No abstract is provided for this article.
CC as L pruebas recabadas sugieren que el hombre influye de una forma apreciable sobre el clima global.” Con estas mesuradas palabras, el Panel Intergubernamental sobre Cambio Climatico (IPCC), financiado por la Organizacion Meteorologica Mundial y el Programa Ambiental de las Naciones Unidas, reconocia en 1995 que los seres humanos no eran en absoluto consecuentes en lo concerniente a la salud del planeta. Lo que el panel no preciso -y 10 que cientificos y politicos discuten acaloradamentees cuando, donde y cuanto se ha notado y se notara esa influencia. Hasta ahora, los cambios climaticos presuntamente relacionados con la actividad humana han sido bastante modestos. Pero las previsiones de varia indole sugieren que el cambio alcanzara una intensidad espectacular hacia mediados del siglo XXI, sobrepasando cuanto se ha visto en la naturaleza en los ultimos 10.000 anos. Aunque algunas regiones pudieran beneficiarse durante cierto tiempo, cabe esperar que, en conjunto, las alteraciones resultaran perjudiciales e incluso catastroficas. Si la ciencia pudiera determinar la cuantfa en que ciertas actividades influyen sobre el clima, se encontraria en mejor situacion a efectos de recetar remedios para las peores alteraciones. iEs posible tal cuantificacion? Creemos que si. Nos parece que puede lograrse hacia el ano 2050, pero solo a condicion de que este objetivo se convierta en prioridad internacional permanente. Pese a la incognoscibilidad inevitable de los pormenores del cambio climatico, es patente que la acci6n humana incluye en la atmosfera de formas diversas y preocupantes. La combustion de carburantes fosiles en centrales termicas y automoviles expulsa particulas y gases que alteran la composicion de la atmosfera. La contaminacion visible, debida a combustibles ricos en azufre incluye aerosoles, particulas micrometricas que crean un cielo de panza de burra. AI reflejar parte de los rayos solares hacia el espacio, estos aerosoles enfrfan la atmosfera; de un modo transitorio, pues ~610 permanecen en el aire algunos dias, hasta que la lluvia los barre y los deposita en
No abstract is provided for this article.
No abstract is provided for this article.
El Niño refers to the exceptionally warm sea temperatures in the tropical Pacific, but it is linked to major changes in the atmosphere through the phenomenon known as the Southern Oscillation (SO), so that the whole phenomenon is called El Niño–Southern Oscillation (ENSO) by scientists. The phenomenon arises because of the coupled atmosphere–ocean interactions whereby the winds create changes in sea temperatures that in turn determine where the main tropical convection and storm activity occur, and thus determine the winds. This article outlines the current understanding of ENSO and the physical connections between the tropical Pacific and the rest of the world, using the 1997–98 El Niño event as a particular illustration. The mechanisms are described along with the interannual variations in climate over time and the associated El Niño events. The impacts are described especially in terms of the associated floods and droughts around the world. An update is included to encompass the super El Niño event of 2015–16.
No abstract is provided for this article.
The offshore stage of the Maul project began with the arrival from Japan in December 1975 of the tower that forms the base for Maui Platform A. After a period of inspection, performed in Golden Bay, the tower was ready to be towed to the installation site on 23 December 1975. It was finally upended, after some delays due to bad weather, on 4 January 1976. When level, pin piles were to be driven through the centre of each leg to secure the tower permanently.' This work was also delayed, largely because of the weather, and it has been stated that the weather in the South Taranaki Bight was the worst experienced in the past 20 years. This paper considers these statements and investigates some aspects of the weather in the South Taranaki Bight, mainly during the period January yo May 1976, compared with previous years.
The United Nations Framework Convention on Climate Change (UNFCCC) is an international environmental treaty adopted on 9 May 1992 and taken up at the Earth Summit in Rio de Janeiro in June 1992. The UNFCCC objective is to “stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.” It set up important annual reporting requirements, including annual meetings of the Conference of the Parties (COP) to assess and promote progress.
