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71.
Pauline Barmby Kathryn M. Perrett Terry J. Bridges 《Monthly notices of the Royal Astronomical Society》2002,329(2):461-464
The M31 globular cluster candidate has long been known to be an extremely red, non-stellar object. The first published spectrum of this object is used to confirm that it is a globular cluster belonging to M31, with rather typical values of and . Using the spectroscopic metallicity to predict the intrinsic colours, we derive a reddening value of , in good agreement with the value obtained using reddening-free parameters. The extinction-corrected magnitude of is (absolute magnitude , which makes it the most luminous globular cluster in M31. We examine van den Bergh's argument regarding the brightest and most-reddened globular cluster in M31; we find that the brightest clusters are more heavily reddened than average, but this can be explained by selection effects rather than a different R V in M31. 相似文献
72.
Water budget management of a coastal pine forest in a Mediterranean catchment (Marina Romea, Ravenna, Italy) 总被引:1,自引:1,他引:0
Pauline N. Mollema Marco Antonellini Giovanni Gabbianelli Emanuele Galloni 《Environmental Earth Sciences》2013,68(6):1707-1721
In Mediterranean coastal catchments, water management for preservation of pine forests and other natural areas faces particular challenges. Limited rainfall, water consumption by vegetation as well as subsidence, drainage and salt water intrusion all play an important role. Traditionally forest and water management are carried out independent of one another and do not consider water budget calculations. We show with this study that is very important to have quantitative information of all the components of the water budget as well as the size of the fresh water lenses in the aquifer to be able to integrate the water- and forest management. We use an integrated hydrologic-ecologic methodology based on easily attainable data to assess the monthly water budget of a coastal catchment, Marina Romea (Ravenna, Italy). We present detailed monthly water table records, rainfall data, drainage data, tree density and tree perimeter and use published sap flow measurements of single pine trees (Pinus Pinea) to quantify the actual transpiration of single pine trees in different periods of the year. Transpiration amounts to 10–30 l per day per tree. These values are confirmed by independent estimates of tree transpiration based on our water budget calculations: 9–34 l/tree/day. Because typically there are so many trees in planted pine forests, the total transpiration rates over the whole watershed take up a large percentage (up to 200 %) of the precipitation. In Marina Romea, four monitoring periods out of twelve, the tree transpiration is larger than precipitation. In nine monitoring periods, drainage in the watershed is larger than precipitation or tree water transpiration. The measurements and calculations show that not much freshwater is left to recharge the fresh water lens underneath Marina Romea. Monthly monitoring of groundwater table elevation and salinity in the pine forest of Marina Romea from March 2007 to February 2008 shows that the groundwater table strongly fluctuates and groundwater salinity is constantly very high (up to 17.7 g/l). Analytical calculations based on the Ghyben Herzberg Dupuit principle suggest that even a small continuous annual recharge of 15 mm could form a 2-m deep freshwater lens in the unconfined aquifer. This freshwater lens is not present in the study area and this is due to the fact that tree water transpiration and drainage take out most of the fresh water coming into the watershed. In catchments like Marina Romea, water consumption by the (natural) vegetation and seasonal differences as well as the fact that fresh water lenses are limited in salty surroundings should be taken into account in water and forest management. 相似文献
73.
Climate and water budget change of a Mediterranean coastal watershed, Ravenna, Italy 总被引:2,自引:0,他引:2
Pauline Mollema Marco Antonellini Giovanni Gabbianelli Mario Laghi Valentina Marconi Andrea Minchio 《Environmental Earth Sciences》2012,65(1):257-276
It is generally difficult to quantify exactly the freshwater going in or out of the coastal watersheds along the northern
Adriatic Sea because, on one hand, excess water is drained and pumped into the sea to prevent flooding but, on the other hand,
water is brought onto the land from far away for irrigation. Fragmentation of water authorities makes it difficult to collect
all the necessary information. Climate change and increasing salinization of the coastal aquifers make it imperative, however,
to better know the quantities of freshwater involved in these small basins. The water budget of a small coastal agricultural
watershed along the Adriatic Sea in Italy (The Quinto Basin near Ravenna) is presented here considering different land uses.
The evaporation of open water and the evapotranspiration of wetlands, pine forests, bare soil and irrigated agriculture are
calculated based on the Penman–Monteith equation and the Cropwat program. The current water budget is based on average climate
data from 1989 to 2008 and drainage and irrigation data. Predictions for future evapotranspiration, net irrigation and hydrologic
deficit are calculated with climate data from IPCC (The Fourth Assessment Report (AR4) 200, Climate change 2007). From the study results, the soil type may determine whether or not a crop will need more or less irrigation in the future.
Regulations on land use should therefore consider which crop type can be grown on a specific soil type. Water budget analysis
in scenarios A1b and A2 both show an increase of water deficits in the summer and an increase of water surplus in the winter.
This is explained by the fact that a larger percentage of the rain will fall in winter and not during the growth season. The
open water evaporation will decrease under future climate scenarios as a result of increased relative humidity in winter and
decreased wind velocity. This may have a positive effect on the water cycle. The current irrigation is very abundant, but
has beneficial effects in contrasting soil salinization and saltwater intrusion into the coastal aquifer. 相似文献
74.
