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1.
利用RIEMS-LRM对黄河河川径流的模拟研究 总被引：11，自引：0，他引：11
ZHANG Jingyong DONG Wenjie FU Congbin WU Lingyun XIONG Zhe MA Jun ZHANG Kejia 《大气科学进展》2003,20(3):415-424
利用区域系统环境集成模式(RIEMS）和一个offline的大尺度汇流模型(LRM)对黄河的河川径流做了模拟。中国科学院大气物理所东亚中心从1991年开始建立和发展RIEMS，并验证RIEMS对东亚区域气候有较好的模拟能力。LRM是以线性时基不变假定为基础并能够计算水的水平传输的数学模型。RIEMS—LRM可以用来模拟和预测大尺度河流的河川径流。RIEMS—LRM在黄河上游河段的应用证实其有能力对大尺度河流的河川径流进行模拟。此外，作还分析了模拟误差产生的原因。 相似文献
2.
介绍了中国科学院大气物理研究所东亚中心在全球变化科学研究方面的一些进展.主要包括:(1)参与了国际和国内全球变化科学的开拓工作;(2)提出了区域水平上的全球变化研究新方向;(3)气候突变和全球增暖的区域响应研究;(4)东亚季风区植被-大气相互作用研究;(5)区域环境系统模式的发展和亚洲区域模式的国际比较研究活动;(6)提出了对全球变化的人类有序适应的概念、试验观测、理论和方法;(7)面向国家需求的全球变化问题北方干旱化研究;(8)陆地生态系统碳循环研究等. 相似文献
3.
南半球中纬度偶极模态与亚洲—非洲夏季降水 总被引：1，自引：1，他引：0
南半球大气环流第一模态为南极涛动, 它表现出较好的纬向对称结构。本工作利用经验正交分解方法研究发现, 在南半球的东半球, 夏季(6~9月)大气环流还存在一个重要的模态。不同于南极涛动, 该模态表现为显著的纬向偶极分布, 本文定义其为偶极模态。在海平面气压场上, 该模态的解释方差可以达到20%以上, 表现出显著的年际变化特征。进一步的研究发现, 该偶极模态与亚非夏季降水存在密切联系, 尤其与我国华南、南亚以及热带非洲东部地区的夏季降水存在显著的正相关关系。机制分析表明, 南半球这一偶极模态的异常会影响东半球越赤道气流的变化, 从而造成向上述三个地区的水汽输送的多寡, 并最终导致这三个地区夏季降水发生变化。本工作揭示的偶极模态变化独立于南极涛动, 研究结果不但可以深化对南半球环流系统变化特征及影响的认识, 而且对亚非夏季降水的变化特征和机制研究也具有重要意义。 相似文献
4.
Abrupt Climate Change around 4 ka BP： Role of the Thermohaline Circulation as Indicated by a GCM Experiment 总被引：8，自引：1，他引：8
A great deal of palaeoenvironmental and palaeoclimatic evidence suggests that a predominant tem-perature drop and an aridification occurred at ca. 4.0 ka BP. Palaeoclimate studies in China support thisdedution. The collapse of ancient civilizations at ca. 4.0 ka BP in the Nile Valley and Mesopotamia hasbeen attributed to climate-induced aridification. A widespread alternation of the ancient cultures was alsofound in China at ca. 4.0 ka BP in concert with the collapse of the civilizations in the Old World. Palaeo-climatic studies indicate that the abrupt climate change at 4.0 ka BP is one of the realizations of the coldphase in millennial scale climate oscillations, which may be related to the modulation of the ThermohalineCirculation (THC) over the Atlantic Ocean. Therefore, this study conducts a numerical experiment ofa GCM with SST forcing to simulate the impact of the weakening of the THC. Results show a drop intemperature from North Europe, the northern middle East Asia, and northern East Asia and a significantreduction of precipitation in East Africa, the Middle East, the Indian Peninsula, and the Yellow RiverValley. This seems to support the idea that coldness and aridification at ca. 4.0 ka BP was caused by theweakening of the THC. 相似文献
5.
