Misplaced Pages

#971028

40-519: Together with the city of Carmen de Patagones across the river in Buenos Aires Province , Viedma is the oldest European settlement in Patagonia , founded by Francisco de Viedma y Narváez under the name of Nuestra Señora del Carmen on 22 April 1779. Originally the two cities were one, called Carmen de Patagones. The original fort was built on the south side of the river in modern Viedma, but it

80-429: A January high of 30.4 °C (86.7 °F) and a low of 14.8 °C (58.6 °F). The diurnal range (difference between average high and average low) is large along with the temperature profile of Viedma makes it appropriate for the development of wide variety of subtropical crops. Humid days are rare owing to the low humidity (around 50%) and a dewpoint temperature of 12 to 13 °C (53.6 to 55.4 °F). During

120-525: A given area are primarily controlled by three factors: Firstly, the amount of water present. Secondly, the amount of energy present in the air and soil (e.g. heat, measured by the global surface temperature ); and thirdly the ability of the atmosphere to take up water ( humidity ). Regarding the second factor (energy and heat): climate change has increased global temperatures (see instrumental temperature record ). This global warming has increased evapotranspiration over land. The increased evapotranspiration

160-671: A low of 43.5% in July to a high of 69% in March. This makes Viedma relatively sunny relative to the average in the country. The highest recorded temperature was 43.7 °C (110.7 °F) on 18 February 1987, while the lowest recorded temperature was −10.8 °C (12.6 °F) on 4 July 1988. The Gobernador Castello Airport ( IATA : VDM , ICAO : SAVV ) serves flights to Buenos Aires , Neuquén , Bariloche , Puerto Madryn , Trelew , Comodoro Rivadavia , Mar del Plata , and other cities in Argentina. It

200-510: A naval base, since the main Argentine safe harbour, the estuary of the Río de la Plata , had been blocked by Brazilian ships. The Brazilian troops attempted to take Carmen de Patagones, but they were repelled by armed residents on 7 March 1827; this date is still commemorated with a festival in the city. The city maintains two imperial Brazilian flags captured during the battle in the central cathedral on

240-524: A surface and the ability of the surface to supply moisture, then PET is a measure of the demand side (also called evaporative demand ). Surface and air temperatures, insolation , and wind all affect this. A dryland is a place where annual potential evaporation exceeds annual precipitation . Often a value for the potential evapotranspiration is calculated at a nearby climatic station on a reference surface, conventionally on land dominated by short grass (though this may differ from station to station). This value

280-414: Is a reflection of the energy available to evaporate or transpire water, and of the wind available to transport the water vapor from the ground up into the lower atmosphere and away from the initial location. Potential evapotranspiration is expressed in terms of a depth of water or soil moisture percentage. If the actual evapotranspiration is considered the net result of atmospheric demand for moisture from

320-582: Is a water deficit, owing to higher temperatures and windier conditions that promote evapotranspiration and drier conditions. In winter and autumn, precipitation occurs regularly resulting in less water deficit owing to lower temperatures, more moderate winds, and higher humidity (lower evapotranspiration). On average, there are 73 days with measurable precipitation. Summers tend to have less rainy days than winter due to rainfall occurring more intensely (shorter bursts). Viedma receives 2620 hours of sunshine per year or 57.7% of possible sunshine per year, ranging from

360-419: Is areas with high water tables , where capillary action can cause water from the groundwater to rise through the soil matrix back to the surface. If potential evapotranspiration is greater than the actual precipitation, then soil will dry out until conditions stabilize, unless irrigation is used. Evapotranspiration can be measured directly with a weighing or pan lysimeter . A lysimeter continuously measures

400-446: Is by calculating the energy balance. λ E = R n − G − H {\displaystyle \lambda E=R_{n}-G-H\,\!} where λE is the energy needed to change the phase of water from liquid to gas, R n is the net radiation, G is the soil heat flux and H is the sensible heat flux . Using instruments like a scintillometer , soil heat flux plates or radiation meters,

440-418: Is called the reference evapotranspiration (ET 0 ). Actual evapotranspiration is said to equal potential evapotranspiration when there is ample water present. Evapotranspiration can never be greater than potential evapotranspiration, but can be lower if there is not enough water to be evaporated or plants are unable to transpire maturely and readily. Some US states utilize a full cover alfalfa reference crop that

SECTION 10

#1732851411972

480-501: Is estimated that on average between three-fifths and three-quarters of land precipitation is returned to the atmosphere via evapotranspiration. Evapotranspiration does not, in general, account for other mechanisms which are involved in returning water to the atmosphere, though some of these, such as snow and ice sublimation in regions of high elevation or high latitude, can make a large contribution to atmospheric moisture even under standard conditions. Levels of evapotranspiration in

520-590: Is located 6 km from the city, and has an average annual traffic of 30,000 passengers. 30 km downstream from Viedma, on the Atlantic shore, the El Cóndor beach resort town (Balneario Massini) is the most visited tourist beach in the area. The Servicios Ferroviarios Patagónico connect with San Carlos de Bariloche . 40°48′S 63°00′W  /  40.800°S 63.000°W  / -40.800; -63.000 Carmen de Patagones Carmen de Patagones

