Tuesday, December 26, 2017

"Inconcievably heavy snowfall" in Alaska's Banana Belt

 During my short time in Cordova, AK, I learned that Southern Alaska is "The Banana Belt" of Alaska.  It rained much, hardly ever did the sun shine, but if it snowed, it wasn't a great amount.  Our recent experience with climate/weather on the West Coast prompted this comment on the California Weather Blog:


"...  recently, the bigger & stronger West Coast ridge has pushed the Pacific storm track even further north. Remarkably, this powerful ridge has forced several very moist atmospheric river storms over the mid-Pacific to make a hard “left turn” over the open ocean–veering directly northward and bringing almost inconceivably heavy snowfall to the coastal mountains of southern Alaska."
The link it to an Anchorage Times article.


Thursday, December 21, 2017

Seasons: 23.44° Solstice "Sun Standing Still"

"Solstice" comes from the Latin word solstitium, meaning "sun standing still".


Wikipedia: "Solstice"

 The seasons occur because the Earth's axis of rotation is not perpendicular to its orbital plane (the “plane of the ecliptic”) but currently makes an angle of about 23.44° (called the "obliquity of the ecliptic"), and because the axis keeps its orientation with respect to an inertial frame of reference. As a consequence, for half the year the Northern Hemisphere is inclined toward the Sun while for the other half year the Southern Hemisphere has this distinction. The two moments when the inclination of Earth's rotational axis has maximum effect are the solstices.

 Wikipedia: Season

 In tropical and subtropical regions there is little annual fluctuation of sunlight. However, there are seasonal shifts of a rainy global-scale low pressure belt called the Intertropical convergence zone. As a result, the amount of precipitation tends to vary more dramatically than the average temperature. When the convergence zone is north of the equator, the tropical areas of the northern hemisphere experience their wet season while the tropics south of the equator have their dry season. This pattern reverses when the convergence zone migrates to a position south of the equator.