HYDRO 2

EARTH’S ATMOSPHERE

• The layers of the gases which protects the earth from the radiations and cosmic rays coming from outer space.

• Acts as a blanket as it keeps the average temperature of the Earth nearly constant.

TROPOSPHERE

• First layer of Earth’s atmosphere • Comes from the Greek root “tropos” means change.

• This layer gets its name from the weather that is constantly changing and mixing up the gases.

• On average, this layer extends from the ground to about 0-12 km (7.5 miles) high.

TROPOSHPERE

Hot air balloons fly within this layer. • Starts on the planet’s surface and stretches up to 7 miles in the air.

• Densest layer: it has more particles and heavier gases than other levels.

• It is where most of the earth’s weather occurs.

TROPOSPHERE

• Warmest at the bottom as it is closer to the heat that the earth is absorbing from the sun.

• As you go farther up into the troposphere, the temperature drops.

STRATOSPHERE

• “Strat” means layer. • it has its own set of layers.

• extends from the tropopause to about 12-50 km (32 miles) above Earth’s surface.

• contains a thin layer of ozone (O3) molecules which forms a protective layer and absorbs harmful ultraviolet radiation from the sun.

STRATOSPHERE

• high-altitude weather balloons flying into the stratosphere for monitoring atmospheric conditions and climate research.

• Stretches for about 30 miles outward into space.

• Maximum height at which jets can fly.

• Contains the ozone layer (layer of molecules that absorbs much of the sun’s powerful ultraviolet rays and protects life on earth)

• All these absorbed rays make the ozone layer quite warm.

TROPOPAUSE

boundary between the stratosphere and troposphere; region where airplanes fly.

MESOSPHERE

• “Meso” means middle. • It is located above the stratosphere and below the thermosphere.

• 35 km (22 miles) thick, 50-85 km from the ground • fewer air molecules to absorb incoming electromagnetic radiation from the sun.

• most meteors burn up.

• About 40 miles above earth’s surface • Where meteors from space burn up and are destroyed

• Coldest layer of the atmosphere: the cold molecules scrape the incoming meteors which cause friction and eventually fire.

MESOSPHERE

• It is so cold because it is far away from the absorbed heat of earth but still quite far from the sun.

• Temperature can be as low as -190°F.

• Meteor • a piece of rock or matter that has been broken off in space and travels through the atmosphere.

• When they cross the mesosphere, friction and momentum cause the meteor to burn up and appear light crossing the sky.

STRATOPAUSE

the transition boundary which separates the mesosphere from the stratosphere.

THERMOSPHERE

• “Thermo” means heat. • It has extremely high temperatures.

• Extends from the mesopause to 700 km (435 miles) above the Earth’s surface.

• Thickest layer in the atmosphere. • Only the lightest gases (mostly oxygen, helium, and hydrogen) are found here. • 300 miles up from earth’s surface

• Where space shuttles and satellites orbit the planet

THERMOSPHERE

• Temperature here is incredibly hot because of energy coming directly from the sun.

• Temperature can reach up to 2,700°F.

• At this height, the air is quite thin and there are very few molecules.

• The aurora (Northern lights and Southern lights) and satellites mostly occur in this layer.

• Aurora • A natural light display in the sky, particularly in the high-latitude regions.

• Caused by the collision of energetic charged particles with atoms in the high-altitude atmosphere.

MESOPAUSE

boundary between the mesosphere and thermosphere; coldest part of Earth’s atmosphere

EXOSPHERE

• “Exo” means outside. • Outermost layer of the Earth’s atmosphere

• Extends from the top of the thermosphere to 10,000 km (6,214 miles) above the Earth’s surface.

• In this layer, atoms and molecules escape into space and higher-altitude satellites orbit our planet.

• Extends about 6,200 miles into space. • Atoms and molecules from Earth escape into outer space and completely leave the planet’s atmosphere.

• Temperatures can vary widely here from very cold to very hot depending on location.

TROPOSPHERE

• During the day, a portion of the incoming of the radiant energy from the sun passes through the atmosphere, is absorbed, and warms the earth’s surface.

• Then the heats reflected from the ground to the tropospheric air by conduction and convection process.

• The temperature gradually decreases with increasing altitude until the tropopause is reached.

