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1.
A Modeling Study of the Effects of Direct Radiative Forcing
Due to Carbonaceous Aerosol on the Climate in East Asia 总被引：6，自引：0，他引：6
The study investigated the effects of global direct radiative forcing due to carbonaceous
aerosol on the climate in East Asia, using the CAM3 developed by NCAR. The results showed that
carbonaceous aerosols cause negative forcing at the top of the atmosphere (TOA) and surface under
clear sky conditions, but positive forcing at the TOA and weak negative forcing at the surface under
all sky conditions. Hence, clouds could change the sign of the direct radiative forcing at the TOA,
and weaken the forcing at the surface. Carbonaceous aerosols have distinct effects on the summer
climate in East Asia. In southern China and India, it caused the surface temperature to increase,
but the total cloud cover and precipitation to decrease. However, the opposite effects are caused
for most of northern China and Bangladesh. Given the changes in temperature, vertical velocity,
and surface streamflow caused by carbonaceous aerosol in this simulation, carbonaceous aerosol
could also induce summer precipitation to decrease in southern China but increase in northern China. 相似文献
2.
The approach of conditional nonlinear optimal perturbation related to parameter (CNOP-P) is employed to provide a possible climate scenario and to study the impact of climate change on the simulated net primary production (NPP) in China within a state-of-the-art Lund-Potsdam-Jena dynamic global vegetation model (LPJ DGVM). The CNOP-P, as a type of climate perturbation to bring variation in climatology and climate variability of the reference climate condition, causes the maximal impact on the simulated NPP in China. A linear climate perturbation that induces variation in climatology, as another possible climate scenario, is also applied to explore the role of variation in climate variability in the simulated NPP. It is shown that NPP decreases in northern China and increases in northeastern and southern China when the temperature changes as a result of a CNOP-P-type temperature change scenario. A similar magnitude of change in the spatial pattern variations of NPP is caused by the CNOP-P-type and the linear temperature change scenarios in northern and northeastern China, but not in southern China. The impact of the CNOP-P-type temperature change scenario on magnitude of change of NPP is more intense than that of the linear temperature change scenario. The numerical results also show that in southern China, the change in NPP caused by the CNOP-P-type temperature change scenario compared with the reference simulated NPP is sensitive. However, this sensitivity is not observed under the linear temperature change scenario. The seasonal simulations indicate that the differences between the variations in NPP due to the two types of temperature change scenarios principally stem from the variations in summer and autumn in southern China under the LPJ model. These numerical results imply that NPP is sensitive to the variation in temperature variability. The results influenced by the CNOP-P-type precipitation change scenario are similar to those under the linear precipitation change scenario, which cause the increasing NPP in arid and semi-arid regions of the northern China. The above findings indicate that the CNOP-P approach is a useful tool for exploring the nonlinear response of NPP to climate variability. 相似文献
3.
4.
利用国家气候中心完成的RegCM4区域气候模式在RCP4.5和RCP8.5两种排放路径下的气候变化动力降尺度试验结果,在检验模式对基准期(1986—2005年)气温和降水模拟能力基础上,进行华北区域21世纪气候变化预估分析。结果表明:RegCM4对华北区域基准期气温和降水的模拟能力较好。未来21世纪,两种情景下华北区域气温、降水、持续干期(consecutive dry days, CDD)和强降水量(R95p)变化逐渐增大,但变化幅度在高排放的RCP8.5情景下更为显著,其中近期(2021—2035年)、中期(2046—2065年)、远期(2080—2098年)RCP8.5情景下年平均气温分别升高1.77、3.44、5.82℃,年平均降水分别增加8.1%、14%、19.3%,CDD分别减少3、3、12 d, R95p分别增加30.8%、41.9%、69.8%。空间上,未来21世纪华北区域内年、冬季、夏季平均气温将一致升高,夏季升温幅度最大;年、冬季、夏季平均降水整体以增加为主,冬季降水增加幅度最大;CDD以减少为主,但近期和中期在山西和京津冀有所增加,而R95p以增加为主,表明21世纪华北区域干旱事件逐渐减少、极端降水事件不断增加。 相似文献
5.
