共查询到20条相似文献，搜索用时 593 毫秒
1.
Richard M. Adams Ronald A. Fleming Ching-Chang Chang Bruce A. McCarl Cynthia Rosenzweig 《Climatic change》1995,30(2):147-167
This study uses recent GCM forecasts, improved plant science and water supply data and refined economic modeling capabilities to reassess the economic consequences of long-term climate change on U.S. agriculture. Changes in crop yields, crop water demand and irrigation water arising from climate change result in changes in economic welfare. Economic consequences of the three GCM scenarios are mixed; GISS and GFDL-QFlux result in aggregate economic gains, UKMO implies losses. As in previous studies, the yield enhancing effects of atmospheric CO2 are an important determinant of potential economic consequences. Inclusion of changes in world food production and associated export changes generally have a positive affect on U.S. agriculture. As with previous studies, the magnitude of economic effects estimated here are a small percentage of U.S. agricultural value. 相似文献
2.
J. Reilly F. Tubiello B. McCarl D. Abler R. Darwin K. Fuglie S. Hollinger C. Izaurralde S. Jagtap J. Jones L. Mearns D. Ojima E. Paul K. Paustian S. Riha N. Rosenberg C. Rosenzweig 《Climatic change》2003,57(1-2):43-67
We examined the impacts on U.S. agriculture of transient climate change assimulated by 2 global general circulation models focusing on the decades ofthe 2030s and 2090s. We examined historical shifts in the location of cropsand trends in the variability of U.S. average crop yields, finding thatnon-climatic forces have likely dominated the north and westward movement ofcrops and the trends in yield variability. For the simulated future climateswe considered impacts on crops, grazing and pasture, livestock, pesticide use,irrigation water supply and demand, and the sensitivity to international tradeassumptions, finding that the aggregate of these effects were positive for theU.S. consumer but negative, due to declining crop prices, for producers. Weexamined the effects of potential changes in El Niño/SouthernOscillation (ENSO) and impacts on yield variability of changes in mean climateconditions. Increased losses occurred with ENSO intensity and frequencyincreases that could not be completely offset even if the events could beperfectly forecasted. Effects on yield variability of changes in meantemperatures were mixed. We also considered case study interactions ofclimate, agriculture, and the environment focusing on climate effects onnutrient loading to the Chesapeake Bay and groundwater depletion of theEdward's Aquifer that provides water for municipalities and agriculture to theSan Antonio, Texas area. While only case studies, these results suggestenvironmental targets such as pumping limits and changes in farm practices tolimit nutrient run-off would need to be tightened if current environmentalgoals were to be achieved under the climate scenarios we examined 相似文献
3.
El Niño/Southern Oscillation (ENSO) is considered one of the most powerful forces driving anomalous global weather patterns. Large-scale seasonal precipitation and temperature changes influenced by ENSO have been examined in many areas of the world. The southeastern United States is one of the regions affected by ENSO events. In this study, remote sensing detection of vegetation response to ENSO phases is demonstrated with one-kilometer biweekly Normalized Difference Vegetation Index (NDVI) data (1989–1999) derived from the Advanced Very High Resolution Radiometer(AVHRR). The impacts of three ENSO phases, cold, warm and neutral, on vegetation were analyzed with a focus on two vegetation cover types, two seasons and two geographic regions within the southeastern U.S. Significant ENSO effects on vegetation were found in cropland and forest vegetation cover types based on image and statistical analysis of the NDVI data. The results indicate that vegetation condition was optimal during the ENSO neutral phase for both agricultural and natural vegetation. 相似文献
4.
The El Niño-Southern Oscillation (ENSO) effect has been found to be associated with regional climate variations in many regions of the world, and, in turn, with variation in crop yields. Previous studies have found that early releases of ENSO phase information could permit agricultural producers to make adjustments in their decisions and in turn generate an increase in agricultural sector welfare. This study examines whether the value of the agricultural responses can be enhanced by releasing more detailed ENSO information. Namely we evaluate the implications for projected agricultural welfare under release and adaptation to the Stone and Auliciems five phase definition of ENSO states as opposed to the more standard three phase definition. This value is estimated using a stochastic, U.S./global agricultural model representing 22 climate years. The results indicate that the release and exploitation of the more detailed ENSO phase definition almost doubles the welfare impact. The results also indicate that there is room for up to another doubling of information value through further refinements. 相似文献
5.
