Research Highlights

07/01/2013

Triggering of El Nino through trade-wind induced charging of the equatorial Pacific

In a recent study by scientists at Boston University, PHOD, and NCAR, a new mechanism was uncovered for initiating ENSO events wherein SLP-generated North Pacific trade winds induce subsurface heat content changes that serve as precursors to El Ninos. This trade-wind charging mechanism of the equatorial Pacific is fundamentally different from any previously diagnosed, and studies examining the surface and subsurface ocean dynamics associated with this mechanism are underway. Full story>>


06/15/2013

Relationship between the off-equatorial current system and the tropical Atlantic variability

Scientists at PHOD developed a synthetic method, which combines high-density expendable bathythermograph (XBT) temperature data along the AX08 XBT transect (which runs between Cape Town and NYC) with altimetric sea level anomalies, to estimate the variability of the off-equatorial currents, such as the North Equatorial Countercurrent and the North Equatorial Undercurrent, on seasonal to interannual timescales. Understanding how the ocean dynamics is liked to anomalies of temperature and wind-stress in the tropical Atlantic is critical to understand the climate and weather variability in the adjacent continental areas. Full story>>


05/07/2013

Global Ocean Surface Velocities from Drifters: Mean, Variance, ENSO Response, and Seasonal Cycle

Using over 30 years of observations from drogued, satellite-tracked surface drifting buoys, Lumpkin and Johnson (2013) developed a methodology to map seasonally-varying surface currents at 1/2 degree resolution. Results from this study can be used to better understand how the ocean transports properties like heat, salt, and passive tracers, and serves as a reference to study changes in ocean currents over time. One key result from this study is the global distribution of mean, seasonal and eddy kinetic energy, which totals 4.6x1017J in the upper 30 m of the ocean and reveals the presence of three large eddy "deserts", one in the Atlantic Ocean and the other two in the Pacific. Full story>>


09/01/2012

Is there an optimal ENSO pattern that enhances large-scale atmospheric processes conducive to tornado outbreaks in the U.S?

The record-breaking U.S. tornado outbreaks in the spring of 2011 prompt the need to identify long-term climate signals that could potentially provide seasonal predictability for U.S. tornado outbreaks. A new research led by scientists in the Physical Oceanography Division of NOAA-AOML used both observations and model experiments to show that a positive phase Trans-Niño may be one such climate signal. Full story>>


09/01/2012

Satellite-derived Heat Content Product Developed at AOML Helps to Understand The Differences in Intensity Between Tropical Storm Isaac and Hurricane Katrina

A news article that appeared in The New York Times on August 27 shows the ocean conditions in the Gulf of Mexico during hurricanes Katrina (August 2005) and Isaac (August 2012). The ocean conditions are depicted by the upper ocean heat content derived from satellite altimetry using a methodology developed at NOAA/AOML. The upper ocean heat content had larger values during Katrina mainly due to an anticyclonic warm ring and an extended Loop Current. These conditions, not found during the passage of Hurricane Isaac, partly contributed to the intensification of Katrina. Full story>>


09/01/2011

What Caused the Significant Increase in Atlantic Ocean Heat Content Since the mid-20th Century?

A new study led by researchers from University of Miami, NOAA-AOML, IFM-GEOMAR, and NCAR explores why the Atlantic Ocean has warmed substantially more than any other ocean basin since the 1950s. The research article published in the Geophysical Research letters evidences that the observed large warming of the Atlantic Ocean since the 1950s is largely induced by an increase in the inter-ocean heat transport from the Indian Ocean via the Agulhas leakage. The study points to an important role played by the Atlantic meridional overturning circulation (AMOC) in the South Atlantic in enhancing the secular warming of the Atlantic Ocean. Full story>>


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