Saturday, June 28, 2014

Atmospheric Rivers

Like an atmospheric river, jet streams are narrow, fast-flowing currents that bend and meander due to the forces of nature.

Jet streams flow at an altitude of 5 to 9 miles above the surface of the Earth. Air currents are created by temperature gradients.

Six jet streams flow west-to-east around the Earth:
  • 2 polar jet streams flow near the Arctic and Antarctic circle;
  • 2 subtropical jet streams flow halfway between the poles and the Equator; and 
  • 2 jet streams flow on either side of the equator.
The polar jet stream in the Northern Hemisphere is created by the cold, dense air masses descending from the Arctic and deflecting warm air masses ascending from the tropics. The currents typically flow at speeds greater than 100 miles per hour (160 km/h).

Jet stream troughs and ridges over North America (NASA)

Jet streams are driven by atmospheric heating (solar radiation) and by the planet's rotation on its axis. The steeper the temperature gradient, the straighter and faster the air current. On the contrary, the gentler the temperature gradient, the slower the air current and the more prone the jet stream path is to undulations. The wavy undulations of the polar jet stream propagate across the mid-latitudes. Large, pronounced meanders of the jet stream path are called Rossby Waves.
“Those who flow as life flows know they need no other force.”
Lao Tzu


Saturday, June 21, 2014

As The Day is Long

It's summer solstice in the Northern Hemisphere.

Summer Solstice Sunrise at Stonehenge

Summer solstice marks the longest period of daylight in the year. The sun is at its farthest point north of the Equator.
This is the solstice, the still point
of the sun, its cusp and midnight,
the year’s threshold
and unlocking, where the past
lets go of and becomes the future;
the place of caught breath…
Margaret Atwood, Eating Fire: Selected Poetry 1965-1995
The word solstice comes from the Latin from sol meaning sun, and stare, or sistere, meaning to stand or stop.

Yin & Yang

The solstice is an astronomical occasion, but also has historical, mythological, and cultural significance.

From Chinese legend today is a celebration of yin, earth, and femininity. Today is winter solstice in the Southern Hemisphere. Winter solstice corresponds to a winter celebration of yang.

Happiness & Daylight

Psychologists have found a correlation between daylight and a measure of happiness.
We identified individual-level diurnal and seasonal mood rhythms in cultures across the globe, using data from millions of public Twitter messages. We found that individuals awaken in a good mood that deteriorates as the day progresses—which is consistent with the effects of sleep and circadian rhythm—and that seasonal change in baseline positive affect varies with change in daylength.
― Golder & Macy, Science
Summer solstice in an opportunity to experience the fullness of the day.
“We all shine the moon and the stars and the sun.”
John Lennon


Saturday, June 14, 2014

Earth Song

Earth sings a broader song than the stanza of human existence.

Some mistakenly suppose we possess Earth.

Ralph Waldo Emerson's poem Hamatreya considers an ego-centric world view.

In the poem Hamatreya, Emerson's narrator Hamatreya is believed to come from a young man found in Hindu scripture who:
upon hearing Earth chant a song to him, loses all earthly ambitions.
Emerson's Hamatreya examines a series of thematic contrasts:
  • Material versus Spiritual - Emerson begins the poem by listing the surnames of Concord settlers. The settlers define themselves by material possessions. Emerson then enumerates the settler's crops, "Hay, corn, roots, hemp, flax, apples, wool, and wood" to emphasize the zeitgeist of ownership, consumption, and alteration of the land through agriculture.
  • Reality versus Illusion - Emerson's Concord settlers believe their notion that nature can be controlled constitutes a special relationship with the land. Because the settlers work the land in an agricultural sense, they view the harvest as the fruits of their labor rather than the result of natural processes. The settlers develop a deluded sense of ownership and the illusion of dominance of their domain.
  • Transience versus Permanence - Emerson submits that the influence of a generation does not extend much beyond the human life-cycle. Further he implies that those thinking to the contrary are misguided by hubris. Ironically, time proves the land is indifferent to the settlers. The existence and impact of the settlers is transient and impermanent.
  • Separateness versus Unity - Emerson describes a world perceived in particulars rather than in totality. The Earth transcends the blink of a human lifetime with indifference. A parcel of Earth is a comparatively insignificant human contrivance. Emerson implies that by recognizing the inevitability of death, and by facing our own physical decomposition, we might better appreciate our physical unity with Earth.
  • Human History versus Universal History - Emerson's poem affirms a more spiritual and universal outlook on history that extends beyond the limits of human history. Human history is typically limited to human events and the achievements of individuals. Emerson addresses the conundrum of reconciling human experience with universal truths and the spiritual realm.
Emerson's Hamatreya includes a poem within a poem. Hamatreya has a section entitled EARTH-SONG, where narrator Hamatreya listens to Earth's chant. The closing stanza of the Earth Song section is the voice of a personified Earth considering control and permanence:
They called me theirs,
Who so controlled me;
Yet every one
Wished to stay, and is gone,
How am I theirs,
If they cannot hold me,
But I hold them?
Emerson deftly addresses our proclivity to hubristic dominance. He reminds us that humans are little more than recycled carbon "in the chill of the grave".
Him to his land, a lump of mould the more.


Saturday, June 7, 2014


Thermal Slope
Clouds can develop in response to lifting.

Topographic rises like mountain ranges wring moisture from the air to create orographic clouds.

Orographic comes from a concatenation of the Greek word for hill (όρος) and the Greek verb to write (γραφία).

Orographic lift occurs when moist air is forced upward as it moves over the thermal slope of a rising mountain.

When air rises, it adiabatically cools which raises its relative humidity to cause clouds. Adiabatic cooling occurs when air temperature decreases via a decrease in air pressure caused by volume expansion.

"I know that I am mortal by nature, and ephemeral; but when I trace at my pleasure the windings to and fro of the heavenly bodies I no longer touch the earth with my feet: I stand in the presence of Zeus himself and take my fill of ambrosia."
― Ptolemy, Ptolemy's Almagest