Wave-tide interaction modulates nearshore wave height     

Lewis  Matt J.  Palmer  Tamsin  Hashemi  Resa  Robins  Peter  Saulter  Andrew  Brown  Jenny  Lewis  Huw  Neill  Simon 《Ocean Dynamics》2019,69(3):367-384

Ocean Dynamics - The combined hazard of large waves occurring at an extreme high water could increase the risk of coastal flooding. Wave-tide interaction processes are known to modulate the wave...  相似文献   

A Holocene record of climate,vegetation change and peat bog development,east Otago,South Island,New Zealand     

Matt S. Mcglone  Janet M. Wilmshurst 《第四纪科学杂志》1999,14(3):239-254

A Holocene record of pollen, macrofossils, testate amoebae and peat humification is presented from a small montane bog. Sediment accumulation began before 9000 yr BP, but peat growth not until ca. 7000 BP. From 12 000 to 7000 yr BP, a shrub–grassland dominated under a dry climate, with increasing conifer forest and tall scrub from ca. 9600 yr BP. At 7000 yr BP a dense montane–subalpine low conifer forest established under a moist, cool climatic regime. Between 7000 and 700 yr BP the bog surface was shrubby, tending to be dry but with highly variable surface wetness. The catchment was affected by major fire at least four times between 4000 and 1000 yr BP. Both fire and bog surface wetness may have been linked to ENSO-caused variations in rainfall. Cooler, cloudier winters and disturbance by fire promoted the expansion of the broadleaf tree Nothofagus menziesii between 4000 yr BP and 1300 yr BP at the expense of the previous conifer forest–scrub vegetation. Polynesian fires (ca. 700 yr BP) reduced the vegetation to tussock grassland and bracken. Deforestation did not markedly affect the hydrology of the site. European pastoralism since ad 1860 has increased run-off and rising water tables in the bog have led to a Sphagnum-dominated cover. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

Estimating past leaf-to-air vapour pressure deficit from terrestrial plant δ13C     

Chris S. M. Turney  James Barringer  John E. Hunt  Matt S. McGlone 《第四纪科学杂志》1999,14(5):437-442

δ¹³C was determined in lignin extracted from present-day cladodes of Phyllocladus alpinus (a small coniferous tree) from seven well-lit sites across New Zealand. The δ¹³C values ranged from −30.9‰ to −23.6‰ and were compared with monthly means of temperature, precipitation, relative humidity and vapour pressure deficit from the nearest recording stations. Of these parameters, the leaf-to-air vapour pressure deficit of the first month of cladode growth and expansion proved to be the most significantly correlated with lignin δ¹³C, over a range of 0.3 to 0.8 kPa, confirming the importance of atmospheric moisture content on stomatal conductance. The carbon isotopic signature of lignin from fossilised cladodes preserved under the Kawakawa Tephra (22.6 k ¹⁴C yr BP) on the North Island is identical to that of the whole tissue, suggesting that for this species at least, fossil material can be used to approximate the lignin δ¹³C. The δ¹³C of species- and organ-specific fossil terrestrial plant material therefore provides an excellent method to quantify past changes in leaf-to-air vapour pressure deficit. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

The relationship between radio luminosity and black hole mass in optically selected quasars     

Ross J. McLure  Matt J. Jarvis 《Monthly notices of the Royal Astronomical Society》2004,353(4):L45-L49

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Polarization signatures of strong gravity in active galactic nuclei accretion discs     

M. Dov&#;iak  V. Karas  G. Matt 《Monthly notices of the Royal Astronomical Society》2004,355(3):1005-1009

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Environmental Stewardship in UK agriculture: A comparison of the environmentally sensitive area programme and the Countryside Stewardship Scheme in South East England   总被引：1，自引：0，他引：1  

Matt Lobley  Clive Potter 《Geoforum》1998,29(4):413-432

Research into the adoption of Environmental Land Management Schemes (ELMS) has typically sought to identify the defining characteristics of participants and the ‘barriers to entry’ that dissuade others from joining. More recently, attention has focused on the motivation of participants and non-participants in helping to understand patterns of participation. This paper compares the pattern of participation in two distinct schemes operating in South East England. Indirect evidence suggests that scheme design and implementation is influencing the type of farmer joining and their motivation for doing so. Results from a survey of farmers also support the idea that the schemes are recruiting from different sections of the farming community. ESA farmers are largely motivated by financial gain, whereas those enrolling land in the Countryside Stewardship Scheme have more clearly defined conservation motives. Although there is also a ‘core’ of resistant non-participants, further changes to the design and delivery of policy could encourage a large number of ‘potential enrolers’ to join.  相似文献   

BeppoSAX observations of GRS 1915+105.     