Abrupt Climate Change around 4 ka BP:Role of the Thermohaline Circulation as Indicated by a GCM Experiment 总被引：11，自引：0，他引：11
A great deal of palaeoenvironmental and palaeoclimatic evidence suggests that a predominant temperature drop and an aridiflcation occurred at ca. 4.0 ka BP. Palaeoclimate studies in China support this dedution. The collapse of ancient civilizations at ca. 4.0 ka BP in the Nile Valley and Mesopotamia has been attributed to climate-induced aridification. A widespread alternation of the ancient cultures was also found in China at ca. 4.0 ka BP in concert with the collapse of the civilizations in the Old World. Palaeoclimatic studies indicate that the abrupt climate change at 4.0 ka BP is one of the realizations of the cold phase in millennial scale climate oscillations, which may be related to the modulation of the Thermohaline Circulation (THC) over the Atlantic Ocean. Therefore, this study conducts a numerical experiment of a GCM with SST forcing to simulate the impact of the weakening of the THC. Results show a drop in temperature from North Europe, the northern middle East Asia, and northern East Asia 相似文献
6.
欧亚大陆夏季地表气温在近四十年有显著的升温趋势,本文基于ERA5再分析数据研究了1979～2019年间欧亚大陆不同区域的夏季地表气温的变化特征,并利用气候反馈响应分析方法揭示了各区域变暖原因的异同。作为全球海拔最高的大地形,青藏高原在过去四十年经历了显著的增温过程。青藏高原周边相对低海拔的地区（如北非—南欧地区、蒙古地区、东北亚地区）同样表现出明显的变暖特征,而高原南侧的南亚地区的地表气温却变化不明显。青藏高原夏季积雪融化引起的地表反照率减小使得更多短波辐射到达地表,放大高原地表增暖。北非—南欧地区增暖则主要源于大气气溶胶含量减少造成的入射短波辐射增加。同时,大气温度升高导致的向下长波辐射增强对北非—南欧地区以及蒙古地区的增暖都有显著贡献。此外,东北亚地区云的减少是造成其地表增暖最主要的过程,而南亚地区则是水汽增加和感热通量减少造成的增温与云和气溶胶增加造成的降温相抵消,因而温度变化幅度不大。 相似文献
7.
The CASA (Carnegie-Ames-Stanford) ecosystem model has been used to estimate monthly carbon fluxes in terrestrial ecosystems from 2000 to 2009, with global data inputs from NASA??s Terra Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation cover mapping. Net primary production (NPP) flux for atmospheric carbon dioxide has varied slightly from year-to-year, but was predicted to have increased over short multi-year periods in the regions of the high-latitude Northern Hemisphere, South Asia, Central Africa, and the western Amazon since the year 2000. These CASA results for global NPP were found to be in contrast to other recently published modeling trends for terrestrial NPP with high sensitivity to regional drying patterns. Nonetheless, periodic declines in regional NPP were predicted by CASA for the southern and western Untied States, the southern Amazon, and southern and eastern Africa. NPP in tropical forest zones was examined in greater detail to discover lower annual production values than previously reported in many global models across the tropical rainforest zones, likely due to the enhanced detection of lower production ecosystems replacing primary rainforest. 相似文献
8.
