Hydrology Midterm Reviewer Flashcards
A multidisciplinary subject that deals with the occurrence, circulation storage, and distribution of surface and groundwater on the earth.
Hydrology
Hydrology deals with ______.
- Occurrence
- Circulation
- Storage
- Distribution
What are the four types of soil?
- Loam
- Clay
- Sandy
- Silt
- well draining
- holds moisture
Loam
- gets waterlogged
- holds nutrients
Clay
- drains quickly
- holds fewer nutrients
Sandy
- easily compacted
- fertile
Silt
Arrangement of the natural and artificial physical features of an area.
Topography
Study of landforms, their processes, form and sediments at the surface of the Earth.
Geomorphology
Science dealing with the atmosphere and its phenomena, including both weather and climate.
Meteorology
Science that deals with the earth’s physical structure and substance, its history, and the processes that act on it.
Geology
Science that deals with the physical and biological properties and phenomena of the sea.
Oceanography
Study of the relationships between living organisms, including humans, and their physical environment; it seeks to understand the vital connections between plants and animals and he world around them.
Ecology
Includes topics form traditional fluid mechanics, hydrodynamics, and water resources engineering.
Hydrology
Branch of Physics concerned with the mechanics of fluids and the forces on them.
Fluid Mechanics
Branch of physics that deals with the motion of fluids and the forces acting on solid bodies immersed in fluids and in motion relative to them.
Hydrodynamics
A specific kind of civil engineering that involves the design of new systems and equipment that help manage human water resources.
Water Resource Engineering
Prime requirement for the existence of life.
Water
_____ and _____ in the Middle East
had early water management practices.
Sumerians, Egyptians
Chinese ancient civilizations along the banks of _______.
Huang He
In 4,000 BC, a dam was built across the ______, and later a canal for fresh water was constructed between ______ and ______.
Nile, Cairo, Suez
In 3,000 BC, groundwater development through wells was known to the people of the ______.
Indus Valley Civilizations
The _______ were the first serious students of hydrology.
Greek Philosophers
Proposed the conversion of moist air into water deep inside mountains.
Aristotle
Suggested the idea of an underground sea as the source of all surface waters systems of Rome based on the cross-sectional area of flow.
Homer
______ constructed numerous aqueducts to serve large cities as well as small towns and industrial sites.
Romans
Romans had _____ aqueducts constructed over a period of 500 years.
11
A watercourse constructed to
carry water from a source to a distribution point far away. In modern engineering, the term aqueduct is used for any system of pipes, ditches, canals, tunnels, and other structures used for this purpose.
Aqueduct
Were first attempted in the water systems of Rome based on the cross-sectional area of flow.
Stream flow measurements
Discovered the relationship between Area, Velocity, and Flow Rate during the Italian Renaissance.
Leonardo da Vinci
First recorded measurement of rainfall and surface flow in the 17th Century.
Perrault
Used a small pan to estimate evaporation in the Mediterranean Sea and made several conclusions.
Halley
Gaged the velocity of flow in the Seine River in Paris.
Mariotte
Mariotte gaged the velocity of flow in the _____ in Paris.
Seine River
Principles involved in the history of Hydrology.
- Bernoulli’s Theorem
- Pitot Tube
- Chezy’s Formula
During the ______, significant advances in groundwater hydrology and hydraulics occurred.
19th Century
Law for flow in porous media
Darcy’s Law
Developed capillary flow equation to describe flow in small channels.
Hagen–Poiseuille Equation
Developed to describe pipe flow around 1850s.
Darcy-Weisbach Equation
Periods in the history of Hydrology
SOMEMERT
- Period of Speculation – before AD 1400
- Period of Observation – 1400-1600
- Period of Measurement – 1600-1700
- Period of Experimentation – 1700-1800
- Period of Modernization – 1800-1900
- Period of Empiricism – 1900-1930
- Period of Rationalization – 1930-1950
- Period of Theorization – 1950 to present
Produced a significant step forward for the field of hydrology, as government agencies began to develop their own programs of hydrologic research.
