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1.
 Based on the China Rural Statistical Yearbook of 1984-2003 published by State Statistics Bureau, and the annual temperature in the same period, impacts of temperature change, agricultural input, and planting area on grain production were analyzed for different regions of China during the last 20 years. The results show that the main characteristic of climate warming has obviously promoted the increase of grain yield in Northeast China, but to some extent suppressed it in North China, Northwest China and Southwest China, and shown no obvious effect on it in East China and Central-South China. The increase in agricultural input facilitated the grain production obviously in various regions in the early stage of the past 20 years, but showed no obvious effect in the late stage. The continuous reduction in sown area had a significant negative effect on the grain production in East China and Central-South China.  相似文献   

2.
Ozone is well documented as the air pollutant most damaging to agricultural crops and other plants. It is reported that tropospheric O3 concentration increases rapidly in recent 20 years. Evaluating and predicting impacts of ozone concentration changes on crops are drawing great attention in the scientific community. In China, main study method about this filed is controlled experiments, for example, Open Top Chambers. But numerical simulation study about impacts of ozone on crops with crop model was developed slowly, what is more, the study about combined impacts of ozone and carbon dioxide has not been reported. The improved agroecosystem model is presented to evaluate simultaneously impacts of tropospheric O3 and CO2 concentration changes on crops in the paper by integrating algorithms about impacts of ozone on photosynthesis with an existing agroecosystem biogeochemical model (named as DNDC). The main physiological processes of crop growth (phenology, leaf area index, photosynthesis, respiration, assimilated allocation and so on) in the former DNDC are kept. The algorithms about impacts of ozone on photosynthesis and winter wheat leaf are added in the modified DNDC model in order to reveal impacts of ozone and carbon dioxide on growth, development, and yield formation of winter wheat by coupling the simulation about impacts of carbon dioxide on photosynthesis of winter wheat which exists in the former DNDC. In the paper, firstly assimilate allocation algorithms and some genetic parameters (such as daily thermal time of every development stage) were modified in order that DNDC can be applicable in North China. Secondly impacts of ozone on crops were simulated with two different methods- one was impacts of ozone on light use efficiency, and the other was direct effects of ozone on leaves photosynthesis. The latter simulated results are closer to experiment measurements through comparing their simulating results. At last the method of direct impacts of ozone on leaf growth is adopted and the coefficients about impacts of ozone on leaf growth and death are ascertained. Effects of climate changes, increasing ozone, and carbon dioxide concentration on agroecosystem are tried to be simulated numerically in the study which is considered to be advanced and credible.  相似文献   

3.
Influences of Tropical Cyclones on China During 1965-2004   总被引：2，自引：0，他引：2  
Using the Joint Typhoon Warning Center （JTWC） and China Meteorological Administration （CMA） tropical cyclone track datasets, variations in frequency and intensity of the affecting-China tropical cyclones （ACTCs） are studied for the period of 1965-2004. First, the differences between the two tropical cyclone datasets are examined. The annual frequencies of tropical cyclones in the western North Pacific basin are reasonably consistent to each other, while the intensity records are less reliable. The annual numbers of ACTCs based on different datasets are close to each other with similar interdecadal and interannual variations. However, the maximum intensity and the annual frequency of ACTCs for strong categories show great dependence on datasets. Tropical cyclone impacts on China show the same variations as the annual number of ACTCs and also show dependence on datasets. Differences in tropical cyclone impacts on China are mainly caused by datasets used. The annual frequency of ACTCs, especially the length of lifetime of ones that make landfall, and the intensity estimates all have effects on the value of impacts on China.  相似文献   