Summary Tropical north Africa depends on rain-fed agriculture as the main economic driver. The variability of climate-sensitive resources
is investigated with a goal to develop statistical long-lead prediction models with reasonable skill. Climate data from NCEP
is analysed in conjunction with agricultural and economic production in various sectors, in addition to the traditional climatic
indices: temperature and rainfall. Key predictors for statistical models include the lower-level zonal wind over the Atlantic
and Pacific Oceans. These exhibit a ‘memory’ that is consistent with sea surface temperatures (SST) through equatorial upwelling
dynamics. Kinematic predictors outperform SST in hindcast fit by an average 33% with respect to various tropical north African
resource indices. A multi-decadal oscillation induces long-term trends in rainfall that contribute to apparently skilful forecasts
based on the interaction of Pacific ENSO and the Atlantic zonal overturning circulation. The skill of statistical forecasts
is lower when the drying trend is removed. 相似文献
6.
ENSO teleconnections imply anomalous weather conditions, causing yield shortages, price fluctuations, and civil unrest. We estimate ENSO’s effect on U.S. county-level corn yield distributions and find that temperature and precipitation alone are not sufficient to summarize the effect of global climate on agriculture. We find that acreage-weighted aggregate impacts mask considerable spatial heterogeneity at the county-level for the mean, variance, and downside risk of corn yields. Impacts for mean yields range from ??24 to 33 % for El Niño and ??25 to 36 % for La Niña, with the geographical center of losses shifting from the Eastern to Western corn belt. ENSO’s effect on the variance of crop yields is highly localized and is not representative of a variance-preserving shift. We also find that downside risk impacts are large and spatially correlated across counties. 相似文献
7.
Summary The El Ni?o-Southern Oscillation (ENSO) climate cycle is the basis for this paper, aimed at providing a diagnostic outlook
on seasonal sea-level variability (i.e. anomalies with respect to the Climatology) for the U.S.-Affiliated Pacific Islands
(USAPI).
Results revealed that the sea-level variations in the northwestern tropical Pacific islands (e.g. Guam and Marshall Islands)
have been found to be sensitive to ENSO-cycle, with low sea-level during El Ni?o and high sea-level during La Ni?a events.
The annual cycle (first harmonic) of sea-level variability in these north Pacific islands has also been found to be very strong.
The composites of SST and circulation diagnostic show that strong El Ni?o years feature stronger surface westerly winds in
the equatorial western/central Pacific, which causes north Pacific islands to experience lower sea-level from July to December,
while the sea-level in south Pacific islands (e.g. American Samoa) remains unchanged. As the season advances, the band of
westerly winds propagates towards the south central tropical Pacific and moves eastward, which causes American Samoa to experience
a lower sea-level from January to June, but with six months time lag as compared to Guam and the Marshalls.
U.S.-Affiliated Pacific Islands are among the most vulnerable communities to climate variability and change. This study has
identified the year-to-year ENSO climate cycle to have significant impact on the sea-level variability of these islands. Therefore,
regular monitoring of the ENSO climate cycle features that affect seasonal sea-level variability would provide substantial
opportunities to develop advance planning and decision options regarding hazard management in these islands. 相似文献
8.
Some argue that global climate change may alter the frequency and strength of extreme events. This paper examines the economic damages in the agricultural sector arising from a shift in El Niño Southern Oscillation (ENSO) event frequency and strength. The assumptions about the frequency of ENSO shift are motivated by an article by Timmermann etal. (1999). The damage estimates reported here are in the context of the global agricultural system. Annual damages in the 3 to 4 hundred million U.S. dollar range are found if only the frequency of ENSO events changes. However, annual damages rise to over $1 billion if the events also intensify in strength. Event anticipation and crop mix adaption on the part of farmers can help offset the damages but cannot fully alleviate them. 相似文献
9.
