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Water Year
A water year (also called ''hydrological year'', ''discharge year'' or ''flow year'') is a term commonly used in hydrology to describe a time period of 12 months for which precipitation totals are measured. Its beginning differs from the calendar year because part of the precipitation that falls in late autumn and winter accumulates as snow and does not drain until the following spring or summer's snowmelt. The goal is to ensure that as much as possible of the surface runoff during the water year is attributable to the precipitation during the same water year. Due to meteorological and geographical factors, the definition of the water years varies. The United States Geological Survey (USGS) defines it as the period between October 1 of one year and September 30th of the next,United States Geological Survey, "Explanations for the National Water Conditions", http://water.usgs.gov/nwc/explain_data.html, Retrieved 16 October 2011. as late September to early October is the time for many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrology
Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydrologist. Hydrologists are scientists studying earth science, earth or environmental science, civil engineering, civil or environmental engineering, and physical geography. Using various analytical methods and scientific techniques, they collect and analyze data to help solve water related problems such as Environmentalism, environmental preservation, natural disasters, and Water resource management, water management. Hydrology subdivides into surface water hydrology, groundwater hydrology (hydrogeology), and marine hydrology. Domains of hydrology include hydrometeorology, surface-water hydrology, surface hydrology, hydrogeology, drainage basin, drainage-basin management, and water quality. Oceanography and meteorology are not included beca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decile
In descriptive statistics, a decile is any of the nine values that divide the sorted data into ten equal parts, so that each part represents 1/10 of the sample or population. A decile is one possible form of a quantile; others include the quartile and percentile.. A decile rank arranges the data in order from lowest to highest and is done on a scale of one to ten where each successive number corresponds to an increase of 10 percentage points. Special usage: The decile mean A moderately robust measure of central tendency - known as the decile mean - can be computed by making use of a sample's deciles D_ to D_ (D_ = 10th percentile, D_ = 20th percentile and so on). It is calculated as follows: : DM = \frac Apart from serving as an alternative for the mean and the truncated mean, it also forms the basis for robust measures of skewness and kurtosis In probability theory and statistics, kurtosis (from , ''kyrtos'' or ''kurtos'', meaning "curved, arching") refers to the degree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seasonal Year
The seasonal year is the time between successive recurrences of a seasonal event such as the flooding of a river, the migration of a species of bird, or the flowering of a species of plant. The need for farmers to predict seasonal events led to the development of calendars. However, the variability from year to year of seasonal events (due to climate change or just random variation) makes the seasonal year very hard to measure. This means that calendars are based on astronomical years (which are regular enough to be easily measured) as surrogates for the seasonal year. For example, the ancient Egyptians used the heliacal rising of Sirius to predict the flooding of the Nile. A study of temperature records over the past 300 years suggests that the seasonal year is governed by the anomalistic year rather than the tropical year. This suggestion is surprising because the season A season is a division of the year based on changes in weather, ecology, and the number of daylight ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrological Modelling
A hydrologic model is a simplification of a real-world system (e.g., surface water, soil water, wetland, groundwater, estuary) that aids in understanding, predicting, and managing water resources. Both the flow and quality of water are commonly studied using hydrologic models. Analog models Prior to the advent of computer models, hydrologic modeling used Analogical models, analog models to simulate flow and transport systems. Unlike mathematical models that use equations to describe, predict, and manage hydrologic systems, analog models use non-mathematical approaches to simulate hydrology. Two general categories of analog models are common; scale model, scale analogs that use miniaturized versions of the physical system and process analogs that use comparable physics (e.g., electricity, heat, diffusion) to mimic the system of interest. Scale analogs Scale models offer a useful approximation of physical or chemical processes at a size that allows for greater ease of visual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Basin
A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the drainage divide, made up of a succession of elevated features, such as ridges and hills. A basin may consist of smaller basins that merge at river confluences, forming a hierarchical pattern. Other terms for a drainage basin are catchment area, catchment basin, drainage area, river basin, water basin, and impluvium. In North America, they are commonly called a watershed, though in other English-speaking places, " watershed" is used only in its original sense, that of the drainage divide line. A drainage basin's boundaries are determined by watershed delineation, a common task in environmental engineering and science. In a closed drainage basin, or endorheic basin, rather than flowing to the ocean, water converges toward the interio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spring Melt
Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a helically coiled tube * Spring (political terminology), often used to name periods of political liberalization * Springs (tide), in oceanography, the maximum tide, occurs twice a month during the full and new moon Places * Spring (Milz), a river in Thuringia, Germany * Spring, Alabel, a barangay unit in Alabel, Sarangani Province, Philippines * Șpring, a commune in Alba County, Romania * Șpring (river), a river in Alba County, Romania * Springs, Gauteng, South Africa * Springs, the location of Dubai British School, Dubai * Spring Village, Saint Vincent and the Grenadines * Spring Village, Shropshire, England United States * Springs, New York, a part of East Hampton, New York * Springs, Pennsylvania, an unincorporated community * Spring, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weighted Average
The weighted arithmetic mean is similar to an ordinary arithmetic mean (the most common type of average), except that instead of each of the data points contributing equally to the final average, some data points contribute more than others. The notion of weighted mean plays a role in descriptive statistics and also occurs in a more general form in several other areas of mathematics. If all the weights are equal, then the weighted mean is the same as the arithmetic mean. While weighted means generally behave in a similar fashion to arithmetic means, they do have a few counterintuitive properties, as captured for instance in Simpson's paradox. Examples Basic example Given two school with 20 students, one with 30 test grades in each class as follows: :Morning class = :Afternoon class = The mean for the morning class is 80 and the mean of the afternoon class is 90. The unweighted mean of the two means is 85. However, this does not account for the difference in number of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CAWR
Coventry University is a public research university in Coventry, England. The origins of Coventry University can be linked to the Coventry School of Design in 1843. It was known as Lanchester Polytechnic from 1970 until 1987, and then as Coventry Polytechnic until it gained university status in 1992. Coventry is the larger of the two universities in the city, the other being the University of Warwick. The Coventry University Group operates campuses in Coventry, Scarborough, London and Wrocław. It has two principal campuses: one in the centre of Coventry where the majority of its operations are located, and one in Central London which focuses on business and management courses. Coventry also governs the higher education institutions CU Coventry, CU Scarborough and CU London. Its colleges, which are made up of schools and departments, run around 300 undergraduate and postgraduate courses. Across the university there are 11 research centres which specialise in different fields ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ad-hoc
''Ad hoc'' is a Latin phrase meaning literally for this. In English, it typically signifies a solution designed for a specific purpose, problem, or task rather than a generalized solution adaptable to collateral instances (compare with ''a priori''). Common examples include ad hoc committees and commissions created at the national or international level for a specific task, and the term is often used to describe arbitration (ad hoc arbitration). In other fields, the term could refer to a military unit created under special circumstances (see ''task force''), a handcrafted network protocol (e.g., ad hoc network), a temporary collaboration among geographically-linked franchise locations (of a given national brand) to issue advertising coupons, or a purpose-specific equation in mathematics or science. Ad hoc can also function as an adjective describing temporary, provisional, or improvised methods to deal with a particular problem, the tendency of which has given rise to the no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwealth usage), snow, ice pellets, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor (reaching 100% relative humidity), so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation; their water vapor does not condense sufficiently to precipitate, so fog and mist do not fall. (Such a non-precipitating combination is a colloid.) Two processes, possibly acting together, can lead to air becoming saturated with water vapor: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