STRATOSPHERE

• Very dry and clouds are rare.

• Ozone absorbs shortwave UV radiation from the sun and converts them into heat.

• The temperature increases with height because more radiation is absorbed at higher altitudes compared to the lower stratosphere.

MESOSPHERE

• Has the coldest temperatures in the atmosphere.

• It becomes cold enough to freeze water vapor in its atmosphere into ice clouds.

• The air density is low than in the stratosphere below. Due to less air particles, not enough heat is absorbed which eventually leads to a colder temperature.

• Carbon Dioxide (CO2) also helps in making this layer cold due to its cooling effect.

MESOSPHERE

• CO2 molecules absorb heat energy when they bounce off other molecules. The CO2 releases some of that energy as photons in a process called “radiative emission.”

• Some of those photons travel upwards, carrying heat away from the mesosphere. Thus, temperature in the mesosphere keeps dropping with increase in altitude until it reaches about -100°C.

THERMOSPHERE

• Temperatures rise continually to well beyond 1000°C.

• Source of heat: radiation emitted by the sun. This layer absorbs much of the radiation that Earth receives from the sun, leaving only a fraction to reach the surface.

• UV radiation, visible light, and high-energy gamma radiation are all absorbed by this layer.

• Since there is little to no atmospheric gases above the thermosphere, there is no absorption of the heat from solar radiation and so temperatures soar.

EXOSPHERE

• Almost a vacuum. • The air is very, very thin. When air is thin, it doesn’t transfer much heat to objects in the air, even if the air is very, very hot.

• Temperature varies greatly and can range from 0 to over 1700°C.

• Colder at night and much hotter during the day

ATMOSPHERE

• The smallest of the Earth’s geological reservoirs.

• limited size that makes the atmosphere potentially so vulnerable to contamination.

• A layer of gases surrounding a planet or other material body of sufficient mass that is held in place by the gravity of the body.

• Is more likely to be retained if the gravity is high and the atmosphere’s temperature is low.

ATMOSPHERIC STABILITY

• A measure of the atmosphere’s tendency to encourage or deter vertical motion, and vertical motion is directly correlated to different types of weather systems and their severity

ABSOLUTE UNSTABLE

– if the environmental lapse rate is greater than 9.8 C per kilometer (i.e. greater than the dry adiabatic rate), then any rising parcel, saturated or not, will be warmer than its environment. The parcel will be buoyant in this case, and so the atmosphere is characterized as absolute unstable.

CONDITIONALLY UNSTABLE

– if the environmental lapse rate ties in the range between 4 C per kilometer and 9.8 C per kilometer, then the atmosphere is characterized as conditionally unstable. A rising parcel could become buoyant if at some point it becomes saturated. Whether it becomes saturated depends on the surface temperature and humidity.

ABSOLUTELY STABLE

– if the environmental lapse rate is less than 4 C per kilometer, then any rising air parcel will be colder than the environment and will sink back down. The atmosphere is characterized as absolutely stable because no matter if the parcel is saturated or not, it cannot become buoyant.

PRECIPITATION

• The water that falls from the atmosphere in either liquid or solid form.

• Results from the condensation of moisture in the atmosphere due to the cooling of a parcel of air.

• Most common cause of cooling is dynamic or adiabatic lifting of the air.

PRECIPITATION

• The term precipitation denotes all forms of water that reach the earth from the atmosphere.

• It is the basic input in hydrology

ADIABETIC LIFTING

means that a given parcel of air is caused to rise with resultant cooling and possible condensation into very small cloud droplets. If these droplets coalesce and become of sufficient size to overcome the air resistance, precipitation in some forms results.

•Topography/region/space

• Temporal/time

Factors Affecting the Type, Properties, and Behavior of Precipitation

WIND, TEMPERATURE, HUMIDITY, PRESSURE

Weather Elements that Affect Precipitation

• The atmosphere must have moisture.

• There must be sufficient nuclei present to aid condensation.

• Water conditions must be good for condensation of water vapor to take place.

• The products of condensation must reach the earth.

FOR PRECIPITATION TO FORM

RAIN

• The most common type of precipitation in our atmosphere.

• Rain is when liquid droplets fall to the surface of the earth.

• The term rainfall is used to describe the precipitation in the form of water drops.