Numerical Simulation for the Impact of Deforestation on Climate in China and Its Neighboring Regions 总被引：2，自引：0，他引：2
ＮｕｍｅｒｉｃａｌＳｉｍｕｌａｔｉｏｎｆｏｒｔｈｅＩｍｐａｃｔｏｆＤｅｆｏｒｅｓｔａｔｉｏｎ ｏｎ Ｃｌｉｍａｔｅ ｉｎ ＣｈｉｎａａｎｄＩｔｓＮｅｉｇｈｂｏｒｉｎｇ ＲｅｇｉｏｎｓＳｏｎｇＹｕｋｕａｎ（宋玉宽）；ＣｈｅｎＬｏｎｇｘｕｎ（陈隆勋）ａｎ... 相似文献
6.
未来气候情景下冬小麦潜在北移区农业气候资源变化特征 总被引：1，自引：0，他引：1
基于区域气候模式系统PRECIS输出的RCP4.5气候情景数据分析表明,相较于1981-2010年,至2071-2097年冬小麦种植北界将平均向北移动147.8 km,北移面积约1.86×105 km2。选取代表光、温、水资源的9项农业气候资源指标,探究未来情景下,2021-2097年冬小麦潜在北移区内农业气候资源变化特征,结果表明：(1)相较于基准时段(1961-1990年),未来潜在北移区内光照资源变化呈减少趋势;热量资源呈明显增加趋势,在21世纪末的30年,波动性加大;降水资源整体增加趋势不明显,但波动性亦呈现增大趋势。(2)未来潜在北移区内,2030T (2021-2050年)、2050T (2041-2070年)和2070T (2061-2090年)时段光照资源在研究区域的东北部减少幅度较大,而在西南部较小;热量资源在研究区域的北部增加比南部明显;降水资源则主要在研究区域的东北部增加明显。 相似文献
7.
Shu Li Tijian Wang Prodromos Zanis Dimitris Melas Bingliang Zhuang 《Acta Meteorologica Sinica》2018,32(2):279-287
The spatial distribution, radiative forcing, and climatic effects of tropospheric ozone in China during summer were investigated by using the regional climate model RegCM4. The results revealed that the tropospheric ozone column concentration was high in East China, Central China, North China, and the Sichuan basin during summer. The increase in tropospheric ozone levels since the industrialization era produced clear-sky shortwave and clear-sky longwave radiative forcing of 0.18 and 0.71 W m–2, respectively, which increased the average surface air temperature by 0.06 K and the average precipitation by 0.22 mm day–1 over eastern China during summer. In addition, tropospheric ozone increased the land–sea thermal contrast, leading to an enhancement of East Asian summer monsoon circulation over southern China and a weakening over northern China. The notable increase in surface air temperature in northwestern China, East China, and North China could be attributed to the absorption of longwave radiation by ozone, negative cloud amount anomaly, and corresponding positive shortwave radiation anomaly. There was a substantial increase in precipitation in the middle and lower reaches of the Yangtze River. It was related to the enhanced upward motion and the increased water vapor brought by strengthened southerly winds in the lower troposphere. 相似文献
8.
Jian Liu Bin Wang So-Young Yim June-Yi Lee Jong-Ghap Jhun Kyung-Ja Ha 《Climate Dynamics》2012,39(5):1063-1072
The global summer monsoon precipitation (GSMP) provides a fundamental measure for changes in the annual cycle of the climate system and hydroclimate. We investigate mechanisms governing decadal-centennial variations of the GSMP over the past millennium with a coupled climate model’s (ECHO-G) simulation forced by solar-volcanic (SV) radiative forcing and greenhouse gases (GHG) forcing. We show that the leading mode of GSMP is a forced response to external forcing on centennial time scale with a globally uniform change of precipitation across all monsoon regions, whereas the second mode represents internal variability on multi-decadal time scale with regional characteristics. The total amount of GSMP varies in phase with the global mean temperature, indicating that global warming is accompanied by amplification of the annual cycle of the climate system. The northern hemisphere summer monsoon precipitation (NHSMP) responds to GHG forcing more sensitively, while the southern hemisphere summer monsoon precipitation (SHSMP) responds to the SV radiative forcing more sensitively. The NHSMP is enhanced by increased NH land–ocean thermal contrast and NH-minus-SH thermal contrast. On the other hand, the SHSMP is strengthened by enhanced SH subtropical highs and the east–west mass contrast between Southeast Pacific and tropical Indian Ocean. The strength of the GSMP is determined by the factors controlling both the NHSMP and SHSMP. Intensification of GSMP is associated with (a) increased global land–ocean thermal contrast, (b) reinforced east–west mass contrast between Southeast Pacific and tropical Indian Ocean, and (c) enhanced circumglobal SH subtropical highs. The physical mechanisms revealed here will add understanding of future change of the global monsoon. 相似文献
9.