4.
In this paper,based on the analysis of the variation of effective accumulated temperature and precipita-tion in the last 100 years,together with the potential impacts of greenhouse effects on the climate in Chinasimulated with the current major climatic models(GFDL,GISS,NCAR,OSU and UKMO),the impacts ofclimate change on rice in the middle and lower reaches of Changjiang River and winter wheat production on theHuang-Huai-Hai Plain~* are simulated with the available weather-yield statistic models on the assumption that te-mperature variation ranges 1—4℃ and precipitation variation ranges ±10—20%.The result is that under thecurrent planting systems and agrotechniques,the impact of climate change on wheat production is more signifi-cant than that on rice;the climatic conditions of agricultural production in the north of China will become morefavourable while those in the south of the middle and lower reaches of Changjiang River remain the same;butthose in the southern part of North China and the basins between Changjiang River and Haihe River are ratherunstable.In general,it is difficult to reach the conclusion that advantages or disadvantages dominate in suchclimate changes because of uncertainties.  相似文献   

5.
Decadal/interdecadal climate variability is an important research focus of the CLIVAR Program and has been paid more attention. Over recent years, a lot of studies in relation to interdecadal climate variations have been also completed by Chinese scientists. This paper presents an overview of some advances in the study of decadal/interdecadal variations of the ocean temperature and its climate impacts, which includes interdecadal climate variability in China, the interdecadal modes of sea surface temperature (SST) anomalies in the North Pacific, and in particular, the impacts of interdecadal SST variations on the Asian monsoon rainfall. As summarized in this paper, some results have been achieved by using climate diagnostic studies of historical climatic datasets. Two fundamental interdecadal SST variability modes (7– 10-years mode and 25–35-years mode) have been identified over the North Pacific associated with different anomalous patterns of atmospheric circulation. The southern Indian Ocean dipole (SIOD) shows a major feature of interdecadal variation, with a positive (negative) phase favoring a weakened (enhanced) Asian summer monsoon in the following summer. It is also found that the China monsoon rainfall exhibits interdecadal variations with more wet (dry) monsoon years in the Yangtze River (South China and North China) before 1976, but vice versa after 1976. The weakened relationship between the Indian summer rainfall and ENSO is a feature of interdecadal variations, suggesting an important role of the interdecadal variation of the SIOD in the climate over the south Asia and southeast Asia. In addition, evidence indicates that the climate shift in the 1960s may be related to the anomalies of the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO). Overall, the present research has improved our understanding of the decadal/interdecadal variations of SST and their impacts on the Asian monsoon rainfall. However, the research also highlights a number of problems for future research, in particular the mechanisms responsible for the monsoon long-term predictability, which is a great challenge in climate research.  相似文献   

6.
The impacts of emissions from industry,power plant,transportation,residential,and biogenic sources on daily maximum surface ozone （O3DM） over the Beijing-Tianjin-Hebei （BTH） region in North China in the summer of 2007 were examined in a modeling study.The modeling system consisted of the Weather Research and Forecasting （WRF） model and the photochemical dispersion model,CAMx.The factor separation technique （FST） was used to quantify the effect of individual emission source types and the synergistic interactions among two or more types.Additionally,the effectiveness of emission reduction scenarios was explored.The industry,power plant,and transportation emission source types were found to be the most important in terms of their individual effects on O3DM.The key contributor to high surface O3 was power plant emissions,with a peak individual effect of 40 ppbv in the southwestern BTH area.The individual effect from the biogenic emission category was quite low.The synergistic effects from the combinations of each pair of anthropogenic emission types suppressed O3 formation,while the synergistic effects for combinations of three were favorable for O3 formation when the industrial and power plant emission source types coexisted.The quadruple synergistic effects were positive only with the combination of power plant,transportation,residential,and biogenic sources,while the quintuple synergistic effect showed only minor impacts on O3DM concentrations.A 30％ reduction in industrial and transportation sources produced the most effective impacts on O3 concentrations,with a maximum decrease of 20 ppbv.These results suggested that the synergistic impacts among emission source types should be considered when formulating emission control strategies for O3 reduction.  相似文献   

