Tag Archives: Madden-Julian Oscillation

The PACIFIC: what’s in a name?

Recent view of the Pacific Ocean from the International Space Station. Although plenty un thunderheads and storm clouds are seen aloft, we can also glimpse the so-called 'peaceful' ocean as the setting sun reflects upon its surface through a clearing in the clouds
Recent view of the Pacific Ocean from the International Space Station. Although plenty of thunderheads and storm clouds are seen aloft, we can also glimpse the so-called ‘peaceful’ ocean as the setting sun reflects upon its surface through a clearing in the clouds

The Pacific Ocean with a total area of 166.2 Million km² covers about 46% of the Earth’s surface, and reaches the deepest point at 11,033 m below water, which is enough to submerge Mount Everest or Mount K2 by more than 2,000 m.

Elevation map of the Pacific Ocean (USGS-NASA) based on satellite remote sensing observations
Elevation map of the Pacific Ocean (USGS-NASA) based on satellite remote sensing observations

When this magnificent Ocean was first sighted by Europeans in 1513 through the eyes of Vasco Nuñez de Balboa, after having crossed the isthmus of Panama he named it “El Mar del Sur” – ‘The Southern Sea’, because he was facing in that direction.

Map of the Pacific Ocean, "The Southern Sea', by Abraham Ortelius (1589), a royal cartographer for the court of Phlip II of Spain clearly showing the American continent separating the Atlantic from the Pacific
Map of the Pacific Ocean, “The Southern Sea’, by Abraham Ortelius (1589), a royal cartographer for the court of Phlip II of Spain clearly showing the American continent separating the Atlantic from the Pacific

Eight years later, the Portuguese explorer Ferdinand Magellan sailing on a world circumnavigation expedition, to discover new trade routes and new worlds for Europe,  named this ‘Southern Sea’ “el Mar PacÍfico” or ‘The Pacific”, ‘The Peaceful Sea’  after rounding Cape Horn, at the tip of South America, under terrible stormy weather and huge seas where three oceans collide, and finding calm seas as he entered what is now known as ‘The Pacific Ocean”.

Is it really ‘peaceful’ and ‘pacific’, this ocean we are referring to? I really thought so the first time my wife and I flew around its northern fringes on our way from California to Japan. This impression was confirmed when I first flew from Los Angeles to Hawaii on a calm November afternoon and I could hardly see a ripple  on the peaceful Pacific waters below until our big jet descended for a landing  at Honolulu International. Peaceful indeed!

But that perspective of peacefulness has changed as my work related to tropical cyclones has progressed. Now I know that, as an average, based on a historical record going back over 150 years, more than 47% of all tropical cyclones worldwide are generated in some corner of the Pacific Ocean on an annual basis, and also some of the most violent storms.

While the eastern east Pacific sub-basin, off the coasts of Mexico and Central America, seems to generate quite a bit of cyclonic activity year in and year out, it is the far northwestern Pacific, starting over the central Pacific and the Philippines Sea, and moving over the south China Sea and the Yellow Sea, that really generate a large number of tropical cyclones every year, certainly a much more than any other cyclogenesis sub-basin in the world.

Water-vapor satellite image (JTWC) of the northwestern Pacific Ocean showing Tropical Storm RAMMASUN aiming for the Philippines
Water-vapor satellite image (JTWC) of the northwestern Pacific Ocean showing Tropical Storm RAMMASUN aiming for the Philippines

Currently we have tropical storm RAMMASUN  over the western Pacific moving in the general direction of Manila, capital of the Philippines.  And, in the same neighborhood we just recently had Super-typhoon NEOGURIS affecting Taiwan and Japan just last week.

Projected track of current Tropical Storm RAMMASUN on 13 July 2014
Projected track of current Tropical Storm RAMMASUN on 13 July 2014

Farther to the east of this cyclonic activity, near the coast of southern Mexico and Central America, we see the entire region from northern South America and Panama all the way up to just south of the Baja California peninsula populated by a persistent ensemble of tropical waves and disturbed weather cells, the norm in recent years, which has already contributed to generating five named-tropical cyclones in the 2014 east Pacific Hurricane Season that only started on 15 May.