Period of Rationalization
Sherman’s Unit Hydrograph
1932
Horton’s Infiltration Theory
1933
Theis’s Non-Equilibrium Equation
1935
Gumbel’s Extreme Value Distribution
1958
The major link between oceans and continents on the planet, facilitating the cycle of water movement on earth.
Atmosphere
Layers of the atmosphere
- Troposphere
- Stratosphere
- Mesosphere
- Ionosphere
- Thermosphere
- Exosphere
The lowest layer of our atmosphere.
Troposphere
We humans live in the _____, and nearly all weather occurs in this layer.
troposphere
Most clouds appear here, mainly because 99% of the water vapor in the atmosphere is found in this layer.
Troposphere
The infamous ozone layer is found within this layer.
Stratosphere
______ molecules in the stratosphere absorb high energy ultraviolet (UV) light from the Sun, converting the UV energy into heat.
Ozone
Commercial passenger jets fly in the
lower ________.
Stratosphere
Commercial passenger jets fly in the
lower ________.
Stratosphere
The coldest temperatures in Earth’s atmosphere, about _______, are found near the top
of the _______.
-90° C (-130° F), mesosphere
High-energy X-rays and UV radiation from the Sun are absorbed in the ______, raising its temperature to hundreds or at times thousands of degrees.
Thermosphere
Many _______ actually orbit Earth within the thermosphere.
satellites
The aurora, the Northern Lights and Southern Lights, occur in this layer.
Thermosphere
Outermost layer of the Earth’s atmosphere.
Expsphere
The theoretical top boundary of the exosphere is 190,00 km which is about _______.
halfway to the Moon
It is not a distinct layer like the other layers. Instead, it is a series of regions in parts of the mesosphere and thermosphere where high-energy radiation from the Sun has knocked electrons loose from their parent atoms and molecules.
Ionosphere
Is both a major catalyst and a balancing factor of atmospheric processes that create the weather in the lower atmosphere.
Water vapor content
Measures the weight of the air per unit area.
Atmospheric Pressure
Average air pressure at sea level is approximately ______.
- 1 atmosphere
- 1013 millibars (mb)
- 14.7 psi
- 760 mm-Hg
- 29.97 in-Hg.
Ideal gas law
𝑃 = 𝜌𝑅𝑇
𝑃 - Pressure
𝜌 - Density
𝑇 - Absolute Temperature
𝑅 - Gas constant
Cold air masses are generally associated with the ______ atmospheric pressure.
higher
A measure of the amount of water vapor in the atmosphere and can be expressed in several ways.
Humidity
The mass of water vapor in a unit volume of air.
- _H = mass of water vapor / volume of air
Absolute Humidity
The mass of the water vapor compared to the total mass of the air parcel.
- _H = mass of water vapor / total mass of air
Specific Humidity
The mass of the water vapor compared to the total mass of the rest of the air parcel.
- __ = mass of water vapor / mass of dry air
Water Mixing Ratio
Represents amount of water in air in percentage.
Relative Humidity
Ratio of the air’s actual water vapor content compared to the amount of water vapor at saturation for that temperature.
Relative humidity
The temperature to which a sample of air must be cooled to reach saturation is defined as the ______.
dew point temperature
Can accept no more vapor.
Saturated
- You may be zapped by doorknobs and light switches.
- A humidifier will help increase humidity
Too Dry (High Pressure)
- Your hair may be frizzier than usual.
- Air conditioning will help lower humidity.
Too Humid (Low Pressure)
It takes approximately ______ to convert 1 g of water to
vapor.
600 cal
Heat is absorbed and no temperature change takes place.
Latent Heat
Latent heat is also known as?
latent energy or heat of transformation
Energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process — usually a first-order phase transition.
Latent Heat
Measure of the amount of heat.
Calorie
Land is heated more rapidly than the sea.
Insolation
Air that descends because it is cool.
High-pressure system
It spreads outward as it nears the ground.
High-pressure system
Brings fair weather, no clouds and precipitation.
High-pressure system
Warm air rises and draws inward toward the center of low pressure..
Low-pressure system
Rising air expands and cools.
Low-pressure system
It brings clouds and precipitation.