India has 64 Mha under forests, of which 72% are tropical moist deciduous, dry deciduous, and wet evergreen forest. Projected changes in temperature, rainfall, and soil moisture are considered at regional level for India under two scenarios, the first involving greenhouse gas forcing, and the second, sulphate aerosols. Under the former model, a general increase in temperature and rainfall in all regions is indicated. This could potentially result in increased productivity, and shift forest type boundaries along attitudinal and rainfall gradients, with species migrating from lower to higher elevations and the drier forest types being transformed to moister types. The aerosol model, however, indicates a more modest increase in temperature and a decrease in precipitation in central and northern India, which would considerably stress the forests in these regions.Although India seems to have stabilized the area under forest since 1980, anthropogenic stresses such as livestock pressure, biomass demand for fuelwood and timber, and the fragmented nature of forests will all affect forest response to changing climate. Thus, forest area is unlikely to expand even if climatically suitable, and will probably decrease in parts of northeast India due to extensive shifting cultivation and deforestation. A number of general adaptation measures to climate change are listed. 相似文献
10.
黑碳气溶胶对我国区域气候影响的数值模拟 总被引：7，自引：0，他引：7
利用区域气候模式RegCM3模拟研究了黑碳气溶胶对我国区域气候的影响。以2000年1、4、7、10月为代表,计算分析了黑碳气溶胶的辐射强迫作用、对大气温度和降水的影响及其季节变化特征。模拟结果显示：黑碳气溶胶在大气层顶产生正的辐射强迫,在地表产生负的辐射强迫;黑碳气溶胶的加入使中国大陆地区地面温度发生明显变化,并呈现显著的季节特征,即1月大部分地区的地面温度均有升高;7月北方增温、南方降温;4月和10月地面温度的变化不明显。模拟结果也表明,黑碳气溶胶的排放使我国长江中下游等南方地区夏季降水增加,而北方部分地区降水减少。 相似文献
11.
东亚地区人为气溶胶直接辐射强迫及其气候效应的数值模拟 总被引：6，自引：6，他引：0
利用耦合化学过程的区域气候模式RegCM3,模拟研究3种主要人为排放气溶胶(硫酸盐、黑碳、有机碳)对东亚区域气候的影响.计算分析近20 a来3种气溶胶的时空分布、综合辐射强迫作用及其对地面气温和降水的影响.模拟结果表明:3种气溶胶冬夏季分布有所不同,冬季气溶胶大值区主要分布在南方地区,而夏季大值区北移;气溶胶短波辐射强迫在大气层顶和地面均为负值;气溶胶的加入对东亚地区地表气温有明显影响,冬季降温中心位于四川盆地,夏季降温大值区位于华北地区.气溶胶直接气候效应使得冬季东亚大部分地区降水减少,夏季东亚地区降水与中国南方地区夏季气溶胶浓度有较好的相关关系,中国东部雨带有南移趋势. 相似文献
12.
利用MM5V3区域气候模式单向嵌套ECHAM5全球环流模式的结果,对中国地区实际温室气体浓度下当代气候(1981—2000年)及IPCC A1B情景下21世纪中期气候(2041—2060年)分别进行了水平分辨率为50 km的模拟试验。首先检验全球和区域模式对当代气候的模拟情况,结果表明:区域模式对中国地区地面温度和降水空间分布的模拟能力优于全球模式;与实际观测相比,区域模式模拟的地面温度在中国大部分地区偏低,模拟的降水量偏多,降水位置偏北。IPCCA1B情景下中国地区21世纪中期气候变化的模式结果显示:各季节地面温度在全国范围内都将比当代升高1.2～3.9℃,且升温幅度具有北方大于南方、冬季大于夏季的时空分布特征;降水变化具有一定的区域性和季节性,秋季和冬季降水在全国大部分地区都将增加10%～30%,春季和夏季降水则呈现"北方减少、南方增多"的趋势,变化幅度在-10%～10%之间。21世纪中期地面温度和降水变化还具有一定的年际特征:地面温度在中国地区各子区域均表现为上升趋势,升温速率在0.7～0.9℃/10a之间,温度变率也比当代有所增大;降水在西北地区略呈下降趋势,在其它子区域均为上升,降水变率的变化具有区域性特征。 相似文献
13.
