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101.
102.
J.?García-SerranoEmail author V.?Guemas F.?J.?Doblas-Reyes 《Climate Dynamics》2015,44(9-10):2539-2555
Identifying regions sensitive to external radiative changes, including anthropogenic (sulphate aerosols and greenhouse gases) and natural (volcanoes and solar variations) forcings, is important to formulate actionable information at multi-year time-scales. Internally-generated climate variability can overcome this radiative forcing, especially at regional level, so that detecting the areas for this potential dominance is likewise critical for decadal prediction. This work aims to clarify where each contribution has the largest effect on North Atlantic sea surface temperature (SST) predictions in relation to the Atlantic multi-decadal variability (AMV). Initialized decadal hindcasts and radiatively-forced historical simulations from the fifth phase of the Climate Model Intercomparison Project are analysed to assess multi-year skill of the AMV. The initialized hindcasts reproduce better the phase of the AMV index fluctuations. The radiatively-forced component consists of a residual positive trend, although its identification is ambiguous. Initialization reduces the inter-model spread when estimating the level of AMV skill, thus reducing its uncertainty. Our results show a skilful performance of the initialized hindcasts in capturing the AMV-related SST anomalies over the subpolar gyre and Labrador Sea regions, as well as in the eastern subtropical basin, and the inability of the radiatively-forced historical runs to simulate the horseshoe-like AMV signature over the North Atlantic. Initialization outperforms empirical predictions based on persistence beyond 1–4 years ahead, suggesting that ocean dynamics play a role in the AMV predictability beyond the thermal inertia. The initialized hindcasts are also more skilful at reproducing the observed AMV teleconnection to the West African monsoon. The impact of the start date frequency is also described, showing that the standard of 5-year interval between start dates yields the main features of the AMV skill that are robustly detected in hindcasts with yearly start date sampling. This work updates previous studies, complementing them, and concludes that skilful initialized multi-model forecasts of the AMV-related climate variability can be formulated, improving uninitialized projections, until 3–6 years ahead. 相似文献
103.
Zhibin Dai Shengbang Qian Eduardo Fernández Lajús G. L. Baume 《Astrophysics and Space Science》2010,330(2):243-248
Two CCD photometries of the intermediate polar TV Columbae are made for obtaining two updated eclipse timings with high precision. There is an interval time ~17 yr since the last mid-eclipse time observed in 1991. Thus, the new mid-eclipse times might offer an opportunity to check the previous orbital ephemerides. A calculation indicates that the orbital ephemeris derived by Augusteijn et al. (Astron. Astrophys. Suppl. Ser. 107:219, 1994) should be corrected. Based on the proper linear ephemeris (Hellier in Mon. Not. R. Astron. Soc. 264:132, 1993), the new orbital period analysis suggests a cyclical period variation in the O–C diagram of TV Columbae. Using Applegate’s mechanism to explain the periodic oscillation in the O–C diagram, the required energy is larger than the energy that a M0-type star can afford over a complete variation period of ~31.0(±3.0) yr. Thus, the light travel-time effect indicates that the tertiary component in TV Columbae may be a dwarf with a low mass, which is near the lower mass limit of ~0.08M ⊙ as long as the inclination of the third body is high enough. 相似文献
104.
Occurrence and fate of polycyclic aromatic hydrocarbons in the coastal surface microlayer 总被引:2,自引:0,他引:2
Polycyclic aromatic hydrocarbons (PAHs) were measured in the coastal sea surface microlayer (SML), the sub-surface waters (SSW) and the overlying atmosphere in order to investigate the influence of the SML on contaminant enrichment and air-sea exchange. Samples were collected at two contrasting locations of the NW Mediterranean, one urban influenced (off Barcelona, Spain) and another comparatively clean (off Banyuls-sur-Mer, France). Statistical data analysis confirmed the accumulation of PAHs in the SML with respect to the SSW (20.3+/-9.1 vs. 13.1+/-10.0 ng L(-1) in the dissolved phase; 709+/-207 vs. 158+/-111 ng g(-1) in the particulate phase). This accumulation was higher at the contaminated location (Barcelona station) compared with the more pristine one, with PAH enrichments 1.5 and 4.5 times higher for the dissolved and particulate phases, respectively, indicating that the enrichment of PAHs in the SML is dominated by particle transport processes. 相似文献
105.