75.
In Lorraine, flooding of the iron mines leads to a degradation of groundwater quality. Based on a global approach, a numerical simulator has been built that can reproduce and predict the evolution of water quality at the overflow point of the mining basin. In order to specify the spatial distribution of these pollutant concentrations, a new model has been developed. The basin is represented as a network of homogeneous reservoirs. Although encouraging, the results show the need to specify the spatial organisation of water flow in order to reproduce the pollutant concentrations in the different monitored wells. To cite this article: P. Collon et al., C. R. Geoscience 337 (2005). 相似文献
76.
77.
Subaerial river bank erosion processes and their interaction with other bank erosion mechanisms on the River Arrow,Warwickshire, UK 总被引:1,自引:0,他引:1
River bank erosion occurs primarily through a combination of three mechanisms: mass failure, fluvial entrainment, and subaerial weakening and weathering. Subaerial processes are often viewed as ‘preparatory’ processes, weakening the bank face prior to fluvial erosion. Within a river basin downstream process ‘domains’ occur, with subaerial processes dominating the upper reaches, fluvial erosion the middle, and mass failure the lower reaches of a river. The aim of this paper is to demonstrate that (a) subaerial processes may be underestimated as an erosive agent, and (b) process dominance has a temporal, as well as spatial, aspect. Bank erosion on the River Arrow, Warwickshire, UK, was monitored for 16 months (December 1996 to March 1998) using erosion pins. Variations in the rate and aerial extent of erosion are considered with reference to meteorological data. Throughout the first 15 months all erosion recorded was subaerial, resulting in up to 181 mm a?1 of bank retreat, compared with 13 to 27 mm a?1 reported by previous researchers. While the role of subaerial processes as ‘preparatory’ is not contended, it is suggested that such processes can also be erosive. The three bank erosion mechanisms operate at different levels of magnitude and frequency, and the River Arrow data demonstrate this. Thus the concept of process dominance has a temporal, as well as spatial aspect, particularly over the short time‐periods often used for studying processes in the field. Perception of the relative efficacy of each erosive mechanism will therefore be influenced by the temporal scale at which the bank is considered. With the advent of global climate change, both these magnitude–frequency characteristics and the consequent interaction of bank erosion mechanisms may alter. It is therefore likely that recognition of this temporal aspect of process dominance will become increasingly important to studies of bank erosion processes. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
78.
79.
Maricar Prudente Shinsuke Tanabe Mafumi Watanbe Annamalai Subramnian Nobuyuki Miyazki Pauline Suarez Ryo Tatsukawa 《Marine environmental research》1997,44(4):415-427
Concentrations of persistent organochlorines were determined in the blubber and melon of 11 species of adult male odontocetis collected from the North Pacific, Indian Ocean and nearby seas. Mean concentrations of DDs (33 μg/g wet wt) were the highest followed by PCBs (32 μg/g wet wt), chlordane compounds (CHLs: 3.7 μg/g wet wt), HCHs (1.1 μg/g wet wt), and HCB (0.32 μg/g wet wt). Odontoceti species inhabiting temperate waters revealed maximum residual concentrations of these contaminants, and the elevated DDT and PCB residues detected seem to suggest that some of the present species might potentially be at high risk. Relatively high DDT concentrations were found in tropical water species, which could be attributed to the current usage of DDT in the tropics and the less movable nature of this compound via long-range atmospheric transport. The HCH levels in animals inhabiting cold and temperate waters were higher than those inhabiting tropical waters, a result that was perhaps reflective of atmospheric transport from the tropical source to the northern sinks. A similar pattern was also observed in PCBs, CHLs and HCB, probably indicating the ongoing discharge of these compounds from mid-latitudes as well as those originating in tropical regions. 相似文献
80.
S. Mahesh Srikanta Murthy K. Pauline Sabina Shinjini Saran Vikram Partap Singh 《Journal of the Geological Society of India》2016,87(2):132-144
The present work deals with the palaeoenvironment and depositional setting of the subsurface sediments from bore hole RT-4 of Tamra block from Raniganj coalfield of Damodar Basin, India. Nineteen shale samples were subjected to palynological and coal petrographical analyses. On the basis of botanical affinity between the miospores and the parent plants as well as the different plant groups, each coal plant assemblage was determined. The dominance of bisaccates such as Scheuringipollenites, Faunipollenites (=Protohaploxypinus), Striatopodocarpites and presence of monosaccates such as Densipollenites, Parasaccites reflect a peat forming community composed mainly of gymnosperms. Subordinate trilete spores derived from filicopsids (Cyclogranisporites, Horriditriletes, Brevitirletes, Callumispora, Microbaculsispora, Microfoveolatispora, Cyclobaculisporites), lycopsids (Indotriradites, Gondispoirtes and Didecitriletes) and sphenopsids (Laevigatosporites ) are less abundant occurring in variable proportions reflecting a hypautocthonous taphocenose. Presence of Botryococccus algae has been recorded. Palynofacies and petrographic analyses suggest deposition in open mires in a Limnic to limno-telmatic conditions with intermittent flooding of the site. 相似文献