A recent modelling study has shown that precipitation and runoff over land would increase when the reflectivity of marine clouds is increased to counter global warming. This implies that large scale albedo enhancement over land could lead to a decrease in runoff over land. In this study, we perform simulations using NCAR CAM3.1 that have implications for Solar Radiation Management geoengineering schemes that increase the albedo over land. We find that an increase in reflectivity over land that mitigates the global mean warming from a doubling of CO2 leads to a large residual warming in the southern hemisphere and cooling in the northern hemisphere since most of the land is located in northern hemisphere. Precipitation and runoff over land decrease by 13.4 and 22.3%, respectively, because of a large residual sinking motion over land triggered by albedo enhancement over land. Soil water content also declines when albedo over land is enhanced. The simulated magnitude of hydrological changes over land are much larger when compared to changes over oceans in the recent marine cloud albedo enhancement study since the radiative forcing over land needed (?8.2?W?m?2) to counter global mean radiative forcing from a doubling of CO2 (3.3?W?m?2) is approximately twice the forcing needed over the oceans (?4.2?W?m?2). Our results imply that albedo enhancement over oceans produce climates closer to the unperturbed climate state than do albedo changes on land when the consequences on land hydrology are considered. Our study also has important implications for any intentional or unintentional large scale changes in land surface albedo such as deforestation/afforestation/reforestation, air pollution, and desert and urban albedo modification. 相似文献
14.
Leo Šeparović Adelina Alexandru René Laprise Andrey Martynov Laxmi Sushama Katja Winger Kossivi Tete Michel Valin 《Climate Dynamics》2013,41(11-12):3167-3201
The fifth-generation Canadian Regional Climate Model (CRCM5) was used to dynamically downscale two Coupled Global Climate Model (CGCM) simulations of the transient climate change for the period 1950–2100, over North America, following the CORDEX protocol. The CRCM5 was driven by data from the CanESM2 and MPI-ESM-LR CGCM simulations, based on the historical (1850–2005) and future (2006–2100) RCP4.5 radiative forcing scenario. The results show that the CRCM5 simulations reproduce relatively well the current-climate North American regional climatic features, such as the temperature and precipitation multiannual means, annual cycles and temporal variability at daily scale. A cold bias was noted during the winter season over western and southern portions of the continent. CRCM5-simulated precipitation accumulations at daily temporal scale are much more realistic when compared with its driving CGCM simulations, especially in summer when small-scale driven convective precipitation has a large contribution over land. The CRCM5 climate projections imply a general warming over the continent in the 21st century, especially over the northern regions in winter. The winter warming is mostly contributed by the lower percentiles of daily temperatures, implying a reduction in the frequency and intensity of cold waves. A precipitation decrease is projected over Central America and an increase over the rest of the continent. For the average precipitation change in summer however there is little consensus between the simulations. Some of these differences can be attributed to the uncertainties in CGCM-projected changes in the position and strength of the Pacific Ocean subtropical high pressure. 相似文献
15.
