Climatology Honor

Nature Study

Requirements

Explain how the following phenomena form: mist, rain, dew, snow, hail and frost.
Answer: 1) Fog: the moist air near the ground is cooled below the dew point and the vapor condenses into droplets suspended in the air. 2) Rain: the vapor rises, condenses in the clouds into droplets that combine until they become too heavy and fall by gravity. 3) Dew: at night, surfaces (leaves, grass) cool down and the vapor in the air in contact with them condenses into liquid drops on them. 4) Snow: in very cold clouds the vapor freezes directly into ice crystals that group into flakes and fall when the temperature is below 0 °C all the way to the ground. 5) Hail: in cumulonimbus clouds, updrafts hurl drops into frozen regions where they freeze; they rise and fall several times, gaining layers of ice until they become heavy and fall as ice stones. 6) Frost: when the surface cools below 0 °C, the vapor in the air freezes directly onto it, forming a thin layer of ice crystals (deposition). — Both fog and dew depend on the dew point, but fog condenses into droplets in the air while dew condenses directly onto the solid surface cooled by nighttime radiation.
Identify in the sky, or in photographs, the following types of clouds: cirrus, cumulus, nimbus and stratus. What type of weather is associated with each of them?
Answer: Cirrus: high, thin and wispy clouds, made of ice crystals — they indicate good weather at the moment, but can announce the arrival of a front and a change of weather in the coming hours. Cumulus: white, fluffy clouds with a flat base and rounded top — associated with good and stable weather; if they grow too much (cumulonimbus), they bring showers. Nimbus (nimbostratus): low, thick, dark-gray clouds that cover the sky — associated with continuous and prolonged rain or snow. Stratus: low clouds in a uniform gray layer, like high mist — associated with overcast weather, drizzle or light drizzle. (Cumulonimbus, a vertically developed nimbus type, bring intense storms with heavy rain, lightning, thunder and sometimes hail.) — Cumulonimbus can reach more than 12 km in altitude, surpassing the tropopause, and are the only clouds capable of generating tornadoes and severe thunderstorms, according to the World Meteorological Organization.
Explain the action of a mercury thermometer, mercury barometer, aneroid barometer and rain gauge.
Answer: 1) Mercury thermometer: measures temperature. The mercury inside a thin glass tube expands (rises) with heat and contracts (falls) with cold; the height on the graduated scale indicates the temperature. 2) Mercury barometer: measures atmospheric pressure. It is an inverted tube closed at the top, full of mercury, immersed in an open reservoir; the air pressure pushes the mercury up and the height of the column (in mmHg) indicates the pressure. 3) Aneroid barometer: measures pressure without liquid, using a sealed, partially evacuated metal capsule that compresses or expands according to the air pressure; the movement drives a pointer on a scale. 4) Rain gauge: measures the amount of rain. The rainwater enters through a funnel and accumulates in a graduated container; the height of the water is read in millimeters (1 mm = 1 liter per m²). — The mercury barometer was invented by Evangelista Torricelli in 1643, and at sea level the column stabilizes at around 760 mm, the value that gives rise to the Torr unit.
Why is it possible for it to rain on one side of a mountain while the other side is dry? Give an illustration from your country or region.
- Why is it cooler and more humid in the mountains than in the valleys?
- From which direction do the rain and good weather generally come in your region?
Answer: 1) Why it rains on one side of the mountain while the other stays dry: the moist air coming from the ocean rises up the windward slope (facing the wind), cools with altitude, and releases the moisture in the form of rain. As it descends the opposite side (leeward), the already dehydrated air warms up and forms a dry region, called a rain shadow. In Brazil, this appears, for example, in the Serra do Mar: the coast (windward) is very rainy and the interior of the plateau, behind the range, is drier. 2) Why it is cooler and more humid in the mountains than in the valleys: the higher the altitude, the lower the temperature (the air becomes thinner and cools), which is why the mountains are cooler. In addition, the moist air that rises cools and condenses into clouds and fog, leaving the slopes more humid than the lower, warmer valleys. 3) From which direction the rain and the good weather generally come in the region: in most of Brazil the rain and instability arrive mainly from the quadrant that brings the cold fronts and moisture (often from the west/northwest and from systems coming from the ocean), while steady, dry weather usually comes with the dry air mass, generally from the opposite quadrant. The observer should confirm the predominant direction in their own locality. — The orographic effect explains why the eastern side of the Andes Mountains in Patagonia is dry while the west receives abundant rains coming from the Pacific, according to INMET climatological atlases.
Demonstrate, with the help of a diagram, how the relationship between the Earth and the Sun produces the different seasons.
Answer: You verify that the Earth's axis is tilted about 23.5° relative to its orbit, causing the northern and southern hemispheres to receive more direct sunlight at opposite times of the year. — The axial tilt of 23.5° was calculated with precision by Eratosthenes in the 3rd century BC and is confirmed by observations of the solstices in June and December by NASA.
What causes lightning and thunder? What are the different types of lightning that exist?
