共查询到20条相似文献，搜索用时 27 毫秒
1.
The scaled-decomposed atmospheric water budget over North America is investigated through the analysis of 25 years of simulation
by the Canadian Regional Climate Model (CRCM) driven by the NCEP–NCAR reanalyses for the period 1975–1999. The time average
and time variability of the atmospheric water budget for the winter and summer seasons are decomposed into their large-scale
and small-scale components to identify the added value of the regional model. For the winter season, the intra-seasonal transient-eddy
variance is the main temporal variability. The large- and small-scale terms are of the same order of magnitude, and are large
over both coasts and weak over the continent. For the summer season, the time–mean atmospheric water budget is rather different
to that of winter, with maximum values over the south-eastern part of the continent. The summer intra-seasonal variance is
about twice stronger than in winter and also dominates the variability, but the inter-monthly variance is non-negligible and
can be in part associated to North American Monsoon System. Over the continent, the intra-seasonal climatological variance
is dominated by the variability of the small scales. The small scales, that is those scales that are only resolved in the
regional model but not in the reanalyses, contribute to the added value in a regional climate simulation. In the winter season,
the added value of the CRCM is large and dominated by oceanic forcing, while in summer, it is dominant (larger than the large
scales) and controlled mainly by convective processes. 相似文献
2.
I. V. Petenko 《Boundary-Layer Meteorology》2001,100(2):287-299
An advanced statistical approach named ``spavelet analysis' is described. The proposed technique combines conventional spectral and wavelet analyses to yield information about duration and periodicity of a phenomenon. The procedure consists in estimation of spectra of the wavelet coefficients at different wavelet scales. Graphic presentation of the calculated spectra in the form of a contour plot versus period and wavelet temporal scale clearly shows the predominant repetition period and durationof the analysed phenomenon. The efficiency of this technique is demonstrated using as examples both model and real atmospheric processes. This approach can have wide practical applications, being a useful tool to analyse not only atmospheric phenomena, but any kinds of random events having some certain duration and periodicity. 相似文献
3.
Summary The west coast of the Indian peninsula receives very heavy rainfall during the summer Monsoon (June–September) season with
average rainfall over some parts exceeding 250 cm. Heavy rainfall events with rainfall more than 15 cm day−1 at one or more stations along the west coast of India occur frequently and cause considerable damage. A special observational
programme, Arabian Sea Monsoon Experiment, was carried out during the monsoon season of 2002 to study these events. The spatial
and temporal distributions of intense rainfall events, presented here, were used for the planning of this observational campaign.
The present study using daily rainfall data for summer monsoon season of 37 years (1951–1987) shows that the probability of
getting intense rainfall is the maximum between 14° N–16° N and near 19° N. The probability of occurrence of these intense
rainfall events is high from mid June to mid August, with a dip in early July. It has been believed for a long time that offshore
troughs and vortices are responsible for these intense rainfall events. However, analysis of the characteristics of cloud
systems associated with the intense rainfall events during 1985–1988 using very high resolution brightness temperature data
from INSAT-IB satellite shows that the cloud systems during these events are characterized by large spatial scales and high cloud tops.
Further study using daily satellite derived outgoing longwave radiation (OLR) data over a longer period (1975–1998) shows
that, most of these events (about 62%) are associated with systems organized on synoptic and larger scales. We find that most
of the offshore convective systems responsible for intense rainfall along the west coast of India are linked to the atmospheric
conditions over equatorial Indian Ocean. 相似文献
4.