Echavarri-Erasun B Juanes JA García-Castrillo G Revilla JA 《Marine pollution bulletin》2007,54(7):941-954
An investigation on the effects of deepwater outfall discharges on the status of rocky reef communities was carried out. The sanitation system was found to be an environmentally suitable option for the protection of those habitats situated in high energy coastal environments. Sediments occurring between the predominating rocky substrates showed low values of the fine fraction (<63microm) and organic matter content. In addition, high average concentrations of Cd, Hg and Zn were found in these sediments, though these values were similar to those registered in non-affected sites, far away from the outfall. On the other hand, those assemblages typical of hard substrates that settled near the outfall showed an increase in total richness and abundance of macroinvertebrates. Moreover, the average number of species of each taxonomic group, a good indicator of the maintenance of the previous trophic structure, only varied considerably over time at the rip-rap protection. In a global context, those changes were not directly related to the discharge disturbances, but to the natural variability or the successional processes occurring within those communities. Only communities dwelling in the rip-rap protection area were affected by the proximity of the discharges. 相似文献
106.
M. Villalobos D. G. García-Payne J. L. López-Zepeda A. E. Ceniceros-Gómez M. E. Gutiérrez-Ruiz 《Aquatic Geochemistry》2010,16(2):225-250
Arsenic from natural and anthropogenic sources is a worldwide contaminant of aqueous environments, such as groundwater and
soils. The present investigation was performed on Mexican soils contaminated with residues from metallurgical processes that
have shown a natural As attenuation. Experimental aqueous arsenic extractions in these were successfully simulated for almost
half of the soil samples using a database updated for all known metal arsenate formation constants, revealing the predominance
of solubility-controlled As mobility via Pb, mixed Pb–Cu, and Ca arsenate solid formation. The relatively low total Fe/As
ratios (2–13 w/w) present in the soils studied, together with the high and equivalent contents of As, Pb, and Cu in these,
favor the precipitation process over As(V) adsorption to Fe oxides, despite a 2% average Fe content in the soils studied.
Under these conditions bicarbonate was found to be a highly unsuitable extractant due to its indirect As release from the
solid arsenates, via heavy metal carbonate precipitation processes. 相似文献
107.
F. Figueroa J. Castro-Larragoitia A. Aragón J. V. García-Meza 《Environmental Earth Sciences》2010,60(2):395-407
The 7-year-old mine tailings pile P2 from Concepción del Oro has been revegetated spontaneously by xerophyte grasses, covering
about the 30% of its surface. To elucidate the effect of the grass cover in the geochemical behavior of the sulfide minerals
(SM) and metals, the strata of four selected profiles (P2-I, P2-II, P2-III and P2-IV, with high, middle, low, and null grass
cover, respectively) were analyzed mineralogically and chemically, using scanner electron microscopy, X-ray diffractometer
and performing a six-step sequential extraction method. An older (50-year-old) and uncovered (without grass cover) profile
of the tailings pile P3 was also analyzed. In all the profiles from P2, the SM oxidation is not yet an extended process; however,
the samples from the uncovered profile P2-IV showed evidences of SM (pyrite and chalcocite) oxidation, as well as the presence
of gypsum and Fe oxides, as the major secondary phases resulted from the SM oxidation. Additionally, the carbonate content
and pH values in P2-IV were lower than in the covered profiles from P2. The oldest and uncovered P3-I profile showed an extensive
oxidation of sulfurs which resulted in the depletion of carbonates and a pH 2. Another distinctive characteristics of the
covered profiles was that Pb, Cu, and Zn were mainly associated with the reducible fractions (carbonates and/or amorphous
oxides); meanwhile, in the uncovered (P2-IV and P3-I) such metals were mainly associated with the oxidizable fraction (crystalline
oxides). The results suggest that the mineralogical transformations control metal stability in plant-covered impoundments
(phytostabilization): the occurrence of a thick grass cover, with an efficient water usage and retention, seems to shun both
the acidic dissolution of carbonates and the reductive dissociation of the formerly present oxyhydroxides, which is desired
for remediation tasks. This is the first report about the effects of grass cover for a carbonaceous and unsaturated mine tailings
from a semiarid region, that can help in a better understanding of the scope of phytoremediation in such conditions. 相似文献
108.
