Tag: Sang-Ki Lee

Journal of Geophysical Research (JGR) Editors' Highlight

Ocean dynamics played key role in Antarctic sea ice changes during past decades

“Much of the work on the cause of Antarctic sea ice over recent decades has focused on atmospheric drivers but this paper focuses on the ocean’s role. The authors analyse the trend of Antarctic sea ice over the past 35 years on the basis of satellite data and model simulations forced with atmospheric reanalysis products. Their findings suggest that ocean processes play a crucial role in determining the seasonality of sea ice trends. They also reveal that the sea-ice response is regional.”

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Underwater Glider Data Improved Intensity Forecasts of Hurricane Gonzalo

In a recent study published in Weather and Forecasting,* AOML researchers and their colleagues used NOAA’s HWRFHYCOM operational hurricane forecast model to quantify the impact of assimilating underwater glider data and other ocean observations into the intensity forecasts of Hurricane Gonzalo (2014). Gonzalo formed in the tropical North Atlantic east of the Lesser Antilles on October […]

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Proposed locations for the western and eastern PIES deployments in the subtropical South Pacific (stars). The magenta line shows the P06 cruise track along 32.5°S. Photo Credit: NOAA.

Project Explores Deep Ocean Heat Accumulation in the South Pacific

One of the most challenging questions in global climate change studies today is how quickly, or if, heat that accumulates within the Earth system penetrates into the deep ocean. Scientists with the University of Miami (UM), AOML, and NASA’s Jet Propulsion Laboratory (JPL) recently tackled this question by using a combination of present-day satellite and in situ observing systems to study the distribution of heat in the oceans. 

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Ocean Temperatures May Hold Key to Predicting Tornado Outbreaks

Tornadoes are one of nature’s most destructive forces. Recent violent and widespread tornado outbreaks in the United States, such as occurred in the spring of 2011, have caused significant loss of life and property. Currently, our capacity to predict tornadoes and other severe weather risks does not extend beyond seven days. Extending severe weather outlooks beyond seven days will assist emergency managers, businesses, and the public prepare the resources needed to prevent economic losses and protect communities. So how can scientists better predict when and where tornadoes are likely to strike, before the tornado season begins?

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(left column) Seasonality of precipitation and 850mb winds for the monsoon regions as measured by the difference between June-July-August-September (JJAS) minus annual mean precipitation and winds. (middle-column) shows the composite difference of JJAS precipitation (shaded) and 850mb wind for each monsoon region with respect to weak minus strong SAMHT at lead-time 20 years after the anomalous SAMHT. Blue stipples indicates regions where precipitation differences are significant at 95% confidence level based on a non-parametric Kolmogorov-Smirnov test. (right-column) Lag-lead Spearman ranked correlation between SAMHT and NH monsoon index. The blue dashed lines depict the 95% significance level based on a non-parametric Kendall-t test. Negative lag indicates periods when SAMHT leads the NH monsoon index. Periods with significant correlation between the SAMHT and monsoon are shaded blue. Image Credit: NOAA AOML.

Meridional heat transport in the South Atlantic reveals links with global monsoons

A recent paper published in the Journal of Climate led by PHOD researchers Hosmay Lopez, Shenfu Dong, Sang-Ki Lee, and Gustavo Goni provides a physical mechanism on how low frequency variability of the South Atlantic Meridional Heat Transport (SAMHT) associated with the Atlantic Meridional Overturning Circulation ( AMOC) may influence decadal variability of atmospheric circulation and monsoons. This is the first attempt to link the South Atlantic Overturning Circulation variability to weather and climate.

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Figure 3 Glider approximate location (black diamond) superimposed on Infrared image of Hurricane Gonzalo on October 14, 1500 UTC, when it travelled the closest to the location of the underwater glider. Credit: image obtained from the Cooperative Institute for Meteorological Satellite Studies.

Underwater gliders observations reveal the importance of salinity effects during passage of Hurricane Gonzalo (2014)

Hurricanes are known to drive the cooling of surface waters as they travel over the ocean, leaving a cooling swath where they pass. The sea surface cooling is mostly caused by mixing forced by the strong winds of the hurricane, which occurs as the mixture of warm surface waters with colder waters that can be as deep as 100 m below the surface.

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Research Shows Indian Ocean Plays Key Role in Global Warming Hiatus

The earth is warming, but atmospheric and oceanic temperatures that rose steadily over the last half century have leveled off and slowed this past decade, causing the appearance of an imbalance in the Earth’s heat budget. Scientists looking to the deep ocean for where the additional heat energy might be stored recently traced a pathway that leads to the Indian Ocean.

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Illustration of increased trade winds in the Pacific and Indian Oceans during the recent warming hiatus, which increased the inter-ocean pressure gradient and thus enhanced Indonesian throughflow. This resulted in an abrupt increase of Indian Ocean heat content. Image credit: NOAA/CIMAS

Indian Ocean Plays Key Role in Global Warming Hiatus

The earth is warming, but temperatures in the atmosphere and at the sea surface that steadily rose in the last half-century have leveled off and slowed in the past decade, causing the appearance of an imbalance in Earth’s heat budget. Scientists are looking into the deep ocean to determine where this additional heat energy could be stored, and recently traced a pathway that leads to the Indian Ocean.

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