Color-enhanced infrared satellite image (NOAA) of the eastern Pacicifc Ocean, north of the equator, showing the ensemble of tropical waves and storm cells that persist over the region on 13 July 2014
Color-enhanced infrared satellite image (NOAA) of the eastern Pacicifc Ocean, north of the equator, showing the ensemble of tropical waves and storm cells that persist over the region on 13 July 2014

So much for being named PACIFIC, for a basin that generates so much cyclonic activity year after year. A region that also triggers major natural factors such as ENSO, El Niño Southern Oscillation and La Niña, the Madden-Julian Oscillation, and the Pineapple Express that influence so much of the North American weather and also have a mostly dampening effect on cyclogenesis in the Atlantic basin.

It would appear, empirically at least, that as the effects of global warming have continued to be felt and the heat energy content of the Pacific Ocean increases proportionally, together with the capacity of the atmosphere for retaining moisture, the potential for cyclogenesis across this large basin has also kept pace.

Only time will tell, but based on my own observations over the past 25 years or so, the name of Pacific is a misnomer at best for this large and wonderful ocean.

The Pacific: what’s in a name?

Winter Weather 2011 and the Pineapple Express

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Tropical moisture-laden air riding the so-called “pineapple express” over the Pacific ocean developes into a storm as it collides with cold artic air driven south by the jet stream. Often such storms are generated by pulses of disturbed weather originating over the Pacific and moving toward the east-northeast at regular intervals. [Image courtesy of NASA Earth Observatory

As the current northern hemisphere winter season has evolved we have witnessed pulses of storms and bad weather progress from the northwestern region of North America toward the east with some regularity. Often as eastern regions are digging from under heavy snowfall and activity-paralyzing winter storms, which bring pronouncements from old-timers of “never before having see anything like this”, a new storm is already forming as warm moisture-laden air from tropical regions over the Pacific collides with the arctic jet stream near the west coast of North America, generating plenty of precipitation over the western regions to then aim for the east.

In monitoring these winter ‘happenings’ I have posted commentary and images about it, on Facebook and Twitter, which have motivated howls of “not another one, please!!” from some who follow such postings. For it would appear the regularity of these impacts, barely leave forever briefer periods of respite for those affected, seem to continuously cause cancellation of airline flights throughout vast regions and near paralysis of human activity in major urban centers throughout the country.

Accompanying these winter activity are numerous questions: is this related to global climate change? Is it just normal, natural climate variability over the northern hemisphere? Does El Nino (ENSO) or La Nina have anything to do with this? Is this the worst we have seen? etc. etc.

Without getting into the complexities of atmospheric physics and the various factors that may be contributing to the winter storm activity we are witnessing this season, I submit the “Pineapple Express”has been the main vehicle for such storms to move from their genesis over the central tropical Pacific, near the Hawaiian Islands, toward the western-northwestern coast of North America to then move on toward the eastern regions of the United States and Canada aided by the arctic jet stream.

The best way to visualize the Pineapple Express is by imagining an atmospheric river of warm air, which holds a huge amount of moisture, as it moves from the central tropical Pacific Ocean generally over or near the Hawaiian Islands toward the east by northeast until it is ‘engaged’ by the southern fringes of the arctic jet stream, which carries it toward the western coast of North America and then overland toward the eastern coastline. When this atmospheric river starts to collide with colder air over North America heavy precipitation in the form of rain and snowfall takes place along its path from west to east. Given the generally larger moisture content in the atmosphere, this has led to extreme snow fall and precipitation over vast regions of the United States this winter. We have all seen the media reports of thousands of flights cancelled, severe degradation of highway and rail travel, and the paralyzation of major urban centers suffering the impacts of winter storms. Empirical data appears to suggest this pattern of late winter extreme storms, which just as quickly yield to spring, may become the norm over the near term as global warming allows the atmosphere to hold more moisture (water), which then leads to extreme precipitation  [snow, rain etc.] events.

In tracking current winter activity I have used output from the geostationary satellites, namely GOES East and GOES West, which allows for a concurrent view of what’s happening over the Pacific Ocean all the way to the eastern regions of North America. A review of these data sets shows the each ‘pulse’ as it was generated over the Pacific, and it also allows one to track its progress and development as it hitches a ride on the arctic jet stream and interacts with masses of frigid air over North America.

Please look at the series of GOES WEST and GOES EAST satellite images taken this February of 2011, which illustrate what has been described above: pineappleexpress2011a

To focus on the Pineapple Express may be oversimplifying what is otherwise a complex atmospheric process where several other contributors are at play, such as the Madden-Julian Oscillation [MJO] and La Nina. However I believe it is important for the general public to highlight the effects of a major contributor to winter storm activity over North America, particularly during the current season.