A numerical model determines how a model state at a particular time changes into the model state at a time. Data assimilation or, more-or-less synonymously, data analysis is the process by which observations of the system are incorporated into the model state of a numerical model of that system. Applications of data assimilation arise in many fields of geosciences, perhaps most importantly in weather forecasting, the initial state of the numerical model cannot therefore be determined from the available observations alone. Instead, the model is used to propagate information from past observations to the current time. This is combined with current observations of the system using a data assimilation method. Most commonly this leads to the numerical modelling system alternately performing a numerical forecast and this is known as analysis/forecast cycling. The forecast from the analysis to the current one is frequently called the background. The data assimilation procedure is invariably multivariate and includes approximate relationships between the variables, the observations are of the actual system, rather than of the models incomplete representation of that system, and so may have different relationships between the variables from those in the model.
To reduce the impact of these problems incremental analyses are often performed and that is the analysis procedure determines increments which when added to the background yield the analysis. As the increments are generally compared to the background values this leaves the analysis less affected by balance errors in the analysed increments. In data assimilation applications, the analysis and forecasts are best thought of as probability distributions, the analysis step is an application of Bayes theorem and the overall assimilation procedure is an example of recursive Bayesian estimation. However, the analysis is usually simplified to a computationally feasible form. If the probability distributions are normal, they can be represented by their mean and covariance, however it is not feasible to maintain the covariance because of the large number of degrees of freedom in the state, so various approximations are used instead. Many methods represent the probability distributions only by the mean and impute some covariance instead, in the basic form, such analysis step is known as optimal statistical interpolation.
Adjusting the initial value of the model instead of changing the state directly at the analysis time is the essence of the variational methods. Nudging, known as Newtonian relaxation or 4DDA, is essentially the same as proceeding in continuous time rather than in discrete analysis cycles, Ensemble Kalman filters represent the probability distribution by an ensemble of simulations, and the covariance is approximated by sample covariance. Data assimilation is a concept encompassing any method for combining observations of such as temperature. The process of entering data into the model to generate initial conditions is called initialization
Steamboat Springs, Colorado
The City of Steamboat Springs, often shortened as Steamboat, is a Home Rule Municipality that is the county seat and the most populous city of Routt County, United States. As of the 2010 census, the city population was 12,088, the city is an internationally known winter ski resort destination. The Steamboat Springs tourism industry is highlighted by Steamboat Ski Resort and it contains the much smaller Howelsen Ski Area. It is located in the valley of the Yampa River, along U. S. Highway 40 just west of the Continental Divide. The area surrounding Steamboat Springs was originally inhabited by the Yampatikas Utes, trappers began to move through the area during the first decades of the 19th century. James Harvey Crawford, the founder of Steamboat Springs, first arrived in the spring of 1874, the Crawford family moved there in 1876, and for the first five years were the sole permanent residents of the town. The native Utes were forcibly removed from the area to a reservation in Utah by the U. S.
Army starting in 1879. Milestones in the development of the town included the first sawmill in 1873, incorporation of the town in 1900. The economy of the region was based on ranching and mining. Steamboat is home to hot springs that are located throughout the area. Upon first hearing a sound, early trappers believed that a steamboat was coming down the river. When the trappers saw that there was no steamboat, and that the sound was coming from a hot spring, skiing was the only method of transportation during harsh and snowy Rocky Mountain winters. In turn, the popularity of skiing as a winter pastime catalyzed development of the town, in 1913, Carl Howelsen, a Norwegian, moved to town and introduced ski jumping. Howelsen built the first jump on Howelsen Hill, now part of the Howelsen Ski Area and he founded the annual Winter Carnival, a celebration still held each winter. The festival includes ski racing and jumping, dog sledding, and chariot events down Lincoln Avenue, light shows on both Mount Werner and Howelsen Hill are highlights.
