- Temperatures - South Pole, Vostok
- Sun, thermal inversion and optical phenomena
- Variations and trends
Antarctica is the coldest continent on Earth.
Larger than Europe, and roughly circular-shaped, this continent is nearly centerd on the South Pole and is surrounded by the three oceans of the Southern Hemisphere, namely, Atlantic, Pacific and Indian.
The situation is quite the opposite in the Arctic region, where there is a frozen ocean (the Arctic Ocean) surrounded by continents.
The South Pole is colder than the North Pole precisely because of this different geographical configuration, to which must be added the influence of the altitude: owing to the huge ice sheet that covers the continent (about 90% of the ice, which corresponds to about 70% of freshwater on our Planet, is found in Antarctica), the average altitude is around 2,000/2,400 meters (6,600/8,000 feet), with large areas above 3,000 meters (9,800 feet), so it is far higher than in the other continents, where it's around 700/800 meters (2,300/2,600 feet).
Because of these factors, at least in the lowest layers of the atmosphere, there is a circulation that prevents the penetration of mild ocean winds towards the interior: both air and sea currents flow around the continent with an almost circular motion, from west to east (the so-called Antarctic Circumpolar Current).
Below the ice cap, there are plains and even depressions, also caused by the enormous weight of the ice itself. However, there are mountains as well, whose highest point is Mount Vinson, 4,892 meters (16,050 feet) high, not far from the Weddell Sea.
There are also two large and partially (but permanently) frozen seas, the Ross Sea and the Weddell Sea, formed by two bays that penetrate the continent.
The total size of the ice sheet (the one that covers the mainland plus the marine one) vary from about 14 million square kilometers (5.4 million square miles) in March to about 22 million km² (8.5 million mi²) in September: in autumn, the ice advances by about 4 km (2.5 mi) a day, and at the end of winter, almost the entire continent is surrounded by sea ice. The largest iceberg that calved from the ice, was 40 km (25 mi) wide and 400 km (250 mi) long, so it was larger than Belgium.
The average temperatures of the continent are extremely low.
At the South Pole, 2,800 meters (9,200 feet) above sea level, the average annual temperature is -49 °C (-56 °F), ranging from about -28 °C (-18 °F) in January to about -59.5 °C (-74.5 °F) in July. The lowest recorded temperature is -83 °C (-117 °F), while the highest is -12 °C (10 °F).
Here are the average temperatures of the South Pole (Amundsen–Scott Station).
|Month||Min (°C)||Max (°C)||Mean (°C)||Min (°F)||Max (°F)||Mean (°F)|
However, the lowest temperature ever recorded in the continent, which is also the world record, belongs to the Russian station of Vostok, 3,500 meters (11,500 feet) above sea level, where the temperature reached as low as -89.2 °C (-128.6 °F) in in 1983. Here, the highest temperature ever measured is -14 °C (7 °F). This station is located near the geometric center of the continent, which is decisively indicating that continentality is a determining factor in temperature distribution, even more than latitude.
Here are the average temperatures of the Vostok station.
|Month||Min (°C)||Max (°C)||Mean (°C)||Min (°F)||Max (°F)||Mean (°F)|
There are also inland areas, with no weather stations, where even lower temperatures have been measured by satellites, such as Dome A, located at 4,000 meters (13,000 feet) above sea level, where a temperature of -93 °C (-135 °F) has been estimated.
In coastal regions, the climate is much milder. This happens because of the lower latitude (in some areas, the coasts are beyond the polar circle) and of the lower altitude (unlike in the interior, where there is a thick ice cap, here we are obviously at sea level), as well as of the influence of the sea. Here, the temperatures rarely drop below -30 °C (-22 °F) even in winter, while they can exceed the freezing point in summer. The highest temperatures ever measured in the continent have been 14.5 °C (58 °F), recorded on January 5, 1974, in the former Vanda Station, located near a salt lake in the McMurdo Dry Valleys, at a latitude of 77 degrees South, and 17.5 °C (63.5 °F), recorded in the Argentine Esperanza base in March 2015 (see below).
