Yosemite

YosemiteBy: Mack Jones and Clayton Kreuger
Introduction: Yosemite National Park is located in Yosemite Nation Park, California, which is in the Sierra Nevadas East of San Francisco. 1 Yosemite was preserved as a national due to its relationship with the past glacier and the underlying bedrock. 1 Yosemite has many stunning features: Yosemite consists of multiple waterfalls, exceeding heights of 2425 feet; the Wawona Tree which collapsed in 1969, but was 227 feet tall, 26 feet wide, and had a hole big enough to drive a car through; and the Half Dome which rises 8000 feet above sea level. Many popular trails consist of, climbing the Half Dome, hiking on trails in Hetch Hetchy.

Geology of Yosemite: The mountain ranges of Yosemite are part of the Sierra Nevada mountain range which has been formed by a continental-continental collision causing uplift and tilt. 1,3 This occured after the Cretaceous time 65 million years ago. 1 Yosemite has a granitic (igneous) based bedrock that has formed due to molten rock solidifying underground and later being exposed at the surface due to weathering and erosion. 1,2 Although Yosemite does not have a monolithic composition of granite rather it is a combination of many different kinds of granite due to many igneous intrusions that have occurred over the past 100 million years. 1,2 These differences are not easily noticeable everywhere but subtle differences in appearance and reaction to weathering and erosion show that there are many different types of granite present across Yosemite. 1 Some metamorphic rocks are present in Yosemite but less than 5% due to weathering and erosion over many years; this erosion exposed the parks granitic core base. 1,3 Other formations within Yosemite have been formed due to mechanical weathering of rivers and glaciers. About 25 million years ago when the mountains of Yosemite grew to the size they are today, drainage patterns established themselves. 1 These rivers cut down into the rock through mechanical weathering creating V-shaped valleys. 1,2,3 2-3 million years ago as the Earth grew colder, the Sierra Nevada mountains had grown large enough for an icefield to form along the range allowing glacier to form. 1,2,3 As glacial ice flowed, much rock and debris was being carried down the mountains. Due to this mechanical weathering, V-shaped valleys were carved into U-shaped valleys which are present in Yosemite today. 1,2 The rock and debris carried by the glacier formed moraines, that are also present today. 2,3 Geological features are one of the main attractions of Yosemite.

Yosemite’s Climate and Weather: The climate and weather change rapidly throughout the year as the seasons change, largely due the elevation of the mountains. 3,7 Starting in the summer, Yosemite is typically warm normally ranging between 60-90 degrees fairenheit and rainy. 7  The temperature range is so great due to the cool wind coming off the Pacific Ocean. 2,3,7 The Sierra Nevada Mountains force the cool air up into the air causing adiabatic cooling and precipitation to occur. 2,3,4,7  The days in the summer are long due to the sun hitting Yosemite more directly typically sunrise is around 6 a.m. and sunset around 8:30 p.m. 8  The Spring and Fall seasons have relatively the same weather. They have a high temperature range between 30-70 degrees, also due to the elevation forcing adiabatic cooling and the cool air blowing off from the Pacific Ocean. 2,7  The Winter Season has temperature ranges between 20-50 degrees. 7  As precipitation from frontal wedging of the mountains occurs the peaks of the mountains gather snow due to the air being colder higher up because of adiabatic cooling but as the snow falls it melts and turns to rainmaking it rainy at the base of Yosemite. <span style="font-family: Helvetica,helvetica,sans-serif; font-size: 70%; vertical-align: super;">2,3,7 <span style="font-family: Helvetica,helvetica,sans-serif;"> The days are normally shorter starting at about 7: 30 a.m. and setting at about 6 p.m. <span style="font-family: Helvetica,helvetica,sans-serif; font-size: 70%; vertical-align: super;">8 <span style="font-family: Helvetica,helvetica,sans-serif;"> As explained the physical features of Yosemite have a huge effect on the climate and weather of Yosemite.

