排序方式： 共有5条查询结果，搜索用时 78 毫秒
1
1.
DAVID SWANLUND RAMONA MARAJ NADINE SCHUURMAN ROXANNE HOPE KATE DONKERS MATT AQUIN GWEN RICKERBY 《Geografiska Annaler: Series A, Physical Geography》2016,98(4):361-368
This study analyses GPS performance in Yukon's Arctic coast to inform future research that uses this technology in the region. To test this, Telonics GPS collars were placed on stakes during the summers of 2009 and 2010 throughout the region for varying lengths of time. The fix records produced by these collars were then collected and cleaned, leaving 30 samples. Using these records combined with a digital elevation model, eight variables were extracted and analysed in an attempt to find relationships, such that a fix rate could be predicted throughout the landscape. The results indicated that very few strong relationships existed. Densiometer values proved to be the only relationship between an environmental variable and fix rate. Available sky and aspect data produced results that were contrary to those expected. Overall, Telonics Generation 3 collars had extremely high fix rates, high accuracy, and low positional dilution of precision. Moreover, there was little variation in these results. This means that future GPS studies in the region would likely require minimal correction for fix rate bias. However, if corrections were to be made, more data would have to be gathered to ensure the results were statistically sound. The analysis suffered from the limitations of small sample size and low sample variance, among several others. Therefore, future studies should increase the number and diversity of sites tested. 相似文献
2.
Kiglapait Mineralogy I: Apatite, Biotite, and Volatiles 总被引：1，自引：2，他引：1
Electron microprobe analyses show that Upper Zone apatites inthe Kiglapait intrusion are fluorine rich and contain minorchlorine and hydroxyl (calculated). Apatite from the Outer BorderZone has a higher Cl content. The refractive indices of UZ apatites have the following ranges: = 1.6345–1.6379, = 1.6326–1.6352, and B = 0.0020–0.0028.The birefringence is low for apatites with these refractiveindices. Some Outer and Upper Border Zone apatites have higherindices of refraction and normal birefringence. Fractional crystallization of the basaltic Kiglapait magma producedcumulus apatite beginning at the 94 per cent solidified levelwhen P2O5 reached saturation in the liquid. The amounts of P2O5and modal apatite decreased gradually from the 94 per cent tothe 99.99 per cent solidified level as the liquid was depletedin P2O5. F and Cl appear to be equally partitioned between theliquid and apatite because no fractionation trends are notedbetween the two halogens. There is a slight decrease in thecalculated ratio OH/F in apatite which suggests possible depletionof OH in the liquid with fractionation. Kiglapait apatites appear to be stoichiometric, based on microprobechemistry, refractive index, and unit cell dimensions. However,infrared absorption analyses show no detectable water, whichleaves approximately 11 per cent of the monovalent anion siteunaccounted for. Anion deficiencies in apatites from low-H2Oenvironments may be explained either by substitution of O forF, or domains of tetracalcium phosphate. Non-cumulus biotite occurs in minor quantities in the intrusion.Electron microprobe analyses of Upper Zone biotites show thatthey contain an average (by weight) pf 0.4 per cent F, 0.07per cent Cl, and 4.0 per cent H2O (calculated). The volatile chemistry of the Kiglapait intrusion is calculatedfrom apatite and biotite chemistry. The intrusion contains anestimated 900 ppm P2O5, 166 ppm F, and 12 ppm Cl. There is amaximum of 68 ppm H2O using calculated H2O from microprobe data,or a minimum of 8 ppm using H2O from infrared analysis. It isproposed that the anhydrous basaltic Kiglapait magma was a secondpartial melt of amphibole-bearing mantle rock. 相似文献
3.
This study provides the first detailed estimate of riverine organic carbon fluxes in British rivers, as well as highlighting major gaps in organic carbon data in national archives. Existing data on organic carbon and suspended solids concentrations collected between 1989 and 1993, during routine monitoring by the River Purification Boards (RPBs) in Scotland and the National River Authorities (NRAs) in England and Wales, were used with annual mean flows to estimate fluxes of dissolved and particulate organic carbon (DOC and POC) in British rivers. Riverine DOC exports during 1993 varied from 7·7–103·5 kg ha−1 year−1, with a median flux of 31·9 kg ha−1 year−1 in the 85 rivers for which data were available. There was a trend for DOC fluxes to increase from the south and east to the north and west. A predictive model based on mean soil carbon storage in 17 catchments, together with regional precipitation totals, explained 94% of the variation in the riverine DOC exports in 1993. This model was used to predict riverine DOC fluxes in regions where no organic carbon data were available. Calculated and predicted fluxes were combined to produce an estimate for exports of DOC to tidal waters in British rivers during 1993 of 0·68±0·07 Mt. Of this total, rivers in Scotland accounted for 53%, England 38% and Wales 9%. Scottish blanket peats would appear to be the largest single source of DOC exports in British rivers. An additional 0·20 Mt of organic carbon were estimated to have been exported in particulate form in 1993, approximately two–thirds of which was contributed by English rivers. It is suggested that riverine losses of organic carbon have the potential to affect the long-term dynamics of terrestrial organic carbon pools in Britain and that rivers may regulate increases in soil carbon pools brought about by climate change. © 1997 by John Wiley & Sons, Ltd. 相似文献
4.
5.
1