排序方式： 共有17条查询结果，搜索用时 406 毫秒
1.
M. Déqué R. G. Jones M. Wild F. Giorgi J. H. Christensen D. C. Hassell P. L. Vidale B. Rockel D. Jacob E. Kjellström M. de. Castro F. Kucharski B. van den Hurk 《Climate Dynamics》2005,25(6):653-670
Four high resolution atmospheric general circulation models (GCMs) have been integrated with the standard forcings of the
PRUDENCE experiment: IPCC-SRES A2 radiative forcing and Hadley Centre sea surface temperature and sea-ice extent. The response
over Europe, calculated as the difference between the 2071–2100 and the 1961–1990 means is compared with the same diagnostic
obtained with nine Regional Climate Models (RCM) all driven by the Hadley Centre atmospheric GCM. The seasonal mean response
for 2m temperature and precipitation is investigated. For temperature, GCMs and RCMs behave similarly, except that GCMs exhibit
a larger spread. However, during summer, the spread of the RCMs—in particular in terms of precipitation—is larger than that
of the GCMs. This indicates that the European summer climate is strongly controlled by parameterized physics and/or high-resolution
processes. The temperature response is larger than the systematic error. The situation is different for precipitation. The
model bias is twice as large as the climate response. The confidence in PRUDENCE results comes from the fact that the models
have a similar response to the IPCC-SRES A2 forcing, whereas their systematic errors are more spread. In addition, GCM precipitation
response is slightly but significantly different from that of the RCMs. 相似文献
2.
R. Schiemann M.-E. Demory M. S. Mizielinski M. J. Roberts L. C. Shaffrey J. Strachan P. L. Vidale 《Climate Dynamics》2014,42(9-10):2455-2468
The dependence of the annual mean tropical precipitation on horizontal resolution is investigated in the atmospheric version of the Hadley Centre General Environment Model. Reducing the grid spacing from about 350 km to about 110 km improves the precipitation distribution in most of the tropics. In particular, characteristic dry biases over South and Southeast Asia including the Maritime Continent as well as wet biases over the western tropical oceans are reduced. The annual-mean precipitation bias is reduced by about one third over the Maritime Continent and the neighbouring ocean basins associated with it via the Walker circulation. Sensitivity experiments show that much of the improvement with resolution in the Maritime Continent region is due to the specification of better resolved surface boundary conditions (land fraction, soil and vegetation parameters) at the higher resolution. It is shown that in particular the formulation of the coastal tiling scheme may cause resolution sensitivity of the mean simulated climate. The improvement in the tropical mean precipitation in this region is not primarily associated with the better representation of orography at the higher resolution, nor with changes in the eddy transport of moisture. Sizeable sensitivity to changes in the surface fields may be one of the reasons for the large variation of the mean tropical precipitation distribution seen across climate models. 相似文献
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Recent results from an enhanced greenhouse-gas scenario over Europe suggest that climate change might not only imply a general mean warming at the surface, but also a pronounced increase in interannual surface temperature variability during the summer season (Schär et al., Nature 427:332–336, 2004). It has been proposed that the underlying physical mechanism is related to land surface-atmosphere interactions. In this study we expand the previous analysis by including results from a heterogeneous ensemble of 11 high-resolution climate models from the PRUDENCE project. All simulations considered comprise 30-year control and enhanced greenhouse-gas scenario periods. While there is considerable spread in the models’ ability to represent the observed summer variability, all models show some increase in variability for the scenario period, confirming the main result of the previous study. Averaged over a large-scale Central European domain, the models simulate an increase in the standard deviation of summer mean temperatures between 20 and 80%. The amplification occurs predominantly over land points and is particularly pronounced for surface temperature, but also evident for precipitation. It is also found that the simulated changes in Central European summer conditions are characterized by an emergence of dry and warm years, with early and intensified depletion of root-zone soil moisture. There is thus some evidence that the change in variability may be linked to the dynamics of soil-moisture storage and the associated feedbacks on the surface energy balance and precipitation. 相似文献
6.
D. T. Mihailović T. J. Lee R. A. Pielke B. Lalić I. D. Arsenić B. Rajković P. L. Vidale 《Theoretical and Applied Climatology》2000,67(3-4):135-151
Summary In the last decade, a vast number of land surface schemes has been designed for use in global climate models, atmospheric
weather prediction, mesoscale numerical models, ecological models, and models of global changes. Since land surface schemes
are designed for different purposes they have various levels of complexity in the treatment of bare soil processes, vegetation,
and soil water movement.
This paper is a contribution to a little group of papers dealing with intercomparison of differently designed and oriented
land surface schemes. For that purpose we have chosen three schemes for classification: i) global climate models, BATS (Dickinson
et al., 1986; Dickinson et al., 1992); ii) mesoscale and ecological models, LEAF (Lee, 1992) and iii) mesoscale models, LAPS
(Mihailović, 1996; Mihailović and Kallos, 1997; Mihailović et al., 1999) according to the Shao et al. (1995) classification.