P. N. Svyashchennikov U. V. Prokhorova B. V. Ivanov 《Russian Meteorology and Hydrology》2020,45(1):22-28
The results of studying the temporal variability of atmospheric circulation in the Western Arctic (the Norwegian and Barents seas) are presented. The daily dataset of Girs-Vangengeim E, W, and C circulation forms for the period of 1891–2016 is used to describe atmospheric circulation. Special attention is given to the estimation of differences in weather conditions during the modern period of warming (1985–2015) and in the period of the first Arctic warming (1920–1950). For the cold (November-March) and warm (April-October) seasons, the trends in the frequency of occurrence of the circulation forms are determined. The occurrence of the number of consecutive days with the same atmospheric circulation form which can be considered as a characteristic of weather stability during the analyzed period of warming, is computed for both seasons. The prevalence of the E circulation form during the warm season is typical of both periods. The modern period of warming in the study area, as compared to the period of the first warming, is characterized by an increase in the occurrence of the C circulation form with a short duration. It is found that the current climate regime is characterized by an increase in surface air temperature against a background of less stable weather conditions. 相似文献
5.
A new winter Aleutian Low (AL) intensity index was defined in this paper. A centurial-long time series of this index was constructed
using the sea level pressure (SLP) data of nearly 100 years. The features of interannual and decadal variability of the winter
AL intensity since 1900 were analyzed by applying the wavelet analysis. The relationship between the winter AL intensity and
atmospheric circulation was examined. The cross-wavelet analysis technique was used to further reveal the relationship between
the AL intensity and sea surface temperature (SST) in the equatorial eastern Pacific (EEP) and tropical Indian Ocean (TIO)
in winter. The results indicate that: 1) On the interannual timescale, the winter AL intensity displays 3–7-yr oscillations,
while on the decadal timescale, 8–10-yr and 16–22-yr oscillations are more obvious. 2) Of the linkage to atmospheric circulation,
both AO (Arctic Oscillation) and PNA (Pacific North America pattern) are closely associated with winter AL intensity on the
interannual timescale, but only PNA contributes to the variation of winter AL intensity on the decadal timescale. 3) As to
the ocean impact, winter EEP SST is a major factor affecting the winter AL intensity on the interannual timescale, especially
on the 3–7-yr periods. However, on the decadal timescale, though both the TIO and EEP SSTs are associated with the AL intensity
in winter, the TIO SST impact is more significant. 相似文献
6.
This study investigates the organised motion near the canopy-atmosphere interface of a moderately dense spruce forest in heterogeneous,
complex terrain. Wind direction is used to assess differences in topography and surface properties. Observations were obtained
at several heights above and within the canopy using sonic anemometers and fast-response gas analysers over the course of
several weeks. Analysed variables include the three-dimensional wind vector, the sonic temperature, and the concentration
of carbon dioxide. Wavelet analysis was used to extract the organised motion from time series and to derive its temporal scales.
Spectral Fourier analysis was deployed to compute power spectra and phase spectra. Profiles of temporal scales of ramp-like
coherent structures in the vertical and longitudinal wind components showed a reversed variation with height and were of similar
size within the canopy. Temporal scales of scalar fields were comparable to those of the longitudinal wind component suggesting
that the lateral scalar transport dominates. The existence of a – 1 power law in the longitudinal power spectra was confirmed
for a few cases only, with a majority showing a clear 5/3 decay. The variation of effective scales of organised motion in
the longitudinal velocity and temperature were found to vary with atmospheric stability, suggesting that both Kelvin-Helmholtz
instabilities and attached eddies dominate the flow with increasing convectional forcing. The canopy mixing-layer analogy
was observed to be applicable for ramp-like coherent structures in the vertical wind component for selected wind directions
only. Departures from the prediction of m = Λ
w
L
s
−1 = 8–10 (where Λ
w
is the streamwise spacing of coherent structures in the vertical wind w and L
s
is a canopy shear length scale) were caused by smaller shear length scales associated with large-scale changes in the terrain
as well as the vertical structure of the canopy. The occurrence of linear gravity waves was related to a rise in local topography
and can therefore be referred to as mountain-type gravity waves. Temporal scales of wave motion and ramp-like coherent structures
were observed to be comparable. 相似文献
7.