560-460: Is lost or intentionally destroyed by clearing and burning, soil moisture is reduced by wind, and soils are easily eroded by high wind and rainfall events. In areas that are not irrigated, actual evapotranspiration is usually no greater than precipitation , with some buffer and variations in time depending on the soil's ability to hold water. It will usually be less because some water will be lost due to percolation or surface runoff . An exception

600-425: Is low, averaging 62%, with the summer months being drier than the winter months. Nonetheless, it is common to have high humidity conditions, particularly during early morning and late evening when temperatures are lower. On average, Viedma receives 394.2 millimetres (16 in) of precipitation per year which is evenly distributed throughout the year. During spring and summer, precipitation occurs irregularly and there

640-405: Is one of the effects of climate change on the water cycle . Vegetation type impacts levels of evapotranspiration. For example, herbaceous plants generally transpire less than woody plants , because they usually have less extensive foliage. Also, plants with deep reaching roots can transpire water more constantly, because those roots can pull more water into the plant and leaves. Another example

680-678: Is responsible for the variability in wind speeds throughout the year. Occasionally, strong gusts exceeding 110 kilometres per hour (68 mph) can occur. Winters are cool with a July mean of 6.6 °C (43.9 °F) and frosts are common, averaging 9–10 days from June to August. During this time of the year, overcast days are more common, averaging 9–10 days per month although sunny days are fairly common as well. Spring and fall are transition seasons featuring warm daytime temperatures and cool nighttime temperatures and are highly variable with some days reaching above 39 °C (102.2 °F) and below −5 °C (23.0 °F). Summers are hot and dry with

720-520: Is that conifer forests tend to have higher rates of evapotranspiration than deciduous broadleaf forests, particularly in the dormant winter and early spring seasons, because they are evergreen . Transpiration is a larger component of evapotranspiration (relative to evaporation) in vegetation-abundant areas. As a result, denser vegetation, like forests, may increase evapotranspiration and reduce water yield. Two exceptions to this are cloud forests and rainforests . In cloud forests, trees collect

760-622: Is the Penman equation . The Penman–Monteith variation is recommended by the Food and Agriculture Organization and the American Society of Civil Engineers . The simpler Blaney–Criddle equation was popular in the Western United States for many years but it is not as accurate in wet regions with higher humidity. Other equations for estimating evapotranspiration from meteorological data include

800-604: Is the southernmost city in the province of Buenos Aires , Argentina. It is located 937 km southwest from the city of Buenos Aires , on the north bank of the Río Negro ("Black River"), near the Atlantic Ocean , and opposite Viedma , capital of the province of Río Negro . The city is the capital of the Patagones Partido , the only administrative division of Buenos Aires Province that lies within Patagonia . The town

840-523: The Makkink equation , which is simple but must be calibrated to a specific location, and the Hargreaves equations . To convert the reference evapotranspiration to the actual crop evapotranspiration, a crop coefficient and a stress coefficient must be used. Crop coefficients, as used in many hydrological models, usually change over the year because crops are seasonal and, in general, plant behaviour varies over

SECTION 20

#1732851411972

880-480: The commission overseeing the project, in 1989. Evapotranspiration Evapotranspiration ( ET ) refers to the combined processes which move water from the Earth's surface (open water and ice surfaces, bare soil and vegetation ) into the atmosphere . It covers both water evaporation (movement of water to the air directly from soil, canopies , and water bodies) and transpiration (evaporation that occurs through

920-414: The stomata , or openings, in plant leaves). Evapotranspiration is an important part of the local water cycle and climate , and measurement of it plays a key role in water resource management agricultural irrigation . Evapotranspiration is defined as: "The combined processes through which water is transferred to the atmosphere from open water and ice surfaces, bare soil and vegetation that make up

960-434: The water balance equation for a given area:. The water balance equation relates the change in water stored within the basin ( S ) to its input and outputs: Δ S = P − E T − Q − D {\displaystyle \Delta S=P-ET-Q-D\,\!} In the equation, the change in water stored within the basin ( ΔS ) is related to precipitation ( P ) (water going into

1000-481: The Earth’s surface." Evapotranspiration is a combination of evaporation and transpiration, measured in order to better understand crop water requirements, irrigation scheduling, and watershed management. The two key components of evapotranspiration are: Evapotranspiration is typically measured in millimeters of water (i.e. volume of water moved per unit area of the Earth's surface) in a set unit of time. Globally, it

1040-406: The basin), and evapotranspiration ( ET ), streamflow ( Q ), and groundwater recharge ( D ) (water leaving the basin). By rearranging the equation, ET can be estimated if values for the other variables are known: E T = P − Δ S − Q − D {\displaystyle ET=P-\Delta S-Q-D\,\!} A second methodology for estimation

1080-692: The components of the energy balance can be calculated and the energy available for actual evapotranspiration can be solved. The SEBAL and METRIC algorithms solve for the energy balance at the Earth's surface using satellite imagery. This allows for both actual and potential evapotranspiration to be calculated on a pixel-by-pixel basis. Evapotranspiration is a key indicator for water management and irrigation performance. SEBAL and METRIC can map these key indicators in time and space, for days, weeks or years. Given meteorological data like wind, temperature, and humidity, reference ET can be calculated. The most general and widely used equation for calculating reference ET

