Deposition of trace substances via cloud interception on a coniferous forest at Kleiner Feldberg

A resistance model to calculate the deposition of cloud droplets on a coniferous forest and some improved parameterizations of the indispensable input parameters are described. The deposition model is adapted to the coniferous forest at the Kleiner Feldberg site and verified by the data of a drip water monitoring station below the forest canopy. The measurements of liqud water content, wind speed and trace substance compounds in cloud water of the Ground-based Cloud Experiment (GCE) at Kleiner Feldberg in 1990 are used to calculate the cloud water deposition fluxes and the deposition of trace substances via cloud water interception. The calculated deposition of trace substances via cloud water interceptions is three to six times higher than via rain during the experiment. On a long term data basis the yearly amount of cloud water deposition is 180 mm year^–1 at Kleiner Feldberg site (840 m a.s.l.) while the precipitation amount is 1030 mm year^–1. Due to higher trace substance concentrations in cloud water compared to rain the ionic deposition via cloud water interception and via precipitation were assessed to be of comparable magnitude.     

A New Approach for Scientific Data Dissemination in Developing Countries: A Case of Indonesia

This short paper is a progress report on our experiences in Indonesia of collecting, integrating and disseminating both global and local scientific data across the country through the web. Our recent efforts are concentrated on improving local public access to global scientific data, and encouraging local scientific data to be more accessible for global communities. We have maintained a well-connected infrastructure and web-based information management systems to realize these objectives. This paper is especially focused on introducing the ARSIP system for mirroring global data and sharing local scientific data, and the newly developed Indonesian Scientific Index for integrating local scientific data through an automated intelligent indexing system.     

Understanding the surface hydrology of the Lake Eyre Basin: Part 1—Rainfall

This is the first of two papers that describe the surface hydrology of the Lake Eyre Basin (LEB) (1,140,000 km²) in central Australia and compares some key characteristics with those observed from arid regions globally. This paper concentrates on annual rainfall, whereas the second paper is devoted to streamflow. The first part describes the LEB's climate (arid to semi-arid), which is dominated by a subtropical high pressure ridge stretching latitudinally across central Australia. Then follow major analyses that include the characteristics of rainfall, wet and dry spell lengths and cumulative surpluses and deficiencies, rainfall trends and intra- and inter-decadal fluctuations, and the relationship between rainfall and El Niño-Southern Oscillation (ENSO). The paper concludes with six conclusions, the key ones being: the variability of the annual rainfall (based on the coefficient of variation) in the LEB is approximately 60% greater than that found for stations located in arid regions in the rest of the world; there is a bias towards longer lengths of dry years than observed in the rest of Australia; and, there is a significant lag correlation between rainfall and ENSO, particularly in the east and in the latter part of a year.     

Bootstrapped discrete scale invariance analysis of geomagnetic dipole intensity

The technique of bootstrapped discrete scale invariance allows multiple time-series of different observables to be normalized in terms of observed and predicted characteristic timescales. A case study is presented using the SINT2000 time-series of virtual axial dipole moment, which spans the past 2 Myr. It is shown that this sequence not only bears a clear signature of a preferred timescale of about 55.6 Ka, but additionally predicts similar features (of shorter and longer duration) that are actually observed on the timescales of historical secular variation and dipole reversals, respectively. In turn, the latter two empirical sources both predict the characteristic timescale found in the dipole intensity sequence. These communal scaling characteristics suggest that a single underlying process could be driving dynamo fluctuations across all three observed timescales, from years to millions of years.     

The Velocity Field and Kinematics of the Galaxy NGC 784 in the Hα Line

In this paper we present the H map, the 2D velocity field and the rotation curve of the galaxy NGC 784 obtained with the ByuFOSC2 scanning Fabry-Perot interferometer, attached at the prime focus of the 2.6-m telescope of Byurakan Observatory. The H image shows several HII condensations along the major axis of the galaxy. The galaxy has an asymmetric distribution of the H emission. The rotation curve is quite symmetric with a low gradient in the central part of the galaxy.     

Meridional transport of sensible heat in contrasting monsoon activity: Spherical harmonic analysis

Spherical harmonic analysis is made of the grid point values of geopotential heights at 700 mb and 300 mb levels for the months April to August for the years 1967 and 1972. The year 1967 is a good monsoon year and 1972 is a bad monsoon year in India. Meridional transport of sensible heat is obtained in wave number domain using spherical harmonic coefficients at 500 mb level form=1 to 10 andn–m=0 to 10, wherem represents the wave number round the globe andn–m gives the numbers of zero points from north pole to south pole excluding the poles themselves.Large northward transports of sensible heat in the month of May and in the monsoon months at the subtropics are characteristic of bad monsoon. Wave 1 transports sensible heat southward (forn–m=0) and wave 2 transports sensible heat northward (forn–m=4). Strengthening of wave 1 is conducive to good monsoon year and strengthening of wave 2 is conducive to bad monsoon year. These are the same features obtained in Fourier analysis. The contrasting features exist in waves 1 and 2 both in good and in bad monsoon and are better defined in the present analysis than in the Fourier analysis of the earlier study. However, waves 1 and 2 reveal clearer contrast in the present analysis than in the Fourier analysis. Bad monsoon activity is associated with large divergence of heart at subtropics and large convergence of heat at extra tropics.     

3D triangulation of a Sun-grazing comet

The bright Kreutz Comet C/2007 L3 (SOHO) entered the fields of view of the twin Solar Terrestrial Relations Observatory (STEREO) COR1 telescopes on 7–8 June 2007. The 12° separation between the two spacecraft at the time afforded the opportunity to derive the position of the comet's tail in three-dimensional space using direct triangulation. The track of the comet's orbit is compared against more traditional orbital calculations using observations from the STEREO COR2 telescopes, and from the Large Angle and Spectrometric Coronagraph (LASCO) aboard the Solar and Heliospheric Observatory (SOHO). The shape of the comet's tail shows that it is composed of dust particles released when the comet was between 18 and 22 solar radii, with no significant dust production after that. The comet did not survive perihelion passage, but a rare faint remnant of the comet tail persisted for several hours after the break-up, and was seen by both the SOHO and STEREO coronagraphs to drift slowly away from the Sun. This tail remnant was found to be composed of particles far back from the head of the comet. The motion of the tail remnant shows a loss of angular momentum during the passage through the solar corona. Atmospheric drag is estimated to account for a significant fraction of this change in angular momentum, but indications are that other mechanisms may be required to completely account for the total amount of change.     

Solar rotation, 1966–1978

Photospheric and chromospheric spectroscopic Doppler rotation rates for the full solar disk are analyzed for the period July, 1966 to July, 1978. An approximately linear secular increase of the equatorial rate of 3.7% for these 12 years is found (in confirmation of Howard, 1976). The high latitude rates above 65 ° appear to vary with a peak-to-peak amplitude of 8%, or more, phased to the sunspot cycle such that the most rapid rotation occurs at, or following, solar maximum. The chromosphere, as indicated by H, has continued to rotate on the average 3% faster than the photosphere agreeing with past observations. Sources of error are discussed and evaluated.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.