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1.
A coupled deterministic hydrological and water temperature model, CEQUEAU, was modified to include soil temperature and crown closure in its calculation of local advective terms in the heat budget. The modified model was than tested to verify its sensitivity to these modifications. An analysis of the heat budget of a small forested catchment in eastern Canada revealed that the advective term related to interflow plays a significant role in the daily water heat budget, providing on average 28% of the local advective budget (which also includes advective heat terms from surface runoff and groundwater) and nearly 14% of the total heat budget (which includes all radiative terms at the water surface, convection and evaporation, as well as the local advective terms). Relative sensitivity indices (RSIs) were used to verify the impact of the newly introduced parameters and variables. Among them, parameters related to the forest cover (crown closure and leaf area index) have a maximum RSI of ?0·6; i.e. a 100% increase in value produces a 60% decrease in the local advective term. Parameters with the greatest influence are the volume of water contributing to interflow and the amplitude of the net radiative flux at the soil surface, which, if doubled, would double the contribution of the local interflow advective term to the heat budget. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
2.
Combining indicator trends to assess ongoing changes in exploited fish communities: diagnostic of communities off the coasts of France 总被引:1,自引:1,他引:1
3.
We have investigated a well-ordered sample of natural Cr-bearing dickite from Nowa Ruda (Lower Silesia, Poland) using electron
paramagnetic resonance (EPR) at X- and Q-band frequencies (9.42 and 33.97 GHz, respectively) and optical diffuse reflectance
spectroscopy. The observation of the spin-forbidden transitions at 15500 and 14690 cm−1 allows us to unambiguously identify the major contribution of octahedrally coordinated Cr3+ ions in the optical spectrum. The X- and Q-band EPR spectra show two superposed Cr3+ signals. The corresponding fine-structure parameters were determined at room temperature and 145 K. These results suggest
the substitution of Cr3+ for Al3+ in equal proportions in the two unequivalent octahedral sites of the dickite structure. In kaolin group minerals, the distortion
around Cr3+ ions (λ≈ 0.2–0.4) in Al sites is significantly less rhombic than that observed around Fe3+ ions (λ≈ 0.6–0.8).
Received: 29 June 2001 / Accepted: 22 October 2001 相似文献
4.
Uniting space, ground, and underwater measurements for improved estimates of rain rate 总被引:1,自引:0,他引:1
Amitai E. Nystuen J.A. Liao L. Meneghini R. Morin E. 《Geoscience and Remote Sensing Letters, IEEE》2004,1(2):35-38
Global precipitation is monitored from a variety of platforms including spaceborne, ground-, and ocean-based platforms. Intercomparisons of these observations are crucial to validating the measurements and providing confidence for each measurement technique. Probability distribution functions of rain rates are used to compare satellite and ground-based radar observations. A preferred adjustment technique for improving rain rate distribution estimates is identified using measurements from ground-based radar and rain gauges within the coverage area of the radar. The underwater measurement of rainfall shows similarities to radar measurements, but with intermediate spatial resolution and high temporal resolution. Reconciling these different measurement techniques provides understanding and confidence for all of the methods. 相似文献
5.
We present an evaluation of the procedure by which model prediction bias is examined in palaeolimnological transfer function inference models. We argue that most of the prediction biases commonly reported in the literature are, in fact, fallacious, and are the artificial consequence of the inappropriate manner in which residuals are traditionally examined. We show that the extent of the specious model bias is entirely predictable from first principles and is essentially determined by the strength of the predictive model. We suggest that the analysis of residuals should always be examined as a function of the model's predictions and we discuss the implications of the old and new approaches. 相似文献
6.
