| 1. |
- Achberger, Christine, 1968, et al.
(author)
-
State of the Climate in 2011
- 2012
-
In: Bulletin of the American Meteorological Society. - 0003-0007. ; 93:7
-
Journal article (peer-reviewed)abstract
- Large-scale climate patterns influenced temperature and weather patterns around the globe in 2011. In particular, a moderate-to-strong La Nina at the beginning of the year dissipated during boreal spring but reemerged during fall. The phenomenon contributed to historical droughts in East Africa, the southern United States, and northern Mexico, as well the wettest two-year period (2010-11) on record for Australia, particularly remarkable as this follows a decade-long dry period. Precipitation patterns in South America were also influenced by La Nina. Heavy rain in Rio de Janeiro in January triggered the country's worst floods and landslides in Brazil's history. The 2011 combined average temperature across global land and ocean surfaces was the coolest since 2008, but was also among the 15 warmest years on record and above the 1981-2010 average. The global sea surface temperature cooled by 0.1 degrees C from 2010 to 2011, associated with cooling influences of La Nina. Global integrals of upper ocean heat content for 2011 were higher than for all prior years, demonstrating the Earth's dominant role of the oceans in the Earth's energy budget. In the upper atmosphere, tropical stratospheric temperatures were anomalously warm, while polar temperatures were anomalously cold. This led to large springtime stratospheric ozone reductions in polar latitudes in both hemispheres. Ozone concentrations in the Arctic stratosphere during March were the lowest for that period since satellite records began in 1979. An extensive, deep, and persistent ozone hole over the Antarctic in September indicates that the recovery to pre-1980 conditions is proceeding very slowly. Atmospheric carbon dioxide concentrations increased by 2.10 ppm in 2011, and exceeded 390 ppm for the first time since instrumental records began. Other greenhouse gases also continued to rise in concentration and the combined effect now represents a 30% increase in radiative forcing over a 1990 baseline. Most ozone depleting substances continued to fall. The global net ocean carbon dioxide uptake for the 2010 transition period from El Nino to La Nina, the most recent period for which analyzed data are available, was estimated to be 1.30 Pg C yr(-1), almost 12% below the 29-year long-term average. Relative to the long-term trend, global sea level dropped noticeably in mid-2010 and reached a local minimum in 2011. The drop has been linked to the La Nina conditions that prevailed throughout much of 2010-11. Global sea level increased sharply during the second half of 2011. Global tropical cyclone activity during 2011 was well-below average, with a total of 74 storms compared with the 1981-2010 average of 89. Similar to 2010, the North Atlantic was the only basin that experienced above-normal activity. For the first year since the widespread introduction of the Dvorak intensity-estimation method in the 1980s, only three tropical cyclones reached Category 5 intensity level-all in the Northwest Pacific basin. The Arctic continued to warm at about twice the rate compared with lower latitudes. Below-normal summer snowfall, a decreasing trend in surface albedo, and above-average surface and upper air temperatures resulted in a continued pattern of extreme surface melting, and net snow and ice loss on the Greenland ice sheet. Warmer-than-normal temperatures over the Eurasian Arctic in spring resulted in a new record-low June snow cover extent and spring snow cover duration in this region. In the Canadian Arctic, the mass loss from glaciers and ice caps was the greatest since GRACE measurements began in 2002, continuing a negative trend that began in 1987. New record high temperatures occurred at 20 m below the land surface at all permafrost observatories on the North Slope of Alaska, where measurements began in the late 1970s. Arctic sea ice extent in September 2011 was the second-lowest on record, while the extent of old ice (four and five years) reached a new record minimum that was just 19% of normal. On the opposite pole, austral winter and spring temperatures were more than 3 degrees C above normal over much of the Antarctic continent. However, winter temperatures were below normal in the northern Antarctic Peninsula, which continued the downward trend there during the last 15 years. In summer, an all-time record high temperature of -12.3 degrees C was set at the South Pole station on 25 December, exceeding the previous record by more than a full degree. Antarctic sea ice extent anomalies increased steadily through much of the year, from briefly setting a record low in April, to well above average in December. The latter trend reflects the dispersive effects of low pressure on sea ice and the generally cool conditions around the Antarctic perimeter.
|
|
| 2. |
- Hernandez-Molina, F. J., et al.