The Steamboat Ski Resort was largely established by two men, Jim Temple and John Fetcher. Temple led the effort to develop the area, Fetcher, a local rancher, was the main designer and builder. The resort opened on what was called Storm Mountain in 1963, the company is one of the largest employers in Routt County and has more than 9,000 employees worldwide
Paradise is an unincorporated town and census-designated place in Clark County, United States, adjacent to the city of Las Vegas. The population was 223,167 at the 2010 census, making it the most populous unincorporated community in Nevada, as an unincorporated town, it is governed by the Clark County Commission with input from the Paradise Town Advisory Board. Paradise was formed on December 8,1950, Paradise contains McCarran International Airport, the University of Nevada, Las Vegas, and most of the Las Vegas Strip. Paradise contains most tourist attractions in the Las Vegas area, excluding downtown, despite this, the name Paradise remains relatively unknown. All Paradise ZIP codes have Las Vegas mailing addresses, the southern part of the Las Vegas Valley was referred to as Paradise Valley as early as 1910, owing to a high water table that made the land particularly fertile for farming. County commissioners established a Paradise school district in 1914, the commission voted to create the unincorporated township of Paradise on December 8,1950.
In 1975, Nevada enacted a law that would have incorporated Paradise into the City of Las Vegas, before it could take effect, the bill was struck down as unconstitutional by the Nevada Supreme Court. According to the United States Census Bureau, the place of Paradise has a total area of 46.7 square miles. At the census of 2010, there were 223,167 people residing in Paradise. The racial makeup was 59. 8% White,8. 9% African American,0. 8% Native American,9. 5% Asian,1. 0% Pacific Islander, and 5. 5% from two or more races. Hispanic or Latino of any race were 31. 2% of the population and 46. 3% of the population was non-Hispanic White. As of the census of 2000, there were 186,070 people,77,209 households, the population density was 3,947.3 people per square mile. There were 85,398 housing units at a density of 1,811.6 per square mile. The racial makeup of the CDP was 72. 51% White,6. 59% African American,0. 77% Native American,6. 52% Asian,0. 59% Pacific Islander,8. 37% from other races, and 4. 65% from two or more races.
Hispanic or Latino of any race were 23. 47% of the population,31. 9% of all households were made up of individuals and 7. 5% had someone living alone who was 65 years of age or older. The average household size was 2.39 and the family size was 3.04. In the CDP, the population was out with 21. 2% under the age of 18,10. 8% from 18 to 24,33. 3% from 25 to 44,23. 6% from 45 to 64. The median age was 35 years, for every 100 females there were 109.1 males
National Oceanic and Atmospheric Administration
The National Oceanic and Atmospheric Administration is an American scientific agency within the United States Department of Commerce focused on the conditions of the oceans and the atmosphere. NOAA warns of dangerous weather, charts seas, guides the use and protection of ocean and coastal resources, and conducts research to improve understanding and stewardship of the environment. In addition to its employees, over 11,000 as of 2015, NOAA research. NOAA plays several roles in society, the benefits of which extend beyond the U. S. economy and into the larger global community. NOAA supplies information to its customers and partners pertaining to the state of the oceans and this is clearly manifest in the production of weather warnings and forecasts through the National Weather Service, but NOAAs information products extend to climate and commerce as well. A Provider of Environmental Stewardship Services, NOAA is the steward of U. S. coastal and marine environments. A Leader in Applied Scientific Research, the five fundamental activities are and observing Earth systems with instruments and data collection networks.
Understanding and describing Earth systems through research and analysis of that data and predicting the changes of these systems over time. Engaging and informing the public and partner organizations with important information, managing resources for the betterment of society and environment. NOAA formed a conglomeration of several existing agencies that were among the oldest in the federal government, NOAA was established within the Department of Commerce via the Reorganization Plan No.4 of 1970. In 2007 NOAA celebrated 200 years of service with its ties to the United States Coast, the NOAA Commissioned Officer Corps is a uniformed service of men and women who operate NOAA ships and aircraft, and serve in scientific and administrative posts. And in addition more than a dozen staff offices, including the Office of the Federal Coordinator for Meteorology, the NOAA Central Library and this is done through a collection of national and regional centers,13 river forecast centers, and more than 120 local weather forecast offices.