The Australian Casey Station is located on the coast of the Indian Ocean, at a latitude of 66 degrees South. Oddly, the average temperature at Casey Station reaches its minimum of -15 °C (5 °F) in May, probably for the change in atmospheric circulation that occurs in winter, while it peaks around -0.5 °C (31.5 °F) in January.
|Month||Min (°C)||Max (°C)||Mean (°C)||Min (°F)||Max (°F)||Mean (°F)|
At the Esperanza Base, located in the southernmost and warmest part of Antarctica, at the tip of the Antarctic Peninsula, at a latitude of 63 ° south, the temperature is even higher, in fact, the daily average ranges from a low of -10.5 °C (13 °F) in June to a high of 1.5 °C (35 °F) in January. The cold record is -38.4 °C (-37.1 °F).
|Month||Min (°C)||Max (°C)||Mean (°C)||Min (°F)||Max (°F)||Mean (°F)|
Along with the record of low temperatures, Antarctica also holds the record of the strongest winds: winds between 100 and 200 kilometers (60 and 125 miles) per hour are not uncommon, but sometimes they even exceed 300 kph (185 mph), with maximum gusts of about 360 kph (220 mph).
The blizzard is so terrible that it is an obstacle to human activities even larger than the cold itself. It usually blows from inland to the sea, it is more intense in winter than in summer, and it is due to the huge difference in temperature (and hence in air pressure) that is generated between inland and coastal areas.
These strong winds cause a huge wind chill (the phenomenon whereby the wind makes it feel colder than the real temperature), so much so that the perceived temperature in the worst moments can be far lower than -100 °C (-150 °F).
The winds that blow from the higher elevations of the interior, and descend in altitude, finally reaching the coasts, are called katabatic. General atmospheric circulation plays a role in the formation of these winds: at high altitudes, subtropical winds blow towards the interior, in order to prevent the continent from getting even colder; then, these air masses descend downwards (subsidence), and after having cooled down above the ice cap, they move towards the exterior of the continent.
In the Dumont d'Urville station, for example, there are on average 11.6 days per month when the wind exceeds 100 kph (60 mph), with a minimum in January (of 7 days) and a maximum in August and September (of 14 days).
This station has experienced at least one episode with wind gusts above 230 kph (145 mph) in all months of the year, and the overall record, which has occurred in June, is an astonishing 324 kph (201 mph).
These cold winds, once they reach the sea, feed low pressure systems which give life to the so-called West Wind Drift, which sweeps the oceans around Antarctica: the result is a stream of water that travels from west to east at a speed of 20 Km (12 mi) per day.
Winds shape the surface of ice and snow, in a manner that reminds of sand dunes in the desert. Actually, precipitation in much of Antarctica is desert-like almost everywhere: in the interior, it's lower than 50 millimeters (2 inches) per year, and it exceeds 300 mm (12 in) only near the coasts, with peaks of 600 mm (23.5 in). Strange as it may seem, drought makes fires dangerous because of the limited availability of liquid water.
Looking at the last two maps, we can see that there is a correspondence between temperature and precipitation. An average temperature of -25 °C (-13 °F) roughly corresponds to an average precipitation of 400 mm (16 in), while temperatures below -55 °C (-67 °F) correspond to precipitation below 50 mm (2 in). This is explained by the fact that at -55 °C (-67 °F), the saturated vapor pressure is 30 times lower than at -25 °C (-13 °F): in other words, the air can hold much less moisture, so it's not able to produce a high amount of precipitation.
And so the coldest areas are extremely arid, among the most arid in the world: precipitation in the South Pole amounts to just 2 mm (0.1 inch) per year, so it practically never snows (or at most, a very light snow falls), and at Vostok, it amounts to about 20 mm (0.9 in) per year, although the wind can carry the snow and accumulate it where it finds obstacles (for example, the buildings of a station).
Here is average precipitation at the Casey Station, which, being on the coast, receives a higher amount of precipitation, largely in the form of snow. However, given the temperature, it is possible that some rain may fall in summer.
Sunshine, temperature inversion and optical phenomena
The amount of sunshine is not very abundant in peripheral and coastal areas: in autumn and winter, the days are very short, while in spring and summer, the sun is often covered by clouds. Here, for example, are the hours of sunshine per day in Casey.
On the contrary, in the central part of the continent, such as the South Pole and Vostok, while it is true that the sun never rises in the long polar night, in the summer months, not only the sun is always above the horizon, but also the sky is almost always clear. So, the Vostok station, as well as the coldest, is also one of the sunniest places on the planet, with 3,760 hours of sunshine per year, despite the fact that the sun does not even rise in the winter months.
However, snow and ice reflect most of the solar radiation that reaches the ground, while in winter, the absence of sunlight causes a radiation deficit, which tends to cool down the soil. This produces a unique temperature inversion, which, in winter, can exceed 30 degrees Celsius (55 degrees Fahrenheit) between the ground and an altitude of 1,000 meters (3,300 feet) above, also because of the warmer subtropical currents, which flow, as mentioned, at high altitudes. In July 1989, at Vostok, a difference of 34 °C (61 °F) was recorded between the ground, where the temperature was -78 °C (-108 °F) and 600 meters (2,000 feet) above, where it was -44 °C (-47 °F); the temperature was -73 °C (-99 °F) still at 8,000 meters (2,600 feet), so it was higher than at ground level.