An investigation into high Reynolds number turbulent flow over a ridge top in New Zealand is described based on high-resolution
in-situ measurements, using ultrasonic anemometers for two separate locations on the same ridge with differing upwind terrain
complexity. Twelve 5-h periods during neutrally stratified and weakly stable atmospheric conditions with strong wind speeds
were sampled at 20 Hz. Large (and small) turbulent length scales were recorded for both vertical and longitudinal velocity
components in the range of 7–23 m (0.7–3.3 m) for the vertical direction and 628–1111 m (10.5–14.5 m) for the longitudinal
direction. Large-scale eddy sizes scaled to the WRF (Weather Research and Forecasting) numerical model simulated boundary-layer
thickness for both sites, while small-scale turbulent features were a function of the complexity of the upwind terrain. Evidence
of a multi-scale turbulent structure was obtained at the more complex terrain site, while an assessment of the three-dimensional
isotropy assumption in the inertial subrange of the spectrum showed anisotropic turbulence at the less complex site and evidence
of isotropic turbulence at the more complex site, with a spectral ratio convergence deviating from the 4/3 or unity values
suggested by previous theory and practice. Existing neutral spectral models can represent locations along the ridge top with
simple upwind complexity, especially for the vertical wind spectra, but sites with more orographic complexity and strong vertical
wind speeds are often poorly represented using these models. Measured spectra for the two sites exhibited no significant diurnal
variation and very similar large-scale and small-scale turbulent length scales for each site, but the turbulence energy measured
by the variances revealed a strong diurnal difference. 相似文献
8.
In a warming climate, atmospheric wave activity and associated weather patterns may change, although conflicting results have been reported on this topic. Additionally, atmospheric wave changes in a future climate have mainly focused on waves of a specified spatial scale, rather than a particular spatiotemporal scale. Here, changes in the variability of Rossby waves of multiple spatiotemporal scales are analyzed using the wavenumber-frequency power spectrum, a tool commonly applied to analyze atmospheric equatorial waves. Daily 500 hPa geopotential height data over 40°–60°N from historical (1950–2005) and future (2006–2099) simulations from 20 models in the Coupled Model Intercomparison Project Phase 5 (CMIP5) under the RCP8.5 scenario were analyzed. When compared to the historical period, the late 21st century climate projections showed a decline in spectral power for both eastward and westward propagating waves with wavenumbers greater than 8 that spanned over all frequencies in all seasons, but an increase in mean power for eastward propagating waves with wavenumbers 1–7 over all frequencies was shown in winter and spring. This increase in power was accompanied by increased variance, i.e., an increased meridional extent of 500 hPa ridges and troughs, and was the result of increases in the mean number of high amplitude events and duration of activity within this wave band. These results indicate that large-scale (~ 104 km) eastward propagating weather systems may intensify with higher amplitudes for ridges and troughs, while short-scale (102–103 km) weather systems may decrease in their intensity due to reduced variability in the late 21st century under the high emissions scenario. Potential mechanisms for these changes are discussed, including enhanced Arctic warming and midlatitude-tropical interactions. 相似文献
9.
Five hundred years of gridded high-resolution precipitation reconstructions over Europe and the connection to large-scale circulation 总被引：1，自引：2，他引：1
We present seasonal precipitation reconstructions for European land areas (30°W to 40°E/30–71°N; given on a 0.5°×0.5° resolved
grid) covering the period 1500–1900 together with gridded reanalysis from 1901 to 2000 (Mitchell and Jones 2005). Principal component regression techniques were applied to develop this dataset. A large variety of long instrumental precipitation
series, precipitation indices based on documentary evidence and natural proxies (tree-ring chronologies, ice cores, corals
and a speleothem) that are sensitive to precipitation signals were used as predictors. Transfer functions were derived over
the 1901–1983 calibration period and applied to 1500–1900 in order to reconstruct the large-scale precipitation fields over
Europe. The performance (quality estimation based on unresolved variance within the calibration period) of the reconstructions
varies over centuries, seasons and space. Highest reconstructive skill was found for winter over central Europe and the Iberian
Peninsula. Precipitation variability over the last half millennium reveals both large interannual and decadal fluctuations.