They are charged with issuing weather and river forecasts, advisories and they issue more than 734,000 weather and 850,000 river forecasts, and more than 45,000 severe weather warnings annually. NOAA data is relevant to the issues of global warming. The NWS operates NEXRAD, a network of Doppler weather radars which can detect precipitation. Many of their products are broadcast on NOAA Weather Radio, a network of transmitters that broadcasts weather forecasts, severe weather statements, watches. The National Ocean Service focuses on ensuring that ocean and coastal areas are safe, healthy, in 1960 TIROS-1, NOAAs first owned and operated geostationary satellite was launched. Since 1966 NESDIS has managed polar orbiting satellites and since 1974 it has operated geosynchronous satellites, in 1979 NOAAs first polar-orbiting environmental satellite was launched
Nevada is a state in the Western, Mountain West, and Southwestern regions of the United States of America. Nevada is the 7th most extensive, the 34th most populous, nearly three-quarters of Nevadas people live in Clark County, which contains the Las Vegas–Paradise metropolitan area where three of the states four largest incorporated cities are located. Nevada is officially known as the Silver State because of the importance of silver to its history and economy. It is known as the Battle Born State, because it achieved statehood during the Civil War, as the Sage-brush State, for the plant of the same name. Nevada borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, Nevada is largely desert and semi-arid, much of it located within the Great Basin. Areas south of the Great Basin are located within the Mojave Desert, while Lake Tahoe, about 86% of the states land is managed by various jurisdictions of the U. S. federal government, both civilian and military.
Before European contact, Native Americans of the Paiute, the first Europeans to explore the region were Spanish. They called the region Nevada because of the snow covered the mountains in winter. The area formed part of the Viceroyalty of New Spain, the United States annexed the area in 1848 after its victory in the Mexican–American War, and it was incorporated as part of Utah Territory in 1850. The discovery of silver at the Comstock Lode in 1859 led to a boom that became an impetus to the creation of Nevada Territory out of western Utah Territory in 1861. Nevada became the 36th state on October 31,1864, as the second of two added to the Union during the Civil War. Nevada has a reputation for its libertarian laws, in 1940, with a population of just over 110,000 people, Nevada was by far the least-populated state, with less than half the population of the next least-populated state. However, legalized gambling and lenient marriage and divorce laws transformed Nevada into a major tourist destination in the 20th century, Nevada is the only U. S.
state where prostitution is legal, though it is illegal in Clark County, Washoe County and Carson City. The tourism industry remains Nevadas largest employer, with mining continuing as a sector of the economy. The name Nevada comes from the Spanish nevada, meaning snow-covered, most Nevadans pronounce the second syllable of their state name using the vowel of trap. Many from outside the Western United States pronounce it with the vowel of father, although the latter pronunciation is closer to the Spanish pronunciation, it is not the pronunciation preferred by most Nevadans. State Assemblyman Harry Mortenson proposed a bill to recognize the alternate pronunciation of Nevada, though the bill was not supported by most legislators, the Nevadan pronunciation is the de facto official one, since it is the one used by the state legislature. Nevada is almost entirely within the Basin and Range Province, and is broken up by many mountain ranges
National University (California)
National University is a private, nonprofit institution of higher education in California. Founded in 1971, National University is headquartered in La Jolla, National University offers academic degree programs at campuses located throughout the state of California, one campus in Nevada, and online. National University’s online academic programs are interactive with streaming videos, real-time discussions, multimedia learning material, programs at National University are concentrated and are designed primarily for adult learners. On campus classes are scheduled during weeknights with an occasional Saturday. National Universitys academic programs include associates degrees, bachelors degrees, masters degrees, teaching credentials, the university offers over 130 undergraduate and graduate degrees, as well as 23 teacher credential/certificate programs. Participating in online education since 1996, National University offers more than 100 graduate and undergraduate degree programs, the school is composed of three departments and offers various bachelors and masters degrees.
National holds teaching contracts with 643 California school districts and approximately 70% of the 26,000 teachers in San Diego County earned their credentials at National University, programs are offered on campus and online. In 2015, National University renamed the School of Education to the Sanford College of Education in honor of philanthropist T. Denny Sanford, the School of Engineering and Computing offers degree programs in engineering, computer science, and related fields. Students can focus on management information systems, construction engineering, electrical engineering, the School of Professional Studies offers several graduate and undergraduate academic degree programs such as digital media, criminal justice, and continuing education programs. National University is geographically dispersed, with its academic and administrative centers located in La Jolla and these centers include all administrative offices of the president, vice presidents, school deans and department chairs, financial aid and admissions.