Giorgio Matt  Enrico Costa  Marco Feroci  Tomaso Belloni  Marco Tavani 《New Astronomy Reviews》1998,42(9-10)

Results from a BeppoSAX observational campaign on GRS 1915+105, performed in October/November 1996, are presented. The source was observed 10 times (nine 10 ksec snapshots, one 100 ksec long observation). The broad band spectral analysis reveals a complex spectrum, including Compton reflection and an iron emission line, probably originating from a relativistic disc.  相似文献   

On the nature of the X-ray absorption in the Seyfert 2 galaxy NGC 4507     

A.Comastri  C.Vignali  M.Cappi  G.Matt  R.Audano  H.Awaki  S.Ueno 《Monthly notices of the Royal Astronomical Society》1998,295(2):443-450

We present results of the ASCA observation of the Seyfert 2 galaxy NGC 4507. The 0.5–10 keV spectrum is rather complex and consists of several components: (i) a hard X-ray power law heavily absorbed by a column density of about 3-10²³ cm⁻², (ii) a narrow Fe Kα line at 6.4 keV, (iii) soft continuum emission well above the extrapolation of the absorbed hard power law and (iv) a narrow emission line at ∼0.9 keV. The line energy, consistent with highly ionized neon (Ne IX ), may indicate that the soft X-ray emission is derived from a combination of resonant scattering and fluorescence in a photoionized gas. Some contribution to the soft X-ray spectrum from thermal emission, as a blend of Fe L lines, by a starburst component in the host galaxy cannot be ruled out with the present data.  相似文献   

Spatial and seasonal distribution of adult Oithona similis in the Southern Ocean: Predictions using boosted regression trees     

Matt H. Pinkerton  Adam N.H. Smith  Ben Raymond  Graham W. Hosie  Ben Sharp  John R. Leathwick  Janet M. Bradford-Grieve 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(4):469-485

We applied a multivariate statistical modelling technique called boosted regression trees to derive relationships between environmental conditions and the distribution of the adult stage of the cyclopoid copepod Oithona similis in the Southern Ocean. Nearly 20 000 samples from the Southern Ocean Continuous Plankton Recorder survey (87% from East Antarctica) were used to model the probability of detection (presence) and relative abundance of adults of this zooplankton species in surface waters. We demonstrate that it is possible to obtain reasonable models for both the presence (area under the Receiver Operating Characteristic curve of 0.77) and relative abundance (28–35% variance explained) of adult O. similis between November and March in much of the Southern Ocean. No investigation was possible where the environmental characteristics were not well represented by the SO-CPR dataset, namely, the Argentine shelf, Weddell Sea, and the frontal region north of the Amundsen Sea, or under sea-ice. Our analyses support the hypothesis that adult O. similis abundance is related to environmental conditions in a broadly similar way throughout the Southern Ocean. Compared to a compilation of net-haul data from the literature, the abundance model explained 34% of the variance in surface concentrations of adult stages of this species, and 23–59% of the variance in depth-integrated abundance of copepodite and adult stages combined. The models show higher occurrence and elevated abundances in a broad circumpolar band between the Antarctic Polar Front and the southern boundary of the Antarctic Circumpolar Current (approximately 54–64°S). Evidence of diel vertical migration by adults of this species north of 65°S was found, with surface abundances 20% higher at night than during the day. There was no evidence of diel migration south of 65°S. Five potential “hotspots” of adult O. similis were identified: in the southern Scotia Sea, two areas off east Antarctica, in the frontal zone north of the Amundsen Sea, and a small area in the outer Bellingshausen Sea. We recommend that a database of all available net-haul data on Oithona similis in the Southern Ocean be created to facilitate further investigations on the circumpolar distribution of this species.  相似文献   

Developing a beam trawl for sampling estuarine fish and crustaceans: assessment of a codend cover and effects of different sizes of mesh in the body and codend     

Rotherham  Douglas; Broadhurst  Matt K.; Gray  Charles A.; Johnson  Daniel D. 《ICES Journal of Marine Science》2008,65(4):687-696

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