An analysis of simulated future surface climate change over the southern half of Korean Peninsula using a RegCM3-based high-resolution
one-way double-nested system is presented. Changes in mean climate as well as the frequency and intensity of extreme climate
events are discussed for the 30-year-period of 2021–2050 with respect to the reference period of 1971–2000 based on the IPCC
SRES B2 emission scenario. Warming in the range of 1–4°C is found throughout the analysis region and in all seasons. The warming
is maximum in the higher latitudes of the South Korean Peninsula and in the cold season. A large reduction in snow depth is
projected in response to the increase of winter minimum temperature induced by the greenhouse warming. The change in precipitation
shows a distinct seasonal variation and a substantial regional variability. In particular, we find a large increase of wintertime
precipitation over Korea, especially in the upslope side of major mountain systems. Summer precipitation increases over the
northern part of South Korea and decreases over the southern regions, indicating regional diversity. The precipitation change
also shows marked intraseasonal variations throughout the monsoon season. The temperature change shows a positive trend throughout
2021–2050 while the precipitation change is characterized by pronounced interdecadal variations. The PDF of the daily temperature
is shifted towards higher values and is somewhat narrower in the scenario run than the reference one. The number of frost
days decreases markedly and the number of hot days increases. The regional distribution of heavy precipitation (over 80 mm/day)
changes considerably, indicating changes in flood vulnerable regions. The climate change signal shows pronounced fine scale
signal over Korea, indicating the need of high-resolution climate simulations 相似文献
16.
Projected changes in South Asian summer monsoon by multi-model global warming experiments 总被引：1，自引：0，他引：1
S. S. Sabade Ashwini Kulkarni R. H. Kripalani 《Theoretical and Applied Climatology》2011,103(3-4):543-565
South Asian summer monsoon (June through September) rainfall simulation and its potential future changes are evaluated in a multi-model ensemble of global coupled climate models outputs under World Climate Research Program Coupled Model Intercomparison Project (WCRP CMIP3) dataset. The response of South Asian summer monsoon to a transient increase in future anthropogenic radiative forcing is investigated for two time slices, middle (2031–2050) and end of the twenty-first century (2081–2100), in the non-mitigated Special Report on Emission Scenarios B1, A1B and A2 .There is large inter-model variability in the simulation of spatial characteristics of seasonal monsoon precipitation. Ten out of the 25 models are able to simulate space–time characteristics of the South Asian monsoon precipitation reasonably well. The response of these selected ten models has been examined for projected changes in seasonal monsoon rainfall. The multi-model ensemble of these ten models projects a significant increase in monsoon precipitation with global warming. The substantial increase in precipitation is observed over western equatorial Indian Ocean and southern parts of India. However, the monsoon circulation weakens significantly under all the three climate change experiments. Possible mechanisms for the projected increase in precipitation and for precipitation–wind paradox have been discussed. The surface temperature over Asian landmass increases in pre-monsoon months due to global warming and heat low over northwest India intensifies. The dipole snow configuration over Eurasian continent strengthens in warmer atmosphere, which is conducive for the enhancement in precipitation over Indian landmass. No notable changes have been projected in the El Niño–Monsoon relationship, which is useful for predicting interannual variations of the monsoon. 相似文献
17.
Zhen-Ming Ge Seppo Kellomäki Heli Peltola Xiao Zhou Hannu Väisänen Harri Strandman 《Climatic change》2013,118(2):259-273
The aim of this study was to estimate the potential impacts of climate change on the spatial patterns of primary production and net carbon sequestration in relation to water availability in Norway spruce (Picea abies) dominated forests throughout Finland (N 60°–N 70°). The Finnish climatic scenarios (FINADAPT) based on the A2 emission scenario were used. According to the results, the changing climate increases the ratio of evapotranspiration to precipitation in southern Finland, while it slightly decreases the ratio in northern Finland, with regionally lower and higher soil water content in the south and north respectively. During the early simulation period of 2000–2030, the primary production and net carbon sequestration are higher under the changing climate in southern Finland, due to a moderate increase in temperature and atmospheric CO2. However, further elevated temperature and soil water stress reduces the primary production and net carbon sequestration from the middle period of 2030–2060 to the final period of 2060–2099, especially in the southernmost region. The opposite occurs in northern Finland, where the changing climate increases the primary production and net carbon sequestration over the 100-year simulation period due to higher water availability. The net carbon sequestration is probably further reduced by the stimulated ecosystem respiration (under climate warming) in southern Finland. The higher carbon loss of the ecosystem respiration probably also offset the increased primary production, resulting in the net carbon sequestration being less sensitive to the changing climate in northern Finland. Our findings suggest that future forest management should carefully consider the region-specific conditions of sites and adaptive practices to climate change for maintained or enhanced forest production and carbon sequestration. 相似文献
18.
