Precipitation and Hydrologic Cycle Quiz

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Questions and Answers

Which type of precipitation consists of droplets larger than 0.5 mm?

Rain (correct)

Drizzle

Mist

Snow

What is the classification of light rain based on intensity?

Between 1 - 2.5 mm h−1

Smaller than 2.5 mm h−1 (correct)

Greater than 7.5 mm h−1

Less than 1 mm h−1

Which of the following is NOT a form of precipitation mentioned?

Drizzle

Snow

Rain

Hail (correct)

Snow is primarily formed from what type of atmospheric process?

Direct reverse sublimation of water vapor Signup and view all the answers

What is the maximum intensity for rain to be classified as moderate?

7.5 mm h−1 Signup and view all the answers

What size range defines drizzle droplets?

Between 0.1 mm and 0.5 mm Signup and view all the answers

Which process is NOT typically associated with the hydrologic cycle?

Combustion Signup and view all the answers

The formation of precipitation is primarily dependent on which of the following phenomena?

Water vapor in the atmosphere Signup and view all the answers

What process describes the formation of hoar frost?

Condensation of water vapor directly into ice crystals Signup and view all the answers

Which type of precipitation is characterized by local whirling thunderstorms?

Thermal convection precipitation Signup and view all the answers

What occurs during the formation of frontal precipitation?

Two air masses of differing temperatures and densities collide Signup and view all the answers

In which scenario would you find a stationary front?

Two air masses move parallel near each other without changing position Signup and view all the answers

What is the primary cause of occlusion in weather patterns?

Cold fronts moving faster than warm fronts Signup and view all the answers

What indicates that a cold front is approaching?

Intense precipitation in a localized area Signup and view all the answers

Which of the following correctly describes dew formation?

Results from the direct condensation of water vapor Signup and view all the answers

Which statement accurately reflects the formation of a warm front?

Warm air replaces a retreating cold air mass gradually Signup and view all the answers

What is the purpose of using a Moving Average in time series analysis?

To smooth out high fluctuations and identify trends Signup and view all the answers

What does the variable 'm' represent in the context of Moving Averages?

The number of years to average the data Signup and view all the answers

Which of the following is NOT true regarding the selection of 'm'?

It is usually an even number Signup and view all the answers

In Central Simple Moving Averages, where is the calculated average placed?

In the middle year of the m-year range Signup and view all the answers

If the annual rainfall in a certain year is less than 20% of the mean, what conclusion can be drawn?

The year experienced a drought or low rainfall Signup and view all the answers

Which calculation would you perform to find the mean of the annual rainfall?

Total Rainfall / Number of Years Signup and view all the answers

What does the term $f_p$ represent in Horton's Equation?

Infiltration capacity at any time $t$ Signup and view all the answers

What effect does increasing the size of 'm' have on the Moving Average?

It greater smooths the data Signup and view all the answers

What is an example of a time series data point from the provided rainfall data?

The rainfall of 462 mm in 1953 Signup and view all the answers

In Philip's Equation, what is the significance of the term $s$?

A measure of soil suction potential Signup and view all the answers

According to Green-Ampt Equation, what does the term $K$ represent?

Darcy's hydraulic conductivity Signup and view all the answers

What type of diagram can be used to represent annual rainfall over time?

Bar Diagram Signup and view all the answers

Why is Central Simple Moving Average considered central?

It centers the mean in the selected range Signup and view all the answers

In Horton's Equation, the decay coefficient $K_h$ depends on which factors?

Soil characteristics and vegetation cover Signup and view all the answers

What assumption is made regarding water availability during computations of infiltration rates?

Water ponds only if it exceeds soil saturation Signup and view all the answers

What does the term $ riangle heta$ represent in the Green-Ampt Equation?

Difference between initial and final moisture contents Signup and view all the answers

What is indicated by the term $F_p$ in Philip's Equation?

Rate of infiltration with time Signup and view all the answers

In the context of Horton’s Equation, what does the term $f_0$ signify?

Initial infiltration capacity at $t = 0$ Signup and view all the answers

Which of the following best describes the condition for ponding of water on soil surface?

Ponding occurs when infiltration capacity is less than rainfall intensity Signup and view all the answers

In the Green-Ampt equation, $ heta_e$ refers to what?

Initial effective saturation of the soil Signup and view all the answers

What occurs at the ponding time, tp?

The soil becomes fully saturated. Signup and view all the answers

Which of the following principles is NOT involved in determining the ponding time?

Cumulative infiltration is constant over time. Signup and view all the answers

How is the infiltration rate (fp) related to cumulative infiltration (Fp) at ponding time?

fp equals rainfall intensity (i) at tp. Signup and view all the answers

What is the first condition involved in the Green-Ampt equation regarding ponding?

Ponding does not occur initially. Signup and view all the answers

In the Green-Ampt equation, how does the hydraulic conductivity (K) affect the infiltration rate?

Higher K leads to higher infiltration rates. Signup and view all the answers

What happens to the vertical moisture profile just before ponding begins?

The soil surface remains unsaturated. Signup and view all the answers

What influence does the difference in moisture content (∆𝜃) have in the infiltration equation?

It adjusts the relationship between fp and Fp. Signup and view all the answers

What is the main effect of exceeding rainfall intensity over the potential infiltration rate?

It initiates ponding on the soil surface. Signup and view all the answers

What is the formula used to calculate the ponding time under constant rainfall intensity?