Low-pressure system
Types of Clouds
- Cumulus
- Stratus
- Stratocumulus
- Altocumulus
- Nimbostratus
- Altostratus
- Cirrus
- Cirrocumulus
- Cirrostratus
- Cumulonimbus
Are the clouds you learned to draw at an early age and that serve as the symbol of all clouds (much like the snowflake symbolizes winter).
Cumulus clouds
Their tops are rounded, puffy, and a brilliant white when sunlit, while their bottoms are flat and relatively dark.
Cumulus clouds
Hang low in the sky as a flat, featureless, uniform layer of grayish cloud.
Stratus clouds
They resemble fog that hugs the horizon (instead of the ground).
Stratus clouds
Are seen on dreary, overcast days and are associated with light mist or drizzle.
Stratus clouds
These are low, puffy, grayish or whitish clouds that occur in patches with blue sky visible in between. When viewed from underneath, they have a dark, honeycomb appearance.
Stratocumulus clouds
They form when there’s weak convection in the atmosphere.
Stratocumulus clouds
The most common clouds in the middle atmosphere. You’ll recognize them as white or gray patches that dot the sky in large, rounded masses or clouds that are aligned in parallel bands.
Altocumulus clouds
They look like the wool of sheep or scales of mackerel fish—hence their nicknames “sheep backs” and “mackerel skies.”
Altocumulus clouds
They can signal thunderstorms to come later in the day. You may also see them out ahead of cold fronts, in which case they signal the onset of cooler temperatures.
Altocumulus clouds
Are often spotted on warm and humid mornings, especially during summer.
Altocumulus clouds
Cover the sky in a dark gray layer. They can extend from the low and middle layers of the atmosphere and are thick enough to blot out the sun.
Nimbostratus clouds
Are the quintessential rain cloud. You’ll see them whenever steady rain or snow is falling (or is forecast to fall) over a widespread area.
Nimbostratus clouds
Appear as gray or bluish-gray sheets of cloud that partially or totally cover the sky at mid-levels.
Altostratus clouds
Even though they cover the sky, you can typically still see the sun as a dimly lit disk behind them, but not enough light shines through to cast shadows on the ground.
Altostratus clouds
Tend to form ahead of a warm or occluded front. They can also occur together with cumulus at a cold front.
Altostratus clouds
Like their name suggests (which is Latin for “curl of hair”), they are thin, white, wispy strands of clouds that streak across the sky.
Cirrus clouds
They are made up of tiny ice crystals rather than water droplets.
Cirrus clouds
NASA’s Earth data site quotes a proverb that sailors learned to warn them of coming rainy weather, “Mares’ tails (_____) and mackerel scales (______) make lofty ships to carry low sails.”
cirrus, altocumulus
Are small, white patches of clouds often arranged in rows that live at high altitudes and are made of ice crystals.
Cirrocumulus clouds
Called “cloudlets,” the individual cloud mounds of ________ are much smaller than that of altocumulus and stratocumulus and often look like grains.
Cirrocumulus clouds
Are rare and relatively short-lived, but you’ll see them in winter or when it’s cold but fair.
Cirrocumulus clouds
Are transparent, whitish clouds that veil or cover nearly the entire sky.
Cirrostratus clouds
A dead giveaway to distinguishing it is to look for a “halo” (a ring or circle of light) around the sun or moon.
Cirrostratus clouds
Indicate that a large amount of moisture is present in the upper atmosphere. They’re also generally associated with approaching warm fronts.
Cirrostratus clouds
Are one of the few clouds that span the low, middle, and high layers.
Cumulonimbus clouds
They resemble the cumulus clouds from which they grow, except they rise into towers with bulging upper portions that look like cauliflower.
Cumulonimbus clouds
Their tops are usually always flattened in the shape of an anvil or plume. Their bottoms are often hazy and dark.
Cumulonimbus clouds
Are thunderstorm clouds, so if you see one you can be sure there’s a nearby threat of severe weather (short but heavy periods of rainfall, hail, and possibly even tornadoes)
Cumulonimbus clouds
Three classifications of clouds
- Color
- Shape
- Altitude or Height
One type of high cloud that is often found in heavy thunderstorms that produce massive rainfall.