Along with electromagnetic factors, temperature inversion causes curious optical phenomena, such as sundogs and halos around the sun or moon.
Owing to both low temperatures and strong winds, the air in Antarctica is characterized by exceptional transparency, brightness and acoustics: it is possible to spot mountains at a distance of as far as 550 km (340 mi).
The absence of objects such as trees and houses, however, makes it very difficult to evaluate the distances. Effects such as light refraction and reflection also cause frequent mirages, favored by the presence of tiny ice crystals that are continuously formed in the air because of low temperatures.
Meteorological observations in Antarctica started very late, partly because of the adverse environmental conditions. Prior to 1957-58, the International Geophysical Year, there were stations only in the Antarctic Peninsula and the Ross Sea. But it did not take long for scientists to understand the importance of knowing the climate of the continent, in addition to the fact that it offers a privileged point of observation for the study of the past and present climate of the Earth (in fact, ice layers preserve the memory of the chemical composition of the atmosphere of past ages, from which we can deduce the air temperature), but also for the climate prediction of the future. Phenomena such as global warming and the ozone hole, which was discovered here and here has its greatest intensity, have attracted and still attract groups of scientists who continually defy the cold and the wind to carry out their studies.
Changes and trends
In Antarctica, temperature variations from year to year are considerable: the standard deviation of the mean annual temperature is generally around 0.61/1.56 °C (1/2.8 °F), while for example it's 0.5 °C (0.9 °F) in London.
The difference in the average temperature from one year to another can be as high as 4 °C (7 °F).
As for the trend, the South Pole does not show a clear temperature rise over time, while coastal areas show a remarkable rise of almost 0.3 °C (0.5 °F) every 10 years in the last 4 decades, with peaks of 0.5 °C (0.9 °F), i.e. more than three times the world average.
On the contrary, until not many years ago, there seemed not to be any increasing trend in temperature in the Arctic.
Contrary to what happens in the rest of the world, where glaciers are retreating both in the mountains and in the Arctic region (see Greenland and Arctic Ocean), the extent of the ice in Antarctica has actually increased (though less than it has declined in the rest of the world). Contrary to what one might think, even this phenomenon may be due to global warming: on the one hand, in cold regions, an increase in temperature allows for an increase in snowfall (as long as the temperature remains below freezing); on the other hand, the greater ice extent may be due to the higher speed at which the ice from the inner part of the continent slides towards the sea. However, by 2017, the Antarctic ice has also fallen to historic lows.
Precipitation is any liquid or frozen water that forms in the atmosphere and falls back to the Earth. It comes in many forms, like rain, sleet, and snow.
The temperature of the cloud and the air between the cloud and the ground create different kinds of precipitation. Rain: Rain made of liquid water droplets falls when temperatures in the air and at the surface are above freezing (32°F, 0°C).
As average temperatures at the Earth's surface rise, more evaporation occurs, which, in turn, increases overall precipitation. Therefore, a warming climate is expected to increase precipitation in many areas.
The average temperature on Earth lies somewhere around 57 degrees Fahrenheit (13.9 degrees Celsius).
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.
In weather, precipitation is any liquid or solid water that falls from the atmosphere to the Earth. For example, rain is liquid water precipitation, and snow is solid water precipitation.
Precipitation is measured by using a rain gauge. A rain gauge is a small tube of glass or plastic with the upper end open. A measuring scale is usually attached to the tube, so that the amount of precipitation can be measured in inches or centimeters.
The most common types of precipitation are rain, hail, and snow. Rain is precipitation that falls to the surface of the Earth as water droplets. Raindrops form around microscopic cloud condensation nuclei, such as a particle of dust or a molecule of pollution.
They are evaporation, condensation, precipitation and collection.
The temperature characteristics of a region are influenced by natural factors such as latitude, elevation and the presence of ocean currents. The precipitation characteristics of a region are influenced by factors such as proximity to mountain ranges and prevailing winds.
Long-term records of temperature and precipitation reveal climate patterns across continents, delineating them into climate regions.
Simply put, precipitation amounts are increasing as temperatures rise because warm air holds more water vapor: a 1°F rise in temperature equals as much as a 4% increase in atmospheric water vapor. Other factors can contribute to rainfall, including El Niño and La Niña .
The average temperature of the air as indicated by a properly exposed thermometer during a given time period, usually a day, a month, or a year. For climatological tables, the mean temperature is generally calculated for each month and for the year.