7.
In the early 1980s, Chinese meteorologists discovered the positive correlation in summer rainfall between India and North China and the correlation was later confirmed by some researches in and outside China. Based on a variety of meteorological data from 1951 to 2005 and numerical simulations, the present study investigates such a correlation between Indian summer monsoon （ISM） and precipitation in North China. Furthermore, we discuss the intrinsic relations of the positive （Northwest India）-negative （the Tibetan Plateau）-positive （North China） precipitation anomaly teleconnection pattern from two aspects of thermal and dynamical factors, which not only confirms the precipitation teleconnection previously discovered again, but also reveals the influence mechanism of the ISM on the rainfall in North China. The results show that： （1） When the ISM is strong （weak）, the precipitation in North China tends to be more （less） than normal; however, when the rainfall in North China is more （less） than normal, the probability of the strengthening （weakening） of the ISM is relatively lower. This implies that the ISM anomaly has more impact on the rainfall in North China. （2） The Indian low usually dominantly impacts the intensity of the ISM. When the Indian low deepens, the low troughs in mid-high latitudes are frequently strengthened, and the ridge of the western Pacific subtropical high （WPSH） extends westward. The southwesterly water vapor transport originated from low-latitudes and the southeasterly water vapor transport along the southwestern flank of the WPSH converge in North China, which is favorable for more rainfall there than normal, and vice versa. （3） The simulations from the regional climate model developed by National Climate Center （ReGCM_NCC） capture the salient feature of the precipitation teleconnection between India and North China. The simulated anomalous atmospheric existence of such a teleconnection from another circulations are close to observatio  相似文献   

8.
Drought events have become more frequent and intense over East Asia in recent decades, leading to hugesocioeconomic impacts. Although the droughts have been studied extensively by cases or for individual regions, theirleading variability and associated causes remain unclear. Based on the Standardized Precipitation Evapotranspiration Index(SPEI) and ERA5 reanalysis product from 1979 to 2020, this study evealuates the severity of spring droughts in East Asiaand investigates their variations and associated drivers. The results indicate that North China and Mongolia have ex perienced remarkable trends toward dryness during spring in recent decades, while southwestern China has witnessed anopposite trend toward wetness. The first Empirical Orthogonal Function mode of SPEI variability reveals a similarseesawing pattern, with more severe dryness in northwestern China, Mongolia, North China, South Korea, and Japan butincreased wetness in Southwestern China and southeast Asia. Further investigation reveals that the anomalously dry (wet)surface in North (Southwestern) China is significantly associated with anomalously high (low) temperature, less (more)precipitation, and reduced (increased) soil moisture during the previous winter and early spring, regulated by an anomalousanticyclone (cyclone) and thus reduced (increased) water vapor convergence. The spring dry-wet pattern in East Asia isalso linked to cold sea surface temperature anomalies in the central-eastern Pacific. The findings of this study haveimportant implications for improving the prediction of spring drought events in East Asia.  相似文献   

9.
Based on analyses of the relationship between Pacific Meridional Mode (PMM) and number of tropical cyclones (TCs) activity over the western North Pacific, the impacts of the PMM on Tc activity over the western North Pacific are studied using numerical simulations with an Atmospheric General Circulation Model (CAM3) of National Center for Atmospheric Research (of USA). The result shows that the PMM has impacts on the large-scale generating environment of TCs, thus affecting their number and strength. The numerical simulations using the NCAR CAM3 indicate that with the inclusion of the forcing from sea surface temperature (SST) of the PMM, there appears a decreased magnitude of the vertical zonal wind shear, large proportion of relative humidity, anomalous westerly wind at low levels and anomalous easterly wind at high levels, in association with anomalous cyclonic circulation at low levels and anomalous anti-cyclonic circulation at high levels over the tropical western Pacific. Thus, the PMM provides favorable environment for the typhoon genesis. In the sensitivity experiment, TCs have larger strength, lower SST at the center, stronger tangential wind at 850 hPa and intensified warm cores at high levels. In this paper, the simulation results are similar to that in the data analyses, which reveals the important impact of the PMM on TC activity over the western North Pacific.  相似文献   