1120-661: The federal capital from Buenos Aires to Viedma. This was to reduce congestion in Buenos Aires, to help develop Patagonia, and to promote the development of the interior. A bill to that effect was passed by Congress the following year, but owing to economic problems, the project had stagnated by the end of the Alfonsín administration in 1989. The main economical activities in the area of the Valle Inferior are cattle, as well as some agriculture with onion , maize and alfalfa being

1160-404: The hottest days in summer when the wind is from the northwest or west, sea breezes can occur that can move inland in the opposite of the mentioned wind directions which moderate summer temperatures. This occurs because when the surrounding land heats faster than the sea, causing the land to have lower atmospheric pressure than the sea which has a relatively higher atmospheric pressure. As a result,

1200-502: The liquid water in fog or low clouds onto their surface, which eventually drips down to the ground. These trees still contribute to evapotranspiration, but often collect more water than they evaporate or transpire. In rainforests, water yield is increased (compared to cleared, unforested land in the same climatic zone) as evapotranspiration increases humidity within the forest (a portion of which condenses and returns quickly as precipitation experienced at ground level as rain). The density of

1240-563: The most important. However, Viedma is mainly an administrative city, being the capital city of the province. Viedma has a cool semi-arid climate ( Köppen climate classification BSk ). The nearby South Atlantic Ocean and the Viedma river moderate the climate. The city is windy throughout the entire year. Average windspeeds ranging from a low of 22.1 kilometres per hour (13.7 mph) to 30.5 kilometres per hour (19.0 mph) in December. Generally,

Viedma, Río Negro - Misplaced Pages Continue

1280-433: The pressure difference causes the sea breeze to move inland to the lower pressure area. In contrast, during night, the reverse occurs as the land cools faster than the surrounding sea. Frosts that occur in winter are usually of short duration and are not intense. The average date of the first frost occurs on 8 April and the last frost occurs on 21 November and there are 210 frost free days in an average year. Relative humidity

1320-582: The site of the original fort where the battle took place. The town and its twin city, Viedma , became the focus of attention in 1986, when President Raúl Alfonsín announced the Patagonia Project , which envisaged the transfer of the nation's capital to a new federal district encompassing the two towns at the mouth of the Río Negro . Approved by the Congress in 1987, the plan was rescinded when Alfonsín's successor, President Carlos Menem , disbanded Entecap,

1360-465: The vegetation blocks sunlight and reduces temperatures at ground level (thereby reducing losses due to surface evaporation), and reduces wind speeds (thereby reducing the loss of airborne moisture). The combined effect results in increased surface stream flows and a higher ground water table whilst the rainforest is preserved. Clearing of rainforests frequently leads to desertification as ground level temperatures and wind speeds increase, vegetation cover

1400-541: The weight of a plant and associated soil, and any water added by precipitation or irrigation. The change in storage of water in the soil is then modeled by measuring the change in weight. When used properly, this allows for precise measurement of evapotranspiration over small areas. Because atmospheric vapor flux is difficult or time-consuming to measure directly, evapotranspiration is typically estimated by one of several different methods that do not rely on direct measurement. Evapotranspiration may be estimated by evaluating

1440-674: The windiest period is from October to February while March to June are the least windy. The cause of this is attributed to the effects produced by the convergence of distinct wind currents originating from the general atmospheric circulation from both the South Atlantic High and the South Pacific High . Being located in a transitional area between the South Atlantic High and the South Pacific High, this geographic location

1480-419: The year: perennial plants mature over multiple seasons, while annuals do not survive more than a few , so stress responses can significantly depend upon many aspects of plant type and condition. Potential evapotranspiration (PET) or potential evaporation (PE) is the amount of water that would be evaporated and transpired by a specific crop , soil or ecosystem if there was sufficient water available. It

1520-545: Was destroyed within a few months. A new fort was built on the north side, in modern Carmen de Patagones. This fort lasted much longer, and the tower still stands today. The town grew and eventually expanded back across the river into modern-day Viedma. On 11 October 1878, the town was split, with the Río Negro as their border. With the Conquest of the Desert , the city became the capital of all Argentine Patagonia and later, when that

1560-521: Was founded in 1779 by Francisco de Viedma , an explorer leading a Spanish expedition commissioned with colonizing Patagonia's shores. In the 19th century, Carmen de Patagones had a fort, and after the May Revolution of 1810, it became a prison for royalists (Spaniards and pro-Spanish locals against the independence movement ). Later, during the Cisplatine War (1825–1828), the town became

1600-460: Was further divided into smaller territories, the capital of the Río Negro Territory . In 1880, Alvaro Barros, the first governor of Río Negro, changed the name of the city to Viedma. During severe flooding in 1889, the capital of Río Negro was temporary moved to Choele Choel , but was quickly restored to Viedma. In 1986, during the presidency of Raúl Alfonsín , a proposal was made to move

#971028