A detailed examination of the Northern Hemisphere monthly mean sea-level grid-point pressures shows a disappointingly large number of problems. The data set extends from 1899–1977 but has originated from eight different sources and discontinuities have been identified with every change in source. We have documented corrections for many of these and have also catalogued 3263 serious errors. These have been corrected or set to missing. Most of the errors are over Asia and are predominant before 1922 or during World War II. Analyses of several different aspects of the data that reveal both the problems and real changes in the atmospheric circulation are presented, along with a comparison of the monthly mean operational U.S. Navy versus U.S. National Meteorological Center analyses. A plea is made for a greater effort in archiving quality controlled climatological data.
Meridional structure and transports of energy in the atmosphere, ocean, and land are evaluated holistically for the mean and annual cycle zonal averages over the ocean, land, and global domains, with discussion and assessment of uncertainty. At the top of the atmosphere (TOA), adjusted radiances from the Earth Radiation Budget Experiment (ERBE) and Clouds and Earth’s Radiant Energy System (CERES) are used along with estimates of energy storage and transport from two global reanalysis datasets for the atmosphere. Three ocean temperature datasets are used to assess changes in the ocean heat content (OE) and their relationship to the net upward surface energy flux over ocean (FoS), which is derived from the residual of the TOA and atmospheric energy budgets. The surface flux over land is from a stand-alone simulation of the Community Land Model forced by observed fields. In the extratropics, absorbed solar radiation (ASR) achieves a maximum in summer with peak values near the solstices. Outgoing longwave radiation (OLR) maxima also occur in summer but lag ASR by 1–2 months, consistent with temperature maxima over land. In the tropics, however, OLR relates to high cloud variations and peaks late in the dry monsoon season, while the OLR minima in summer coincide with deep convection in the monsoon trough at the height of the rainy season. Most of the difference between the TOA radiation and atmospheric energy storage tendency is made up by a large heat flux into the ocean in summer and out of the ocean in winter. In the Northern Hemisphere, the transport of energy from ocean to land regions is substantial in winter, and modest in summer. In the Southern Hemisphere extratropics, land − ocean differences play only a small role and the main energy transport by the atmosphere and ocean is poleward. There is reasonably good agreement between FoS and observed changes in OE, except for south of 40°S, where differences among several ocean datasets point to that region as the main source of errors in achieving an overall energy balance. The winter hemisphere atmospheric circulation is the dominant contributor to poleward energy transports outside of the tropics [6–7 PW (1 petawatt = 1015 W)], with summer transports being relatively weak (∼3 PW)—slightly more in the Southern Hemisphere and slightly less in the Northern Hemisphere. Ocean transports outside of the tropics are found to be small (<2 PW) for all months. Strong cross-equatorial heat transports in the ocean of up to 5 PW exhibit a large annual cycle in phase with poleward atmospheric transports of the winter hemisphere.
An analysis of the global redistribution of mass during the FGGE year indicates that the global circulation was highly anomalous in several respects, especially from April to July 1979. For the 56 to year period 1924-1980, sea-level pressures over the northern hemisphere during the FGGE year were second highest in spring and highest in summer. In April and June, the anomalies were 1-in-100-year events. At the same time, sea-level pressure deficits and an exceptionally deep circumpolar trough were recorded over the Southern Hemisphere. Such compensation between the hemispheres, through the constraint of conservation of mass, provides support for the highly typical nature of the circulation analyzed to exist over the Southern Hemisphere throughout the FGGE year. The Southern Hemisphere circulation was characterized by an exceptionally deep circumpolar trough, an increase in westerlies from 40 deg to 70 deg S, and a decrease in westerlies to the north. In winter, the subtropical jet was weaker and the polar jet stronger than normal, so that a pronounced double jet structure prevailed. In summer, the jet was shifted south by 3 deg latitude. A southward shift in storm tracks accompanied these changes year round in a manner consistent with theory.
