Elements of Hydrologic Cycle Flashcards
The process by which water changes from liquid to gas or vapor state
evaporation
evaporation is the ____ ____ through which water moves from a liquid state back into the water cycle as atmospheric water vapos
primary pathway
t or f: hydrologic cycle is an endless cycle
t
it is the number of grams of water per cubic meter
absolute humidity
(density iyahang unit)
the maximum amount of moisture the air can hold in a given temperature
saturation humidity
saturation humidity is ____ proportional to temperature
directly
it is the ratio of absolute humidity to saturation humidity for the temperature of the air mass
relative humidity
as relative humidity approaches ___%, the process of ____ ceases
100% ; evaporation
t or f: as air mass rises into the atmopshere, the temperature decreases, lowering down saturation humidity until it levels off with absolute himidity
t
what happens when air mass can no longer hold all of its humidity?
water condenses
if the ____ remains constant, the _____ humidity will rise. when it reaches 100%, any further cooling will result in ____.
absolute humidity ; relative humidity; condensation
temperature at which condensation will begin
dew point
transpiration is
water pumping of plants from the ground into the atmopshere
this is the process where growing plants continuously pump water from the ground into the atmosphere
transpiration
transpiration transfers water from roots to leaves through
osmotic pressure
t or f: dense and large drainage basin have larger amount of transpiration
T
opening surface of leaves where air may pass through and enable gas exchange
stomata
plants on land have their stomata on the ______ of their leaves
underside
floating aquatic plants have stomata on the ______ of their leaves
upper surface
amount of transpiration is a function of ____ and ___ of drainage basin
density and size
t or f: transpiration is important during growing season
t
___ of transpiration takes place during daylight, when _____ is occurring
95% ; photosynthesis
transpiration is driven by ____ and ___
solar energy and gas exchange
transpiration is limited by
availability of soil water
soil-water content becomes so low, surface tension exceeds osmotic pressure causing water to no longer enter the roots
wilting point
plants with taproot system extending to the water table
phreatophytes
desert plants
xerophytes
cacti, succulents
aquatic plants
hydrophytes
accounts for all the movement of water to the air from sources such as soil, canopy interception, and water bodies
evapotranspiration
evapotranspiration accounts for all the water movement into the air such as, _____, _____, and ____
soil moisture, canopy interception, and water bodies
t or f: evapotranspiration is low in an area with coarse soil and have limited soil moisture storage
T
t or f: small pore spaces in soil is good in preserving soil moisture, therefore resulting in high volume of evapotranspiration
t
evapotranspiration can be measured directly through a
lysimeter
lysimeter is set ____
outdoors
changes in ____ reveal how much of the added water is lost to _____
soil-moisture storage ; evapotranspiration
formula for evapotranspiration
Et = Si + Ir + Pr - Sf - De
Evapotranspiration is equal to the initial soil-water content plus irrigation water added plus precipitation minus the final volume of soil-water content and excess drainage
condensation generally requires a surface or nucleus on which to form, what are examples of these nucleus?
salts, clay minerals, combustion products,
when an air mass with a ______ lower than ____ is cooled without loosing moisture, the _____ will approach 100% as the air approaches the _____ temperature
relative humidity ; 100% ; relative humidity ; dew point temperature
t or f: when air mass is saturated, condensation may start to occur
T
process of condensation
- relative humidity approaches 100%, air mass can no longer hold the moisture
- water vapor turns to tiny water droplets and ice crystals
- water droplets mix with particulate matter (aerosols)
- atmosphere is saturated with moisture, forming clouds
- cloud elements collide and coalesce, raindrops begin to form
t or f: absence of nuclei may become supersaturated without the formation of raindrops or ice crystal
T
Parameters needed to initiate precipitation
- humid air mass must be cooled to dew-point temperature
- condensation of freezing nuclei must be present
- droplets must coalesce to form raindrops
- raindrops must be of sufficient size when they leave the clouds to ensure that they will not totally evaporate before they reach the ground
air masses are cooled by a process called ___
adiabatic expansion
occurs when the air mass rises in the atmosphere and expands owing to the decreasing pressure
adiabatic expansion
when the air mass reaches a ______ temperature, further lifting and cooling will cause ______ and the ______ is released
dew point ; condensation; latent heat of vaporization
an open container used to measure rainfall
rain gauge
t or f: any open container can be used to catch and measure rainfall
T
t or f: the size of opening has little effect on the catch, except for very small (less than 3cm in diameter) openings
t
where should you place a rain gauge
as close to the ground as possible
open area, away from trees and buildings
on steep slopes, have the orifice opening parallel to the slope
rain gauges should be placed as close to the ground as possible to avoid ___
wind
can be used to measure intensity of precipitation in an area
radar
if the ______ is of uniform ____, then a simple ____ of the ___ data for each station is plotted
rain gauge network; density ; arithmetic average ; point-rainfall
rain gauge network over a drainage basin. precipitation amounts are given in ____. Station location are at ____
centimeters ; decimal places
if the rain gauge network is not uniform, what adjustment should be done?
draw precipitation contour map with isohyetal lines
what are isohyetal lines?
lines of equal rainfall
____ are lines of equal rainfall, with a contour interval of ___. The contours are based on simple ____
isohyetal lines ; 0.5 cm ; linear interpolation
the _____ to adjust non-uniform gauge distribution uses a ____ for each rain gauge.
Thiessen Method ; weighing factor
construction of thiessen polygons
- stations are connected with lines
- perpendicular bisector of each line are found
- bisectors are extended to form polygons around each station
t or f: vegetation affects rate of precipitation
t
creation of micro-climates over small distances or different rates of precipitation on mountains or different geological landforms
orographic effect
shows the discharge of a river at a single location as a function of time
stream hydrographs
stream hydrographs are separated into:
horton overland flow, baseflow, direct precipitation, and interflow
Continuous input of groundwater baseflow allows
streams in many areas to keep flowing at some
minimum level, often called ______. This keeps streams from going dry between precipitation events
baseflow conditions
amount of time for water to move across the landscape and into channels; will vary
depending on the distance between where the rain
is falling and the particular channel where discharge
is being measured.
lag time
The upper portion of the drainage system is called the____ while the lower portion is the ____
headwaters ; mouth
how does water table gradient affect baseflow and streams?
if water table gradient is high, more baseflow, higher discharge, and deeper streams
typical in humid regions, where groundwater recharges stream
gaining stream (effluent streams)
typical in arid regions where streams recharge groundwater
losing streams (influent streams)
t or f: a stream that is gaining during low flow periods can temporarily become a losing stream during flood stage
t