SHOWERS

– heavy, large drops of rain and usually only last a period.

DRIZZLE

– usually last longer and are made up of smaller droplets of water.

SNOW

• The second most common precipitation.

• Consists of ice crystal which usually combine to form flakes.

• Forms when the water vapor turns directly into ice without ever passing through a liquid state. This happens as water condenses around ice crystal.

HAIL

• A showery precipitation in the form of irregular pellets or lumps of ice of size ranging from 5 to 125 mm. It occurs in violent thunderstorms in which vertical currents are very strong.

• It is created when moisture and wind are together. Inside the cumulonimbus clouds ice crystals forms and begin to fall towards the surface of earth.

o Spherical

o Conical

o Irregular

SHAPES OF HAIL PARTICLES

FOG

• There is really no different between fog and the clouds that are high in the sky.

• In simple terms, ___ is a cloud that has formed near the surface of the earth.

DEW

• The small drops of water which can be found on cool surface like grass in the morning.

• This is the result of atmospheric vapor condensing on the surface in the colder night air.

• Dew point is the temperature in which condensation starts to take place or when dew is created.

MIST

• A bunch of small droplets of water which are in the air.

• Occurs with cold air when it is above a warm surface, for example water.

• Fog and mist are very similar, the only difference is their visibility.

• If you cannot see 1 kilometer or less, you know you’re dealing with fog.

• You can see visuals through mist, and it is more haze looking than a thicker substance.

GLAZE

• The ice coating, generally clear and smooth, formed on exposed surfaces by freezing of super cooled water deposited by rain or drizzle.

CYCLONIC PRECIPITATION

• lifting of air converging into a low-pressure area (also known as cyclone) • occurs when warm, moist air is drawn into a lowpressure, cold front. The warm air rises as it is drawn into the low-pressure zone and is subjected to adiabatic cooling

FRONTAL PRECIPITATION

• The interface between two distinct air masses.

• Under certain favorable conditions when warm air mass and cold air mass meet, the warmer air mass is lifted over the colder one with the formation of a front.

WARM FRONT PRECIPITATION

warm air advancing upward over a colder air mass; has a slow rate of ascent.

COLD FRONT PRECIPITATION

warm air forced upward by an advancing cold air mass; the leading edge of the cold air mass is a cold front; faster rate of ascent; rainfall is showery in nature or high precipitation rate.

CONVECTIVE PRECIPITATION

Rising of warmer, lighter air in colder, denser surroundings: there is a change in temperature such as unequal heating at the surface or unequal cooling at the top of the air layer; may experience a scattered rain showers and cloud bursts.

OROGRAPHIC PRECIPITATION

• mechanical lifting of air mass over mountain barriers.

• results when an air mass is lifted as it encounters topographic obstacles.

ARTIFICIALLY INDUCED PRECIPITATION

conducted to modify and control weather condition

CLOUD SEEDING/ MODIFICATION

a type of artificially induced precipitation to dissipate cloud or stimulate precipitation.

CYCLONE

• A large low-pressure region with circular wind motion.

• large revolving tropical storms caused by winds blowing around a central area of low atmospheric pressure.

• a rapid rotating storm originating over tropical oceans from where it draws the energy to develop.

TROPICAL CYCLONE

• Typhoon: Southeast Asia; Cyclone: India; Hurricane: USA

• A wind system with an intensely strongly depression.

• The normal areal extent of a cyclone is about 100 – 200 km in diameter.

• The isobars are closely spaced, and the winds are anticlockwise in the northern hemisphere.

• The center of the storm, called the eye, which may extend to about 10 -50 km in diameter.

EXTRATROPICAL CYCLONE

• Cyclones formed in locations outside the tropical zone.

• Associated with frontal system, they possess a strong counterclockwise wind circulation in the northern hemisphere.

• The magnitude of precipitation and wind velocities are relatively lower than those of a tropical cyclone.

ANTICYCLONES

• These are regions of high pressure, usually of large extent.

• Cause clockwise wind circulation in northern hemisphere.

• Winds are moderate speed; cloudy and precipitation conditions exist.

YIELD POINT DATA

Commonly uses rain gauge since the area of considered in measuring the precipitation is about 20 cm only.

• Done in small regions.

AREAL DATA

• Uses radar where the area covered for measurement is at around 2.5 square kilometers.

