Cloud measurements on day 245 of gate

Abstract

On day 245 of GATE (2 September 1974) two lines of convection ‐ north (N) and south (S) ‐ were studied by aircraft stacked vertically, patrolling a north‐south line at longitude 22.85° W of length about 200 km. These lines were part of a complex of convection related to an easterly wave. Photogrammetry shows that the northern line consisted at first of a dense aggregate of small clouds, of width roughly 50 m at cloud base. There were a few tall clouds. No line organization was apparent from the aircraft at 1208 GMT. Fifteen minutes later there was line organization, readily apparent from the DC‐6 aircraft. From study of Electra and DC‐6 records, it appears that a vigorous cold northeasterly surface current initiated line N, and that this was a downdraft originating at altitude about 2.5 km in a mesoscale cloud feature to the north. It appears further that penetrative convection to 14 km followed after the first rain, which moistened air near the surface, and thus lowered cloud bases from about 500 to 350 m.

In overhangs of cloud, anvils to the north of line S, active cloud towers only about 2 km wide were found. The anvils were roughly 2 km thick. Patterns of clouds corresponded to a profile of A/B‐scale divergence; active towers at low levels corresponded to convergence up to the 60 kPa level, and stratus coincided with A/B‐scale divergence aloft at about 50 and 26 kPa.

Statistical analyses from the aircraft films indicated that the area covered by clouds of dark base ‐ signifying concentrated updrafts ‐ was ～5%, much less than that covered by rain at cloud base, ～ 18%. Cloud cover at altitude 4 km was ～ 10%.     

Climate change,income and happiness: An empirical study for Barcelona

The present article builds upon the results of an empirical study exploring key factors which determine life satisfaction in Barcelona. Based on a sample of 840 individuals we first look at the way changes in income, notably income reductions, associated with the current economic situation in Spain, affect subjective well-being. Income decreases which occur with respect to one year ago have a negative effect on happiness when specified in logarithmic terms, and a positive one when specified as a dummy variable (and percentage change). The divergence in results is discussed and various explanations are put forward. Both effects are however temporary and do not hold for a period longer than a year, probably for reasons of adaptation and a downward adjustment of reference consumption and income levels. Next, we examine the implications of experiencing forest fires and find a lasting negative effect on life satisfaction. Our results suggest that climate policy need not reduce happiness in the long run, even when it reduces income and carbon-intensive consumption. Climate policy may even raise life well-being, if accompanied by compensatory measures that decrease formal working hours and reference consumption standards, while maintaining employment security.     

Systematics of superoutbursts in dwarf novae

Photometric properties of known and suspected members of the SU UMa subclass of dwarf novae are tabulated and discussed. The precessing disc model of superoutbursts gives a satisfactory quantitative explanation of the periods of superhumps and their changes during superoutburst. The systems such as WZ Sge and HV Vir that have very long intervals between superoutbursts are deduced to be beyond the orbital period minimum, and have degenerate secondaries. The systems such as V1159 Ori that have extremely short recurrence times have high rates of mass transfer and are the equivalent of the Z Cam subclass that occurs at longer orbital periods.A simplified analytical approach to the theory of accretion discs is able to explain the correlations between normal and superoutburst recurrence times. It also explains the slope of the plateau region of superoutbursts, and why the slope is shallower in the very short recurrence time systems.     

Uy phoenicis: RR lyrae variable,not dwarf nova

Stellar and atomic systems obey analogous angular momentum/mass relationships and analogous angular momentum/magnetic dipole moment relationships. The dimensional constants in both pairs of angular momentum laws appear to be related by a simple set of self-similar scaling equations, suggesting that atomic and stellar systems may be self-similar.     