Applying running correlations, we found major non-stationarities in the relation between large-scale circulation and regional
precipitation. For several periods during the last 500 years, we identified key atmospheric modes for southern Spain/northern
Morocco and central Europe as representations of two precipitation regimes. Using scaled composite analysis, we show that
precipitation extremes over central Europe and southern Spain are linked to distinct pressure patterns. Due to its high spatial
and temporal resolution, this dataset allows detailed studies of regional precipitation variability for all seasons, impact
studies on different time and space scales, comparisons with high-resolution climate models as well as analysis of connections
with regional temperature reconstructions.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
10.
Ramzi Touchan Elena Xoplaki Gary Funkhouser Jürg Luterbacher Malcolm K. Hughes Nesat Erkan Ünal Akkemik Jean Stephan 《Climate Dynamics》2005,25(1):75-98
This study represents the first large-scale systematic dendroclimatic sampling focused on developing chronologies from different
species in the eastern Mediterranean region. Six reconstructions were developed from chronologies ranging in length from 115 years
to 600 years. The first reconstruction (1885–2000) was derived from principal components (PCs) of 36 combined chronologies.
The remaining five, 1800–2000, 1700–2000, 1600–2000, 1500–2000 and 1400–2000 were developed from PCs of 32, 18, 14, 9, and
7 chronologies, respectively. Calibration and verification statistics for the period 1931–2000 show good levels of skill for
all reconstructions. The longest period of consecutive dry years, defined as those with less than 90% of the mean of the observed
May–August precipitation, was 5 years (1591–1595) and occurred only once during the last 600 years. The longest reconstructed
wet period was 5 years (1601–1605 and 1751–1755). No long term trends were found in May–August precipitation during the last
few centuries. Regression maps are used to identify the influence of large-scale atmospheric circulation on regional precipitation.
In general, tree-ring indices are influenced by May–August precipitation, which is driven by anomalous below (above) normal
pressure at all atmospheric levels and by convection (subsidence) and small pressure gradients at sea level. These atmospheric
conditions also control the anomaly surface air temperature distribution which indicates below (above) normal values in the
southern regions and warmer (cooler) conditions north of around 40°N. A compositing technique is used to extract information
on large-scale climate signals from extreme wet and dry summers for the second half of the twentieth century and an independent
reconstruction over the last 237 years. Similar main modes of atmospheric patterns and surface air temperature distribution
related to extreme dry and wet summers were identified both for the most recent 50 years and the last 237 years. Except for
the last few decades, running correlation analyses between the major European-scale circulation patterns and eastern Mediteranean
spring/summer precipitation over the last 237 years are non-stationary and insignificant, suggesting that local and/or sub-regional
geographic factors and processes are important influences on tree-ring variability over the last few centuries. 相似文献
11.
D. M. Sonechkin N. M. Astafyeva N. M. Datsenko N. N. Ivachtchenko B. Jakubiak 《Theoretical and Applied Climatology》1999,64(1-2):131-142
Summary The surface air temperature time series of both hemispheres and the North Atlantic European area as well as the Southern
Oscillation (SO) index time series were analysed using a wavelet transform technique. The values of the so-called singularity
exponents of these series were estimated and compared with such estimations for some surrogate time series artificially created
from the observed temperature series. It was concluded that the climate dynamics on interannual and interdecadal scales may
be considered as a kind of classical Brownian motion although its consideration as a flicker-noise is also possible. The extracted
temperature variations were shown to be closely coupled with the SO process. The wavelet-transformed SO series reveals itself
as a whole self-similar “tree” the main branches of which are the appearances of the strongest El-Ninos of 1898 – 1899, 1941 – 1942,
and 1982 – 1983. Similar “trees” can be seen in the wavelet-transformed temperature series. Thus, the extracted temperature
variations were shown to be closely coupled with the SO process, and a decomposition of the current global climate dynamics
into three climatic epochs (of about 40-year long) seems to be appropriate.