10.
This study aims at exploring potential impacts of land-use vegetation change (LUC) on regional climate variability and extremes. Results from a pair of Australian Bureau of Meteorology Research Centre (BMRC) climate model 54-yr (1949-2002) integrations have been analysed. In the model experiments, two vegetation datasets are used, with one representing current vegetation coverage in China and the other approximating its potential coverage without human intervention. The model results show potential impacts ...  相似文献   

11.
To study the prediction of the anomalous precipitation and general circulation for the summer(June–July–August) of1998, the Community Climate System Model Version 4.0(CCSM4.0) integrations were used to drive version 3.2 of the Weather Research and Forecasting(WRF3.2) regional climate model to produce hindcasts at 60 km resolution. The results showed that the WRF model produced improved summer precipitation simulations. The systematic errors in the east of the Tibetan Plateau were removed, while in North China and Northeast China the systematic errors still existed. The improvements in summer precipitation interannual increment prediction also had regional characteristics. There was a marked improvement over the south of the Yangtze River basin and South China, but no obvious improvement over North China and Northeast China. Further analysis showed that the improvement was present not only for the seasonal mean precipitation, but also on a sub-seasonal timescale. The two occurrences of the Mei-yu rainfall agreed better with the observations in the WRF model,but were not resolved in CCSM. These improvements resulted from both the higher resolution and better topography of the WRF model.  相似文献   

12.
East Asian summer climate is strongly affected by extratropical circulation disturbances.In this study,impacts of four atmospheric teleconnections over Eurasia on East Asian summer rainfall are investigated using National Centers for Environmental Prediction/National Center for Atmospheric Research （NCEP/NCAR） reanalysis data and Climatic Research Unit （CRU） land precipitation data during 1979-2009.The four teleconnections include the Scandinavian （SCA）,the Polar/Eurasian （PEU）,the East Atlantic/Western Russian （EAWR）,and the circumglobal teleconnection （CGT）.Moreover,the related changes of lower-tropospheric circulation are explored,specifically,the low pressure over northern East Asia （NEAL） and the subtropical high over the western North Pacific （WNPSH）.The results presented are in the positive phase.The PEU and SCA induce significant negative anomalies in North China rainfall （NCR）,while the CGT induces significant positive anomalies.In the past three decades,the PEU and SCA explain more than 20％ of the variance in NCR,twice that explained by the CGT,suggesting a more important role of the former two teleconnections in NCR variation than the latter one.Meanwhile,the PEU and SCA reduce rainfall in Northeast China and South Korea,respectively,and the CGT enhances rainfall in Japan.The rainfall responses are attributed to the SCA-induced northward shift of the NEAL,and PEU-induced northward shift and weakening of the NEAL,respectively.For the CGT,the dipole pattern of rainfall anomalies between North China and Japan is affected by both westward extension of the NEAL and northwestward expansion of the WNPSH.In addition,the EAWR leads to an increase of sporadic rainfall in South China as a result of the eastward retreat of the WNPSH.  相似文献   

13.
The features of water vapor transport, such as temporal evolution, vertical structure and spatial pattern, over North China during the prolonged drought in the summer of 1980 have been analyzed through computation of water vapor flux based on the once daily ECMWF grid-point data at 12GMT. The results indicate that it is unlikely that the characteristics of the atmospheric mass divergence, ascending motion and stratification stability in North China were completely opposite to those in the Yangtze River Valley, where the heavy flood occurred in the summer of 1980. It is major differences that the strong ascending motion and significant water vapor convergence overlap fairly well each other in the vertical levels in the Yangtze River Valley, while the maximum ascending motion is accompanied by water vapor divergence or weak water vapor convergence in North China. This vertical structure in North China results in insufficient water vapor supply and, therefore, little condensation and precipitation in the m  相似文献   

