HYDROLOGY (GROUP 1)

BASED ON QUIZ 1

Frontal and Non-Frontal

Two types of cyclonic precipitation.

Point Rainfall Measurement

It refers to the collection of precipitation data at a specific location over a defined period.

Convective Precipitation

A type of precipitation that is driven by the sun's heating of the ground, causing air to rise.

Orographic Precipitation

A type of precipitation that is driven by air being forced to rise over physical barriers like mountains.

mm & inches

What are the units used in measuring rainfall?

Rain Gauges

What is the instrument used to measure point rainfall?

Non-recording Rain Gauges

Are simpler instruments designed to measure the total amount of rainfall over a specific period. Unlike recording gauges, they do not provide continuous or time-stamped data.

Recording Rain Gauge

Are advanced instruments designed to measure and automatically record rainfall over time. These devices provide continuous data, making them indispensable for detailed analysis and research.

Hurricane or Cyclone

Other term for typhoon?

Shape

As the droplet increases, air resistance causes deformation. What rainfall characteristic is being described?

Depth

____ is the volume of rain over an area (mm).

Frequency

It is the average recurrence interval of storms having the same duration and volume (depth).

Seasonal Distribution

It refers to the time of year when various rainfall amounts occur.

Supercooled water

It is the state of liquid that is called below its freezing point without turning into ice?

Updraft

It's known as the upward movement gas?

• Evaporation

• Condensation

• Precipitation

What are the three (3) Hydrological Cycle?

Bergeron Process

It is the process where the water freezes as the ice crystals collides with super-cooled water

Collision - Coalescence Process

This method is suited to clouds whose base does not exceed the freezing point.

1. Rain

2. Drizzle

3. Snow

4. Hail

5. Snow Pallets

6. Sleet

Give the Six (6) forms of Precipitation

Cyclonic Precipitation

It is caused by the rising or lifting of air as it converges on an area of low pressure.

Hurricanes and Typhoons

Develop over tropical oceans that have a surface water temperature greater than 29 degree Celsius.

0.1 mm to 6 mm

Rainfall droplets vary in diameter, typically between _______

Duration

Time at which rain occurs (hr)

Intensity

Amount of rain in a certain time (mm/hr)

Hyetograph

is a graphical representation of the relationship between the rainfall intensity and time, typically used to assess stormwater runoff, design drainage system, and manage flood risk.

• Observer Error

• Clogging

• Cold Weather Issues

• Automated Gauge Issues

Several factors that can affect the accuracy of rainfall measurement.

1. Tipping Bucket Rain Gauge

2. Weighing Rain Gauge

3. Optical Rain Gauge

4. Ultrasonic Rain Gauge

5. Acoustic Rain Gauge

Types of Recording Rain Gauges

1. Standard Rain Gauge

2. Floating Rain Gauge

3. Stevenson-Type Rain Gauge

Types of Non-recording Rain Gauges

Tipping Bucket Rain Gauge

• is an automated device designed for continuous rainfall monitoring. It features a funnel that directs rain into a small, pivoting bucket.

• commonly employed in automated weather stations and urban drainage systems

Weighing Rain Gauge

• operates by measuring the weight of precipitation collected in a container.

• This highly accurate instrument is frequently used in research stations and for meteorological studies requiring detailed data.

Optical Rain Gauge

• employs advanced technology, using laser or infrared beams to detect raindrops as they pass through the sensor.

• Their ability to provide detailed information about rainfall intensity and droplet size makes them ideal for studying localized rain events, such as microbursts, which are critical for aviation safety.

Ultrasonic Rain Gauge

use sound waves to measure the size, speed, and intensity of raindrops as they pass through a designated detection area.

Acoustic Rain Gauge

detects rainfall by measuring the sound generated when raindrops hit a specific surface.

Standard Rain Gauge

is a simple yet effective device consisting of a cylindrical container with a funnel that directs rain into a graduated measuring tube.

Floating Rain Gauge

• is designed to collect rain in a container with a floating mechanism that rises as the water level increases. The height of the float is then used to calculate the amount of rainfall.

• This gauge is typically robust, designed to withstand harsh outdoor conditions.

Stevenson-Type Rain Gauge

incorporates protective housing around the collection container to minimize evaporation and reduce the effects of wind.