Arias-Molinares Daniela García-Palomares Juan Carlos Romanillos Gustavo Gutiérrez Javier 《Journal of Geographical Systems》2023,25(3):403-427
Journal of Geographical Systems - In the past ten years, cities have experienced a burst of micromobility services as they offer a flexible transport option that allows users to cover short trips... 相似文献
109.
David Barriopedro David Gallego M. Carmen Alvarez-Castro Ricardo García-Herrera Dennis Wheeler Cristina Peña-Ortiz Susana M. Barbosa 《Climate Dynamics》2014,43(3-4):939-955
A monthly index based on the persistence of the westerly winds over the English Chanel is constructed for 1685–2008 using daily data from ships’ logbooks and comprehensive marine meteorological datasets. The so-called Westerly Index (WI) provides the longest instrumental record of atmospheric circulation currently available. Anomalous WI values are associated with spatially coherent climatic signals in temperature and precipitation over large areas of Europe, which are stronger for precipitation than for temperature and in winter and summer than in transitional seasons. Overall, the WI series accord with the known European climatic history, and reveal that the frequency of the westerlies in the eastern Atlantic during the twentieth century and the Late Maunder Minimum was not exceptional in the context of the last three centuries. It is shown that the WI provides additional and complementary information to the North Atlantic Oscillation (NAO) indices. The analysis of WI series during the industrial era indicates an overall good agreement with the winter and high-summer NAO, with the exception of several multidecadal periods of weakened correlation. These decoupled periods between the frequency and the intensity of the zonal flow are interpreted on the basis of several sources of non-stationarity affecting the centres of the variability of the North Atlantic and their teleconnections. Comparisons with NAO reconstructions and long instrumental indices extending back to the seventeenth century suggest that similar situations have occurred in the past, which call for caution when reconstructing the past atmospheric circulation from climatic proxies. The robustness and extension of its climatic signal, the length of the series and its instrumental nature make the WI an excellent benchmark for proxy calibration in Europe and Greenland. 相似文献
110.
The model of Paillard and Parrenin (Earth Planet Sci Lett 227(3–4):263–271, 2004) has been recently optimized for the last eight glacial cycles, leading to two different relaxation models with model-data correlations between 0.8 and 0.9 (García-Olivares and Herrero (Clim Dyn 1–25, 2012b)). These two models are here used to predict the effect of an anthropogenic CO 2 pulse on the evolution of atmospheric CO 2, global ice volume and Antarctic ice cover during the next 300 kyr. The initial atmospheric CO 2 condition is obtained after a critical data analysis that sets 1300 Gt as the most realistic carbon Ultimate Recoverable Resources (URR), with the help of a global compartmental model to determine the carbon transfer function to the atmosphere. The next 20 kyr will have an abnormally high greenhouse effect which, according to the CO 2 values, will lengthen the present interglacial by some 25 to 33 kyr. This is because the perturbation of the current interglacial will lead to a delay in the future advance of the ice sheet on the Antarctic shelf, causing that the relative maximum of boreal insolation found 65 kyr after present (AP) will not affect the developing glaciation. Instead, it will be the following insolation peak, about 110 kyr AP, which will find an appropriate climatic state to trigger the next deglaciation. 相似文献