14.
The Eurasian teleconnection pattern(EU) is an important low-frequency pattern with well-known impacts on climate anomalies in Eurasia. The difference of low-level v-winds in several regions in the Eurasian mid–high latitudes is defined as the EU index(EUIV). In this study, the relationship between the winter EUIVand precipitation in the following summer over China is investigated. Results show that there is a significant positive(negative) correlation between the winter EUIVand the following summer precipitation over North China(the Yangtze River–Huaihe River basins). Meanwhile, an interdecadal variability exists in the interannual relationship, and the correlation has become significantly enhanced since the early 1980 s.Thus, the proposed EUIVmay have implications for the prediction of summer precipitation anomalies over China. In positive winter EUIVyears, three cyclonic circulation anomalies are observed—over the Ural Mountains, the Okhotsk Sea, and the subtropical western North Pacific. That is, the Ural blocking and Okhotsk blocking are inactive, zonal circulation prevails in the mid–high latitudes, and the western Pacific subtropical high tends to be weaker and locates to the north of its normal position in the following summer. This leads to above-normal moisture penetrating into the northern part of East China, and significant positive(negative) precipitation anomalies over North China(the Yangtze River–Huaihe River basins), and vice versa. Further examination shows that the SST anomalies over the Northwest Pacific and subtropical central North Pacific may both contribute to the formation of EUIV-related circulation anomalies over the western North Pacific.  相似文献   

15.
The low frequency oscillation in both hemispheres and its possible role in the dust weather storm events over North China in 2002 are analyzed as a case study. Results show that the Aleutian Low is linked with the Circumpolar Vortex in the Southern Hemisphere on a 30-60-day oscillation, with a weak Circumpolar Vortex tending to deepen the Aleutian Low which may be helpful for the generation of dust storm events. The possible mechanism behind this is the inter-hemispheric interaction of the mean meridional circulation, with the major variability over East Asia. The zonal mean westerly wind at high latitudes of the Southern Hemisphere in the upper level troposphere may lead that of the Northern Hemisphere, which then impacts the local circulation in the Northern Hemisphere. Thus, the low frequency oscillation teleconnection is one possible linkage in the coupling between the Southern Hemisphere circulation and dust events over North China. However, the interannual variation of the low frequency oscillation is unclear.  相似文献   

16.
Impacts of Coastal SST Variability on the East Asian Summer Monsoon   总被引：4，自引：0，他引：4  
The impacts of the seasonal and interannual SST variability in the East Asia coastal regions （EACRSST） on the East Asian summer monsoon （EASM） have been examined using a regional climate model （PδRCM9） in this paper. The simulation results show that the correlation between the EACRSST and the EASM is strengthened after the mid-1970s and also the variability of the EACRSST forcing becomes much more important to the EASM interannual variability after the mid-1970s. The impacts of the EACRSST on the summer precipitation over each sub-region in the EASM region become weak gradually from south to north, and the temporal evolution features of the summer precipitation differences over North and Northeast China agree well with those of the index of EASM （IEASM） differences.
The mechanism analyses show that different EACRSST forcings result in the differences of sensible and latent heat flux exchanges at the air-sea interface, which alter the heating rate of the atmosphere. The heating rate differences induce low level air temperature differences over East Asia, resulting in the differences of the land-sea thermal contrast （LSTC） which lead to 850 hPa geopotential height changes. When the 850 hPa geopotential height increases over the East Asian continent and decreases over the coast of East China and the adjacent oceans during the weakening period of weakens consequently. On the contrary, the EASM enhances during the strengthening period of the LSTC.  相似文献   

