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81.
S. A. Myslenkov V. S. Arkhipkin A. V. Pavlova S. A. Dobrolyubov 《Russian Meteorology and Hydrology》2018,43(10):670-678
The results of wind wave hindcast for the Caspian Sea for the period of 1979–2017 are presented. The WAVEWATCHIII wave model and wind forcing from the NCEP/CFSR reanalysis are used. The modeling is performed on the unstructured grid with the spacing to 1 km in the coastal zone. Mean and extreme values of wave height, length, and period are provided. It is shown that the maximum height of waves of 3% probability of exceedance is 11.7 m. The interannual variability of wave parameters is analyzed. No unambiguous trend towards increase or decrease in the storm activity was revealed over the hindcasting period. 相似文献
82.
Indicator Kriging without Order Relation Violations 总被引:2,自引:1,他引:1
Raimon Tolosana-Delgado Vera Pawlowsky-Glahn Juan-Jose Egozcue 《Mathematical Geosciences》2008,40(3):327-347
Indicator kriging (IK) is a spatial interpolation technique aimed at estimating the conditional cumulative distribution function
(ccdf) of a variable at an unsampled location. Obtained results form a discrete approximation to this ccdf, and its corresponding
discrete probability density function (cpdf) should be a vector, where each component gives the probability of an occurrence
of a class. Therefore, this vector must have positive components summing up to one, like in a composition in the simplex.
This suggests a simplicial approach to IK, based on the algebraic-geometric structure of this sample space: simplicial IK
actually works with log-odds. Interpolated log-odds can afterwards be easily re-expressed as the desired cpdf or ccdf. An
alternative but equivalent approach may also be based on log-likelihoods. Both versions of the method avoid by construction
all conventional IK standard drawbacks: estimates are always within the (0,1) interval and present no order-relation problems
(either with kriging or co-kriging). Even the modeling of indicator structural functions is clarified. 相似文献
83.
Ben Yang Yun Qian Larry K. Berg Po-Lun Ma Sonia Wharton Vera Bulaevskaya Huiping Yan Zhangshuan Hou William J. Shaw 《Boundary-Layer Meteorology》2017,162(1):117-142
We evaluate the sensitivity of simulated turbine-height wind speeds to 26 parameters within the Mellor–Yamada–Nakanishi–Niino (MYNN) planetary boundary-layer scheme and MM5 surface-layer scheme of the Weather Research and Forecasting model over an area of complex terrain. An efficient sampling algorithm and generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of simulated turbine-height wind speeds. The results indicate that most of the variability in the ensemble simulations is due to parameters related to the dissipation of turbulent kinetic energy (TKE), Prandtl number, turbulent length scales, surface roughness, and the von Kármán constant. The parameter associated with the TKE dissipation rate is found to be most important, and a larger dissipation rate produces larger hub-height wind speeds. A larger Prandtl number results in smaller nighttime wind speeds. Increasing surface roughness reduces the frequencies of both extremely weak and strong airflows, implying a reduction in the variability of wind speed. All of the above parameters significantly affect the vertical profiles of wind speed and the magnitude of wind shear. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability. 相似文献
84.
Ute C. Herzfeld Craig S. Lingle Cecily Freeman Chris A. Higginson Michael P. Lambert Li-Her Lee Vera A. Voronina 《Mathematical Geology》1997,29(6):859-890
The Antarctic Ice Sheet plays a major role in the global system, and the large ice streams discharging into the circumpolar
sea represent its gateways to the world’s oceans. Satellite radar altimeter data provide an opportunity for mapping surface
elevation at kilometerresolution with meteraccuracy. Geostaristical methods have been developed for the analysis of these
data. Applications to Seasat data and data from the Geosat Exact Repeat Mission indicate that the grounding line of Lambert
Glacier/Amery Ice Shelf, the largest ice stream in East Antarctica, has advanced 10–12 km between 1978 and 1987–89. The objectives
of this paper are to explore possibilities and limitations of satellite-altimetry-based mapping to capture changes for shorter
time windows and for smaller areas, and to investigate some methodological aspects of the data analysis. We establish that
one season of radar altimeter data is sufficient for constructing a map. This allows study of interannual variation and is
the key for a limeseries analysis approach to study changes in ice streams. Maps of the lower Lambert Glacier and the entire
Amery Ice Shelf are presented for austral winters 1978, 1987, 1988, and 1989. As a first step toward understanding the dynamics
of the ice-stream/iceshelf system, elevation changes are calculated for grounded ice, the grounding zone, and floating ice.
In the absence of (sufficient) surface gravity control for the Lambert Glacier/Amery Ice Shelf area, altimetry-based maps
may facilitate improvement of geoid models as they provide constraints on the terrain correction in the inverse gravimetric
problem. 相似文献
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88.
G. A. Tyusov E. M. Akentyeva T. V. Pavlova I. M. Shkolnik 《Russian Meteorology and Hydrology》2017,42(12):775-782
The aspects ofthe impact ofcurrent and future (in the middle of the 21st century) climate change on the operational safety and efficiency of traditional energy sources (thermal, nuclear, and hydroelectric power stations) in seven regions of Russia are considered. The climate change projections are provided by the ensemble of the MGO regional climate model with the resolution of 25 km under the IPCC RCP8.5 scenario. The regions with the highest weather- and climate-related risk for the energy production are identified, and some recommendations on the risk reduction are provided. 相似文献
89.
90.
Food webs and carbon flux in the Barents Sea 总被引:6,自引:3,他引:6
Paul Wassmann Marit Reigstad Tore Haug Bert Rudels Michael L. Carroll Haakon Hop Geir Wing Gabrielsen Stig Falk-Petersen Stanislav G. Denisenko Elena Arashkevich Dag Slagstad Olga Pavlova 《Progress in Oceanography》2006,71(2-4):232
Within the framework of the physical forcing, we describe and quantify the key ecosystem components and basic food web structure of the Barents Sea. Emphasis is given to the energy flow through the ecosystem from an end-to-end perspective, i.e. from bacteria, through phytoplankton and zooplankton to fish, mammals and birds. Primary production in the Barents is on average 93 g C m−2 y−1, but interannually highly variable (±19%), responding to climate variability and change (e.g. variations in Atlantic Water inflow, the position of the ice edge and low-pressure pathways). The traditional focus upon large phytoplankton cells in polar regions seems less adequate in the Barents, as the cell carbon in the pelagic is most often dominated by small cells that are entangled in an efficient microbial loop that appears to be well coupled to the grazing food web. Primary production in the ice-covered waters of the Barents is clearly dominated by planktonic algae and the supply of ice biota by local production or advection is small. The pelagic–benthic coupling is strong, in particular in the marginal ice zone. In total 80% of the harvestable production is channelled through the deep-water communities and benthos. 19% of the harvestable production is grazed by the dominating copepods Calanus finmarchicus and C. glacialis in Atlantic or Arctic Water, respectively. These two species, in addition to capelin (Mallotus villosus) and herring (Clupea harengus), are the keystone organisms in the Barents that create the basis for the rich assemblage of higher trophic level organisms, facilitating one of the worlds largest fisheries (capelin, cod, shrimps, seals and whales). Less than 1% of the harvestable production is channelled through the most dominating higher trophic levels such as cod, harp seals, minke whales and sea birds. Atlantic cod, seals, whales, birds and man compete for harvestable energy with similar shares. Climate variability and change, differences in recruitment, variable resource availability, harvesting restrictions and management schemes will influence the resource exploitation between these competitors, that basically depend upon the efficient energy transfer from primary production to highly successful, lipid-rich zooplankton and pelagic fishes. 相似文献