A weather chart includes an isobar chart and the representation, with opportune symbols, of the principal atmospheric parameters, such as wind direction and speed, types of clouds and extension of the cloud formations, the position of warm, cold and occluded fronts and the high and low pressure centres.
While an average temperature is the average of the extremes and everything in between, the typical temperature is the temperature you would most expect for a location.
Precipitation is water released from clouds in the form of rain, freezing rain, sleet, snow, or hail. It is the primary connection in the water cycle that provides for the delivery of atmospheric water to the Earth. Most precipitation falls as rain.
Climate change can affect the intensity and frequency of precipitation. Warmer oceans increase the amount of water that evaporates into the air. When more moisture-laden air moves over land or converges into a storm system, it can produce more intense precipitation—for example, heavier rain and snow storms.
The main types of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel, and hail. Precipitation happens when water vapour (reaching 100 percent relative humidity) saturates a portion of the atmosphere so that the water condenses and 'precipitates' or falls.
1 : a substance separated from a solution or suspension by chemical or physical change usually as an insoluble amorphous or crystalline solid. 2 : a product, result, or outcome of some process or action.
- Rain. Most commonly observed, drops larger than drizzle (0.02 inch / 0.5 mm or more) are considered rain. ...
- Drizzle. Fairly uniform precipitation composed exclusively of fine drops very close together. ...
- Ice Pellets (Sleet) ...
- Hail. ...
- Small Hail (Snow Pellets) ...
- Snow. ...
- Snow Grains. ...
- Ice Crystals.
Answer: The sun's heat vaporises water into vapour. This vapour cools down and condenses to become clouds. This may then fall on the surface of Earth in the form of rain, snow or sleet. This phenomenon of water falling back onto the surface of the earth in the form of rain, snow or sleet is called precipitation.
- Measurement of Rainfall Using Raingauges. Non-recording Raingauge. Recording Rain Gauges.
- Selection of Rain Gauge Stations. Rainfall Measurements by Radar.
In the ECMWF Integrated Forecasting System (IFS), total precipitation is rain and snow that falls to the Earth's surface. It is the sum of large-scale precipitation and convective precipitation. Large-scale precipitation is generated by the cloud scheme in the IFS.
Weather forecasts are based on complex mathematical equations where the variables are determined through observations such as precipitation amount and intensity. So, precipitation measurement is important for weather forecasting. What else, precipitation is a resource of fresh water.
Weather is the combination of four factors––temperature, wind, precipitation, and sunlight and clouds––that occur at a given place and time. These factors are changing all the time; therefore, weather is changing all the time.
The main forms of precipitation include drizzle, rain, sleet, snow, graupel and hail.
The five main types of weather are: sunny, cloudy, windy, rainy, and stormy.
There are many different types of precipitation —rain, snow, hail, and sleet for example—yet they all have a few things in common. They all come from clouds. They are all forms of water that fall from the sky.
So how can we understand this magical process called the water cycle? There are four main parts to the water cycle: Evaporation, Convection, Precipitation and Collection. Evaporation is when the sun heats up water in rivers or lakes or the ocean and turns it into vapour or steam.
The four main types of precipitation: rain, snow, hail and sleet all form by one of these two processes: the process of coalescence, Bergeron process. There are only two types of clouds that produce precipitation: cumulonimbus and nimbostratus.
Factors that Affecting Controlling Temperature Control
The latitude of the place. The altitude of the place. Distance from the sea. The air- mass circulation.
These are temperature, atmospheric pressure, cloud formation, wind, humidity and rain. A small change to any of these conditions can create a different weather pattern.
There are six main components, or parts, of weather. They are temperature, atmospheric pressure, wind, humidity, precipitation, and cloudiness. Together, these components describe the weather at any given time.
Latitude plays an important role in determining the climate of a region. At higher elevation, temperature decreases while precipitation increases. Temperature and precipitation determine what types of plants can grow in an area. Animals and other living things depend on plants.
The measurement of the weather is not only important day to day but is important in the forecasting of approaching dangerous weather (storms, cyclones, floods). By developing measuring tools, meteorologists are able to develop better warning systems that will help save people's lives, properties and businesses.
When two aqueous solutions are added together and a precipitate is formed, this reaction is called a precipitation reaction or double decomposition. This reaction is used to prepare insoluble salts. The heat given out in a precipitation reaction is called the heat of precipitation.
Cloud seeding sprays small particles, such as silver iodide, upon clouds in order to increase precipitation. It has been used in a variety of drought-prone countries, including the United States, China, India and Russia.
