Impact of remotely sensed soil moisture and precipitation on soil moisture prediction in a data assimilation system with the JULES land surface model

We show that satellite-derived estimates of shallow soil moisture can be used to calibrate a land surface model at the regional scale in Ghana, using data assimilation techniques. The modified calibration significantly improves model estimation of soil moisture. Specifically, we find an 18 % reduction in unbiased root-mean-squared differences in the north of Ghana and a 21 % reduction in the south of Ghana for a 5-year hindcast after assimilating a single year of soil moisture observations to update model parameters. The use of an improved remotely sensed rainfall dataset contributes to 6 % of this reduction in deviation for northern Ghana and 10 % for southern Ghana. Improved rainfall data have the greatest impact on model estimates during the seasonal wetting-up of soil, with the assimilation of remotely sensed soil moisture having greatest impact during drying-down. In the north of Ghana we are able to recover improved estimates of soil texture after data assimilation. However, we are unable to do so for the south. The significant reduction in unbiased root-mean-squared difference we find after assimilating a single year of observations bodes well for the production of improved land surface model soil moisture estimates over sub-Saharan Africa

Spectroscopy of ions using fast beams and ion traps

A knowledge of the spectra of ionized atoms is of importance in many fields. They can be studied in a wide variety of light sources. In recent years techniques coming under the broad heatings of fast beams and ion traps have been used extensively for such investigations. This article considers the advantages that various techniques have for particular applications

The FERRUM project: laboratory-measured transition probabilities for Cr II

Aims: We measure transition probabilities for Cr II transitions from the z ^4H_J, z ^2D_J, y ^4F_J, and y ^4G_J levels in the energy range 63000 to 68000 cm^{-1}. Methods: Radiative lifetimes were measured using time-resolved laser-induced fluorescence from a laser-produced plasma. In addition, branching fractions were determined from intensity-calibrated spectra recorded with a UV Fourier transform spectrometer. The branching fractions and radiative lifetimes were combined to yield accurate transition probabilities and oscillator strengths. Results: We present laboratory measured transition probabilities for 145 Cr II lines and radiative lifetimes for 14 Cr II levels. The laboratory-measured transition probabilities are compared to the values from semi-empirical calculations and laboratory measurements in the literature.Comment: 13 pages. Accepted for publication in A&

Beam-Foil Measurements of Singlet Levels in Bi IV and Some Newly-Assigned Levels in Bi V

Abstract The beam-foil technique has been used to measure the lifetimes of five levels in Bi IV and nine levels in Bi V, six of which are new assignments. Cascade correction has been applied to the analysis of the resonance levels 6s6p 'P, in Bi IV and 6p 2P,,2,3,2 in Bi V

Blackbody-radiation shift in a 88Sr+ ion optical frequency standard

The blackbody radiation (BBR) shift of the 5s - 4d_{5/2} clock transition in 88Sr+ is calculated to be 0.250(9) Hz at room temperature, T=300K, using the relativistic all-order method where all single and double excitations of the Dirac-Fock wave function are included to all orders of perturbation theory. The BBR shift is a major component in the uncertainty budget of the optical frequency standard based on the 88Sr+ trapped ion. The scalar polarizabilities of the 5s and 4d_{5/2} levels, as well as the tensor polarizability of the 4d_{5/2} level, are presented together with the evaluation of their uncertainties. The lifetimes of the 4d_{3/2}, 4d_{5/2}, 5p_{1/2}, and 5p_{3/2} states are calculated and compared with experimental values.Comment: 6 page

Calculations of parity nonconserving s-d transitions in Cs, Fr, Ba II, and Ra II

We have performed ab initio mixed-states and sum-over-states calculations of parity nonconserving (PNC) electric dipole (E1) transition amplitudes between s-d electron states of Cs, Fr, Ba II, and Ra II. For the lower states of these atoms we have also calculated energies, E1 transition amplitudes, and lifetimes. We have shown that PNC E1 transition amplitudes between s-d states can be calculated to high accuracy. Contrary to the Cs 6s-7s transition, in these transitions there are no strong cancelations between different terms in the sum-over-states approach. In fact, there is one dominating term which deviates from the sum by less than 20%. This term corresponds to an s-p_{1/2} weak matrix element, which can be calculated to better than 1%, and a p_{1/2}-d_{3/2} E1 transition amplitude, which can be measured. Also, the s-d amplitudes are about four times larger than the corresponding s-s transitions. We have shown that by using a hybrid mixed-states/sum-over-states approach the accuracy of the calculations of PNC s-d amplitudes could compete with that of Cs 6s-7s if p_{1/2}-d_{3/2} E1 amplitudes are measured to high accuracy.Comment: 15 pages, 8 figures, submitted to Phys. Rev.

The employee as 'Dish of the Day’:human resource management and the ethics of consumption

This article examines the ethical implications of the growing integration of consumption into the heart of the employment relationship. Human resource management (HRM) practices increasingly draw upon the values and practices of consumption, constructing employees as the ‘consumers’ of ‘cafeteria-style’ benefits and development opportunities. However, at the same time employees are expected to market themselves as items to be consumed on a corporate menu. In relation to this simultaneous position of consumer/consumed, the employee is expected to actively engage in the commodification of themselves, performing an appropriate organizational identity as a necessary part of being a successful employee. This article argues that the relationship between HRM and the simultaneously consuming/consumed employee affects the conditions of possibility for ethical relations within organizational life. It is argued that the underlying ‘ethos’ for the integration of consumption values into HRM practices encourages a self-reflecting, self-absorbed subject, drawing upon a narrow view of individualised autonomy and choice. Referring to Levinas’ perspective that the primary ethical relation is that of responsibility and openness to the Other, it is concluded that these HRM practices affect the possibility for ethical being

Light Element Abundances From z=0 To z=5

Plausible ratios of deuterium to hydrogen D/H as a function of metallicity, time, and redshift are investigated. Guided by the heavy element abundance patterns observed locally in Galactic dwarf stars and at large redshift in quasi-stellar object absorption line systems, empirical evolution of the relative abundance ratios Li/D, B/D, N/D, O/D, and F/D for QSO absorption line systems are given for the possible evolutionary patterns in D/H. Shortened abstract.Comment: 30 pages including 8 figures, ApJ in pres