informe de hidrologia ingles

7/24/2019 Informe de Hidrologia Ingles

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PROFESSOR :Jose del Carmen Ramos Arbul.

CYCLE :

VI

SECTION :

"B"MEMBERS :

Sarabia Perez Norbil.

Rojas Cabrera, Kinder Henr.

Al!arado San#ez, $enis Rumario.

%ejia Idro&o, Karen Azuena.

C H I C' A () * + -

Hdrolo&


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FACULTY OF ENGINEERING

School of Civil Engineering

INTRODUCTION

As part of hydrology course that is taught to students in Civil Engineering, in order to

provide students with the study and knowledge in this discipline - a summary of the topic

"EVAPO!A#P$!A$O evaporation %it is presented in this paper&

'uch of the water that reaches the earth returns to the atmosphere as vapor

(evaporation), or *y plants (transpiration)+ iven the diculty of measuring separately

the two terms is determined *y evapotranspiration& he in.uence of these phenomena on

the hydrological cycle is very important+ on average, over /01 of the precipitation that

reaches the earth is returned to the atmosphere *y evapotranspiration, reaching this

2gure in some places up to 301& 4rom the point of view of engineering hydrology is

important to know, 2rst, the amount of water lost *y evaporation in large tanks, such as

dams, lakes or driving systems, and, moreover, the amount of water it is necessary to

irrigation systems, to determine the sources and dimensions of supply systems&

HI$R)')IA *


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1.OBJECTIVES

1.1. GENERAL PURPOSE

$nvestigate and e5plain the physical processes of evaporation and

evapotranspiration&

1.2. SPECIFIC OBJECTIVES

6e2ne the process of evaporation& E5plain the factors controlling evaporation& $ntroduce the di7erent methods and instruments for measuring evaporation& Conceptuali8e the process of evapotranspiration& E5plain the factors in.uencing evapotranspiration&

$ntroduce the di7erent methods and instruments for measuring evapotranspiration& 6e2ne in.uential meteorological evaporation and evapotranspiration&

2. JUSTIFICATION

his paper we show it as practical learning and course development+ which,$t helps us

to know everything a*out the processes of evaporation and evapotranspiration&

4or this reason we decided to conduct an investigation and information gathering

*i*liographic various media in *oth English and #panish, *eing careful with every

paragraph of information collected to optimi8e understanding and easy to understand

what it covers and what is involved in this issue&

THEORETICAL FRAMEWORK

3. EVAPORATION

3.1. Def!"!#

Physical process *y which water changes from li9uid to gas, returning directly to

the atmosphere as vapor from free water surfaces such as oceans, lakes and

rivers, wetlands, soil, and vegetation wet &Evaporation phenomena involved in the hydrological cycle from the time the

rainfall reaching the soil surface& 4inally, the water permeating the surface layers

of the soil, comes from the recent rains, in2ltrated in small depth or rises *y

HI$R)')IA /


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capillarity of the water ta*le is directly through the mulch an important source for

evaporation&

D$%"#&' %$( e)$*#+$"!# !' ,!)e -:

E=K(Ewea)

:here;

E; 6aily evaporation&

Ew; saturated vapor pressure to water temperature&

Ea; Vapour pressure air (a*out


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3.2.1.1. S#%$+ +$!$"!#Energy source to supply the latent heat of vapori8ation&

3.2.1.2. A!+ "e*e+$"4+e

he role of air temperature is dou*le that increases the kinetic energy of the

molecules and lowers the surface tension tries to retain them&

3.2.1.3. W!he wind speed is re9uired for stirring and mi5ing the lower layers with the

upper wet lower moisture content&

3.2.1.5. A"#'*0e+!/ *+e''4+eEvaporation increases, at lower air pressure, other factors held constant&

>owever, it has *een o*served that with increasing altitude decreases

evaporation& $t is dicult to assess the relative e7ect of each of the a*ove

meteorological factors that control evaporation, any conclusions must *e

limited in terms of the time period considered&

3.2.2.Ge#,+$*0!/$% $/"#+' 6$"4+e # "0e e)$*#+$"!, '4+$/e7

:ater volume

:ater 9uality

:ater surface

$ce, snow, other

4loors

3.2.2.1. De*"0 # "0e ($"e+ )#%4e.?akes or deep reservoirs have increased storage capacity shallow heat storage,

this fact has a marked in.uence on the seasonal variations and even in the

daily .uctuation of evaporation&

3.2.2.2. W$"e+ 84$%!"he e7ect of salinity or the presence of dissolved solids in the water, reduce the

vapor pressure of the solution, and there*y reduces evaporation& 4or instance in

sea water, the evaporation is a*out


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3.2.2.3. S!9e # "0e +ee '4+$/eAs the si8e of the evaporating surface grows, the magnitude of evaporation

decreases, *ecoming negligi*le in large lakes, on the other hand when the

amount of evaporating surface, evaporation is reduced increases&

3.2.2.5. E)$*#+$"!# # '#( $ !/eEvaporation from snow and ice is a phenomenon still poorly studied& $t is known

only that evaporation from the snow increases with increasing content in li9uid

phase has, hence evaporations are older shortly *efore the thaw&

3.2.2.. E)$*#+$"!# +# '#!%he evaporation rate from a saturated ground is appro5imately e9ual to the

evaporation of water from an area close to the same temperature& :hen

starting to dry soil evaporation decreases and 2nally stops *ecause there is no

mechanism to transport water from a considera*le depth&

3.3. E)$*#+$"!# *+#/e'':hereas evaporation from a water surface (lakes, rivers, etc&) as the simplest

form of process, this can *e schemati8ed as follows;:ater molecules are in constant motion& :hen they reach the li9uid surface

temperature increases the e7ect of solar radiation, and thus its speed, thus

increasing its kinetic energy to get rid of some attraction ad@acent molecules and

through the gas-li9uid interface *ecoming steam& hus, the air layer immediately

a*ove the surface *ecomes saturated with moisture& #imultaneously evaporating

the reverse process *y which the molecules condense *ack to li9uid state and is

also developed& he di7erence *etween the num*er of molecules leaving the

li9uid and the num*er of molecules returning to it marks the glo*al nature of the

phenomenon& $f positive evaporation occurs, if negative, condensation&

HI$R)')IA 1


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3.5. E)$*#+$"!# e$'4+ee"$n order to standardi8e the measurements of the magnitudes involved in the

water cycle, evaporation is measured in millimeters sually the time period

considered in mm B day is accompanied mm B month, etc&$t should *e noted that adopting the unit of measure mm is signi2cant *ecause it

indicates that evaporation is a surface phenomenon& 4or e5ample, the lower the

evaporation of a small reservoir surface and deep, than that corresponding to one

large surface and shallow, although the volume of water stored in *oth is the

same&

o measure the evaporation have the following methods;

$nstrumental methods (evaporation tanks and evaporimeters)

heoretical methods (:ater alance)

Empirical formulas ('eyer, Penman)

Aerodynamic estimate&

E'"!$"!# e"0#':3.5.1.Pe$ e'"!$"!# e"0#.

Approach to estimate the potential evaporation with an energy *ased on theincoming radiation& hese components eliminate evaporation process varia*le

surface temperature, which is not a standard weather measurement, resulting

the following e9uation known as the com*ination Penman e9uation to estimate

the potential evaporation&

HI$R)')IA 2

34#an&e zone.


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:here; Epen; the daily potential evaporation from a saturated surface& !n; the daily net radiation at the surface evaporation& :; is a function of the average daily wind speed& D; it is the psychrometric constant& ; it is the latent heat of vapori8ation&

3.5.2.Ae+#$!/ e"0#ased on the vapor di7usion process& he general di7usion of vapor di7usion&

Presents serious diculties, as the general e9uation of vapor di7usion presents

simple solutions only under special conditions.

Eo=(a+bu )(e1e2 )

:here;u F average wind speed&

e1y e

2: #team pressure levels z1y z2 .

a y b hey are coecients&

$f the vapor pressure of the surface temperature, this is e9ual to steam

evaporation e1e'

1alatemperaturat'

1 alatemperatura

t's of the *oundary layer *etween water and air, and the air temperature,

then; e

2es la presion de vapor deaire ea

1eae '

E0=(a+bu)

:here the evaporation rate per unit area and type can *e estimated through

measurements of wind on one level, and the di7erence enters the vapor

pressure of water at the *oundary layer *etween air and water, and the

pressure in the air& he constant * must *e determined for each locality&

3.5.3.Me"0# # ee+, -$%$/e

HI$R)')IA 5


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$t is *ased on the principle of energy& Energy *alance *etween the surface and

the neigh*oring air can *e e5pressed as;

Gs F 4c H !I H ?eo:here;!I; li9uid .ow radiation4c; heat .ow into the .oorGs; sensi*le heat .u5 to the atmosphere?eo; latent heat .u5 or 9uantity of energy spent on evaporation& $t is e9ual to

the evaporation

3.5.5.E)$*#+$"!# T$;'One of the most used instruments for measuring evaporation consists of tanks,

with a common principle as the water lost to evaporation contained in a deposit

of regular dimensions& hey are usually made of galvani8ed iron, 8inc or copper,

various models di7ering from each other *y their si8e, shape and location on

the ground&

6eposits or evaporation tanks can *e of three types;

4oreign (placed on the soil surface) uried 4loating (for measurements in large li9uid masses, reservoirs and lakes)&

3.5.5.1. E


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$t installs on a

.oor with

hardwood

*races,

lattice-

shaped, so that its *ottom is a*out IJ cm *ase& soil, in order to allow air to

circulate freely under the tank& $n order to standardi8e the criteria for facilities

placed in an area su*@ect to the ma5imum possi*le sunshine is followed& he

water level in the tank should *e up to Jcm& its upper edge and pull water is

added or when the level variation, in one way or another, is more than


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uried tank "colorado"$t parallelepiped shaped with s9uare cross section of 0,3IK m on a side and

0&KM< m& o install it *uried in the ground so that their upper edges remain

I0cm on the surface thereof& he water level in the tank is kept *eing .ush

appro5imately with the surrounding ground&

3.5.5.3. F%#$"!, "$;'anks or .oating evaporimeter is used *y the # eological #urvey, has a

circular section with an area of 0&


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'easure water levels is to measure the di7erence of evaporation produced in

the time elapsed *etween measurements (


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and with it will come up the saucer, you can read directly on the scale, the num*er of

millimeters has fallen the water level&

3.5..2. Evaporimeter type ?ivingstone

Present in the air, a hollow porous sphere (?ivingstone type) or a disc (ellanitype), porous porcelain, with distilled water on the inside and in communication

with a container that ensures replacement .uid, aided *y the atmospheric

pressure&he reduction of the water contained therein, indicates the amount evaporated&

$n practice they are often used as research apparatus and to make

determinations of agronomic application, having also *een used to study

perspiration&

3.5..3. Pich evaporimeter$t consists of a glass tu*e whose dimensions vary according to the models (of I

to I&


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the lower end, which is covered a 2lter paper disc of given si8e (usually N cm in

diameter and 0&J mm thick), held *y a clamp and a spring (4igure c)&Once 2lled with distilled water, invest carefully and hangs from the upper end,

with fre9uent install inside the weather shelter& :ater progressively evaporates

through the paper 2lter, *eing read descent of the li9uid column in the

graduated tu*e, generally every


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$n theory the method is very simple, *ut in practice rarely gives relia*le results&

he reason is that the measurement errors of the volumes involved and storage

directly a7ect the calculation of evaporation& Of all the words that come into the

e9uation, the more dicult to assess is the in2ltration (Og), *ecause it must *e

estimated indirectly from groundwater levels, permea*ility, etc&

3.5.>.E*!+!/$% #+4%$' 6+ee ($"e+ '4+$/e'7'any empirical e5pressions have *een developed for estimating the

evaporation from open water surfaces, linking it to some factors that in.uence

the phenomenon, encompassing other empirical coecients (constants for each

site), to *e ad@usted according to the o*tained e5perimental measurements&

'ost of the empirical formulas have *een proposed are *ased on the

appro5imate approach 6alton%s law () Ev=k(esea)

here are a num*er of formulas of this type, *ut they are all very similar, so in

this section mention only a few&:here;Ev F 6aily evaporation in mm&

es F #aturated vapor pressure for the surface temperature, mm>g&

ea F Vapor pressure in the air, in mm>g&

$t should *e noted that V and P ,, are daily average values when calculating

average monthly E and if calculated& All these formulas have local or regional

HI$R)')IA -


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validity& $t shall specify the value of the coecients they contain through local

o*servations es eaE vm

5. EVAPOTRANSPIRATION5.1. Def!"!#

Evapotranspiration is the com*ination of two separate processes where*y water is

lost, water evaporation from the soil surface and crop transpiration, therefore, all

factors that a7ect evaporation and transpiration, in.uence the

evapotranspiration&

=nowledge of evapotranspiration or consumptive use is a determining factor in

the design of irrigation systems, including the works of storage, transmission,

distri*ution and drainage&

Especially useful volume of a dam to supply irrigation area depends greatly on the

consumptive use&

HI$R)')IA 1


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5.2. F$/"#+' $?e/"!, e)$*#"+$'*!+$"!# 6ET7E is a phenomenon largely dependent on weather conditions, soil and

vegetation.After a rain or a sprinkler, the interface *etween the soil-plant system and the air

is saturated, and o*viously transpiration and evaporation are in the potential

value, *eing then the function of many factors evapotranspiration (E F f (c, s, v,

f, g, G))

C%!$"!/ $/"#+' 6/7:radiation, temperature and humidity, wind speed, etc& S#!% $/"#+' 6'7:water conductivity, thickness of the active layer, surface heat,

water capacity, surface roughness, etc& F$/"#+' *%$" 6)7:water conductivity of tissue, the epigeal part structure, ?A$

inde5, density and depth of the root system, etc&

HI$R)')IA 2

3!a7o8rans7ira8ion 7roess.


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P0"#@"e/0!/$% $/"#+' 67: tillage, crop rotation, orientation of the lines of

planting, population density, type and intensity of pruning, etc& Ge#,+$*0!/$% $/"#+' 6,7:areal e5tent, climatic variation over the considered

area, etc& W$"e+ $)$!%$-%e $" "0e !"e+$/e (!"0 "0e $"#'*0e+e 67:whose origin is

the rain, irrigation and B or water intake of the water ta*le&

5.3. Me$'4+ee" # e)$*#"+$'*!+$"!#4rom the practical viewpoint, since evapotranspiration depends, among others,

two very varia*le factors dicult to measure, such as the moisture content of soil

and vegetative plant development, hornthwaite introduced a new concept,

optimi8ing *oth Eto potential evapotranspiration factors&

5.3.1.Ree+e/e *#"e"!$% e)$*#"+$'*!+$"!# 6E"#7.he potential of a reference culture (Eto) in mm B day, evapotranspiration was

de2ned *y 6oorem*os and Pruit (4AO, I3/J) as; "he evaporation rate in mm B

day from a large area of grass (grass) reen L IJ cmuniform, actively growing,

completely shading the soil surface and does not suer from water shortages. "

5.3.2.A/"4$% e)$*#"+$'*!+$"!# 6ETR7$n practice, the cultures are grown in conditions far removed from the optimum

moisture& herefore to calculate for e5ample the demand for irrigation has to *e

*ased on the actual evapotranspiration (E!), which takes into account the

availa*le water in the soil and environmental conditions in which a particular

crop develops&

he actual evapotranspiration of a crop, at some point in its growth cycle can

*e e5pressed as;

E! F Eto =c kh

:here;

Eto F reference crop potential evapotranspiration

=c F crop coecient

=h F coecient of soil moisture

HI$R)')IA 5


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he crop coecient kc depends on the anatomorfolQgicas and physiological

characteristics of the species and e5presses the change in their a*ility to

e5tract soil water during the growing season&

he humidity coecient kh is an e5pression of the transport mechanism of

water to the atmosphere through the soil and the plant, which depends on the

degree of availa*ility of water, the water potential gradient *etween the .oor

and the surrounding atmosphere and the a*ility of the system to convey water&

5.3.2.1. L'!e"e+'

A lysimeter is an underground tank, generally rectangular (K&


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he ground surface is thus su*@ected to atmospheric agents (measured in a

weather station) and receives natural rainfall (measured *y a rain gauge), and

eventually arti2cial inputs, properly controlled& he content of the lysimeter soil

is well drained to a certain level (the level of the *ottom of Cu*a or higher) and

drainage water is collected and measured&

Evapotranspiration (E) for a certain period can *e calculated if the rainfall and

other inputs (A) produced in that period, the corresponding drainage () and

the variation of the amount of water collected in the lysimeter (R#) are known

applying the e9uation of *alance hidrolQgico&Para determine R# can use two

methods;

5.3.2.1.1. T*e' L'!e"e+'Among the various types of the lysimeters weighing the drainage without

suction and suction drainage they are included& ?ysimeters heavy measure

weight changes of a volume of soil& he drainage without suction collect

ground water seeping down naturally *y soil, that is, the water moves *y

gravity& A drainage lysimeters suction suction is applied to e5tract ground

water slowly through a porous material&

HI$R)')IA *+

Figure 4.4. 'sime8ers 87es.


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he design of the drainage without suction lysimeters to capture soil water

that otherwise would *ecome reach groundwater or lower soil hori8ons

water& $n contrast, suction drainage lysimeters are designed to capture soil

water could a*sor* plant roots&

he data o*tained *oth from evapotranspirometers as lysimeter, even in the

same manner and operation are not compara*le, *eing a7ected *y speci2c

factors such as impaired soil structure+ limiting root development of plants

and diculty in producing the device, the same pro2le of temperature and

humidity in the natural terrain&

5.3.2.2. G%$9!, +$e

his device is sometimes used for measuring evapotranspiration soil wasessential not alter& A *ottomless metal frame, the cover is constituted *y an

inclined glass, is slightly recessed in the ground& he water evaporates to

condense on the cold wall forming a glass that slides into a trough pouring

to a container capacity& he conditions governing evaporation under the

frame are not the same as in the free atmosphere, so it is necessary to

evaluate the e5isting ratio k outdoor evaporation and evaporation under the

frame+ for this evaporation o*served in two tanks 2lled with moist earth, of

which one is covered with a frame, while the other remains outdoorscompared& he coecient k is sometimes the order of J, which limits the

precision of the method&

5.3.3.I!+e/" #+ e*!+!/$% e"0#' 6*#"e"!$% e)$*#"+$'*!+$"!#7'ost of these methods are too theoretical as they have *een deducted

under de2ned conditions *etween regions and their application re9uires

certain information not generally availa*le to have& 4or e5ample the method

of hornthwaite potential evapotranspiration calculated using e5isting data

from the monthly average temperatures, the use of urc precipitation and

mean temperature of a *asin, and laney and Criddle and Christensen

rassi and make use of solar radiation&

HI$R)')IA *


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5.3.3.1. T0#+"0($!"e e"0#he formula is *ased on temperature and latitude, useful for estimating

potential evapotranspiration and has the advantage that the formula uses

weather data availa*le (average monthly temperature)& he method gives

provides good results in wet areas with a*undant vegetation&

hornthwaite, empirically found the following e5pressions;

i=(t5 )1.514

I=I

12

i

a=675109I3771107I2+1792105I+0.49239

ET0=

12d

30 16

(10t

I

)

a

:here;

Eto F 'onthly potential evapotranspiration in mm B month

i F thermal monthly inde5

$ F hermal annual rate

F monthly mean temperature of the month, in S CA F constants to *e determined, depending on each place&

F ma5imum num*er of sunshine hours for the month in 9uestion,

depending on latitude

6 F the num*er of days in the month&

HI$R)')IA **


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Accepta*le results are o*tained in wet areas with a*undant vegetation, *ut the

errors increase in arid or semi-arid areas&

5.3.3.2. B%$e@C+!%e e"0#he method considers the E is proportional to the product of the temperature

*y the percentage of annual hours of sunshine per day during the period,

usually a month& $n order to *etter de2ne the e7ects of climate on crop water

needs, the method of laney-Criddle was amended *y 6ooren*os and Pruitt

(I3/K) for reference evapotranspiration (Egr)& Considering the overall levels of

humidity, wind and sunshine, the Egr calculated *est re.ects the e7ects of

climate on evapotranspiration&

According to 4AO (I3LM) the e9uation lane method - Criddle is;