RCP4.5情景下中国未来干湿变化预估 总被引：5，自引：0，他引：5
本文采用国际耦合模式比较计划第五阶段(CMIP5)中21个气候模式的试验数据, 利用土壤湿度以及由其他8个地表气象要素计算所得的干旱指数, 预估了RCP4.5(Representative Concentration Pathway 4.5)情景下21世纪中国干湿变化。结果表明:全球气候模式对1986～2005年中国现代干湿分布具备模拟能力, 尽管在西部地区模式与观测间存在一定的差异。在RCP4.5情景下, 21世纪中国区域平均的标准化降水蒸散发指数和土壤湿度均有减小趋势, 与之对应的是短期和长期干旱发生次数增加以及湿润区面积减小。从2016到2100年, 约1.5%～3.5%的陆地面积将从湿润区变成半干旱或半湿润区。空间分布上, 干旱化趋势明显的区域主要位于西北和东南地区, 同时短期和长期干旱发生次数在这两个地区的增加幅度也最大, 未来干旱化的发生时间也较其他地区要早;只在东北和西南地区未来或有变湿倾向, 但幅度较小。在季节尺度上, 北方地区变干主要发生在暖季, 南方则主要以冷季变干为主。造成中国干旱化的原因主要是由降水与蒸散发所表征的地表可用水量减少。 相似文献
19.
The response of monsoon circulation in the northern and southern hemisphere to 6?ka orbital forcing has been examined in 17 atmospheric general circulation models and 11 coupled ocean–atmosphere general circulation models. The atmospheric response to increased summer insolation at 6?ka in the northern subtropics strengthens the northern-hemisphere summer monsoons and leads to increased monsoonal precipitation in western North America, northern Africa and China; ocean feedbacks amplify this response and lead to further increase in monsoon precipitation in these three regions. The atmospheric response to reduced summer insolation at 6?ka in the southern subtropics weakens the southern-hemisphere summer monsoons and leads to decreased monsoonal precipitation in northern South America, southern Africa and northern Australia; ocean feedbacks weaken this response so that the decrease in rainfall is smaller than might otherwise be expected. The role of the ocean in monsoonal circulation in other regions is more complex. There is no discernable impact of orbital forcing in the monsoon region of North America in the atmosphere-only simulations but a strong increase in precipitation in the ocean–atmosphere simulations. In contrast, there is a strong atmospheric response to orbital forcing over northern India but ocean feedback reduces the strength of the change in the monsoon although it still remains stronger than today. Although there are differences in magnitude and exact location of regional precipitation changes from model to model, the same basic mechanisms are involved in the oceanic modulation of the response to orbital forcing and this gives rise to a robust ensemble response for each of the monsoon systems. Comparison of simulated and reconstructed changes in regional climate suggest that the coupled ocean–atmosphere simulations produce more realistic changes in the northern-hemisphere monsoons than atmosphere-only simulations, though they underestimate the observed changes in precipitation in all regions. Evaluation of the southern-hemisphere monsoons is limited by lack of quantitative reconstructions, but suggest that model skill in simulating these monsoons is limited. 相似文献
20.
MIROC_Hires模式模拟我国极端降水非均匀性在CO2浓度增加下的响应 总被引：1，自引：1，他引：0
利用日本东京大学气候系统研究中心、日本环境研究所和日本地球环境研究中心联合研制的全球海气耦合气候系统模式(MIROC_Hires)输出的逐日降水资料,探讨CO2浓度增加下我国极端降水非均匀性的响应及其可能机制。结果表明:(1)就气候平均而言,CO2浓度增加后,我国南部地区极端降水事件的发生更为集中,而北方地区的极端降水事件分布较平均。(2)从年际变率来看,我国南部地区极端降水事件集中度在"A1B试验"中偏小,年际之间的差异不大,而北方地区的极端降水集中度增加,年际之间变化剧烈。(3)CO2浓度增加后,南方和北方地区在水平和垂直上的增温幅度不一致,且整层大气平均的稳定度呈现出南北反相差异。这种不均匀增暖的分布很可能是导致我国极端降水非均匀性在CO2浓度增加后变化的原因。 相似文献