Global monsoons in the mid-Holocene and oceanic feedback 总被引：10，自引：3，他引：10
The response of the six major summer monsoon systems (the North American monsoon, the northern Africa monsoon, the Asia monsoon, the northern Australasian monsoon, the South America monsoon and the southern Africa monsoon) to mid-Holocene orbital forcing has been investigated using a coupled ocean–atmosphere general circulation model (FOAM), with the focus on the distinct roles of the direct insolation forcing and oceanic feedback. The simulation result is also found to compare well with the NCAR CSM. The direct effects of the change in insolation produce an enhancement of the Northern Hemisphere monsoons and a reduction of the Southern Hemisphere monsoons. Ocean feedbacks produce a further enhancement of the northern Africa monsoon and the North American monsoon. However, ocean feedbacks appear to weaken the Asia monsoon, although the overall effect (direct insolation forcing plus ocean feedback) remains a strengthened monsoon. The impact of ocean feedbacks on the South American and southern African monsoons is relatively small, and therefore these regions, especially the South America, experienced a reduced monsoon regime compared to present. However, there is a strong ocean feedback on the northern Australian monsoon that negates the direct effects of orbital changes and results in a strengthening of austral summer monsoon precipitation in this region. A new synthesis is made for mid-Holocene paleoenvironmental records and is compared with the model simulations. Overall, model simulations produce changes in regional climates that are generally consistent with paleoenvironmental observations. 相似文献
9.
Northern Hemisphere circulations differ considerably between individual El Niño-Southern Oscillation events due to internal atmospheric variability and variation in the zonal location of sea surface temperature forcing over the tropical Pacific Ocean. This study examines the similarities between recent Northern Hemisphere droughts associated with La Niña events and anomalously warm tropical west Pacific sea surface temperatures during 1988–1989, 1998–2000, 2007–2008 and 2010–2011 in terms of the hemispheric-scale circulations and the regional forcing of precipitation over North America and Asia during the cold season of November through April. The continental precipitation reductions associated with recent central Pacific La Niña events were most severe over North America, eastern Africa, the Middle East and southwest Asia. High pressure dominated the entire Northern Hemisphere mid-latitudes and weakened and displaced storm tracks northward over North America into central Canada. Regionally over North America and Asia, the position of anomalous circulations within the zonal band of mid-latitude high pressure varied between each La Niña event. Over the northwestern and southeastern United States and southern Asia, the interactions of anomalous circulations resulted in consistent regional temperature advection, which was subsequently balanced by similar precipitation-modifying vertical motions. Over the central and northeastern United States, the spatial variation of anomalous circulations resulted in modest inter-seasonal temperature advection variations, which were balanced by varying vertical motion and precipitation patterns. Over the Middle East and eastern Africa, the divergence of moisture and the advection of dry air due to anomalous circulations enhanced each of the droughts. 相似文献
10.
不同区域气候模式对中国地区温度和降水的长期模拟比较 总被引：19，自引：9，他引：19
利用亚洲区域模式比较计划RMIP第二阶段五个区域模式和一个变网格全球模式，对中国地区1988年12月～1998年11月十年模拟的平均温度和降水结果，分析比较了不同区域气候模式对中国地区温度和降水的模拟能力。研究结果表明:几乎所有模式都能模拟出中国地区多年平均温度和降水的基本空间分布形态，但模式模拟的温度普遍偏低，在大部分区域，大多数模式模拟的降水偏多，而且不同模式之间存在较大差别。模式能较好地反映出中国地区温度的年际变化，对夏季降水的年际变化模拟较差，对冬季模拟较好。 相似文献
11.
The Afro-Asian summer monsoon is a zonally planetary-scale system, with a large-scale rainbelt covering Africa, South Asia and East Asia on interdecadal timescales both in the past century(1901–2014) and during the last three decades(1979–2014). A recent abrupt change of precipitation occurred in the late 1990 s. Since then, the entire rainbelt of the Afro-Asia monsoon system has advanced northwards in a coordinated way. Consistent increases in precipitation over the Huanghe–Huaihe River valley and the Sahel are associated with the teleconnection pattern excited by the warm phase of the Atlantic Multidecadal Oscillation(AMO). A teleconnection wave train, with alternating cyclones/anticyclones, is detected in the upper troposphere. Along the teleconnection path, the configuration of circulation anomalies in North Africa is characterized by coupling of the upper-level anticyclone(divergence) with low-level thermal low pressure(convergence), facilitating the initiation and development of ascending motions in the Sahel. Similarly, in East Asia, a coupled circulation pattern also excites ascending motion in the Huanghe–Huaihe River valley. The synchronous increase in precipitation over the Sahel and Huanghe–Huaihe River valley can be attributed to the co-occurrences and in-phase changes of ascending motion. On the other hand, the warm phase of the AMO results in significant warming in the upper troposphere in North Africa and the northern part of East Asia. Such warming contributes to intensification of the tropical easterly jet through increasing the meridional pressure gradient both at the entrance region(East Asia) and the exit region(Africa). Accordingly, precipitation over the Sahel and Huanghe–Huaihe River valley intensifies, owing to ageostrophic secondary cells. The results of this study provide evidence for a consistent and holistic interdecadal change in the Afro-Asian summer monsoon. 相似文献
12.