Yongxin Zhang Yun Qian Valérie Dulière Eric P. Salathé Jr L. Ruby Leung 《Climatic change》2012,110(1-2):315-346
Surface temperature, precipitation, specific humidity and wind anomalies associated with the warm and cold phases of ENSO simulated by WRF and HadRM are examined for the present and future decades. WRF is driven by ECHAM5 and CCSM3, respectively, and HadRM is driven by HadCM3. For the current decades, all simulations show some capability in resolving the observed warm-dry and cool-wet teleconnection patterns over the PNW and the Southwest U.S. for warm and cold ENSO. Differences in the regional simulations originate primarily from the respective driving fields. For the future decades, the warm-dry and cool-wet teleconnection patterns in association with ENSO are still represented in ECHAM5-WRF and HadRM. However, there are indications of changes in the ENSO teleconnection patterns for CCSM3-WRF in the future, with wet anomalies dominating in the PNW and the Southwest U.S. for both warm and cold ENSO, in contrast to the canonical patterns of precipitation anomalies. Interaction of anomalous wind flow with local terrain plays a critical role in the generation of anomalous precipitation over the western U.S. Anomalous dry conditions are always associated with anomalous airflow that runs parallel to local mountains and wet conditions with airflow that runs perpendicular to local mountains. Future changes in temperature and precipitation associated with the ENSO events in the regional simulations indicate varying responses depending on the variables examined as well as depending on the phase of ENSO. 相似文献
10.
A four-dimensional variational (4D-Var) data assimilation method is implemented in an improved intermediate coupled model (ICM) of the tropical Pacific. A twin experiment is designed to evaluate the impact of the 4D-Var data assimilation algorithm on ENSO analysis and prediction based on the ICM. The model error is assumed to arise only from the parameter uncertainty. The “observation” of the SST anomaly, which is sampled from a “truth” model simulation that takes default parameter values and has Gaussian noise added, is directly assimilated into the assimilation model with its parameters set erroneously. Results show that 4D-Var effectively reduces the error of ENSO analysis and therefore improves the prediction skill of ENSO events compared with the non-assimilation case. These results provide a promising way for the ICM to achieve better real-time ENSO prediction. 相似文献
11.
This article describes a study employing a risk-assessment methodology for evaluating uncertain future climatic conditions. To understand the implications of uncertainty on risk and to provide a near-term rationale for policy interventions, the study estimated the impacts from responses to climate change on U.S. state- and national-level economic activity. The study used results of the climate-model CMIP3 dataset developed for the Intergovernmental Panel on Climate Change’s (IPCC) Fourth Assessment Report to 1) estimate a proxy for representing climate uncertainty over the next 40 years, 2) map the simulated weather from the climate models hydrologically to the county level to determine the physical consequences on economic activity at the state level, and 3) perform a detailed, economy-wide, 70-industry analysis of economic impacts among the interdependent lower-48 states for the years 2010 through 2050. The analysis determined the interacting industry-level effects, employment impacts at the state level, interstate population migration, consequences to personal income, and ramifications for the U.S. trade balance. When compared to a baseline economic forecast, the calculations produced an average risk of damage of $1 trillion to the U.S. economy from climate change over the next 40 years, with losses in employment equivalent to nearly 7 million full-time jobs. Added uncertainty would increase the estimated risk. 相似文献
12.
A hybrid coupled model (HCM) for the tropical Pacific ocean-atmosphere system is employed for ENSO prediction. The HCM consists
of the Geophysical Fluid Dynamics Laboratory ocean general circulation model and an empirical atmospheric model. In hindcast
experiments, a correlation skill competitive to other prediction models is obtained, so we use this system to examine the
effects of several initialization schemes on ENSO prediction. Initialization with wind stress data and initialization with
wind stress reconstructed from SST using the atmospheric model give comparable skill levels. In re-estimating the atmospheric
model in order to prevent hindcast-period wind information from entering through empirical atmospheric model, we note some
sensitivity to the estimation data set, but this is considered to have limited impact for ENSO prediction purposes. Examination
of subsurface heat content anomalies in these cases and a case forced only by the difference between observed and reconstructed
winds suggests that at the current level of prediction skill, the crucial wind components for initialization are those associated
with the slow ENSO mode, rather than with atmospheric internal variability. A “piggyback” suboptimal data assimilation is
tested in which the Climate Prediction Center data assimilation product from a related ocean model is used to correct the
ocean initial thermal field. This yields improved skill, suggesting that not all ENSO prediction systems need to invest in
costly data assimilation efforts, provided the prediction and assimilation models are sufficiently close.
Received: 17 April 1998 / Accepted: 22 July 1999 相似文献
13.
