g. (a) a mixture of shot-noise pulses with two or more constant durations, (b) the shape of the basic shot-noise pulse, (c) bunching of the pulses, (d) superposition of wave-packets or temporal oscillations. But we have not yet reached any definite understandings in the nature of the variabilities. The substructure of the fluctuations on a time scale of milliseconds suggested by two investigations is also discussed.Paper presented at the COSPAR Symposium on Fast Transients in X- and Gamma-Rays, held at Varna, Bulgaria, 29–31 May, 1975.     

On the largest angular size-redshift diagram for quasars

The envelope function in the largest angular size-redshift diagram for quasars is shown to be a consequence of the distribution of their redshifts and to have no intrinsic physical significance.     

Polarization measurements of solar type III radio bursts at 25.3 MHz

We report the results of 1966, 1968, and 1969 polarization measurements of solar type III radio noise bursts made by recording the output of two orthogonally polarized receiving channels and subsequent digital processing of selected data. The processed data yield total intensity, degree of polarization, ellipticity, and polarization ellipse orientation at 1 second intervals. The measurements are made in a 100 Hz bandwith to minimize the influence of the propagating medium on the measurements. The mean degree of polarization was found to be about 65% in contrast to previous studies which indicated that type III events were more weakly polarized. By assuming that type III bursts are flare related we study the polarization characteristics of type III bursts as a function of the solar longitude of the related flares. The relation between type III event polarization characteristics and flare importance is also investigated. The significance of polarization measurements in studies of solar radio events is pointed out and suggestions for further theoretical research are given.