These schemes were compared using surface fluxes and leaf temperature outputs obtained by time integrations of data sets derived
from the micrometeorological measurements above a maize field at an experimental site in De Sinderhoeve (The Netherlands)
for 18 August, 8 September, and 4 October 1988. Finally, comparison of the schemes was supported applying a simple statistical
analysis on the surface flux outputs.
Received November 23, 1999 Revised August 18, 2000 相似文献
7.
Andrew Dawson Adrian J. Matthews David P. Stevens Malcolm J. Roberts Pier Luigi Vidale 《Climate Dynamics》2013,41(5-6):1439-1452
The extra-tropical response to El Niño in configurations of a coupled model with increased horizontal resolution in the oceanic component is shown to be more realistic than in configurations with a low resolution oceanic component. This general conclusion is independent of the atmospheric resolution. Resolving small-scale processes in the ocean produces a more realistic oceanic mean state, with a reduced cold tongue bias, which in turn allows the atmospheric model component to be forced more realistically. A realistic atmospheric basic state is critical in order to represent Rossby wave propagation in response to El Niño, and hence the extra-tropical response to El Niño. Through the use of high and low resolution configurations of the forced atmospheric-only model component we show that, in isolation, atmospheric resolution does not significantly affect the simulation of the extra-tropical response to El Niño. It is demonstrated, through perturbations to the SST forcing of the atmospheric model component, that biases in the climatological SST field typical of coupled model configurations with low oceanic resolution can account for the erroneous atmospheric basic state seen in these coupled model configurations. These results highlight the importance of resolving small-scale oceanic processes in producing a realistic large-scale mean climate in coupled models, and suggest that it might may be possible to “squeeze out” valuable extra performance from coupled models through increases to oceanic resolution alone. 相似文献
8.
Prognostic canopy air space solutions for land surface exchanges 总被引：1，自引：0，他引：1
Summary Three generations of land surface models have been developed over the course of the last twenty years, which include increasing levels of complexity. The latest generation incorporates photosynthesis and physiological responses to environmental CO2, a gas that is strongly controlled by atmospheric vertical stability and by land surface exchanges. A new set of prognostic equations, providing a new solution core for one such land surface model, SiB2, is introduced here. The new equation set makes use of canopy air space variables which are prognostic and allow for the storage of heat, water and carbon at that level, providing both a new memory for the coupled system and a better representation of observed canopy processes. Results from off-line simulation using FLUXNET data from Europe, over a range of environmental and climatic conditions, indicate that the new solution core is able to represent land surface exchanges with equal or better skill than the set it replaces. At the same time, this new formulation provides a simplified mathematical framework, more suitable for further model development. 相似文献
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Summary The importance of linking measurements, modeling and remote sensing of land surface processes has been increasingly recognized in the past years since on the diurnal to seasonal time scale land surface–atmosphere feedbacks can play a substantial role in determining the state of the near-surface climate. The worldwide Fluxnet project provides long term measurements of land surface variables useful for process-based modeling studies over a wide range of climatic environments.In this study data from six European Fluxnet sites distributed over three latitudinal zones are used to force three generations of LSMs (land surface models): the BUCKET, BATS 1E and SiB 2.5. Processes simulating the exchange of heat and water used in these models range from simple bare soil parameterizations to complex formulations of plant biochemistry and soil physics.Results show that – dependent on the climatic environment – soil storage and plant biophysical processes can determine the yearly course of the land surface heat and water budgets, which need to be included in the modeling system. The Mediterranean sites require a long term soil water storage capability and a biophysical control of evapotranspiration. In northern Europe the seasonal soil temperature evolution can influence the winter energy partitioning and requires a long term soil heat storage scheme. Plant biochemistry and vegetation phenology can drive evapotranspiration where no atmospheric-related limiting environmental conditions are active. 相似文献
10.
Christoph C. Raible Carlo Casty Jürg Luterbacher Andreas Pauling Jan Esper David C. Frank Ulf Büntgen Andreas C. Roesch Peter Tschuck Martin Wild Pier-Luigi Vidale Christoph Schär Heinz Wanner 《Climatic change》2006,79(1-2):9-29
A detailed analysis is undertaken of the Atlantic-European climate using data from 500-year-long proxy-based climate reconstructions, a long climate simulation with perpetual 1990 forcing, as well as two global and one regional climate change scenarios. The observed and simulated interannual variability and teleconnectivity are compared and interpreted in order to improve the understanding of natural climate variability on interannual to decadal time scales for the late Holocene. The focus is set on the Atlantic-European and Alpine regions during the winter and summer seasons, using temperature, precipitation, and 500 hPa geopotential height fields. The climate reconstruction shows pronounced interdecadal variations that appear to “lock” the atmospheric circulation in quasi-steady long-term patterns over multi-decadal periods controlling at least part of the temperature and precipitation variability. Different circulation patterns are persistent over several decades for the period 1500 to 1900. The 500-year-long simulation with perpetual 1990 forcing shows some substantial differences, with a more unsteady teleconnectivity behaviour. Two global scenario simulations indicate a transition towards more stable teleconnectivity for the next 100 years. Time series of reconstructed and simulated temperature and precipitation over the Alpine region show comparatively small changes in interannual variability within the time frame considered, with the exception of the summer season, where a substantial increase in interannual variability is simulated by regional climate models. 相似文献