From its administrative center, the university more than 28 academic campuses throughout urban areas in California. Campus locations include, National University offers reduced tuition for classes on base for qualified military students, admission offices and Learning Centers are located on many U. S. Trustees have a responsibility to the university as a whole. Among other responsibilities, the board elects the president, adopts an annual plan of financial operation, day-to-day responsibility for administration of the university is delegated by the trustees to the president. The Board of Trustees consists of 25 voting members, two ex-officio members, the president of the university and the chancellor of the system, have voting privileges. The Board meets three times a year in San Diego, National University has an enrollment size that represents the second-largest private, non-profit institution of higher education in California. The average age of a NU student age is 32 and roughly 23,000 full-time undergraduate and graduate students are currently enrolled, nine percent of the student body are in the military.
National University ranks as one of the largest graduate student institutions of education in the United States with 23,909 students officially enrolled
Silver iodide is an inorganic compound with the formula AgI. The compound is a yellow solid, but samples almost always contain impurities of metallic silver that give a gray coloration. The silver contamination arises because AgI is highly photosensitive and this property is exploited in silver-based photography. Silver iodide is used as an antiseptic and in cloud seeding. The structure adopted by silver iodide is temperature dependent, Below 420 K and this phase is encountered in nature as the mineral iodargyrite. Above 420 K, the α-phase becomes more stable and this motif is a body-centered cubic structure which has the silver centers distributed randomly between 6 octahedral,12 tetrahedral and 24 trigonal sites. At this temperature, Ag+ ions can move rapidly through the solid, the transition between the β and α forms represents the melting of the silver sublattice. The entropy of fusion for α-AgI is approximately half that for sodium chloride and this can be rationalized by considering the AgI crystalline lattice to have already partly melted in the transition between α and β polymorphs. A metastable γ-phase exists below 420 K with the zinc blende structure, silver iodide is prepared by reaction of an iodide solution with a solution of silver ions.
The solid is a mixture of the two principal phases, dissolution of the AgI in hydroiodic acid, followed by dilution with water precipitates β-AgI. Alternatively, dissolution of AgI in a solution of concentrated silver nitrate followed by dilution affords α-AgI, if the preparation is not conducted in the absence of sunlight, the solid darkens rapidly, the light causing the reduction of ionic silver to metallic. The photosensitivity varies with sample purity, the crystalline structure of β-AgI is similar to that of ice, allowing it to induce freezing by the process known as heterogeneous nucleation. Approximately 50,000 kg are used for cloud seeding annually, extreme exposure can lead to argyria, characterized by localized discoloration of body tissue
Reno is a city in the U. S. state of Nevada. It is in Northern Nevada, approximately 22 miles from Lake Tahoe, known as The Biggest Little City in the World, Reno is famous for its casinos and as the birthplace of Caesars Entertainment Corporation. It is the county seat of Washoe County, in the part of the state. The city sits in a desert at the foot of the Sierra Nevada. Archaeological finds place the border for the prehistoric Martis people in the Reno area. As early as the mid 1850s a few settled in the Truckee Meadows. Gold was discovered in the vicinity of Virginia City in 1850, and a modest mining community developed, to provide the necessary connection between Virginia City and the California Trail, Charles W. Fuller built a log toll bridge across the Truckee River in 1859. A small community that would service travelers soon grew up near the bridge, after two years, Fuller sold the bridge to Myron C. Lake, who continued to develop the community with the addition of a grist mill, kiln, in 1864, Washoe County was consolidated with Roop County, and Lakes Crossing became the largest town in the county.
Lake had earned himself the founder of Reno. Lake deeded land to the CPRR in exchange for its promise to build a depot at Lakes Crossing, once the railroad station was established, the town of Reno officially came into being on May 9,1868. CPRR construction superintendent Charles Crocker named the community after Major General Jesse Lee Reno, in 1871, Reno became the county seat of the newly expanded Washoe County, replacing the previous county seat, located in Washoe City. However, political power in Nevada remained with the communities, first Virginia City and Tonopah. The extension of the Virginia and Truckee Railroad to Reno in 1872 provided a boost to the new citys economy. Despite this, Nevada is still the third-largest gold producer in the world, after South Africa and Australia, the Reno Arch was erected on Virginia Street in 1926 to promote the upcoming Transcontinental Highways Exposition of 1927. The arch included the words Nevadas Transcontinental Highways Exposition and the dates of the exposition.
