A historical review and assessment of urban heat island research in Singapore

This historical review of 20 studies since the 1960s examines the influence of urban development on the thermal environment in Singapore, a fast growing tropical island city‐state. Past observations are critically assessed with regard to experimental controls and station metadata. Given the availability of historical climate and developmental data spanning almost 50 years, changes in urban heat island (UHI) intensity and spatial coverage can be traced temporally. Rapid urban expansion in Singapore is clearly reflected in spatially and temporally changing air and surface temperature patterns. The nocturnal canopy‐layer UHI intensity – measured as the difference between the commercial urban core and undeveloped areas close to primary or secondary rainforests for example – doubled in magnitude between 1965 and 2004. At the same time, the spatial extent of the nocturnal UHI has also expanded with the development of new housing and industrial districts. The influence of the growing city is also reflected in surface temperature. Two satellite images dated 13 years apart demonstrate the encroachment of areas with high surface temperatures into previously cooler areas during daytime corresponding with new public housing estates and low‐rise residential areas or facilities being built. The results from our study contribute to the growing body of tropical heat island research. They provide baseline data for future research and urban development in the Singapore context and, more generally, offer important cues for urban planners to make tropical cities more sustainable.     

Locating the Pc 1 generation region by a statistical analysis of ground based observations

A statistical study using data from four geomagnetic recording stations with McIlwain parameters from L = 2.5 to 6.6, suggests that the general source location of Pc 1 micropulsations lies close to the plasmapause.For each station a contour plot of the number of Pc 1 events occurring at specific K_p, and LT intervals is constructed and a curve representing the plasmapause being overhead at this station is superimposed. The relative positions of the plasmapause curve and the contour maxima are taken to indicate the position of the Pc 1 source location.     

Perturbation of a satellite orbiter by the oblateness of the primary planet

The perturbation of an orbiter around a large satellite of a giant planet (Jupiter, Saturn, Uranus or Neptune) produced by the oblateness of the planet is investigated. The perturbing force of theJ ₂-term (general case) and theJ ₄-term (special case of small eccentricity and inclination) is expanded in an appropriate form and the main term and the parallactic term are given explicitly. The variations of the orbital elements are derived using the stroboscopic method. An example shows that the perturbation of the orbit cannot be neglected.     

Lunar cartography with the Apollo 17 Alse radar imagery

Lunar position differences between thirteen lunar craters in Mare Serenitatis were computed from VHF radar-imagery obtained by the Lunar Sounder instrument flown on the Apollo 17 Command Module. The radar-derived position differences agree with those obtained by conventional photogrammetric reductions of Apollo metric photography. This demonstrates the feasibility of using the Apollo Lunar Sounder data to determine the positions of lunar features along the Apollo 17 orbital tracks. This will be particularly useful for western limb and farside areas, where no Apollo metric camera pictures are available.This paper presents the results of one phase of research carried out at the Jet Propulsion Laboratory, California Institute of Technology, under Contract No. NAS 7-100, sponsored by the National Aeronautics and Space Administration.     

Stress orientations found in north-east Germany differ from the West European trend

Knowledge about the acting stresses is of crucial importance for understanding the tectonics of a region. Data about the stress field in north-eastern Germany used to be very rare. In general, it was assumed that the orientation of the larger horizontal principal stress (S_H) is similar to that found for western Germany and central West-Europe, i.e. NW–SE. To check this, several borehole logs of the late 1980s were analysed for information on the principal horizontal stress orientations: they include Four-Arm-Dipmeter and borehole televiewer data from 15 boreholes. The depth range of our stress results reaches from 1500 to 6700 m. They were compared to a few other data, especially from hydraulic fracturing, and to recent findings on the stresses in the Northwest German basin. In contrast to expectation, S_H derived from breakout orientations below the salt layers displayed N to NE orientation. The latter was found at 10 locations spread over the NE-German basin from Berlin to the Baltic sea, from the Polish border to the former border between East and West Germany. Moreover, this stress rotation in the subsaline formations seems to be the continuation of a trend found in the NW German basin.     

On wind shear at fronts and inversions

Summary In the past, experimental investigations as well as theoretical considerations have shown that within fronts and inversions wind shear and vertical temperature gradient adjust in such a way that the Richardson number is at its critical value. Results from aircraft measurements now suggest that the shear within moving cold fronts, warm fronts and inversions shows different behaviour because of the different mechanisms controlling the Richardson numbers. This leads to higher Richardson numbers, and therefore to lower amounts of wind shear within moving cold fronts when compared to warm fronts and inversions.With 9 Figures     

Beobachtungen an künstlichen Forellenlaichgruben

Ohne Zusammenfassung     

Toward green cartography & visualization: a semantically-enriched method of generating energy-aware color schemes for digital maps

ABSTRACT

We introduce a semantically-enriched method of generating color schemes for various types of digital maps that reduces the energy consumption of the display device while preserving the quality of the original design. Energy-aware design intersects two important trends in cartography. First, as more maps are viewed today on mobile, battery life has become a central constraint influencing design. Second, there is increasing need for green computing, which encourages the efficient use of energy to limit environmental impacts. This paper focuses on one important aspect of energy-aware cartography: color design. Existing research on energy-aware color adjustment methods apply broadly to images or websites. However, the colors used in maps have more structured semantic relationships than most documents viewed on mobile devices, and efforts to account for these relationships while reducing energy consumption are limited. To fill this gap, we mathematically formalize energy-aware map-color adjustment as a constrained optimization problem: we define energy consumption as the objective function and model the preservation of semantic relationships as the search constraints. We evaluate our proposed method against a common color dimming method using four maps with different semantic relationships. The evaluation suggests that our proposed method better preserves the original color semantics.     

Tracing the history of submarine hydrothermal inputs and the significance of hydrothermal hafnium for the seawater budget—a combined Pb-Hf-Nd isotope approach

Secular variations in the Pb isotopic composition of a mixed hydrogenous-hydrothermal ferromanganese crust from the Bauer Basin in the eastern Equatorial Pacific provide clear evidence for changes in hydrothermal contributions during the past 7 Myr. The nearby Galapagos Rise spreading center provided a strong hydrothermal flux prior to 6.5 Ma. After 6.5 Ma, the Pb became stepwise more radiogenic and more similar to Equatorial Pacific seawater, reflecting the westward shift of spreading to the presently active East Pacific Rise (EPR). A second, previously unrecognized enhanced hydrothermal period occurred between 4.4 and 2.9 Ma, which reflects either off-axis hydrothermal activity in the Bauer Basin or a late-stage pulse of hydrothermal Pb from the then active, but waning Galapagos Rise spreading center.Hafnium isotope time-series of the same mixed hydrogenous-hydrothermal crust show invariant values over the past 7 Myr. Hafnium isotope ratios, as well as Nd isotope ratios obtained for this crust, are identical to that of hydrogenous Equatorial Pacific deep water crusts and clearly indicate that hydrothermal Hf, similar to Nd, does not travel far from submarine vents. Therefore, we suggest that hydrothermal Hf fluxes do not contribute significantly to the global marine Hf budget.