(author)
-
Oceanographic processes and morphosedimentary products along the Iberian margins: A new multidisciplinary approach
- 2016
-
In: Marine Geology. - : Elsevier BV. - 0025-3227. ; 378, s. 127-156
-
Journal article (peer-reviewed)abstract
- Our understanding of bottom-currents and associated oceanographic processes (e.g., overflows, barotropic tidal currents) including intermittent processes (e.g., vertical eddies, deep sea storms, horizontal vortices, internal waves and tsunamis) is rapidly evolving. Many deep-water processes remain poorly understood due to limited direct observations, but can generate significant depositional and erosional features on both short and long term time scales. This paper represents a review work, which describes for the first time these oceanographic processes and examines their potential role in the sedimentary features along the Iberian continental margins. This review explores the implications of the studied processes, given their secondary role relative to other factors such as mass-transport and turbiditic processes, and highlights three major results: a) contourite depositional and erosional features are ubiquitous along the margins, indicating that bottom currents and associated oceanographic processes control the physiography and sedimentation; b) the position of interfaces between major water masses and their vertical and spatial variation in time specifically appears to exert primary control in determining major morphologic changes along the slope gradient, including the contourite terraces development; and c) contourites deposits exhibit greater variation than the established fades model suggests. Therefore, a consistent facies model however faces substantial challenges in terms of the wide range of oceanographic processes that can influence in their development. An integrated interpretation of these oceanographic processes requires an understanding of contourites, seafloor features, their spatial and temporal evolution, and the near-bottom flows that form them. This approach will synthesize oceanographic data, seafloor morphology, sediments and seismic images to improve our knowledge of permanent and intermittent processes around Iberia, and evaluate their conceptual and regional role in the margin's sedimentary evolution. Given their complexes, three-dimensional and temporally-variable nature, integration of these processes into sedimentary, oceanographic and climatological frameworks will require a multidisciplinary approach that includes Geology, Physical oceanography, Paleoceanography and Benthic Biology.
|
|
| 3. |
- Hernandez Molina, Javier, et al.
(author)
-
Oceanographic processes and products around the Iberian margin: a new multidisciplinary approach : Procesos oceanográficos y sus productos alrededor del margen de Iberia: una nueva aproximación multidisciplinar
- 2015
-
In: Boletín Geológico y Minero. - 0366-0176 .- 0366-0176. ; 126:2-3, s. 279-326
-
Journal article (peer-reviewed)abstract
- Our understanding of the role of bottom-current and associated oceanographic processes (as overflows, barotropic currents, tides or intermittent processes like giant vertical eddies, deep sea storms, horizontal vortices, internal waves and tsunamis) is rapidly improving. But, most of these oceanographic deep-water processes remains poorly understood and have been rarely observed but believed to be capable of generating depositional and erosional features in many contexts at both short and long term. In present compilation we described these oceanographic processes including examples or their potential role in the sedimentation processes around the Iberia margin. Importance of these processes is highlighted and its implication discussed to demonstrate that these oceanographic processes are very important is affecting the shape and evolution of the Iberian continental margin and adjacent oceanic basins although is not still considered as important as other factors as mass-transport deposits and turbiditic processes. To have a better understanding on the implication of all these oceanographic processes connections have to be made between (contourite) sea-floor features, their spatial and temporal evolution, and the near-bottom flows that form them. The only way to achieve that in next decades is by a more intensive collaboration between specialist from Geology, Oceanography and Benthic Biology in new multi-disciplinary studies. Consequently, further multi-disciplinary approach uses oceanographic data, sea-floor morphology, sediments and seismic characterization will be essential for improve our knowledge of these permanent and intermittent processes around Iberia and evaluate their conceptual and regional role in the margins evolution over time and space.
|
|