Eto=p (0 .46T+8.13)

:here;

Eto, reference evapotranspiration (mm B day), average daily temperaturep, average annual percentage daily light hours

A**%!/$"!#:

$t is recommended that in areas which include temperature data his formula should

*e used particularly in semi arid areas&

A)$"$,e':

Easy applica*ility

D!'$)$"$,e':

6o not use in e9uatorial regions, or high altitude areas where the minimum

temperature is very low and very strong radiation levels of daytime radiation&

5.3.3.3. T4+/ e"0#

9#e Pries8le;9alor e is used as an a77ro4ima8ion ?or alula8in& onsiderin&

e!a7o8rans7ira8ion.

HI$R)')IA */


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@#ere 8#e oe??iien8 b !alues ran&in& ?rom .*1 8o e8lands =rela8i!e #umidi8 1+> and .20

?or arid areas =rela8i!e #umidi8 D1+>. 9#e da8a reargreaves, temperature and radiation can *e used

together to e7ectively predict the variation of Eo&>argreaves and !yley (I3LJ) pu*lished an e9uation for Eo, developed *ased

on measurements of several lysimeters, and comparisons with other methods

are cali*rated *ased on L years of measured E values for gra8ing tall fescueand corresponding weather data 6avis (California, #A)&

According to >argreaves and #amani (I33I) >argreaves e9uation is e5pressed

as follows;

HI$R)')IA *0


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Eto=0.0023!A(T " #+17.8 )T $0.5

:here;

Eto, reference evapotranspiration (mm B day)&

!A, e5traterrestrial radiation in mm B day evaporation

TC, medium temperature (ma5 H min) B < (C)&

6, ma5-min emperature range (S C)

A**%!/$-!%!":

>argreaves (I3L


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ETo=0.408 % (!n& )+

900

T+273us(esea)

%+(1+0.34 us)

:here;

Eo reference evapotranspiration (mm B day)

!n net radiation at the crop surface ('U B m < d)

soil heat .u5 ('U B m < d)

, average air temperature (S C)


27/27



:e presented the di7erent methods and instruments for measuring

evapotranspiration&

B!-%!#,+$*0:

@ RAGHUNATH H.M. 62=7. H+#%#, 6P+!/!*%e' @ A$%'!' @ De'!,7

.Se,4$ E!"!#. Ne( $,e !"e+$"!#$% *4-%!'0e+'. ISBN (10): 81-224-2332-9. P.

60-87

(e-,+$*0:

@ E. K$+%''# POMADE L .. Methods of Estimating Potential and current

Evaporation. Recovered from:

http://www.civil.utah.edu/~mizukami/coursework/cveen7!"/E#Measurem

ent.pdf

@ E)$*#+$"!# e)$*#"+$'*!+$"!# $ '#!% #!'"4+e.Re/#)e+e +#:0""*:(((.(0/#'.#+,0(+*,4!e/0$*"e+'e,%!'0#+!,!$%WMO1=E

2V#%IC05U*2e.*

HI$R)')IA *2
http://www.civil.utah.edu/~mizukami/coursework/cveen7920/ETMeasurement.pdfhttp://www.civil.utah.edu/~mizukami/coursework/cveen7920/ETMeasurement.pdfhttp://www.whycos.org/hwrp/guide/chapters/english/original/WMO168_Ed2008_Vol_I_Ch4_Up2008_en.pdfhttp://www.whycos.org/hwrp/guide/chapters/english/original/WMO168_Ed2008_Vol_I_Ch4_Up2008_en.pdfhttp://www.whycos.org/hwrp/guide/chapters/english/original/WMO168_Ed2008_Vol_I_Ch4_Up2008_en.pdfhttp://www.whycos.org/hwrp/guide/chapters/english/original/WMO168_Ed2008_Vol_I_Ch4_Up2008_en.pdfhttp://www.civil.utah.edu/~mizukami/coursework/cveen7920/ETMeasurement.pdfhttp://www.civil.utah.edu/~mizukami/coursework/cveen7920/ETMeasurement.pdf

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