Hydrology, Climate Change, Meteorology, and Precipitation Flashcards

Vocabulary flashcards generated from the Hydrology lecture transcript covering watershed mechanics, climate change, meteorology, precipitation analysis, and statistical hydrology.

Hydrology

The science dealing with the occurrence, distribution, and disposal of water on the planet Earth, focusing on natural processes across various phases of the hydrologic cycle.

Hydraulics

The branch of engineering that applies fluid mechanics principles to man-made processes dealing with the collection, storage, control, transport, regulation, measurement, and use of water.

Catchment Area (Watershed / Drainage Basin)

A well-defined area of land that intercepts rainfall and transports it to a common stream or outlet.

Swale

A topographic feature characterized by bent contour lines that point uphill.

Ridge

A topographic feature characterized by bent contour lines that point downhill.

Saddle

A topographic transition point located between two ridges and two swales.

Napindan Hydraulic Control Structure (NHCS)

A hydraulic structure constructed to regulate the flow exchanges between the Pasig River and Napindan Channel to manage water storage in Laguna de Bay.

Rosario Weir and Manggahan Floodway

Engineered flood control structures that divert excess floodwaters from the Marikina River to Laguna de Bay to mitigate downstream flooding in Metro Manila.

Weather

Atmospheric conditions that occur locally over short periods of time, ranging from minutes to hours or days.

Climate

The long-term regional or global average of temperature, humidity, and rainfall patterns observed over seasons, years, or decades.

Ozone Layer

A thin layer in the stratosphere composed of ozone ($O_3$) molecules that absorbs almost all of the Sun's harmful ultraviolet light.

Ozone Depletion

The thinning of the stratospheric ozone layer primarily caused by chlorofluorocarbons (CFCs).

El Niño Phenomenon

A climate pattern caused by the warming of sea surface temperatures in the Pacific ocean, characterized by weakened trade winds and resulting in dry spells, droughts, and stronger typhoons in the Philippines.

La Niña Phenomenon

A climate pattern characterized by unusually cold ocean temperatures in the Equatorial Pacific and strong trade winds, bringing increased rainfall and tropical storms.

Global Warming

The long-term heating of Earth's climate system observed since the pre-industrial period (1850–1900) due to human activities, measured as the average increase in Earth's global surface temperature.

Climate Change Mitigation

Actions aimed at reducing climate change by decreasing the flow of heat-trapping greenhouse gases into the atmosphere or enhancing carbon sinks.

Climate Change Adaptation

Adjusting life and infrastructure to actual or expected future climate changes to reduce vulnerability to harmful effects.

Solar Radiation

Electromagnetic radiation emitted by the Sun, primarily in short wavelengths ranging from $0.1$\,\mu m to $4.0$\,\mu m.

Solar Constant

The rate at which solar radiation reaches the upper limits of Earth's atmosphere on a surface normal to incident radiation at Earth's mean distance from the Sun, commonly valued at $1,374\,W/m^2$.

Albedo

The percentage of incoming solar radiation reflected directly from a surface.

Aphelion

The point in Earth's orbit when it is farthest from the Sun, occurring around July 4.

Perihelion

The point in Earth's orbit when it is closest to the Sun, occurring around January 3.

Solstice

The time when the Sun's apparent path is displaced farthest north (Tropic of Cancer) or south (Tropic of Capricorn) from Earth's equator.

Equinox

The time when the Sun passes directly over the equator, causing day and night to be of equal length globally.

Relative Humidity

The ratio of the amount of water vapor present in the air to the maximum amount of water vapor the air can hold at a given temperature.

Coriolis Effect

The deflection of moving air masses caused by Earth's rotation from west to east, producing easterly airflow toward the equator and westerly airflow toward the poles.

Front

A transition zone or boundary at Earth's surface between two different air masses of varying temperature and humidity characteristics.

Habagat (Southwest Monsoon)

The hot and moist summer monsoon wind from the Indian Ocean affecting the Philippines from May to September, bringing rain over the western seaboard.

Amihan (Northeast Monsoon)

The dry and cold winter monsoon wind from Siberia affecting the Philippines from October to March, bringing rain over the eastern seaboard.

Intertropical Convergence Zone (ITCZ)

A low-pressure belt circling Earth near the equator where trade winds from the Northern and Southern Hemispheres converge, generating vigorous thunderstorm activity.

Tropical Cyclone

An intense low-pressure weather system with maximum sustained winds of at least $30\,kph$ rotating inwardly around a central eye.

Precipitation

Any form of atmospheric moisture that condenses and falls to the Earth's surface.

Cloud Seeding

An artificial weather modification process that introduces nucleating agents, such as silver iodide, into clouds to induce precipitation.

Convective Precipitation

Precipitation caused by air being drawn upward by warm surface heating and convective action, typically forming thunderstorm cells.

Orographic Precipitation

Precipitation that occurs when a moist air mass is forced to rise over a topographic barrier, such as a mountain range.

Arithmetic Average Method

A method for estimating average rainfall over a watershed by taking the simple mean of rainfall depths recorded at uniformly distributed gauges.

Thiessen Polygon Method

A technique for determining weighted areal average rainfall by constructing perpendicular bisectors between adjacent gauges to form representative polygon areas.

Isohyetal Method

A method for calculating average rainfall over an area using lines of equal precipitation depth (isohyets) and multiplying intermediate enclosed areas by average boundary values.

Station-Average Method

A method used to estimate missing rainfall data when the annual catch of all index gauges differs by less than $10\%$ from the gauge of interest.

Normal-Ratio Method

A method used to estimate missing rainfall data when the annual catch of at least one index gauge differs by more than $10\%$ from the gauge of interest, weighting individual records by normal annual catches.

Double-Mass-Curve Analysis

A graphical method used to detect and adjust inconsistencies in a rain gauge record caused by relocations or changes in exposure by plotting cumulative catch against cumulative index averages.

Hyetograph

A plot or graph showing rainfall intensity or depth as a function of time.

Recurrence Interval (Return Period, T)

The average number of years within which a storm or flood event of a given magnitude is expected to be equaled or exceeded once.

Deterministic Process

A hydrologic process governed by definite physical laws where the output is strictly predictable for a given input without chance elements.

Probabilistic Process

A hydrologic process governed by chance phenomena independent of time-series order.

Stochastic Process

A hydrologic process governed by chance phenomena where the chronological sequence of occurrence (time-series dependence) is included in analysis.

Annual Series

A hydrologic data series selecting only the single maximum event recorded in each calendar year.

Partial Duration Series

A hydrologic data series consisting of all independent events that exceed a specified threshold magnitude, regardless of when they occur.