Received May 4, 1998 Revised April 25, 1999 相似文献
12.
Christoph Thomas Jens-Christopher Mayer Franz X. Meixner Thomas Foken 《Boundary-Layer Meteorology》2006,119(3):563-587
This study applies acoustic sounding to observe coherent structures in the roughness sublayer (RSL) above tall vegetated surfaces. Data were collected on 22 days during two separate field experiments in summer 2003. A quality control scheme was developed to ensure high data quality of the collected time series. The data analysis was done using both discrete and continuous wavelet transform. The flow in the RSL was found to be a superposition of dynamic Kelvin–Helmholtz instabilities and convective mixing. The characteristic time scales for coherent structures resulting from the dynamic instabilities were observed to be approximately 20–30 s while thermal eddies have much larger time scales of 190–210 s. The degree of vertical coherency in the RSL increases with the flow evolving from neutral to near-convective conditions. This increase in the degree of organisation is attributed to the evolution of attached thermal eddies. The coherent structures resulting from instabilities were found to be present throughout the RSL but do not contribute to the increased vertical coherency. An alternative conceptual approach for the definition of the RSL is proposed, which yields its maximum vertical extent to five times the canopy height. 相似文献
13.
The variations noticed in the atmospheric electric field recorded at Pune (18o32’N, 73o51’E, 559 m ASL), a tropi-cal inland station located in Deccan Plateau, India, during the period 1930-1987, have been examined in relation to the variations observed in the Angstrom turbidity coefficient (β) and selected meteorological parameters. The month-ly and annual mean values of the atmospheric electric field, Angstrom turbidity coefficient (β), rainfall, temperature and relative humidity for the years 1930-1938, 1957-1958, 1964-1965, 1973-1974 and 1987 were considered in the study.The results of the above study indicated gradual increases in the atmospheric electric field over the period of study (1930-1987) which is statistically significant at less than 5% level. The increases noticed during different periods varied from 30 to 109 %. The increase noticed during the period (1930-1938) and (1973-1974) was maximum (109%). The Angstrom turbidity coefficient also showed systematic increases during the period of study, which is consistent. The diurnal curve of the atmospheric electric field at the station by and large, showed a double oscillation, which is generally observed in the continental environments. 相似文献
14.
NCEP/GFS analysis is used to investigate the scale dependence and the interplay between the terms of the atmospheric water
budget over West Africa using a dedicated decomposition methodology. The focus is on a 2-month period within the active monsoon
period of 2006. Results show that the dominant scales of seasonal mean precipitation and moisture flux divergence over West
Africa during the monsoon period are large scales (greater than 1,400 km) except over topography, where mean values of small
scales (smaller than 900 km) are strong. Correlations between moisture flux divergences in monsoon and African Easterly Jet
layers and precipitation indicate that precipitation is strongly correlated to moisture flux divergence via both large-scale
and small-scale processes, but the correlation signal is quite different depending on the region and vertical layer considered.
The analysis of the scales associated with the rainfall and the local evaporation over 3 different regions shows that positive
correlation exists over the ocean between precipitation and evaporation especially at large scale. Over the continent south
of the Sahel, the correlation is negative and driven by large scale. Over the northern part of Sahel, positive correlation
is found, only at small scales during the active monsoon period. Lag correlation reveals that the maximum evaporation over
the Sahel occurs 1–3 days after the maximum precipitation with maximum contribution from small-scale processes during the
first day. This study shows that NCEP/GFS reproduces well the known atmospheric water budget features. It also reveals a new
scale dependence of the relative role of each term of the atmospheric water budget. This indicates that such scale decomposition
approach is helpful to clarify the functioning of the water cycle embedded in the monsoon system. 相似文献
15.
Seasonal to interannual climate predictability in mid and high northern latitudes in a global coupled model 总被引：3，自引：2，他引：1
The upper limit of climate predictability in mid and high northern latitudes on seasonal to interannual time scales is investigated
by performing two perfect ensemble experiments with the global coupled atmosphere–ocean–sea ice model ECHAM5/MPI-OM. The ensembles
consist of six members and are initialized in January and July from different years of the model’s 300-year control integration.
