Physical parameters of the martian atmosphere

The following physical parameters have been computed from 0 to 200 km altitude; (1) pressure, (2) density (3), speed of sound, (4) density, (5) number density, (6) mean free path, (7) viscosity, (8) pressure scale, (9) mean particle velocity, (10) collisional frequency and (11) columnar mass.The Viking measurements have been used as input data. A critical comparison of the computed pressures and densities, is given, useful for future explorations.     

Groundwater overdraft vulnerability and environmental impact assessment in Arusha

A simple approach is proposed for identifying areas vulnerable to groundwater overdraft. The methodology utilizes GIS techniques to analyze and evaluate controlling factors in areas with little data. The proposed methodology was applied in Arusha. Water demand in Arusha Municipality and its environs has increased to about 5.3% annually since 1999. Groundwater levels have declined. The aquifer hydrogeological variables were evaluated for impact to potential groundwater overdraft by overlay and index techniques. The spatial distribution of overdraft vulnerability was discussed. The northwestern part of Arusha is the most vulnerable to overdraft and possible serious environmental impacts. The Loruvani area has the most potential for aquifer development due to its permeability, high recharge rate, massive aquifer thickness and low drawdown.     

Northward migration under a changing climate: a case study of blackgum (Nyssa sylvatica)

Species are predicted to shift their distribution ranges in response to climate change. Region-wide, empirically-based studies, however, are still limited to support these predictions. We used a model tree species, blackgum (Nyssa sylvatica), to study climate-induced range shift. Data collected from two separate sampling periods (1980s and 2007) by the USDA’s Forestry and Inventory Analysis (FIA) Program were used to investigate changes in abundance and dominance, and shifts in distribution, of blackgum in four ecoregions of the eastern United States. Our results indicated new recruitment of blackgum in the northern portion of its range, along with increases in both density and annual rates of change in importance value (IV). Conversely, declines in recruitment were found in the southern portion of blackgum’s range, along with decreases in density and IV. The center portion of blackgum’s range had mixed patterns of change (i.e., both increases and decreases) throughout. A northward range expansion was also detected by comparing blackgum’s historic range to where it was detected during our two more-recent sampling periods. Our findings suggest that blackgum is migrating north in response to climate change. Our study also suggests two broader implications about tree migration patterns in response to climate change: (1) species can respond to changing climate in relatively short time periods, at least for generalist species such as blackgum, and (2) climate-induced vegetation dynamic patterns can be detected at the regional level, but are inherently complex.     

Four new species of the lanternfish genus Diaphus (Myctophidae) from the Indo‐Pacific

Four new species of the genus Diaphus are described. Three of these are in the subgeneric group with a suborbital luminous organ and are members of the D. fulgens species group with a raised AOa₁ photophore. D. impostor sp. nov. from the Indo‐West Pacific is most similar to D. aliciae, differing in lower gill raker count and smaller size. D. wisneri sp. nov. from north of Hawaii and south Pacific lacks a luminous scale at the PLO and has a lower gill raker count than similar species. D. kora sp. nov. from north‐east of New Zealand has a large luminous scale at the PLO, and a longer Vn and lower gill raker counts than similar species. D. kapalae sp. nov. from the south‐western Pacific is most similar to D. splendidus and D. antonbruuni, from which it differs by the presence of an Ant, higher gill raker counts, and position of the VLO photophore.     

Velocity measurements in the East Auckland Current north‐east of North Cape,New Zealand

Flow in the East Auckland Current (EAUC) system to the north‐east of North Cape, New Zealand is examined using data from two current meter mooring arrays, with supporting data from conductivity/temperature/depth (CTD) and satellite altimetry. Variable currents up to 45 cm s_–1 were observed. The variability was partly attributable to changes in position and strength of the North Cape Eddy whose centre lies some 150 km offshore. The observed flows across the mooring line correlate well with those estimated from satellite altimetry. This gives confidence in the use of the satellite data to estimate the transport variability in the EAUC in the 1992–2001 period. No seasonal cycle was found in the volume transports but rather broadband variability at periods longer than 100 days.     

Antarctic Intermediate Water variability in the northern New Zealand region

In the region between 30°S and northern New Zealand, vertical salinity profiles through the core of the Antarctic Intermediate Water (AAIW) show a high degree of spatial and temporal variability, and this variability is much larger than that found in nearby ocean areas. Characteristic features are interleaving of salinity layers and large changes in the salinity minimum between adjacent stations. Quantifying the changes through the calculation of an intrusion index highlights the degree of variability and the importance of boundary mixing along the New Zealand slope. However, the main cause of the variability is the meeting and mixing of higher salinity AAIW, arriving from the north‐west (having travelled around the subtropical gyre) with lower salinity AAIW arriving by more direct entry from the north‐east. These waters meet in the region through the action of the meso‐scale eddy field. Present data indicate that where strong salinity interleaving occurs, the length scales are of the order of 10 km and the time scales are of the order of a few days. Resolution of the processes at work will require studies on finer scales than presently available.