Cumulonimbus clouds
Are very high collections of ice crystals and often indicate the approach of a cold front and that weather is about to change.
Cirrus clouds
Is essentially a low cloud with a base that is very near the ground, often reducing the visibility in the area around it.
Fog
The general circulation of wind across the earth is caused by the ______ heating of earth’s surface through solar input, and by the earth’s rotation.
uneven
At the ______, solar radiation input and temperature are greatest because of the shape and
tilt of the globe relative to the sun.
equator
______ latitudinal circulation cells transport heat from the equator to the poles.
Three
The Coriolis Effect is named after French mathematician and physicist ________________.
Gaspard-Gustave de Coriolis
A phenomenon that causes fluids, like water and air, to curve as hey travel across or above the Earth’s surface.
Coriolis Effect
Best known for his work on the supplementary forces that are detected in a rotating frame of reference.
Gaspard-Gustave de Coriolis
Are prevailing winds from the west toward the east in the middle latitudes between 30- and 60-degrees latitude.
Westerlies / Antitrades
They originate from the high-pressure areas in the horse latitudes and trend towards the poles and steer extratropical cyclones in this general manner.
Westerlies / Antitrades
Are the permanent east-to-west prevailing winds that flow in the Earth’s equatorial region.
Easterlies
- Are regions located at about 30 degrees north and south of
the equator. - These latitudes are characterized by calm winds
and little precipitation.
Horse Latitudes
Near the equator is another region of light and variable winds called the ______, or the ______. This is the area of maximum solar heating, where surface air rises and flows toward both poles.
doldrums, intertropical convergence zone
First observed in 1946, are narrow bands of high-speed winds that circle each hemisphere like great rivers, at elevations extending from 2.5 or 3 miles to above the tropopause.
Jet Streams
Are large bodies of air with fairly consistent temperature and humidity gradients in the horizontal direction at a given altitude.
Air masses
Two Classification of air masses
- Source of generation
- Latitude of generation
Source of air masses from which they were generated.
- Land (continental), c
- Water (maritime), m
Latitude of generation of air masses.
- Tropical (hot), T
- Polar (cold), P
- Arctic (cold), A
- Antarctic (cold), AA
The boundary between one air mass and another is called a _______.
frontal zone, or front.
When cold air moves under warm air, which is less dense, and pushes the warm air up.
Cold front
Associated with:
- Frequent rain with possible thunderstorms.
- Cooler temperature and dryer air after front passes.
Cold front
When hot air pushes against the cold air.
Warm front
Associated with light rain, and humid temperatures.
Warm front
Air masses on either side of the boundary are not moving or are barely moving.
Stationary front
Associated with cloudy and overcast with light showers. Conditions do not change until another system passes through.
Stationary front
When warm front is overtaken by a cold front.
Occluded front
Associated with severe snowstorms.
Occluded front
- Generation of a cyclone.
- Process or start of a cyclone.
Cyclogenesis
- Dissipation of a cyclone.
- End of a cyclone.
Cyclolysis
Indicator that a strong weather phenomenon will occur.
Occluded front
Are tropical storms that form over the North Atlantic Ocean and Northeast Pacific.
Hurricanes
Are formed over the South Pacific and Indian Ocean
Cyclones
Are formed over the Northwest Pacific Ocean.
Typhoons
Activity that is characterized by cumulonimbus clouds that can produce heavy rainfall, thunder, lightning, and occasionally hail.
Thunderstorm
Are the result of strong vertical movements in the atmosphere.
Thunderstorms
Hydrologic Cycle based on the diagram.
P - precipitation
R - runoff (surface)
T - transpiration
E - evaporation
F - infiltration
G - grounwater flow
Each path of the hydrologic cycle involves one or more of what following aspects?
I. Transportation of Water
II. Temporary Storage of Water
III. Change of State of Water
The main components of the hydrologic cycle can be broadly classified as ________ (flow) components and ________ components as below:
transportation, storage
Transportation Components
- Precipitation
- Evaporation
- Transpiration
- Infiltration
- Runoff
Storage components of precipitation.