Precipitation is weather. Precipitation moves moisture from the upper levels of the atmosphere to the lower levels and the surface. Generally as rain or snow. If the average amounts of precipitation that fall changes the 30 year average either wetter or drier, that is climate change.
When they encounter a warm mass of air, the warm air is forced up, over the top of the cooler air. As the warm air rises, water vapor in that air condenses and cools. As it does so, clouds form, eventually leading to precipitation.
For the entire United States, excluding Hawaii and Alaska, the average amount of moisture falling as rain and snow is 30.21 inches (767 millimetres).
Take the temperature readings on the hour for a 24-hour period. Add the hourly readings together, then divide that number by 24 to get the mean daily temperature.
Where did 98.6 degrees come from? In the mid-1800s a German physician, Carl Wunderlich, measured axillary (armpit) temperatures from about 25,000 people and found that the average was 98.6˚ F (37˚ C). And so, we've believed that ever since.
- What do we measure? Temperature. A thermometer ...
- Precipitation. A rain gauge Precipitation is measured using a rain gauge . ...
- Wind direction. A wind vane Wind direction is reported by the direction it is blowing from, according to the compass. ...
- Wind speed. An anemometer ...
- Atmospheric pressure. A barometer
Temperature Scales. There are three temperature scales in use today, Fahrenheit, Celsius and Kelvin. Fahrenheit temperature scale is a scale based on 32 for the freezing point of water and 212 for the boiling point of water, the interval between the two being divided into 180 parts.
Monthly precipitation is calculated by summing the daily precipitation for each month. All monthly amounts are then summed and divided by the number of months used in the period (years) selected. The Yearly Total is the sum of the averages for individual months shown in Column 5.
Some forecasters emphasize the chance you will see rain at some time during the forecast period. Others emphasize the area affected. If they say 60% chance of rain, 60% of their area will experience rain at some point during the forecast period. The forecaster will often mention which interpretation they adhere to.
Weather is what you see outside on any particular day. So, for example, it may be 75° degrees and sunny or it could be 20° degrees with heavy snow. That's the weather.
This phenomenon of water falling back onto the surface of the earth in the form of rain, snow or sleet is called precipitation.
Complete answer: Precipitation is the process in which water from the atmosphere falls back on earth in liquid or frozen form. Precipitation can occur in the form of rain, sleet and snow. -Water in the oceans, seas, rivers and other water bodies evaporate due to heat of the sun.
Precipitation is water that falls back to the surface of the earth upon condensing in the atmosphere. In other words, any form of water which falls, whether it is in liquid or frozen form, falls as precipitation only.
Answer 1: Precipitation is any type of water that forms in the Earth's atmosphere and then drops onto the surface of the Earth. When a portion of the atmosphere becomes saturated with water vapor, it condenses and precipitates. Most common forms of precipitation are rain, snow, drizzle, hail, etc.
Answer: The constant movement of water from the Earth to the atmosphere and back to the Earth through the process of evaporation, condensation and precipitation is known as the water cycle.
The water cycle shows the continuous movement of water within the Earth and atmosphere. It is a complex system that includes many different processes. Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow.
What causes rain? Clouds are made of water droplets. Within a cloud, water droplets condense onto one another, causing the droplets to grow. When these water droplets get too heavy to stay suspended in the cloud, they fall to Earth as rain.
The process where the water droplets fall down due to its heavy weight is called precipitation. This is the third step in the water cycle. Precipitation can be in different forms like dew drops, fog or rainfall.
1. Clouds: They are formed when water vapour condenses over dust particles and forms water droplets. 2. Dew: It is formed when the water vapour comes in contact with cool surfaces like grass and leaf and forms tiny water droplets.
Ans. (a) Falling of moisture in the form of rainfall, snow, fog, sleet, and hailstone is termed as precipitation.
The role of trees in the water cycle is to add water to the atmosphere through the process of transpiration. During this process, the plants release water from their leaves. This moisture contributes to the formation of rain clouds, which release the water back onto the Earth's surface.
In the water cycle, water from lakes, rivers, and oceans evaporate and enter the atmosphere where it cools, condenses into liquid water, and comes back to Earth as rain.
The water cycle is an extremely important process because it enables the availability of water for all living organisms and regulates weather patterns on our planet.
Precipitation reactions are reactions occurring in an aqueous solution medium in which two ionic bonds combine resulting in the formation of insoluble salt. These insoluble salts formed in the reaction are called precipitates. Potassium nitrate and silver chloride are the products of the given chemical reaction.
Complete answer: Precipitation is the process by which takes place once the water vapour condenses to form water droplets in clouds and once they become heavy enough, fall to the ground in various forms. These forms include rainfall, snowfall, hail, etc.