Engineering Hydrology

Presented By : Asif NadeemReg No : BSCT 01123192Presented To : Sir Hassan

Topic

Measurements of Temperature

Measurements of Temperature:

The temperature is measured with the help of thermometer.

Types of Thermometer:

There are two types of thermometer .1) Maximum Thermometer ( Mercury Type)2) Minimum Thermometer ( Alcoholic Type)

1)Maximum Thermometer : (Mercury Type)

Maximum thermometer that record the Highest temperature to which it has been exposed ( e.g by allowing the arise of mercury passed a restriction in the tube but preventing the mercury on contraction ) it is most commonly used to measure the daily temperature .

Maximum Thermometer

it work simply and we can easily used it.

2) Minimum thermometer:

It is used to measure the minimum temperature within a period (usually daily) and is an alcohol-in-glass thermometer. There is a very light, about 2cm dumb-bell shaped dark glass index within the alcohol column.

Where we Placed Thermometer

Air circulation is relatively Unobstructed

No Direct Sun Rays

No precipitation

Instrument Shelter The thermometer

are placed in white wooden boxes are called instrument shelter.

4.5 feet Above to the ground.

Take readings at 8am & 5pm.

Laps Rate:

Laps Rate is defined as the change in temperature per unit distance the vertical direction from the earth surface.

The average value of laps rate is 3.6 degree foreign height per thousand feet.

Types of Laps Rate

1. Dry Adiabatic Laps Rate

2. Saturated Adiabatic Laps Rate

3. Pseudo Adiabatic Laps Rate

1) Dry Adiabatic Laps rate: Air is not fully Saturated.Its average value is 17.71 Degree

foreign Height /1000m.

2) Saturated Adiabatic Laps Rate:

Air is fully saturated .Average value is 9.84 Degree foreign Height /1000m.

3) Pseudo Adiabatic Laps Rate:

After Rain fall Average value is 9.84 Degree foreign

height / 1000m.

M . ASIF