RAIN GAUGE

• A device that hydrologists and meteorologists to collect and measure the amount of liquid precipitation over a certain region over time.

• It is used to calculate the amount of rainfall by measuring the depth of the precipitation that falls over a given region (often measured in millimeters). (Rain Gauge Investigation - Science World, 2022)

• A meteorological device used to determine how much rain falls in a specific length of time over a specified region.

PLUVIOMETER,OMBROMETER, HYETOMETER

sometimes used to designate a rain gauge.

a. The ground must be level and in the open and the instrument must present a horizontal catch surface.

b. The gauge must be set as near the ground as possible to reduce wind effects but it must be sufficiently high to prevent splashing, flooding, etc.

c. The instrument must be surrounded by an open fenced area of at least 5.5 m by 5.5 m. No object should be nearer to the instrument than 30 m or twice the height of the obstruction.

CONSIDERATION FOR SETTING UP A RAIN GAUGE

SIMON’S GAUGE

– it essentially consists of a circular collecting area of 12.7 cm (5 inches) diameter connected to a funnel.

RECORDING RAIN GAUGE

Produce a continuous plot of rainfall against time to provide valuable data of intensity and duration of rainfall for hydrological analysis of storms.

• An instrument that automatically records the amount of precipitation collected as a function of time.

TIPPING BUCKET TYPE RAIN GAUGE

• A recording rain gauge in which the water collected continuously drains through a funnel into one of a pair of chambers or buckets that are balanced bistable on a horizontal axis.

• Not applicable for snow

• 30.5 cm size rain gauge • The catch from the funnel falls onto one of pair of small buckets.

• Measures the rainfall with at least count of 1 mm

WEIGHING BUCKET TYPE RAIN GAUGE

consists of an arrangement of a bucket mounted on a weighing scale.

• It is made up of a receiver bucket held up by a spring balance, lever balance, or other weighing device.

• Records the weight of the snow or rain.

• In this rain gauge, the catch from the funnel empties into a bucket mounted on a weighing scale.

• The weight of the bucket and its contents are recorded on a clock – work – driven chart

NATURAL SIPHON TYPE RAIN GAUGE

• Also known as the float-type gauge.

• This type of rain gauge consists of a funnel-shaped collector that leads to the floating chamber causing a float to rise. As the rainfall gets accumulated on the collector, the float subsequently rises, and the pen attached to the float through a lever system records the elevation of the float on a rotating drum through a clockwise mechanism.

DOST PAGASA AUTOMATED RAIN GAUGE

• Developed to gather and record the amount of rainfall over a set of periods of time and automatically sends the data to a central based station on a predetermined interval basin.

• Rainfall data are sent wirelessly through the cellular network as a text message or Short Messaging System (SMS)

• Designed to be rugged and standalone, the station can be deployed even in the harshest remote areas and can operate continuously, as it gets power from the sun,

MASS CURVE OF RAINFALL

• A plot of the accumulated precipitation against time, plotted in chronological order.

HYETOGRAPH

• A plot of the intensity of rainfall against the time interval.

• Derived from the mass curve and is usually represented as a bar chart.

• A very convenient way of representing the characteristics of a storm and is particularly important in the development of design storms to predict extreme flood.

• The area under a hyetograph represents the total precipitation received in the period.

POINT RAINFALL

• Also known as station rainfall • Refers to the rainfall data of a station.

• Depending upon the need, data can be listed as daily, weekly, monthly, seasonal, or annual values for various periods.

• Graphically these data are represented as plots of magnitude vs. chronological time in the form of a bar diagram.

THIESSEN MEAN METHOD

In this method, rainfall recorded at each station are given a weightage based on an area closest to the stations. The procedure of determining the weighting area is as follows: the catchment area is drawn to a scale and the positions of the six stations marked on it.

ISOHYETAL METHOD

line joining points of equal rainfall magnitude. In the isohyetal method, the catchment area is drawn to scale and the rain gauge stations are marked.

ARITHMETHICAL MEAN METHOD

If 𝑃1,𝑃2, … ,𝑃𝑖 , … , 𝑃𝑛 are the rainfall values in each period in N stations within a catchment, then the value of themean precipitation P bar over the catchment by the arithmetic – mean method is: