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1.
Water-soluble dicarboxylic acids (DCAs), ketoacids, and α-dicarbonyls in the marine aerosol samples collected over the Southern Ocean and western Pacific Ocean were determined. Oxalic acid was the most abundant species, followed by malonic acid and then succinic acid. It is suggested that aerosol concentrations of the organics over the Southern Ocean in this work represent their global background levels. Over the Southern Ocean, total concentrations of DCAs ranged from 2.9 to 7.2 ng m−3 (average: 4.5 ng m−3), ketoacids from 0.14 to 0.40 ng m−3 (av.: 0.28 ng m−3), and dicarbonyls from 0.06 to 0.29 ng m−3 (av.: 0.11 ng m−3). Over the western Pacific, total concentrations of DCAs ranged from 1.7 to 170 ng m−3 (av.: 60 ng m−3), ketoacids from 0.08 to 5.3 ng m−3 (av.: 1.8 ng m−3), and dicarbonyls from 0.03 to 4.6 ng m−3 (av.: 0.95 ng m−3). DCAs over the western Pacific have constituted a large fraction of organic aerosols with a mean DCAs-C/TC (total carbon) of 7.0% (range: 0.59–14%). Such a high value was in contrast to the low DCAs-C/TC (av.: 1.8%; range: 0.89–4.0%) for the Southern Ocean aerosols. Based on the relative abundances and latitudinal distributions of these organics, we propose that long-range atmospheric transport is more important over the western Pacific Ocean, in contrast, in situ photochemical production is more significant over the Southern Ocean although absolute concentrations of the organics are much lower.  相似文献   

2.
环球海洋大气气溶胶化学研究 III：金属形态和入海通量   总被引：8，自引：0，他引：8  
陈立奇  余群  杨绪林 《大气科学》1994,18(2):215-223
中国第三次南极考察和环球科学考察，历经北太平洋、南太平洋、南极半岛海域、南大西洋、北印度洋、以及沿途近岸海域，共收集58个气溶胶样品，采用石墨炉原子吸收法分析其中的水可溶态和酸可溶态的Mn、Fe、Pb、Cu、Cd。气溶胶中金属表现明显陆源向大洋输送的浓度梯度，近岸海域上空金属含量大于大洋上空含量，北太平洋上空含量高于南太平洋和南极半岛海域。气溶胶中金属的水可溶程度，在近岸海域上空依次为Cd＞Mn＞Cu＞Fe＞Pb，百分比分量分别为39%，36%， 23%，14%和5.3%；在大洋上空依次为Cd＞Mn＞Fe＞Cu＞pb，百分比分量分别为62%，44%，11%，3.1%和2.5%。本文还计算和比较各观测海区上空金属从大气输入海水的通量。  相似文献   

3.
Responses of global ocean circulation and temperature to freshwater runoff from major rivers were studied by blocking regional runoff in the global ocean general circulation model(OGCM)developed at the Massachusetts Institute of Technology.Runoff into the tropical Atlantic,the western North Pacific,and the Bay of Bengal and northern Arabian Sea were selectively blocked.The blocking of river runoff first resulted in a salinity increase near the river mouths(2 practical salinity units).The saltier and,therefore,denser water was then transported to higher latitudes in the North Atlantic,North Pacific,and southern Indian Ocean by the mean currents.The subsequent density contrasts between northern and southern hemispheric oceans resulted in changes in major ocean currents.These anomalous ocean currents lead to significant temperature changes(1°C-2°C)by the resulting anomalous heat transports.The current and temperature anomalies created by the blocked river runoff propagated from one ocean basin to others via coastal and equatorial Kelvin waves.This study suggests that river runoff may be playing an important role in oceanic salinity,temperature,and circulations;and that partially or fully blocking major rivers to divert freshwater for societal purposes might significantly change ocean salinity,circulations,temperature,and atmospheric climate.Further studies are necessary to assess the role of river runoff in the coupled atmosphere-ocean system.  相似文献   

4.
应用一个嵌套了海洋生物地球化学循环的太平洋环流碳循环模式,分析了1960～2000年太平洋不同海区海气碳通量随时间的变化。模拟结果显示,赤道太平洋为大气CO2的排放区,南、北太平洋(南、北纬15°至模式计算区域南、北边界)为吸收区。3个海区海气碳通量随时间均存在显著的波动,其中赤道太平洋海气碳通量年际波动最显著。3个海区海气碳通量年际波动对气候事件的响应并不一致,在El Niño年赤道太平洋冷舌的强度和总溶解无机碳(DIC)的浓度以及输出生产力均会受到上升流减弱的影响而降低,La Niña年这些海气碳通量控制要素的分布情况则正好相反,但在南北太平洋副热带以及高纬度海区,El Niño和La Niña对这些要素带来的影响却并不一定相反,对输出生产力的影响甚至是一致的。以海表温度(SST)为例考察海气碳通量与物理场之间的关系表明,在赤道太平洋上升流对DIC的影响是控制海气碳通量变化的主要因素,而在其他海区,尤其是副热带海区,由于垂直运动的年际变化较小,且生物生产力水平较低,SST的波动对海气碳通量年际变化的影响更加重要。  相似文献   

5.
Under future scenarios of business-as-usual emissions, the ocean storage of anthropogenic carbon is anticipated to decrease because of ocean chemistry constraints and positive feedbacks in the carbon-climate dynamics, whereas it is still unknown how the oceanic carbon cycle will respond to more substantial mitigation scenarios. To evaluate the natural system response to prescribed atmospheric ??target?? concentrations and assess the response of the ocean carbon pool to these values, 2 centennial projection simulations have been performed with an Earth System Model that includes a fully coupled carbon cycle, forced in one case with a mitigation scenario and the other with the SRES A1B scenario. End of century ocean uptake with the mitigation scenario is projected to return to the same magnitude of carbon fluxes as simulated in 1960 in the Pacific Ocean and to lower values in the Atlantic. With A1B, the major ocean basins are instead projected to decrease the capacity for carbon uptake globally as found with simpler carbon cycle models, while at the regional level the response is contrasting. The model indicates that the equatorial Pacific may increase the carbon uptake rates in both scenarios, owing to enhancement of the biological carbon pump evidenced by an increase in Net Community Production (NCP) following changes in the subsurface equatorial circulation and enhanced iron availability from extratropical regions. NCP is a proxy of the bulk organic carbon made available to the higher trophic levels and potentially exportable from the surface layers. The model results indicate that, besides the localized increase in the equatorial Pacific, the NCP of lower trophic levels in the northern Pacific and Atlantic oceans is projected to be halved with respect to the current climate under a substantial mitigation scenario at the end of the twenty-first century. It is thus suggested that changes due to cumulative carbon emissions up to present and the projected concentration pathways of aerosol in the next decades control the evolution of surface ocean biogeochemistry in the second half of this century more than the specific pathways of atmospheric CO2 concentrations.  相似文献   

6.
Decadal prediction skill in a multi-model ensemble   总被引：4，自引：3，他引：1  
Decadal climate predictions may have skill due to predictable components in boundary conditions (mainly greenhouse gas concentrations but also tropospheric and stratospheric aerosol distributions) and initial conditions (mainly the ocean state). We investigate the skill of temperature and precipitation hindcasts from a multi-model ensemble of four climate forecast systems based on coupled ocean-atmosphere models. Regional variations in skill with and without trend are compared with similarly analysed uninitialised experiments to separate the trend due to monotonically increasing forcings from fluctuations around the trend due to the ocean initial state and aerosol forcings. In temperature most of the skill in both multi-model ensembles comes from the externally forced trends. The rise of the global mean temperature is represented well in the initialised hindcasts, but variations around the trend show little skill beyond the first year due to the absence of volcanic aerosols in the hindcasts and the unpredictability of ENSO. The models have non-trivial skill in hindcasts of North Atlantic sea surface temperature beyond the trend. This skill is highest in the northern North Atlantic in initialised experiments and in the subtropical North Atlantic in uninitialised simulations. A similar result is found in the Pacific Ocean, although the signal is less clear. The uninitialised simulations have good skill beyond the trend in the western North Pacific. The initialised experiments show some skill in the decadal ENSO region in the eastern Pacific, in agreement with previous studies. However, the results in this study are not statistically significant (p?≈?0.1) by themselves. The initialised models also show some skill in forecasting 4-year mean Sahel rainfall at lead times of 1 and 5?years, in agreement with the observed teleconnection from the Atlantic Ocean. Again, the skill is not statistically significant (p?≈?0.2). Furthermore, uninitialised simulations that include volcanic aerosols have similar skill. It is therefore still an open question whether initialisation improves predictions of Sahel rainfall. We conclude that the main source of skill in forecasting temperature is the trend forced by rising greenhouse gas concentrations. The ocean initial state contributes to skill in some regions, but variations in boundary forcings such as aerosols are as important in decadal forecasting.  相似文献   

7.
The impact of sea surface temperature (SST) on winter haze in Guangdong province (WHDGD) was analyzed on the interannual scale. It was pointed out that the northern Indian Ocean and the northwest Pacific SST play a leading role in the variation of WHDGD. Cold (warm) SST anomalies over the northern Indian Ocean and the Northwest Pacific stimulate the eastward propagation of cold (warm) Kelvin waves through the Gill forced response, causing Ekman convergence (divergence) in the western Pacific, inducing abnormal cyclonic (anticyclonic) circulation. It excites the positive (negative) Western Pacific teleconnection pattern (WP), which results in the temperature and the precipitation decrease (increase) in Guangdong and forms the meteorological variables conditions that are conducive (not conducive) to the formation of haze. ENSO has an asymmetric influence on WHDGD. In El Ni?o (La Ni?a) winters, there are strong (weak) coordinated variations between the northern Indian Ocean, the northwest Pacific, and the eastern Pacific, which stimulate the negative (positive) phase of WP teleconnection. In El Ni?o winters, the enhanced moisture is attributed to the joint effects of the horizontal advection from the surrounding ocean, vertical advection from the moisture convergence, and the increased atmospheric apparent moisture sink (Q2) from soil evaporation. The weakening of the atmospheric apparent heat source (Q1) in the upper layer is not conducive to the formation of inversion stratification. In contrast, in La Ni?a winters, the reduced moisture is attributed to the reduced upward water vapor transport and Q2 loss. Due to the Q1 increase in the upper layer, the temperature inversion forms and suppresses the diffusion of haze.  相似文献   

8.
Deposition of atmospheric mineral particles in the North Pacific Ocean   总被引：5，自引：0，他引：5  
Total deposition of atmospheric mineral particles (wet plus dry) has been measured during consecutive two-week sampling intervals from January, 1981 to March, 1982 at four island stations (Midway, Oahu, Enewetak, and Fanning) of the SEAREX Asian Dust Study Network in the North Pacific. The total deposition of mineral aerosol during the period from February to June is higher than that during the period from July to January at most of the stations. A systematic geographical trend is apparent in the dust flux, with greater fluxes at higher latitudes. The deposition values are correlated with the atmospheric mineral particle concentrations at these stations. The mineral particles are transported from arid regions in Asia to the North Pacific, and the annual dust deposition to the ocean appears to be dominated by sporadic dust events of short duration. Wet deposition dominates the removal of dust particles from the atmosphere over the North Pacific. The total deposition of atmospheric mineral material to the central North Pacific is estimated to be 20×1012 g yr-1.  相似文献   

9.
《大气与海洋》2012,50(4):307-317
ABSTRACT

This study investigates the response of the subtropical gyre circulation in the North Pacific Ocean to quadrupled CO2 using the Community Earth System Model, version 1 (CESM1). In particular, an overriding technique is applied to isolate and quantify the effects of wind stress and thermal warming caused by CO2 emissions. Results show that, in response to the increase in CO2, the total mass transport in the subtropical gyre is reduced by approximately 11%. This reduction results mainly from negative anomalies of the wind stress curl over the subtropical region, with a smaller contribution from the thermal warming effect. Furthermore, a detailed analysis finds that the change in the subtropical gyre is baroclinic in nature [i.e., the gyre appears to be spin-up in the upper ocean (above 300?m) but spin-down in the lower thermocline (from 300 to 1500?m)]. This reversal between the upper ocean and lower thermocline is a result of the thermal warming effect, which intensifies ocean stratification, hindering the transfer of momentum from the upper layers to the lower layers and leading to an acceleration of the gyre in the upper ocean but a deceleration in the lower thermocline. Another feature of the response of the subtropical gyre to quadrupled CO2 is the respective poleward and equatorward movements of its northern and southern boundaries, which is a result of the change in the zero wind stress curl lines.  相似文献   

10.
Volatile organic iodine compounds (VOIs) emitted from the ocean surface to the air play an important role in atmospheric chemistry. Shipboard observations were conducted in Funka Bay, Hokkaido, Japan, bimonthly or monthly from March 2012 to December 2014, to elucidate the seasonal variations of VOI concentrations in seawater and their sea-to-air iodine fluxes. The bay water exchanges with the open ocean water of the North Pacific twice a year (early spring and autumn). Vertical profiles of CH2I2, CH2ClI, CH3I, and C2H5I concentrations in the bay water were measured bimonthly or monthly within an identified water mass. The VOI concentrations began to increase after early April at the end of the diatom spring bloom, and represented substantial peaks in June or July. The temporal variation of the C2H5I profile, which showed a distinct peak in the bottom layer from April to July, was similar to the PO4 3? variation profile. Correlation between C2H5I and PO4 3? concentrations (r = 0.93) suggests that C2H5I production was associated with degradation of organic matter deposited on the bottom after the spring bloom. CH2I2 and CH2ClI concentrations increased substantially in the surface and subsurface layers (0–60 m) in June or July resulted in a clear seasonal variation of the sea-to-air iodine flux of the VOIs (high in summer or autumn and low in spring).  相似文献   

11.
Mode water is a distinct water mass characterized by a near vertical homogeneous layer or low potential vorticity, and is considered essential for understanding ocean climate variability. Based on the output of GFDL CM3, this study investigates the response of eastern subtropical mode water(ESTMW) in the North Pacific to two different single forcings: greenhouse gases(GHGs) and aerosol. Under GHG forcing, ESTMW is produced on lighter isopycnal surfaces and is decreased in volume. Under aerosol forcing, in sharp contrast, it is produced on denser isopycnal surfaces and is increased in volume.The main reason for the opposite response is because surface ocean-to-atmosphere latent heat flux change over the ESTMW formation region shoals the mixed layer and thus weakens the lateral induction under GHG forcing, but deepens the mixed layer and thus strengthens the lateral induction under aerosol forcing. In addition, local wind changes are also favorable to the opposite response of ESTMW production to GHG versus aerosol.  相似文献   

12.
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   

13.
A box model is used to explore the detailed chemistry of C2 and C3 organic compounds in the marine troposphere by tracing the individual reaction paths resulting from the oxidation of ethane, ethene, acetylene, propane, propene and acetic acid. The mechanisms include chemical reactions in the gas phase and in the aqueous phase of clouds and aerosol particles at cloud level under conditions resembling those in the northern hemisphere. Organic hydroperoxides are found to be important intermediate products, with subsequent reactions leading partly to the formation of mixed hydroxy or carbonyl hydroperoxides that are readily absorbed into cloud water, where they contribute significantly to the formation of multifunctional organic compounds and organic acids. Organic hydroperoxides add little to the oxidation of sulfur dioxide dissolved in the aqueous phase, which is dominated by H2O2. Next to acetaldehyde and acetone, glycol aldehyde, glyoxal, methyl glyoxal and hydroxy propanone are prominent oxidation products in the gas and the aqueous phase. Acetaldehyde is not efficiently converted to acetic acid in clouds; the major local sources of acetic acid are gas-phase reactions. Other acids produced include hydroperoxy acetic, glycolic, glyoxylic, oxalic, pyruvic, and lactic acid. The mechanism of Schuchmann et al. (1985), which derives glycolic and glyoxylic acid from the oxidation of acetate, is found unimportant in the marine atmosphere. The principal precursors of glyoxylic acid are glyoxal and glycolic acid. The former derives mainly from acetylene and ethene, the latter from glycolaldehyde, also an oxidation product of ethene. The oxidation of glyoxylic acid leads to oxalic acid, which accumulates and is predicted to reach steady state concentrations in the range 30–90 ng m−3. This is greater, yet of the same magnitude, than the concentrations observed over the remote Pacific Ocean.  相似文献   

14.
Abstract

The relationship between the Arctic and subarctic sea‐ice concentration (SIC) anomalies, particularly those associated with the decadal‐scale Greenland and Labrador Seas “Ice and Salinity Anomalies (ISAs) “, and the overlying atmospheric circulation fluctuations is investigated using the singular value decomposition (SVD) and composite map analysis methods. The data analyzed are monthly SIC and sea level pressure (SLP) anomalies, which cover the northern hemisphere poleward of 45°N and extend over the 41‐year period 1954–1994.

The SVD1 (first) mode of the coupled variability, which accounts for 57% of the square covariance, is for the most part an atmosphere‐to‐ice forcing mode characterized by the decadal timescale. The aforementioned ISA anomalies are clearly captured by this mode whose SIC anomalies are dominated by a strong dipole across Greenland. However, as part of the same mode, there is also a weaker SIC dipole in the northern North Pacific which has opposite‐signed anomalies in the Sea of Okhotsk and the Bering Sea. It is also shown that there exists a significant negative correlation between the decadal SIC variability in the Greenland‐Barents Seas region associated with this mode and the North Atlantic Oscillation, whose spectrum also exhibits a quasi‐decadal signal.

The SVD2 mode accounts for 12% of the square covariance and shows no evidence of a dominant forcing field of either SIC or SLP. This SVD mode exhibits very low frequency (interdecadal) variability, and its co‐variability is mainly concentrated in the northern North Pacific. It appears to be a high‐latitude extension of the recently investigated interdecadal North Pacific Oscillation. The spatial structure of the second mode complements the case of the first SVD mode whose co‐variability mainly occurs in the northern North Atlantic.  相似文献   

15.
Weekly aerosol samples were collected from March 1981 to June 1983 at the six stations in the western North Pacific region and analyzed for Ca and Na. By coupling data with those previously reported for Al (Tsunogai et al., 1985), the following results and conclusion have been obtained. There was a positive correlation between the atmospheric concentration of Al and the concentration of nonsea salt Ca (nssCa). The nssCa/Al ratios from the six stations, however, considerably varied (from 0.84±0.36 to 3.00±1.91), and the ratios were usally larger than those of the crustal average or of usual soil in Japan. The Ca/Al ratios of Asian desert soil and loess vary from 0.52 to 1.29, which are similar to the nssCa/Al ratios of aerosols in the surface air over the western North Pacific region except at Onna, Okinawa. The exception may be due to a local effect of coral. These results suggest that a large part of nonsea salt Ca in the surface air over the western North Pacific is derived from arid regions in Asia and that the nssCa/Al ratio in aerosol varies with that of the source material.  相似文献   

16.
The Department of Energy (DOE) supported Parallel Climate Model (PCM) makes use of the NCAR Community Climate Model (CCM3) and Land Surface Model (LSM) for the atmospheric and land surface components, respectively, the DOE Los Alamos National Laboratory Parallel Ocean Program (POP) for the ocean component, and the Naval Postgraduate School sea-ice model. The PCM executes on several distributed and shared memory computer systems. The coupling method is similar to that used in the NCAR Climate System Model (CSM) in that a flux coupler ties the components together, with interpolations between the different grids of the component models. Flux adjustments are not used in the PCM. The ocean component has 2/3° average horizontal grid spacing with 32 vertical levels and a free surface that allows calculation of sea level changes. Near the equator, the grid spacing is approximately 1/2° in latitude to better capture the ocean equatorial dynamics. The North Pole is rotated over northern North America thus producing resolution smaller than 2/3° in the North Atlantic where the sinking part of the world conveyor circulation largely takes place. Because this ocean model component does not have a computational point at the North Pole, the Arctic Ocean circulation systems are more realistic and similar to the observed. The elastic viscous plastic sea ice model has a grid spacing of 27?km to represent small-scale features such as ice transport through the Canadian Archipelago and the East Greenland current region. Results from a 300?year present-day coupled climate control simulation are presented, as well as for a transient 1% per year compound CO2 increase experiment which shows a global warming of 1.27?°C for a 10?year average at the doubling point of CO2 and 2.89?°C at the quadrupling point. There is a gradual warming beyond the doubling and quadrupling points with CO2 held constant. Globally averaged sea level rise at the time of CO2 doubling is approximately 7?cm and at the time of quadrupling it is 23?cm. Some of the regional sea level changes are larger and reflect the adjustments in the temperature, salinity, internal ocean dynamics, surface heat flux, and wind stress on the ocean. A 0.5% per year CO2 increase experiment also was performed showing a global warming of 1.5?°C around the time of CO2 doubling and a similar warming pattern to the 1% CO2 per year increase experiment. El Niño and La Niña events in the tropical Pacific show approximately the observed frequency distribution and amplitude, which leads to near observed levels of variability on interannual time scales.  相似文献   

17.
用太平洋区域30a逐月混合层厚度(dml)及浅层海温(Ts)距平资料,分析了20°S以北太平洋区域dml年际变率的地理分布和季节变化,得到两个纬向dml高变率带,它们分别位于北太平洋(45°N附近)和赤道中、西太平洋。重点分析了赤道太平洋dml高变率带,并对其上混合层气候位置、dml年际异常与ElNino事件关系及伴随强ElNino事件的dml正异常东传等作了初步分析。  相似文献   