Yosemite Biome:

Yosemite is in the Alpine biome. In the Alpine biome the air temperature is colder than one would expect at sea level. <span style="font-family: Helvetica,helvetica,sans-serif; font-size: 70%; vertical-align: super;">4 <span style="font-family: Helvetica,helvetica,sans-serif;"> Rainfall is also fairly constant due to the rising of air due to Sierra Nevada mountain range. Yosemite is on the windward side of the Sierra Nevada Mountain Range: thus, as the air masses rise on the windward side of the mountain, adiabatic cooling occurs, which decreases the capacity. <span style="font-family: Helvetica,helvetica,sans-serif; font-size: 70%; vertical-align: super;">2,5 <span style="font-family: Helvetica,helvetica,sans-serif; font-size: 97%; vertical-align: sub;"> Due to the change in water vapor capacity, the relative humidity (a ratio of specific humidity:capacity) increases. <span style="font-family: Helvetica,helvetica,sans-serif; font-size: 67.9%; vertical-align: super;">2 <span style="font-family: Helvetica,helvetica,sans-serif; font-size: 97%; vertical-align: sub;"> Eventually, the the realtive humidity reaches 100%: therefore, rain occurs. <span style="font-family: Helvetica,helvetica,sans-serif; font-size: 67.9%; vertical-align: super;">2 <span style="font-family: Helvetica,helvetica,sans-serif; font-size: 101%; vertical-align: sub;">Due to the temperature, humidity, and other weather related features of the Alpine BIome, certain plants and animal life live here, because of the suitable living conditions. Common plants in the Alpine biome consist of coniferous trees, such as furs and pines; moss; Giant Sequoias; California Black Oak; Ponderossa Pine; Incense-Cedar; Mariposa Lily; and Dogwood. <span style="font-family: Helvetica,helvetica,sans-serif; font-size: 70.7%; vertical-align: super;">4,5 While there is a vast varity of plants in Yosemite, there are also many animals. Some animals in Yosemite National Park consist of: the California ground Squirrel, Black Bears, rattlesnakes, and rainbow trout. 7



Human Impact:

As Yosemite National Park becomes more popular, human impact will have a greater effect. The "Half Dome" in Yosemite is a popular climbing area. 1 A very minor result of the ropes being fastened in the rocks could result in mechanical weathering. 2 Just like an other national park, polution and human use of trails injure the natural habitat, insignificantly.

<span style="display: block; font-family: Times New Roman; font-size: 12pt; line-height: 200%; text-align: center;">Works Cited "The Alpine Biome." //Marietta College//. Web. 13 June 2010. <http://www.marietta.edu/~biol/biomes/alpine.htm>. Tarbuck, Edward J., Frederick K. Lutgens, and Dennis Tasa. //Prentice Hall Earth Science//. Needham, Mass. ; Upper Saddle River, N.J.: Pearson/Prentice Hall, 2006. Print. Web. "Yosemite - Yosemite National Park - Lodging Near Yosemite." //Online Travel Guides of Travel Destinations - Las Vegas, Caribbean, Hawaii and Machu Picchu//. Web. 13 June 2010. <http://www.destination360.com/north-america/us/california/yosemite>. "Yosemite National Park - Climate - US-Parks.com." //National Parks Travel Guide - US-Parks.com//. Web. 13 June 2010. <http://www.us-parks.com/yosemite-national-park/climate.html>. "Yosemite National Park - Climate - US-Parks.com." //National Parks Travel Guide - US-Parks.com//. Web. 13 June 2010. <http://www.us-parks.com/yosemite-national-park/climate.html>. "Yosemite National Park Geology." //Welcome to ScienceViews.com//. Web. 13 June 2010. <http://www.scienceviews.com/parks/ygeology.html>. "Yosemite National Park (U.S. National Park Service)." //U.S. National Park Service - Experience Your America//. Web. 13 June 2010. <http://www.nps.gov/yose>.