The component masses of the cataclysmic variable V347 Puppis

We present time-resolved spectroscopy and photometry of the double-lined eclipsing cataclysmic variable V347 Pup (=LB 1800). There is evidence of irradiation on the inner hemisphere of the secondary star, which we correct for using a model to give a secondary-star radial velocity of   K _R= 198 ± 5 km s⁻¹  . The rotational velocity of the secondary star in V347 Pup is found to be   v sin  i = 131 ± 5 km s⁻¹  and the system inclination is   i = 840 ± 23  . From these parameters we obtain masses of   M ₁= 0.63 ± 0.04 M_⊙  for the white dwarf primary and   M ₂= 0.52 ± 0.06 M_⊙  for the M0.5V secondary star, giving a mass ratio of   q = 0.83 ± 0.05  . On the basis of the component masses, and the spectral type and radius of the secondary star in V347 Pup, we find tentative evidence for an evolved companion. V347 Pup shows many of the characteristics of the SW Sex stars, exhibiting single-peaked emission lines, high-velocity S-wave components and phase-offsets in the radial velocity curve. We find spiral arms in the accretion disc of V347 Pup and measure the disc radius to be close to the maximum allowed in a pressureless disc.     

TU Ophiuchi: Mira variable — Not dwarf nova

High-speed photometry, spectroscopy, and visual observations of TU Oph show it to be a Mira variable, not a dwarf nova as originally classified or a UV Cet star as tentatively classified.     

Forbidden lines of Ca II in the photospheric spectrum

On scans obtained with the Oxford photoelectric spectrometer, the [Ca ii] transition 4s ²S_1/2-3d ²D_3/2; is identified with a weak Fraunhofer line. It is argued that the strength of the line is consistent with the abundance of calcium which is derived from the permitted lines of Ca i and Ca ii.     

On the general properties of the secondaries of cataclysmic variable stars

The mass-radius, mass-orbital period, spectral type-orbital period and absolute magnitude-orbital period relationships for the secondary star components of cataclysmic variable (CV) binary stars are discussed. By comparing these with those expected for systems containing Roche lobe-filling main sequence stars, using empirical data for low-mass main sequence stars, it is shown thatas a group the CV secondaries do not differ significantly from main sequence stars.     

Global exposure to river and coastal flooding: Long term trends and changes

Flood damage modelling has traditionally been limited to the local, regional or national scale. Recent flood events, population growth and climate change concerns have increased the need for global methods with both spatial and temporal dynamics. This paper presents a first estimation of global economic exposure to both river and coastal flooding for the period 1970–2050, using two different methods for damage assessment. One method is based on population and the second is based on land-use within areas subject to 1/100 year flood events. On the basis of population density and GDP per capita, we estimate a total global exposure to river and coastal flooding of 46 trillion USD in 2010. By 2050, these numbers are projected to increase to 158 trillion USD. Using a land-use based assessment, we estimated a total flood exposure of 27 trillion USD in 2010. For 2050 we simulate a total exposure of 80 trillion USD. The largest absolute exposure changes between 1970 and 2050 are simulated in North America and Asia. In relative terms we project the largest increases in North Africa and Sub-Saharan Africa. The models also show systematically larger growth in the population living within hazard zones compared to total population growth. While the methods unveil similar overall trends in flood exposure, there are significant differences in the estimates and geographical distribution. These differences result from inherent model characteristics and the varying relationship between population density and the total urban area in the regions of analysis. We propose further research on the modelling of inundation characteristics and flood protection standards, which can complement the methodologies presented in this paper to enable the development of a global flood risk framework.     

57-second oscillations in Nova Centauri 1986 (V842 Cen)

High-speed photometry in 2008 shows that the light curve of V842 Cen possesses a coherent modulation at 56.825 s, with sidebands at 56.598 and 57.054 s. These have appeared since this nova remnant was observed in 2000 and 2002. We deduce that the dominant signal is the rotation period of the white dwarf primary and the sidebands are caused by reprocessing from a surface moving with an orbital period of 3.94 h. Thus, V842 Cen is an intermediate polar (IP) of the DQ Herculis subclass, is the fastest rotating white dwarf among the IPs and is the third fastest known in a cataclysmic variable. As in other IPs, we see no dwarf nova oscillations, but there are often quasi-periodic oscillations in the range 350–1500 s. There is a strong brightness modulation with a period of 3.78 h, which we attribute to negative superhumps, and there is an even stronger signal at 2.886 h which is of unknown origin but is probably a further example of that seen in GW Lib and some other systems. We used the Swift satellite to observe V842 Cen in the ultraviolet and in X-rays, although no periodic modulation was detected in the short observations. The X-ray luminosity of this object appears to be much lower than that of other IPs in which the accretion region is directly visible.