18.
Previous studies with single models have suggested that El Niño teleconnections over North America could be different in a future warmer climate due to factors involving changes of El Niño event amplitude and/or changes in the midlatitude base state circulation. Here we analyze a six-member multi-model ensemble, three models with increasing future El Niño amplitude, and three models with decreasing future El Niño amplitude, to determine characteristics and possible changes to El Niño teleconnections during northern winter over the North Pacific and North America in a future warmer climate. Compared to observed El Niño events, all the models qualitatively produce general features of the observed teleconnection pattern over the North Pacific and North America, with an anomalously deepened Aleutian Low, a ridge over western North America, and anomalous low pressure over the southeastern United States. However, associated with systematic errors in the location of sea surface temperature and convective heating anomalies in the central and western equatorial Pacific (the models’ anomaly patterns are shifted to the west), the anomalous low pressure center in the North Pacific is weaker and shifted somewhat south compared to the observations. For future El Niño events, two different stabilization experiments are analyzed, one with CO2 held constant at year 2100 concentrations in the SRES A1B scenario (roughly doubled present-day CO2), and another with CO2 concentrations held constant at 4XCO2. Consistent with the earlier single model results, the future El Niño teleconnections are changed in the models, with a weakened as well as an eastward- and northward-shifted anomalous low in the North Pacific. This is associated with weakened anomalous warming over northern North America, strengthened cooling over southern North America, and precipitation increases in the Pacific Northwest in future events compared to present-day El Niño event teleconnections. These changes are consistent with the altered base state upper tropospheric circulation with a wave-5 pattern noted in previous studies that is shown here to be consistent across all the models whether there are projected future increases or decreases in El Niño amplitude. The future teleconnection changes are most consistent with this anomalous wave-5 pattern in the models with future increases of El Niño amplitude, but less so for the models with future decreases of El Niño amplitude.  相似文献   

19.
Interannual and interdecadal variabilities in the Pacific are investigated with a coupled atmosphere-ocean GCM developed at MRI, Japan. The model is run for 70 years with flux adjustments. The model shows interannual variability in the tropical Pacific which has several typical characteristics shared with the observed ENSO. A basin-scale feature of the principal SST variation for the ENSO time scale shows negative correlation in the central North Pacific with the tropical SST, similar to that of the observed one. Associated variation of the model atmosphere indicates an intensification of the Aleutian Low and a PNA-like teleconnection pattern as a response to the tropical warm SST anomaly. The ENSO time scale variability in the midlatitude ocean consists of the westward propagation of the subsurface temperature signal and the temperature variation within the shallow mixed layer forced by the anomalous atmospheric heat fluxes. For the interdecadal time scale, variation of the SST is simulated realistically with a geographical pattern similar to that for the ENSO time scale, but it has a larger relative amplitude in the northern Pacific. For the atmosphere, spatial structure of the variation in the interdecadal time scale is also similar to that in the ENSO time scale, but has smaller amplitude in the northern Pacific. Long oceanic spin-up time (>∼10 y) in the mid-high latitude, however, makes oceanic response in the interdecadal time scale larger than that in the ENSO time scale. The lagged-regression analysis for the ocean temperature variation relative to the wind stress variation indicates that interdecadal variation of the ocean subsurface at the mid-high latitudes is considered as enhanced ocean gyre spin-up process in response to the atmospheric circulation change at the mid-high latitudes, remotely forced by the interdecadal variation of the tropical SST. Received: 6 November 1995 / Accepted: 19 April 1996  相似文献   

20.
We use a coupled climate–carbon cycle model of intermediate complexity to investigate scenarios of stratospheric sulfur injections as a measure to compensate for CO2-induced global warming. The baseline scenario includes the burning of 5,000 GtC of fossil fuels. A full compensation of CO2-induced warming requires a load of about 13 MtS in the stratosphere at the peak of atmospheric CO2 concentration. Keeping global warming below 2°C reduces this load to 9 MtS. Compensation of CO2 forcing by stratospheric aerosols leads to a global reduction in precipitation, warmer winters in the high northern latitudes and cooler summers over northern hemisphere landmasses. The average surface ocean pH decreases by 0.7, reducing the calcifying ability of marine organisms. Because of the millennial persistence of the fossil fuel CO2 in the atmosphere, high levels of stratospheric aerosol loading would have to continue for thousands of years until CO2 was removed from the atmosphere. A termination of stratospheric aerosol loading results in abrupt global warming of up to 5°C within several decades, a vulnerability of the Earth system to technological failure.  相似文献   

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