Video Experimental Relacionado
Updated: Aug 4, 2026
09:06
Removal of Exogenous Materials from the Outer Portion of Frozen Cores to Investigate the Ancient Biological Communities Harbored Inside
Published on: July 3, 2016
Dinámica de la oscilación del Atlántico Norte registrada en los núcleos de hielo de Groenlandia
1C. Appenzeller and T. F. Stocker, Climate and Environmental Physics, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland. M. Anklin, Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ 85721, USA.
Science (New York, N.Y.)
|October 17, 1998
Resumen
Los núcleos de hielo de Groenlandia revelan que la Oscilación del Atlántico Norte (NAO) es un patrón climático intermitente, no persistente. Sus fases activas muestran variabilidad a corto plazo, con tendencias a largo plazo observadas desde mediados del siglo XIX.
Área de la Ciencia:
- Paleoclimatología Paleoclimatología
- Ciencias del clima Ciencias del clima Ciencias del clima Ciencias del clima
- Ciencias de la atmósfera Ciencias atmosféricas.
Sus antecedentes:
- La Oscilación del Atlántico Norte (NAO) es un patrón climático significativo que influye en el clima en toda la región del Atlántico Norte.
- Comprender el comportamiento a largo plazo y la frecuencia de la NAO es crucial para el modelado y la predicción del clima.
- Estudios anteriores han explorado la variabilidad de NAO, pero una reconstrucción detallada a lo largo de varios siglos utilizando datos proxy específicos es valiosa.
Objetivo del estudio:
- Para reconstruir un índice anual proxy de la Oscilación del Atlántico Norte (NAO) que abarca los últimos 350 años.
- Investigar la naturaleza intermitente del NAO, identificando sus fases activa y pasiva.
- Para determinar las frecuencias dominantes y las escalas temporales de la variabilidad de NAO.
Principales métodos:
- Utilizando datos de núcleos de hielo cuidadosamente seleccionados de Groenlandia como un proxy para la reconstrucción del clima.
- Desarrollar un índice anual de la NAO basado en los datos de núcleos de hielo analizados.
- Aplicar análisis de series temporales para identificar frecuencias de oscilación y comportamientos de fase.
Principales resultados:
- El índice de NAO reconstruido indica que el NAO es una oscilación climática intermitente, caracterizada por fases temporalmente activas y pasivas.
- No se encontró evidencia para una frecuencia única, persistente y plurianual de la OAN.
- Durante las fases activas, la energía NAO se concentra en períodos más cortos de aproximadamente 15 años.
- La variabilidad en escalas de tiempo de 80 a 90 años se ha observado desde mediados del siglo XIX.
Conclusiones:
- El NAO exhibe un comportamiento intermitente en lugar de una oscilación consistente a largo plazo.
- La variabilidad a corto plazo (menos de 15 años) domina durante las fases activas de NAO.
- La variabilidad a largo plazo (80-90 años) ha surgido más recientemente, específicamente desde mediados del siglo XIX, lo que sugiere cambios potenciales en la dinámica de NAO.
Videos de Conceptos Relacionados
01:50Global Climate Change
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
01:21Isothermal Processes
A thermodynamic process that occurs at constant temperature is called an isothermal process. Heat slowly flows into the system or out of the system to maintain thermal equilibrium. Processes involving phase changes like water evaporation into steam or freezing water into ice at a constant temperature are examples of Isothermal Processes.
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
An ideal gas can also undergo isothermal expansion or compression.
For example, consider 1 mole of an ideal gas inside an isolated cylinder at initial volume V...
01:21Isochoric and Isobaric Processes
A thermodynamic process that occurs at constant volume is called an isochoric process. According to the first law of thermodynamics, heat supplied or removed from the system is partially utilized to perform work and change the internal energy of the system. However, in an isochoric process, the volume remains constant. Hence, the work done by the system is zero. Therefore, the exchange of heat changes the internal energy of the system only.
Suppose 1000 g of water is heated from 40 degrees...
Suppose 1000 g of water is heated from 40 degrees...
01:28Magnetostatic Boundary Conditions
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
01:03Precipitation Gravimetry
Precipitation gravimetry is based on converting an analyte into a sparingly soluble precipitate, which is separated by filtration and weighed. An ideal precipitate should be pure, insoluble, of known composition, and easily filtered from the reaction mixture.
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
01:23Coriolis Force
An accelerating particle experiences a force equal to the mass multiplied by the acceleration in an inertial frame of reference. Consider a particle in a non-inertial frame of reference, such as a sliding ball on a rotating table. The acceleration of the ball in this rotating reference frame is different than in the intertial frame, which modifies its equation of motion. The fictitious forces acting additionally on a rotating frame of reference alter Newton's Second Law expression. Centripetal...