A natural montmorillonite containing radiation-induced defects was studied with Electron Paramagnetic Resonance (EPR) spectroscopy (X- and Q-band). A first dominant native defect, namely native defect 1, is identified. It gives rise to an orthorhombic spectrum with gx= 2.004 ± 0.005 gy= 2.010 ± 0.003, gz= 2.065 ± 0.002. Simulation of the EPR spectrum at X- and Q-band reveals a second native defect with isotropic spectrum at g= 2.019 ± 0.005. Both are electron holes trapped on oxygen atoms of the structure. The native defect 1 is located on an oxygen-silicon bond or a non-bonding orbital parallel to the c* axis. These defects are annealed at 500°C and the half-life determined for native defect 1 is circa 3,000 years. Irradiations with beta rays produced two additional hole centers of lower stability and distinct EPR parameters. Artificial irradiations show that montmorillonite can be used as a dosimeter in a large dose range. 相似文献
7.
Veli‐Pekka Salonen Julien Moreau Outi Hyttinen Kari O. Eskola 《Boreas: An International Journal of Quaternary Research》2014,43(3):627-638
Finnish Lapland is known as an area where numerous sites with sediments from Pleistocene glacial and interglacial periods occur. Recent sedimentological observations and dating call for reinterpretation of the record, which shows a complicated Mid‐Weichselian ice‐sheet evolution within the ice‐divide zone. Here, a large, previously unstudied section from a former Hannukainen iron mine was investigated sedimentologically and dated with optically stimulated luminescence (OSL). Ten sedimentary units were identified displaying a variety of depositional environments (glacial, glaciolacustrine, fluvial and aeolian). They are all – except for the lowermost, deeply weathered till – interpreted to be of Mid‐ or Late Weichselian/Holocene age. Five OSL samples from fluvial sediments give ages ranging from 55 to 35 ka, indicating two MIS 3 ice‐free intervals of unknown duration. The Mid‐Weichselian interstadial was interrupted by a re‐advance event, which occurred later than 35 ka and caused glaciotectonic deformation, folding and stacking of older sediments. This new evidence emphasizes the importance of the Kolari area when unravelling the complex Late Pleistocene glacial history of northern Finland and adjacent regions. 相似文献
8.
Segmentation and kinematics of the North America‐Caribbean plate boundary offshore Hispaniola 下载免费PDF全文
Sylvie Leroy Nadine Ellouz‐Zimmermann Jordane Corbeau Frédérique Rolandone Bernard Mercier de Lépinay Bertrand Meyer Roberte Momplaisir José‐Luis Granja Bruña Anne Battani Céline Baurion Evgueni Burov Valérie Clouard Rémy Deschamps Christian Gorini Youri Hamon Manfred Lafosse Jottin Leonel Laetitia Le Pourhiet Pilar Llanes Estrada Nicolas Loget Francis Lucazeau Daniel Pillot Jeffrey Poort Kevin R. Tankoo José‐Luis Cuevas José‐Fernando Alcaide Claude Jean Poix Alfonso Muñoz‐Martin Serge Mitton Yamil Rodriguez Julien Schmitz Leonardo Seeber Andres Carbo‐Gorosabel Santiago Muñoz 《地学学报》2015,27(6):467-478
We explored the submarine portions of the Enriquillo–Plantain Garden Fault zone (EPGFZ) and the Septentrional–Oriente Fault zone (SOFZ) along the Northern Caribbean plate boundary using high‐resolution multibeam echo‐sounding and shallow seismic reflection. The bathymetric data shed light on poorly documented or previously unknown submarine fault zones running over 200 km between Haiti and Jamaica (EPGFZ) and 300 km between the Dominican Republic and Cuba (SOFZ). The primary plate‐boundary structures are a series of strike‐slip fault segments associated with pressure ridges, restraining bends, step overs and dogleg offsets indicating very active tectonics. Several distinct segments 50–100 km long cut across pre‐existing structures inherited from former tectonic regimes or bypass recent morphologies formed under the current strike‐slip regime. Along the most recent trace of the SOFZ, we measured a strike‐slip offset of 16.5 km, which indicates steady activity for the past ~1.8 Ma if its current GPS‐derived motion of 9.8 ± 2 mm a?1 has remained stable during the entire Quaternary. 相似文献
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