The potential prognostic predictability is analyzed for a set of oceanic and atmospheric climate parameters. The predictability
of the atmospheric circulation is small except for southeastern Europe, parts of North America and the North Pacific, where
significant predictability occurs with a lead time of up to half a year. The predictability of 2 m air temperature shows a
large land–sea contrast with highest predictabilities over the sub polar North Atlantic and North Pacific. A combination of
relatively high persistence and advection of sea surface temperature anomalies into these areas leads to large predictability.
Air temperature over Europe, parts of North America and Asia shows significant predictability of up to half a year in advance.
Over the ice-covered Arctic, air temperature is not predictable at time scales exceeding 2 months. Sea ice thickness is highly
predictable in the central Arctic mainly due to persistence and in the Labrador Sea due to dynamics. Surface salinity is highly
predictable in the Arctic Ocean, northern North Atlantic and North Pacific for several years in advance. We compare the results
to the predictability due to persistence and show the importance of dynamical processes for the predictability. 相似文献
16.
Three-hour and daily mean measurements of the module of an average speed and wind gusts were analyzed over 2001–2006 in the
Chernobyl NPP region using wavelet analysis and the method of the Herst normalized range. Diurnal and seasonal fluctuations
are revealed, the periodicity of 8, 16, and 60 days is not well-pronounced. The derived Herst high-value coefficients (∼0.7–0.8)
against the background of well-pronounced seasonal and other fluctuations of an average wind speed are indicative of the fact
that its temporal variability is far from being random. The analysis is performed to predict the concentration of radioactive
aerosols released from the Ukrytie object (the damaged unit 4 of the ChNPP), whose changes correlate with the wind speed. 相似文献
17.
Interdecadal variability of the relationship between the East Asian winter monsoon and ENSO 总被引：2，自引：0，他引：2
W. Zhou X. Wang T. J. Zhou C. Li J. C. L. Chan 《Meteorology and Atmospheric Physics》2007,98(3-4):283-293
Summary The authors examine relationships between the East Asian winter monsoon and the ENSO, particularly on the interdecadal timescales.
Based on the analyses of SLP data from 1899 to 1997, the East-Asian winter monsoon index (WMI) is defined as the zonal difference
of SLP between ∼120° E and ∼160° E. It is found that 18 out of 28 strong winter monsoon years are either before the development
of an El Ni?o or during the decaying La Ni?a event, 12 out of 28 weak winter monsoon are before the development of a La Ni?a
or during the decaying El Ni?o event. There is a significant positive correlation coefficient value of about 0.49 between
the normalized 11-yr running mean of WMI and ENSO index, however, the WMI-ENSO relationship is not consistently highly correlated.
The temporal evolution of correlation between WMI and ENSO indices in both 11-yr and 21-yr moving window shows that the WMI-ENSO
relationship clearly undergo low-frequency oscillation. Obviously, both observational and IPSL air-sea coupled modeling WMI
index has a near-decadal peak with PDO timescales and internal peaks with ENSO timescales by applying the Multitaper method.
Moreover, the cross wavelet and wavelet coherence analysis of WMI/ENSO indicate that there is a larger significant sections
with an in phase behavior between WMI and ENSO at period of 20–30 yrs, suggesting that the interdecadal variation of the WMI-ENSO
relationship might exist. 相似文献
18.