Using reanalysis data provided by the U.S.National Centers for Environmental Prediction/National Center for Atmospheric Research,the potential relationship between the El Ni?o-Southern Oscillation (ENSO) cycle and blocking highs in three key regions of Eurasia (Ural,Baikal,and Okhotsk) from 1950 to 2008 is analyzed.Composite analysis of 500 hPa geopotential height field during different stages of ENSO reveals that in the winters of El Ni?o (EN) years,there is significant negative anomaly of geopotential height in the three key regions.In the winters of La Ni?a (LN) years,on the other hand,significant positive anomaly of geopotential height is observed in Eastern Ural,Baikal,and Okhotsk.In summer,Okhotsk exhibits positive anomaly,which is significant at a confidence level of 90% by Student’s t-test during the developing stage of an LN year.In the developing stage of an EN year,geopotential height field at 500 hPa manifests positive (negative) anomaly in Baikal (Ural and Okhotsk),while the geopotential height field at 500 hPa exhibits positive (negative) anomaly in Ural and Okhotsk (Baikal) during the decaying stage of both EN and LN years.However,these abnormities are insignificant in a developing EN year,decaying EN year,and the summer of a decaying LN year.By analyzing 500 hPa geopotential height field during different phases of the ENSO cycle,it is observed that results of the case study are consistent with those of composite analysis.Annual average blocking is likewise examined during the different stages of ENSO from 1950 to 2008.Combined with composite analysis and case study,results indicate that blockings in the three key regions are suppressed (enhanced) during the winters of EN (LN) years.In summer,the influence of ENSO on the blockings in the three key regions is not as significant as that in winter.Evidently,developing LN may enhance blockings in Okhotsk.Influence factors on blockings are various and complex.This paper indicates that the influence of ENSO on blockings cannot be neglected,and that it is crucial to related operational forecasting as a potential signal. 相似文献
14.
Application of the Analogue-Based Correction of Errors Method in ENSO Prediction 总被引：2，自引：0，他引：2 
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下载免费PDF全文 In this study, a method of analogue-based correction of errors（ACE） was introduced to improve El Ni？o-Southern Oscillation（ENSO） prediction produced by climate models. The ACE method is based on the hypothesis that the flow-dependent model prediction errors are to some degree similar under analogous historical climate states, and so the historical errors can be used to effectively reduce such flow-dependent errors. With this method, the unknown errors in current ENSO predictions can be empirically estimated by using the known prediction errors which are diagnosed by the same model based on historical analogue states. The authors first propose the basic idea for applying the ACE method to ENSO prediction and then establish an analogue-dynamical ENSO prediction system based on an operational climate prediction model. The authors present some experimental results which clearly show the possibility of correcting the flow-dependent errors in ENSO prediction, and thus the potential of applying the ACE method to operational ENSO prediction based on climate models. 相似文献
15.
为了改善模式初始场质量,减少初值与模式不协调对ENSO预测的影响,针对国家气候中心NCCo海-气耦合模式原初始化方案动力小协调的问题,从利用模式长期耦合模拟资料中的模式气候吸引子信息的角度出发,发展了一种获取观测资料中与模式相协调分量的信息重构方法,提出了一种模式气候吸引子信息约束下的动力协调初始化方案.对该方案回报检验的结果表明:通过反演NCCo海-气耦合模式模拟资料中的模式气候吸引子信息,有助于获取观测资料中与模式相协调的信息分量特征,实现了初始化过程中动力模式与所同化观测资料间的协调.这种基于信息重构方法的动力协调初始化方案,既可以延续原初始化方案利用观测信息较多的优势,又克服了原方案中观测资料和动力模式不协调的缺陷.这种新的初始化方案,消除了观测资料和模式不协调在初始场中产生的小尺度高频噪声,突出了与NCCo模式动力特征相适应的ENSO尺度信息.进而抑制了初始场中高频噪声所引起的快变预报误差的增长,提高了模式的预测技巧. 相似文献
16.
Hong-Li Ren Fei Zheng Jing-Jia Luo Run Wang Minghong Liu Wenjun Zhang Tianjun Zhou Guangqing Zhou 《Acta Meteorologica Sinica》2020,34(1):43-62
Remarkable progress has been made in observations, theories, and simulations of the ocean-atmosphere system, laying a solid foundation for the improvement of short-term climate prediction, among which Chinese scientists have made important contributions. This paper reviews Chinese research on tropical air-sea interaction, ENSO dynamics, and ENSO prediction in the past 70 years. Review of the tropical air-sea interaction mainly focuses on four aspects: characteristics of the tropical Pacific climate system and ENSO; main modes of tropical Indian Ocean SSTs and their interactions with the tropical Pacific; main modes of tropical Atlantic SSTs and inter-basin interactions; and influences of the mid-high-latitude air-sea system on ENSO. Review of the ENSO dynamics involves seven aspects: fundamental theories of ENSO; diagnosis and simulation of ENSO; the two types of ENSO; mechanisms of ENSO initiation; the interactions between ENSO and other phenomena; external forcings and teleconnections; and climate change and the ENSO response. The ENSO prediction part briefly summarizes the dynamical-statistical methods used in ENSO prediction, as well as the operational ENSO prediction systems and their applications. Lastly, we discuss some of the issues in these areas that are in need of further study. 相似文献
17.
