Atmospheric and glow images from the Shuttle     

E. J. Llewellyn  I. C. McDade  M. R. Gale  D. J. W. Kendall  R. L. Gattinger  S. B. Mende  G. R. Swenson  W. S. C. Brooks 《Surveys in Geophysics》1987,9(2):149-168

The use of simple photographic cameras on early Shuttle missions allowed spacecraft glow to be clearly identified, and its potential for the contamination of weak atmospheric emissions to be estimated. Since those early flights the equipment has been extensively modified so that it is now possible to obtain images with a spectral resolution of 0.1 nm. The early Shuttle glow observations are reviewed and the use of spatially scanned filters to obtain spectral results is described. These glow measurements are discussed in terms of some current ideas for vehicle induced glows and it is suggested that the glow intensity may be controlled by the temperature of the glowing surface. An example of an atmospheric image obtained with the interference filter camera is presented and the limitations in the use of such images are discussed.  相似文献   

High population connectivity and Pleistocene range expansion in the direct-developing plough shell Bullia rhodostoma along the South African coast     

T Muteveri  CA Matthee  RCK Bowie 《African Journal of Marine Science》2015,37(1):21-31

Pleistocene climatic and oceanographic changes have influenced the distribution of marine biodiversity in southern Africa. Most evidence, however, has been derived from rocky shore or demersal taxa; data on sandy shore species are limited, despite severe threats to many sandy beach ecosystems. To test the effects of past climatic changes on sandy shore species, we sampled 140 smooth plough shell Bullia rhodostoma individuals from eight localities and generated phylogeographic data derived from the mtDNA cytochrome c oxidase subunit 1 (COI) marker. Nuclear markers (ATPSα, ATPSβ, ANT, SRPS4, TBP, LTRS and ZMP) showed no sequence variation. Bullia rhodostoma exhibited shallow genetic differentiation (Φ_ST = 0.07, p < 0.05) across its range. Isolation-by-distance suggests a stepping-stone model of migration, which is expected given the species’ direct-development life-history strategy. Demographic reconstruction suggests a post-LGM (Last Glacial Maximum) range expansion, concordant with the signal of shallow genetic differentiation. Phylogeographic patterns obtained suggest that, during lower sea levels than current, B. rhodostoma could have been restricted to the South-West Coast, the central Agulhas Bioregion and probably also the East Coast. When climatic conditions changed and temperatures began to rise after the LGM, the species began a rapid westward range expansion from these refugial regions.  相似文献   

Evidence and mechanisms for Appalachian Basin brine migration into shallow aquifers in NE Pennsylvania,USA   总被引：1，自引：1，他引：0  

Garth T. Llewellyn 《Hydrogeology Journal》2014,22(5):1055-1066

Multiple geographic information system (GIS) datasets, including joint orientations from nine bedrock outcrops, inferred faults, topographic lineaments, geophysical data (e.g. regional gravity, magnetic and stress field), 290 pre-gas-drilling groundwater samples (Cl–Br data) and Appalachian Basin brine (ABB) Cl–Br data, have been integrated to assess pre-gas-drilling salinization sources throughout Susquehanna County, Pennsylvania (USA), a focus area of Marcellus Shale gas development. ABB has migrated naturally and preferentially to shallow aquifers along an inferred normal fault and certain topographic lineaments generally trending NNE–SSW, sub-parallel with the maximum regional horizontal compressive stress field (orientated NE–SW). Gravity and magnetic data provide supporting evidence for the inferred faults and for structural control of the topographic lineaments with dominant ABB shallow groundwater signatures. Significant permeability at depth, imparted by the geologic structures and their orientation to the regional stress field, likely facilitates vertical migration of ABB fluids from depth. ABB is known to currently exist within Ordovician through Devonian stratigraphic units, but likely originates from Upper Silurian strata, suggesting significant migration through geologic time, both vertically and laterally. The natural presence of ABB-impacted shallow groundwater has important implications for differentiating gas-drilling-derived brine contamination, in addition to exposing potential vertical migration pathways for gas-drilling impacts.  相似文献