Airglow from Jupiter's nightside and crescent: Ultraviolet spectrometer observations from Voyager 2

The Voyager Ultraviolet Spectrometer has made extensive observations of airglow from Jupiter's dark-side equatorial latitudes. The brightness of H Lyman α (Lyα), the only emission detected, varies between 700 and 1000 rayleighs (R) as a function of lungitude. The dark side of Jupiter is illuminated by sky background Lyα arising from resonance scattering of the solar Lyα line by the neutral hydrogen of the interstellar medium. Calculations show that resonance scattering of this sky background by hydrogen in Jupiter's thermosphere will produce about 300 R of Lyα emission. The additional Lyα observed is probably excited by electrons and protons precipitating at equatorial latitudes. Based on the 500-R upper limit set here on the dark-side H₂ Lyman and Werner bands, and the Lyα measurements, the exciting particles are thought to have a soft energy spectrum and deposit about 0.04 erg cm^?2 sec^?1 in the atmosphere. There is evidence for an asymmetrical precipitation pattern associated with the longitudinal variation in Ly α emission, and a suggestion of a strong day-night difference in precipitation as well.     

The Hard X-ray Imaging Spectrometer (HXIS)

The HXIS, a joint instrument of the Space Research Laboratory at Utrecht, The Netherlands, and the Department of Space Research of the University of Birmingham, U.K., images the Sun in hard X-rays: Six energy bands in energy range 3.5–30 keV, spatial resolution 8 over Ø 240 and 32 over Ø 624 field of view, and time resolution of 0.5–7 s depending on the mode of operation. By means of a flare flag it alerts all the other SMM instruments when a flare sets in and informs them about the location of the X-ray emission. The experiment should yield information about the position, extension and spectrum of the hard X-ray bursts in flares, their relation to the magnetic field structure and to the quasi-thermal soft X-rays, and about the characteristics and development of type IV electron clouds above flare regions.     

Principal Modes and Related Frequencies of Sea Surface Temperature Variability in the Pacific Coast of North America

We examined monthly time-series (1950 to 1999) of sea surface temperature (SST) anomalies in 47 quadrants (2° × 2°) along the Pacific coast of North America. Correlation, clustering and principal components analyses were applied to identify the spatial structure in coastal SST. The resulting modes and the individual series were investigated using spectral analysis to identify the most significant time-scales of variability, and the propagation of the main signals was explored by computing the wavenumber-frequency spectrum of each spatial mode. Results showed that coastal SST variability in the northeast Pacific conformed to three main geographical modes. A tropical mode extends from the equator to about the entrance to the Gulf of California. This mode appears related to two low frequency components of the El Niño-Southern Oscillation of about 3 and 5 years. The SST anomaly related to these signals propagates poleward, seemingly at low speeds (≈0.08 m s^?1). A temperate (or transitional) mode, which includes the coastal areas along the California Current System, also shows the 5-year signal plus a decadal-scale component (periods between 10–17 years). Finally, a subarctic mode includes the coastal areas along the Gulf of Alaska and is dominated by the interdecadal variability that is characterized by the Pacific Decadal Oscillation.     

Mind mapping as an interactive tool for engaging complex geographical issues

Students and communities engaging with complex geographical issues require tools to assist them structure and contextualise data. This paper examines the use of mind mapping as a tool in geographical education. Case studies are presented from a sample of undergraduate and cross-cultural educational settings demonstrating the use of mind mapping in communication, analysis and problem solving. In critiquing this educational tool, we conclude that mind mapping is particularly effective with communities whose cultures are strong on visual communication but weaker on written communication and in cross-cultural situations where use of written English would disadvantage learners.     

Interactive effects of iron,irradiance and CO2 on Ross Sea phytoplankton

We conducted a factorial shipboard continuous culture experiment to examine the interactive effects of altered iron, irradiance and CO₂ on the summer phytoplankton community of the Ross Sea, Antarctica. After 18 days of continuous incubation, iron enrichment increased phytoplankton biomass, nutrient drawdown, diatom and Phaeocystis abundance, and some photosynthetic parameters. High irradiance significantly increased the number of Phaeocystis antarctica colonies, as well as P. antarctica abundance relative to diatoms. Iron and light had significant interactive effects on diatom and P. antarctica pigment concentrations, P. antarctica colony abundance, and Si:N, Si:C, and N:P ratios. The major influence of high CO₂ was on diatom community structure, by favoring the large centric diatom Chaetoceros lineola over the small pennate species Cylindrotheca closterium. The ratio of centric to pennate diatoms was significantly responsive to changes in all three variables individually, and to all of their possible two- and three-way combinations. These results suggest that shifts in light, iron, and CO₂ and their mutual interactions all play a role in controlling present day Ross Sea plankton community structure, and need to be considered when predicting the possible future responses of biology and biogeochemistry in this region.     

Development of a three‐dimensional watershed modelling system for water cycle in the middle part of the Heihe rivershed,in the west of China

A three‐dimensional numerical modelling system is developed to study transformation processes of water resources in alluvial fan and river basin along the middle reaches of the Heihe River Basin, Northwest China, an arid and semi‐arid region. Integrating land utilization, remote sensing and geographic information systems, we have developed a numerical modelling system that can be used to quantify the effects of land use and anthropogenic activities on the groundwater system as well as to investigate the interaction between surface water and groundwater. Various hydraulic measurements are used to identify and calibrate the hydraulic boundary conditions and spatial distributions of hydraulic parameters. In the modelling study, various water exchanges and human effects on the watershed system are considered. These include water exchange between surface water and groundwater, groundwater pumping, lateral water recharges from mountain areas, land utilization, and infiltration and evaporation in the irrigation and non‐irrigation areas. The modelling system provides a quantitative method to describe spatial and temporal distributions and transformations between various water resources, and it has application to other watersheds in arid and semi‐arid areas. Copyright © 2011 John Wiley & Sons, Ltd.