Answer: Lightning is an electrical discharge between opposite charges accumulated within cumulonimbus clouds, between clouds, or between the cloud and the ground. Thunder is the sound produced by the violent and sudden expansion of the air superheated by the lightning bolt (reaching ~30,000 °C), which expands faster than the speed of sound and generates the boom. Since light travels faster than sound, we see the lightning before we hear the thunder. Types of lightning: (1) intra-cloud (within the same cloud, the most common); (2) cloud-to-cloud (from one cloud to another); (3) cloud-to-ground (the most dangerous, descending from the cloud to the ground); (4) ground-to-cloud (upward, starting from tall structures); (5) special types such as branched lightning, 'ball lightning' (rare), and upper-atmosphere phenomena (sprites, blue jets, and elves). — The air heated by lightning reaches five times the temperature of the Sun's surface, creating a shock wave that propagates as the boom of thunder, according to INPE.
With the help of a diagram, demonstrate what convection is and what its relationship to wind is.
Answer: Convection is the transport of heat through the movement of a fluid (air or water). In the air: the air near the ground heated by the Sun becomes less dense and lighter, so it rises (updraft), creating a region of low pressure at the surface. As it rises, the air cools, becomes denser, and descends at another point (downdraft), forming a convection cell. Relationship with wind: the wind is precisely the air that moves horizontally from areas of high pressure (cold air descending) to areas of low pressure (warm air rising), seeking equilibrium. Thus, the differences in heating and convection are the direct cause of wind — for example, the sea breeze (day) and land breeze (night) between the sea and the land. — The principle of convection was described by James Hutton in 1788 and explains phenomena such as sea breezes, in which the land heats up faster than the sea and generates wind from the sea toward the continent.
Explain how radars, satellites and computers are used in weather forecasting.
Answer: Radar: emits radio waves that bounce off raindrops and hail; from the returning echo, it detects the position, intensity, and movement of precipitation within storms at short range (very short-term forecasting, nowcasting). Satellites: orbit above the atmosphere and provide large-scale images of clouds, cold/warm fronts, hurricanes, and atmospheric systems, tracking their movement over large areas and oceans. Computers: receive all this data (radar, satellite, surface stations, balloons) and run numerical forecast models — the physical equations of the atmosphere solved on supercomputers — which calculate how the weather will evolve over the next hours and days, generating the maps and forecasts we see. — The first operational weather radar appeared in 1947 in the USA, and geostationary satellites such as NOAA's GOES have monitored the Earth from about 36,000 km of altitude since 1975.
Explain how the following items can affect the weather:
- Jet streams
- Volcanic eruptions
Answer: How each item can affect the weather/climate: 1) Volcanic eruptions: inject sulfur dioxide and ash into the stratosphere, forming aerosols that reflect sunlight back into space and temporarily cool the Earth for months or years. 2) Ocean currents (e.g., El Niño and La Niña): alter the temperature of the Pacific waters, changing patterns of rain and drought throughout the world, including in Brazil. 3) Mountains/relief: force the air to rise (orographic rain on one side, drought/rain shadow on the other) and deflect winds. 4) Large bodies of water (sea, lakes): moderate the temperature, making the climate more humid and stable near the coast. 5) Deforestation and human activity: reduce local humidity and rainfall. 6) Urbanization: cities form 'heat islands', becoming warmer than the surrounding countryside. — The eruption of Pinatubo in the Philippines, in 1991, released about 20 million tons of SO₂ into the stratosphere and lowered the average global temperature by around 0.5 °C between 1991 and 1993, according to NASA.
Make a drawing showing the water cycle in meteorology.
Answer: The hydrological cycle was formalized by Pierre Perrault in 1674, when he demonstrated that rainfall was sufficient to feed the rivers of the Seine basin, according to UNESCO.
Make a simple weather vane or rain gauge.
Answer: You use a wide-mouthed cylindrical container, install a funnel of the same catchment area at the top, and a graduated ruler on the side. The correct measurement is made in millimeters, considering the height of the accumulated water after each rainfall, always in an open location. — The standard Ville de Paris rain gauge, officially adopted by INMET in Brazil, has a catchment area of 200 cm² and measures precipitation in millimeters equivalent to one liter per square meter.
Keep a weather chart for a week and record the weather reading at 12-hour intervals. Include the following:
- Temperature
- Humidity (dew, fog, rain, frost, or snow)
- Cloud formation
- Wind direction
Answer: You need to take the readings always at the same times, in a fixed location protected from direct sun and rain, using the same calibrated instruments. Recording temperature, humidity, clouds, and wind direction in a standardized way allows the data to be compared reliably from day to day. — Official INMET stations follow the protocol of the World Meteorological Organization, with synoptic readings every 3 hours in a standard thermometric shelter painted white and ventilated.
Complete the reading of the following passages: Genesis 1, Jonah 1 and 2, and Matthew 8:23-27. After reading, take part in a discussion about why the climate was created, what the relationship is between climate and the will of God, and how the climate can be used by God as a tool of Salvation.'
Answer: You observe that Jesus rebukes the wind and the agitated sea, showing that He has direct authority over the forces of nature. The episode teaches that God is Lord over the weather and can intervene, even though He normally sustains creation through regular natural laws. — The biblical text of Matthew 8:26 records that there was a great calm immediately after Jesus' command, an event that the disciples recognized as a sign of divinity when they asked 'what manner of man is this?'.