After the exposition, the Reno City Council decided to keep the arch as a permanent downtown gateway, no acceptable slogan was received until a $100 prize was offered, and G. A. Burns of Sacramento was declared the winner on March 14,1929, with Reno, The Biggest Little City in the World
Great Basin College
Great Basin College is a member of the Nevada System of Higher Education, located in Elko, United States. Opened in 1967 as Elko Community College, it was renamed to Northern Nevada Community College. The College offers two-year and four year degrees in a variety of disciplines and it offers Associate of Applied Science degrees in the areas of business, computer office technology, criminal justice, early childhood education, industrial technology, land surveying and nursing. Additionally, it offers four degrees in elementary and secondary education, applied science, land surveying, nursing. As a comprehensive college, the institution provides instruction and training for students interested in career, certificate programs and short-term training programs exist in several business, secretarial/administrative assistant and industrial arts fields. Great Basin College has its campus in Elko, in northeastern Nevada. Residence halls are available at the Elko campus, branch campuses serve the communities of Battle Mountain, Ely and Winnemucca.
Satellite centers are located in nearly 20 communities across rural Nevada
AT&T Inc. is an American multinational telecommunications conglomerate, headquartered at Whitacre Tower in downtown Dallas, Texas. AT&T is the third-largest company in Texas, as of February 2017, AT&T is the 12th largest company in the world as measured by a composite of revenues, profits and market valuation. AT&T is the largest telecommunications company in the world by revenue, as of 2017, it is the 18th-largest mobile telecom operator in the world, with 135 million mobile customers. AT&T was ranked at #4 on the 2017 rankings of the worlds most valuable brands published by Brand Finance, Southwestern Bell changed its name to SBC Communications Inc. in 1995. In 2005, SBC purchased former parent AT&T Corp. and took on its branding, with the merged entity naming itself AT&T Inc. and using the iconic AT&T Corp. logo and stock-trading symbol. The current AT&T reconstitutes much of the former Bell System and includes ten of the original 22 Bell Operating Companies, AT&T can trace its origin back to the original Bell Telephone Company founded by Alexander Graham Bell after his invention of the telephone.
This monopoly was known as the Bell System, and during this period, for periods of time, the former AT&T was the worlds largest phone company. In 1982, U. S. regulators broke up the AT&T monopoly, requiring AT&T to divest its regional subsidiaries and these new companies were known as Regional Bell Operating Companies, or more informally, Baby Bells. AT&T continued to long distance services, but as a result of this breakup, faced competition from new competitors such as MCI. Southwestern Bell was one of the created by the breakup of AT&T. The architect of divestiture for Southwestern Bell was Robert G. Pope, the company soon started a series of acquisitions. This includes the 1987 acquisition of Metromedia mobile business, and the acquisition of several companies in the early 1990s. In the half of the 1990s, the company acquired several other companies, including some Baby Bells. During this time, the changed its name to SBC Communications. By 1998, the company was in the top 15 of the Fortune 500, in 2005, SBC purchased AT&T for $16 billion.
After this purchase, SBC adopted the better-known AT&T name and brand, the current AT&T claims the original AT&Ts history as its own, though its corporate structure only dates from 1983. It retains SBCs pre-2005 stock price history, in September 2013, AT&T announced it would expand into Latin America through a collaboration with Carlos Slims América Móvil. In December 2013, AT&T announced plans to sell its Connecticut wireline operations to Stamford-based Frontier Communications, in July 2015, AT&T purchased DirecTV for $48.5 billion, or $67.1 billion including assumed debt
Snowpack forms from layers of snow that accumulate in geographic regions and high altitudes where the climate includes cold weather for extended periods during the year. Snowpacks are an important water resource that feed streams and rivers as they melt, snowpacks are both the drinking water source for many communities and a potential source of flooding. Snowpacks contribute mass to glaciers in their accumulation zone, assessing the formation and stability of snowpacks is important in the study and prediction of avalanches. Snow is studied in a global context of impact on animal habitats. An important effort is put into snow classification, both as an hydrometeor and on the ground, snowpack modeling is done for snow stability, flood forecasting, water resource management, and climate studies. Snowpack modeling is either done by simple, statistical methods such as day or complex, physically based energy balance models such as the SNOWPACK model. Advection Glaciation Glacier mass balance Hydrology Subnivean climate SNOWPACK CROCUS SnowModel