By KRISTIN RYPDAL NATHAN RIVE TERJE K. BERNTSEN ZBIGNIEW KLIMONT TORBEN K. MIDEKSA GUNNAR MYHRE RAGNHILD B. SKEIE 《Tellus. Series B, Chemical and physical meteorology》2009,61(4):625-641
Abatement of particulate matter has traditionally been driven by health concerns rather than its role in global warming. Here we assess future abatement strategies in terms of how much they reduce the climate impact of black carbon (BC) and organic carbon (OC) from contained combustion. We develop global scenarios which take into account regional differences in climate impact, costs of abatement and ability to pay, as well as both the direct and indirect (snow-albedo) climate impact of BC and OC. To represent the climate impact, we estimate consistent region-specific values of direct and indirect global warming potential (GWP) and global temperature potential (GTP). The indirect GWP has been estimated using a physical approach and includes the effect of change in albedo from BC deposited on snow. The indirect GWP is highest in the Middle East followed by Russia, Europe and North America, while the total GWP is highest in the Middle East, Africa and South Asia. We conclude that prioritizing emission reductions in Asia represents the most cost-efficient global abatement strategy for BC because Asia is (1) responsible for a large share of total emissions, (2) has lower abatement costs compared to Europe and North America and (3) has large health cobenefits from reduced PM10 emissions. 相似文献
13.
INFORM Risk Index is a global indicator-based disaster risk assessment tool that combines hazards, exposure, vulnerability and lack of coping capacity indicators with the purpose to support humanitarian crisis management decisions considering the current climate and population. In this exploratory study, we extend the Index to include future climate change and population projections using RCP 8.5 climate projections of coastal flood, river flood and drought, and SSP3 and SSP5 population projections for the period 2036 to 2065. For the three hazards considered, annually 1.3 billion people (150% increase), 1.8 billion people (249% increase) and 1.5 billion people (197% increase) in the mid-21st century are projected to be exposed under the 2015, SSP3 and SSP5 population estimates, respectively. Drought shows the highest exposure levels followed by river flood and then coastal flood, with some regional differences. The largest exposed population is projected in Asia, while the largest percent changes are projected in Africa and Oceania. Countries with largest current and projected risk including non-climatic factors are generally located in Africa, West and South Asia and Central America. An uncertainty analysis of the extended index shows that it is generally robust and not influenced by the methodological choices. The projected changes in risk and coping capacity (vulnerability) due to climate change are generally greater than those associated with population changes. Countries in Europe, Western and Northern Asia and Africa tend to show higher reduction levels in vulnerability (lack of coping capacity) required to nullify the adverse impacts of the projected amplified hazards and exposure. The required increase in coping capacity (decreased vulnerability) can inform decision-making processes on disaster risk reduction and adaptation options to maintain manageable risk levels at global and national scale. Overall, the extended INFORM Risk Index is a means to integrate Disaster Risk Reduction and Climate Change Adaptation policy agendas to create conditions for greater policy impact, more efficient use of resources and more effective action in protecting life, livelihoods and valuable assets. 相似文献
14.
A regional climate model, the Weather Research and Forecasting (WRF) Model, is forced with increased atmospheric CO2 and anomalous SSTs and lateral boundary conditions derived from nine coupled atmosphere–ocean general circulation models to produce an ensemble set of nine future climate simulations for northern Africa at the end of the twenty-first century. A well validated control simulation, agreement among ensemble members, and a physical understanding of the future climate change enhance confidence in the predictions. The regional model ensembles produce consistent precipitation projections over much of northern tropical Africa. A moisture budget analysis is used to identify the circulation changes that support future precipitation anomalies. The projected midsummer drought over the Guinean Coast region is related partly to weakened monsoon flow. Since the rainfall maximum demonstrates a southward bias in the control simulation in July–August, this may be indicative of future summer drying over the Sahel. Wetter conditions in late summer over the Sahel are associated with enhanced moisture transport by the West African westerly jet, a strengthening of the jet itself, and moisture transport from the Mediterranean. Severe drought in East Africa during August and September is accompanied by a weakened Indian monsoon and Somali jet. Simulations with projected and idealized SST forcing suggest that overall SST warming in part supports this regional model ensemble agreement, although changes in SST gradients are important over West Africa in spring and fall. Simulations which isolate the role of individual climate forcings suggest that the spatial distribution of the rainfall predictions is controlled by the anomalous SST and lateral boundary conditions, while CO2 forcing within the regional model domain plays an important secondary role and generally produces wetter conditions. 相似文献
15.
根据1979~2016年春季海表温度、土壤温度以及大尺度气候指数与中亚地区夏季温度的相关关系,确定了印度洋东南部海表温度、非洲西北部土壤温度、大西洋多年代际振荡（AMO）和东亚/西俄型（EA/WR）4个春季预测因子,进而建立了中亚地区夏季温度的预测模型。春季印度洋东南部海表温度暖异常、非洲西北部土壤温度暖异常、AMO正异常与EA/WR负异常均对应夏季中亚地区500 hPa位势高度场正异常,为该地区夏季高温发生提供有利条件。预测模型留一法交叉验证产生的1979~2016年中亚地区夏季温度无（有）趋势的时间序列与观测的无（有）趋势的时间序列的相关为0.65（0.74）,表明该预测模型具有良好的预测能力。研究结果有望帮助提高中亚地区夏季温度的预测技巧。 相似文献
16.
根据台湾省及东南亚地区高空天气图资料及探空资料，分析东风喷射气流之平均位置和特性，并就青藏高原、副热带西风喷射气流和东风喷射气流之关系，讨论东风喷射气流之成因以及对北半球天气和气候之影响，东风喷射气流之南北两侧存在着极强烈的混切现象，这种温切现象不但与东风喷射气流有关，而且对高空民航机之飞航安全有极重大的影响。 相似文献
17.
2001年全球重大气候事件概述 总被引：1，自引：0，他引：1
全球气候仍持续偏暖。亚洲大部出现异常冷冬，许多地区遇到数十年未见的风雪严寒；美国冬季也连续遭受暴风雪袭击。东亚、南亚、中亚有西亚发生了大范围的持久干旱，南亚、东南亚夏季暴雨频繁，造成严重洪涝灾害。欧洲、非洲及南美洲的许多国家和地区降水异常偏多，导致不同程度的洪水，俄罗斯西伯利亚地区发生百年不遇的大洪水。北大西洋飓风较常年显著偏多，西北太平洋台风也给沿海地区带来严重灾害。 相似文献
18.
Aerosols make a considerable contribution to the climate system through their radiative and cloud condensation nuclei effects, which underlines the need for understanding the origin of aerosols and their transport pathways. Seasonal distribution of mineral dust around the globe and its correlation with atmospheric circulation is investigated using satellite data, and meteorological data from ECMWF. The most important sources of dust are located in North Africa, the Middle East and Southwest Asia with an observed summer maximum, and East Asia with a spring peak. Maximum dust activity over North Africa and the Middle East in summer is attributed to dry convection associated with the summertime low-pressure system, while unstable weather and dry conditions are responsible for the spring peak in dust emission in East Asia. Intercontinental transport of mineral dust by atmospheric circulation has been observed, including trans-Atlantic transport of North African dust, trans-Pacific transport of Asian dust, and transport of dust from the Middle East across the Indian Ocean. The extent of African dust over the Atlantic Ocean and its latitudinal variation with season is related to the large-scale atmospheric circulation, including seasonal changes in the position of the intertropical convergence zone (ITCZ) and variation of wind patterns. North African aerosols extend over longer distances across the North Atlantic in summer because of greater dust emission, an intensified easterly low level jet (LLJ) and strengthening of the Azores-Bermuda anticyclonic circulation. Transport of East Asian aerosol is facilitated by the existence of a LLJ that extends from East Asia to the west coast of North America. 相似文献
19.
Skill and reproducibility of seasonal rainfall patterns in the tropics in ECHAM-4 GCM simulations with prescribed SST 总被引：1，自引：1，他引：0
The ECHAM4 atmospheric general circulation model (GCM) has been integrated at T30 resolution through the period 1960–1994
forced with the observed sea-surface temperatures (SSTs) as compiled at the Hadley Centre (GISST2.2). Three experiments were
made starting from different initial conditions. The large-scale tropical precipitation patterns simulated by the model have
been studied, focusing on the skill (i.e. the capability to simulate the observed anomaly over land areas) and reproducibility
(i.e. the GCM’s interannual rainfall variance that is independent from the initial conditions). Analysis of variance is used
to estimate the reproducibility amongst ensemble members at each grid-box, but most emphasis is placed on large-scale patterns,
as revealed by various singular value decomposition analyses (SVDAs), between observed and model fields (OM analyses) and
amongst the different model runs (MM analyses). Generally, it is found that the first model mode in the MM analysis is very
similar to that in the OM analysis, suggesting the model mode with strongest reproducibility is also the mode which tallies
best with observations. For the global tropics, the first MM mode is highly reproducible (external variance above 90%) and
the first OM couplet is very skillful (correlation between observed and model SVDA time series is over 0.84). The extent to
which skill and reproducibility is related to El Nino/Southern Oscillation (ENSO) has been investigated by comparing the OM
and MM time series with the Southern Oscillation Index (SOI). For the global tropics, most of the OM and MM variance is common
with the SOI, though in boreal summer, the first modes do also have some clear independence from the SOI. The analyses were
repeated at the regional scale for Oceania, tropical America, tropical Africa and tropical Southeast Asia. A highly reproducible
mode is found in all cases except October-December in Africa. Skill, while always positive, is more variable, strongest for
Oceania and tropical America and weakest for Africa. Comparisons with the SOI suggest skill in tropical America and tropical
Africa has substantial components that are independent of the SOI, especially in boreal spring and summer when the tropical
Atlantic SSTs are strongly related to the leading OM and MM time series.
Received: 1 January 1997 / Accepted: 28 July 1997 相似文献
20.
Water harvesting has been widely applied in different social-ecological contexts, proving to be a valuable approach to sustainable intensification of agriculture. Global estimates of the potential of water harvesting are generally based on purely biophysical assessments and mostly neglect the socioeconomic dimension of agriculture. This neglect becomes a critical factor for the feasibility and effectiveness of policy and funding efforts to mainstream this practice. This study uses archetype analysis to systematically identify social-ecological regions worldwide based on >160 successful cases of local water harvesting implementation. We delineate six archetypal regions which capture the specific social-ecological conditions of the case studies. The archetypes cover 19% of current global croplands with hotspots in large portions of East Africa and Southeast Asia. We estimate that the adoption of water harvesting in these cropland areas can increase crop production up to 60–100% in Uganda, Burundi, Tanzania and India. The results of this study can complement conventional biophysical analysis on the potential of these practices and guide policy development at global and regional scales. The methodological approach can be also replicated at finer scales to guide the improvement of rainfed agricultural. 相似文献