Mitsuaki Horiguchi Taiichi Hayashi Ahoro Adachi Shigeru Onogi 《Boundary-Layer Meteorology》2012,144(2):179-198
Large-scale turbulence structures in the near-neutral atmospheric boundary layer (ABL) are investigated on the basis of observations made from the 213-m tall meteorological tower at Tsukuba, Japan. Vertical profiles of wind speed and turbulent fluxes in the ABL were obtained with sonic anemometer-thermometers at six levels of the tower. From the archived data, 31 near-neutral cases are selected for the analysis of turbulence structures. For the typical case, event detection by the integral wavelet transform with a large time scale (180 s) from the streamwise velocity component (u) at the highest level (200 m) reveals a descending high-speed structure with a time scale of approximately 100 s (a spatial scale of 1 km at the 200-m height). By applying the wavelet transform to the u velocity component at each level, the intermittent appearance of large-scale high-speed structures extending also in the vertical is detected. These structures usually make a large contribution to the downward momentum transfer and induce the enhancement of turbulent kinetic energy. This behaviour is like that of “active” turbulent motions. From the analysis of the two-point space–time correlation of wavelet coefficients for the u velocity component, the vertical extent and the downward influence of large-scale structures are examined. Large fluctuations in the large-scale range (wavelet variance at the selected time scale) at the 200-m level tend to induce the large correlation between the higher and lower levels. 相似文献
19.
北京气候中心气候系统模式研发进展——在气候变化研究中的应用 总被引：4，自引：2，他引：2
吴统文 宋连春 李伟平 王在志 张华 辛晓歌 张艳武 张莉 李江龙 吴方华 刘一鸣 张芳 史学丽 储敏 张洁 房永杰 汪方 路屹雄 刘向文 魏敏 刘茜霞 周文艳 董敏 赵其庚 季劲钧 Laurent Li 周明煜 《气象学报》2014,72(1):12-29
较全面地介绍了北京气候中心气候系统模式(BCC_CSM)研发所取得的一些进展及其在气候变化研究中的应用,重点介绍了全球近280 km较低分辨率的全球海-陆-气-冰-生物多圈层耦合的气候系统模式BCC_CSM1.1和110 km中等大气分辨率的BCC_CSM1.1(m),以及大气、陆面、海洋、海冰各分量模式的发展。BCC_CSM1.1和BCC_CSM1.1(m)气候系统模式均包含了全球碳循环和动态植被过程。当给定全球人类活动导致的碳源排放后,就可以模拟和预估人类活动对气候变化的影响。BCC_CSM1.1和BCC_CSM1.1(m)已应用于IPCC AR5模式比较,为中外开展气候变化机理分析和未来气候变化预估提供了大量的试验数据。还介绍了BCC_CSM1.1和BCC_CSM1.1(m)参与国际耦合模式比较计划(CMIP5)的大量试验分析评估结果,BCC_CSM能够较好地模拟20世纪气温和降水等气候平均态和季节变化特征,以及近1000年的历史气候变化,所预估的未来100年气候变化与国际上其他模式的CMIP5试验预估结果相当。初步的分析表明,分辨率相对高的BCC_CSM1.1(m)在区域气候平均态的模拟上优于分辨率较低的BCC_CSM1.1。 相似文献
20.
Renguang Wu 《Climate Dynamics》2010,34(5):629-642
Analysis of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) data for the period 1998–2007 reveals large
subseasonal fluctuations in sea surface temperature (SST) of the South China Sea during the summer monsoon onset. These subseasonal
SST changes are closely related to surface heat flux anomalies induced by surface wind and cloud changes in association with
the summer monsoon onset. The SST changes feed back on the atmosphere by modifying the atmospheric instability. The results
suggest that the South China Sea summer monsoon onset involves ocean–atmosphere coupling on subseasonal timescales. While
the SST response to surface heat flux changes is quick and dramatic, the time lag between the SST anomalies and the atmospheric
convection response varies largely from year to year. The spatial–temporal evolution of subseasonal anomalies indicates that
the subseasonal variability affecting the South China Sea summer monsoon onset starts over the equatorial western Pacific,
propagates northward to the Philippine Sea, and then moves westward to the South China Sea. The propagation of these subseasonal
anomalies is related to the ocean–atmosphere interaction, involving the wind-evaporation and cloud-radiation effects on SST
as well as SST impacts on lower-level convergence over the equatorial western Pacific and atmospheric instability over the
Philippine Sea and the South China Sea. 相似文献