Storage on Land Surface
Storage components of evaporation.
Soil Moisture Storage
Storage components of transpiration.
Groundwater Storage
Denotes all forms of water that reach the earth from the atmosphere.
Precipitation
- Made of liquid water droplets falls when temperatures in the air and at the surface are above freezing (32°F, 0°C).
- Can start as water droplets or ice crystals in a cloud but always falls as liquid water.
Rain
- The balls of ice that fall from clouds and can even put dents in cars.
- Created in thunderstorm clouds.
- Water droplets form in the cloud and get pushed upward, where temperatures are colder.
Hail
- The icy precipitation that forms when a thin layer of warmer air comes between layers of cold air.
- A top layer of below-freezing air creates ice crystals that melt as they fall through a thin layer of above-freezing air.
- If there’s enough room between the warmer air and the ground, the water droplets re-freeze in a bottom layer of below-freezing air and fall as _____.
Sleet
- Falls like rain, but as soon as it touches the ground, it freezes! It starts as ice crystals.
- The ice crystals melt and turn into water droplets as they go through a layer of above-freezing air.
- If the temperature in a thin layer of air at the surface is below freezing, the water droplets freeze when they land.
Freezing rain
- Is a frosty kind of snow.
- It forms in below-freezing temperatures when snow crystals in the cloud collide with very cold-water droplets.
- The water droplets freeze loosely onto the snow, giving graupel a slushy texture.
Graupel
- Falls when all the air between the cloud and Earth’s surface is below freezing.
- If you look at snowflakes closely, you can see their unique and beautiful shapes.
Snow
Classifications of precipitation
- Light Rain - trace to 2.5 mm/h
- Moderate Rain - 2.5 mm/h – 7.5 mm/h
- Heavy Rain >7.5 mm/h
Classifications of precipitation
- Light Rain - trace to 2.5 mm/h
- Moderate Rain - 2.5 mm/h – 7.5 mm/h
- Heavy Rain >7.5 mm/h
Is an instrument used by meteorologists and hydrologists to gather and measure the amount of liquid precipitation over a predefined area, over a period of time?
Rain Gauge
As this type of rain gauge can also be used to measure snow, it is alternatively known as a _______.
cylindrical rain/snow gauge
It consists of a cylindrical vessel with a uniform diameter from top to bottom and an orifice at the top. It does not have a funnel.
Cylindrical rain gauge
Cylindrical rain gauges are regulated by?
Commission for Instruments and Methods of Observation (CIMO)
Are the type used at non-automated observatories. With such devices, the observer takes measurements using a rain-measuring glass at regular intervals.
Ordinary rain gauges
It enables automatic, continuous measurement and recording of precipitation.
Siphon rain gauge
This type of rain gauge generates an electric signal (i.e., a pulse) for each unit of precipitation collected, and allows automatic or remote observation with a recorder or a counter. The only requirement for the instrument connected to the rain gauge is that it must be able to count pulses.
Tipping Bucket rain gauge
The airflow around the rain gauge should be as _______ as possible.
horizontal
Avoid sites that are ______, _______ or _______.
concave, elevated or tilted
Choose a site ______ from precipices or mountain ridges, where local winds are strongly distorted.
far
Avoid sites where the wind blows through or _______.
stagnates
Choose sites ________ from other instruments, trees or buildings.
away
Ideally, the instrument should be installed at a distance from such objects equivalent to at least ______ their height.
two to four times
As the wind speed near the ground increases with height, the efficiency of precipitation collection the _________ higher a gauge is placed.
decreases
Accordingly, the receptacle should be placed as _______ as possible.
low
However, too low a setting will result in the _______ of splashed rainwater from the ground or the introduction of ground snow in the case of a snowstorm.
entry
The ground surface around the rain gauge should be ________and _______ to prevent raindrops from splashing into the unit from outside.
flat and covered with short grass (lawn) or gravel
Is effective in reducing the influence of wind?
Windshield
Types of Windshield
- Nipher Windshield (Canada_
- Sweeden type (Sweeden)
- Cylindrical type (Japan)
- Tretyakov type (Russia)
- Norway type (Norway)