四个耦合模式ENSO后报试验的“春季预报障碍” 总被引：2，自引：0，他引：2
用CliPAS计划中3个气候模式和中国科学院大气物理研究所耦合模式FGOALS-g短期气候异常回报试验结果,将动力和统计方法相结合,考察了1982—2003年厄尔尼诺/拉尼娜事件发展期和衰减期海表温度春季可预报性障碍现象。结果表明,所考察的耦合模式对ENSO事件预报的误差发展存在明显的季节依赖性,最大误差增长通常发生在春季,发生显著的可预报性障碍现象。进一步分析发现厄尔尼诺事件和拉尼娜事件在发展期的季节预报障碍现象比衰减期明显,以厄尔尼诺事件发展期春季可预报性障碍现象最为显著,拉尼娜事件衰减期季节预报障碍现象不显著。研究还发现,预报误差的增长在ENSO事件冷暖位相具有显著的非对称性,发展期暖位相预报误差强于冷位相,而衰减期冷位相的预报误差比暖位相大。通过回归分析,诊断了海-气相互作用的强度,发现耦合系统在春季最不稳定,使预报误差最易在春季发展,从而导致可预报性障碍。 相似文献
18.
The retrospective prediction of ENSO from 1881 to 2000 by a hybrid coupled model: (II) Interdecadal and decadal variations in predictability 总被引：1，自引：0，他引：1
In this study, the retrospective predictions of ENSO (El Niño and Southern Oscillation) were performed for the period from 1881 to 2000 using a hybrid coupled model, which is an ocean general circulation model coupled to a linear statistical atmospheric model, and using a newly developed initialization scheme of SST assimilation by Ensemble Kalman Filter. With the retrospective predictions of the past 120 years, some important issues of ENSO predictability (measured by correlation and RMSE skills of NINO3 sea surface temperature anomaly index) were studied including decadal/interdecadal variations in ENSO predictability and the mechanisms responsible for these variations. Emphasis was placed on investigating the relationship between ENSO predictability and various characteristics of ENSO system such as the signal strength, the irregularity of periodicity, the noise and the nonlinearity. It is found that there are significant decadal/interdecadal variations in the prediction skills of ENSO during the past 120 years. The ENSO events were more predictable during the late nineteenth and the late twentieth centuries. The decadal/interdecadal variations of prediction skills are strongly related to the strength of sea-surface temperature anomaly (SSTA) signals, especially to the strength of SSTA signals at the frequencies of 2–4 year periods. The SSTA persistence, dominated by SSTA signals at frequencies over 4-year periods, also has a positive relationship to prediction skills. The high-frequency noise, on the other hand, has a strong inverse relationship to prediction skills, suggesting that it also probably plays an important role in ENSO predictability. 相似文献
19.
20.
Chaoxia Yuan Tomoki Tozuka Willem A. Landman Toshio Yamagata 《Climate Dynamics》2014,42(11-12):3357-3374
Prediction skill for southern African (16°–33°E, 22°–35°S) summer precipitation in the Scale Interaction Experiment-Frontier coupled model is assessed for the period of 1982–2008. Using three different observation datasets, deterministic forecasts are evaluated by anomaly correlation coefficients, whereas scores of relative operating characteristic and relative operating level are used to evaluate probabilistic forecasts. We have found that these scores for December–February precipitation forecasts initialized on October 1st are significant at 95 % confidence level. On a local scale, the level of prediction skill in the northwestern and central parts of southern Africa is higher than that in northeastern South Africa. El Niño/Southern Oscillation (ENSO) provides the major source of predictability, but the relationship with ENSO is too strong in the model. The Benguela Niño, the basin mode in the tropical Indian Ocean, the subtropical dipole modes in the South Atlantic and the southern Indian Oceans and ENSO Modoki may provide additional sources of predictability. Within the wet season from October to the following April, the precipitation anomalies in December-February are the most predictable. This study presents promising results for seasonal prediction of precipitation anomaly in the extratropics, where seasonal prediction has been considered a difficult task. 相似文献