$t_p = \frac{K S_c \Delta \theta}{i(i - K)}$ Signup and view all the answers

What was the calculated ponding time for rainfall intensity of 1 cm/h?

10.5 hr Signup and view all the answers

For the given silt loam soil, what is the value of $, \Delta \theta S_c$ used in the calculations?

5.68 cm Signup and view all the answers

How does the infiltration rate at ponding compare to the rainfall intensity?

It is equal to the rainfall intensity. Signup and view all the answers

What was the depth of water infiltrated at ponding for a rainfall intensity of 5 cm/h?

0.85 cm Signup and view all the answers

Which equation is not mentioned for fitting infiltration models to data?

Darcy's Law Signup and view all the answers

In the context of infiltration testing, what does the cumulative infiltration depth represent?

The total amount of water that has infiltrated over time. Signup and view all the answers

What characteristic does a line graph represented by ln$(f_p - f_c)$ indicate in the Horton's equation?

The decay of infiltration capacity over time. Signup and view all the answers

Study Notes

Preface

This module aims to provide a detailed presentation of hydrology theory and application.
The hydrologic cycle and processes, including precipitation, evaporation, infiltration, overland flow, groundwater flow, and surface runoff generation, are covered.
The work was influenced by peer reviews and faculty feedback to ensure module quality for local government units (LGUs).

Unit 3: Precipitation

3.1 Introduction

Precipitation encompasses all forms of water reaching Earth from the atmosphere.
This chapter introduces important aspects of rainfall data collection and analysis.

3.2 Topics

3.2.1 Formation of Precipitation

Precipitation forms in various forms, including:
- Drizzle: Very light, uniform precipitation, composed of numerous small droplets (diameter > 0.1 mm, < 0.5 mm).
- Rain: Precipitation consisting of water drops larger than 0.5 mm. Classified as light (intensity < 2.5 mm/hr), moderate (2.5-7.5 mm/hr), or heavy (> 7.5 mm/hr).
- Snow: Precipitation in the form of branched hexagonal or star-like ice crystals. Agglomerates into snowflakes at freezing temperatures, with a specific gravity around 0.1.
- Sleet: Precipitation made of transparent pellets or grains of ice, formed from raindrops passing through colder air.
- Glaze/Freezing rain: Ice deposited on cold surfaces by drizzle or rain.
- Snow pellets (or graupel): White, opaque grains (diameter 0.5-5 mm).
- Small hail: White, semi-transparent or translucent grains (diameter 2-5 mm). Usually accompanied by rain when above freezing temperatures.
- Soft hail: Round, opaque grains similar to small hail but disintegrates easily.
Hail: Balls or irregular ice chunks (5-50 mm, or larger). Formed through alternating rising and falling movements during violent, prolonged convective storms.

3.2.3 Rainfall Characteristics

Rainfall depth: Total height of rainfall (mm) in a given area.
Rainfall duration: Length of time rainfall occurs.
Rainfall intensity: Ratio of total rainfall depth to duration (mm/hr).
Hyetograph: Graphical representation of rainfall intensity over time.

3.2.4 Point-Rainfall Measurement

Point rainfall: Rainfall data collected at a specific location.
Data frequency: Can be daily, weekly, monthly, seasonal, or annual.
Graphical representation: Bar diagrams are used to plot magnitude versus time.
Moving average: A smoothing technique to identify trends in the rainfall data. A moving average creates a consistent trendline that smooths out erratic data points.

Unit 4: Infiltration

4.1 Introduction

Infiltration is the process of water entering the soil surface.

4.2 Topics

4.2.1 Definition of Infiltration

Infiltration is the flow of water into the ground through the soil surface.
Soil moisture distribution is shown during infiltration.

4.2.2 Factors Affecting Infiltration

Slope: Steeper slopes lead to increased surface runoff and reduced infiltration.
Degree of saturation: Saturated soil restricts infiltration.
Porosity: The void space in soil influences infiltration.
Permeability: The rate at which water moves through soil.
Packing: Loose soil allows more infiltration.
Sorting: Uniform particle size promotes better infiltration.
Shape: Rounded particles allow more easy infiltration.
Capillarity: Water's upward movement in the soil.
Vegetation: Roots increase infiltration and reduce soil erosion.
Land use: Impacts infiltration due to changes in soil structure.

4.2.2 Infiltration Measurements

Single ring infiltrometer: A metal cylinder used to measure infiltration in one direction.
Double ring infiltrometer: Used to measure infiltration in one direction and measure from the annular space between the two rings.
Observation in pits and ponds: A method that notes depth changes.
Catch basins: Called lysometers. Infiltrating water can be measured and the infiltration rate can be obtained.
Artificial rain simulators: Uniform rate water application.
Hydrograph Analysis: Runoff from a storm is measured for infiltration estimation.

3. 3 Assessment

Focuses on rainfall recording practices, different precipitation types, rain gauge types, estimating missing rainfall data, and rainfall characteristics, with specific questions.
Includes problem-solving exercises and data analysis techniques.

3. 4 References

This section lists the sources used in creating the study material
Includes links to relevant resources

Studying That Suits You

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Description

Test your knowledge on precipitation types and the hydrologic cycle with this engaging quiz. From differentiating between drizzle and rain to understanding snow formation, each question challenges your understanding of atmospheric processes. Perfect for students studying meteorology or environmental science.