17.
The impact of strong (weak) intraseasonal oscillation (ISO) over South China Sea (SCS) and South Asia (SA) in summer on the SCS and SA summer monsoon and the summer rainfall in Eastern China are studied by using the NCEP-NCAR analysis data and the rainfall data of 160 stations in China from 1961 to 2010. It is found that the impacts are significantly different in different months of summer. The study shows that in June and July cyclonic (anticyclonic) atmospheric circulation over SCS and SA corresponds to strong (weak) ISO over SCS. In August, however, strong (weak) ISO over SCS still corresponds to cyclonic (anticyclonic) atmospheric circulation over SA. In June and August cyclonic (anticyclonic) atmospheric circulation over South Asia corresponds to strong (weak) ISO over SA while a strong (weak) ISO corresponds to anticyclonic (cyclonic) atmospheric circulation over SA in July. Besides, in June the strong (weak) ISO over SA corresponds to cyclonic (anticyclonic) atmospheric circulation over SCS, while in July and August the atmospheric circulation is in the same phase regardless of whether the ISO over SA is strong or weak. The impacts of the strong（weak）ISO over SCS on the rainfall of eastern China are similar in June and July, which favors less (more) rainfall in Yangtze-Huaihe Rivers basin but sufficient (deficient) rainfall in the south of Yangtze River. However, the impacts are not so apparent in August. In South Asia, the strong (weak) ISO in July results in less (more) rainfall in the south of Yangtze River but sufficient (deficient) rainfall in Yangtze-Huaihe Rivers basin. The influence on the rainfall in eastern China in June and August is not as significant as in July.  相似文献   

18.
Climate data from the Climatic Research Unit(CRU) for the period 1901–2013 are used to investigate the drought response to air temperature change over China on the centennial scale. Drought is observed to have increased evidently across China, except for some regions in eastern China. This increase is much stronger in northern China compared to southern China, especially in Northwest and North China. These change characteristics of drought are closely associated with air temperature change, with the severe droughts in the major drought episodes of the last century generally coinciding with higher temperatures. The significantly increasing trend of drought in China based on observations only appears when considering the effects of air temperature change,which can explain ~49% of droughts in observations and30%–65% of droughts in Coupled Model Intercomparison Project Phase 5(CMIP5) model simulations. Furthermore, the response of drought to air temperature change generally increases as the drought time scale increases.Furthermore, drought shows relatively high sensitivity in spring and early summer in China on the centennial scale.  相似文献   

19.
We evaluated the ability of the Beijing Climate Center models on different horizontal resolutions(BCC-CSM1.1 on approximately 280-km resolution and BCC-CSM1.1 m on approximately 110-km resolution) in simulating the nearsurface wind speeds(NWS) in China during 1961–2005. The spatial distribution of the annual mean NWS over China is better captured by BCC-CSM1.1 m than by BCC-CSM1.1 due to the finer resolution. The weakened NWS over China during 1961–2005 cannot be reproduced by BCC-CSM1.1, whereas BCC-CSM1.1 m is able to simulate the decreasing trend of the autumn NWS in North China, although the magnitude is about 1/3 of the observed value.This is attributed to the better performance of this finer-resolution model in reproducing the increase in sea level pressure over Mongolia and North China over the past 45 years. The results suggest that increasing the horizontal resolution of the BCC-CSM model has improved its ability in reproducing the spatial distribution and long-term changes of NWS over China. Future projections by BCC-CSM1.1 m under different Representative Concentration Pathway(RCP) scenarios demonstrate that the autumn NWS in North China will decrease during the 21 st century under both the middle(RCP4.5) and high(RCP8.5) emission scenarios, with a higher decreasing rate under RCP8.5.  相似文献   

20.
Anomalous patterns of the atmospheric circulation and climate are studied corresponding to the two basic interdecadal variation modes of sea surface temperature (SST) in the North Pacific, namely, the 25-35-year mode and the 7-10-year mode. Results clearly indicate that corresponding to the positive and negative phases of the interdecadal modes of SST anomaly (SSTA) in the North Pacific, the anomalous patterns of the atmospheric circulation and climate are approximately out of phase, fully illustrating the important role of the interdecadal modes of SST. Since the two interdecadal modes of SSTA in the North Pacific have similar horizontal structures, their impacts on the atmospheric circulation and climate are also analogous. The impact of the interdecadal modes of the North Pacific SST on the atmospheric circulation is barotropic at middle latitudes and baroclinic in tropical regions.  相似文献   

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