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Pressure Gradient - defined as the change Wind Channeling - in geographical in atmospheric pressure per unit of features like valleys or canyons, pressure horizontal distance, typically expressed in gradients can cause localized...

Pressure Gradient - defined as the change Wind Channeling - in geographical in atmospheric pressure per unit of features like valleys or canyons, pressure horizontal distance, typically expressed in gradients can cause localized increases in pascals per meter (Pa/m) or millibars per wind speed due to channeling effects. kilometer (hPa/km). Coriolis Effect - arises from the Earth's Horizontal Pressure Gradient - this rotation, causing moving objects (such as component is responsible for wind air masses) to deflect to the right in the generation. It occurs when there is a Northern Hemisphere and to the left in the difference in pressure between two points Southern Hemisphere. This deflection is at the same altitude. not due to any force acting on the object itself but is a result of the object's motion Vertical Pressure Gradient - refers to how relative to the rotating Earth. [Fc pressure changes with altitude. In the =2mvsin(ϕ)] troposphere, pressure decreases with height, typically at a rate of about 1 inch of In the Northern Hemisphere - winds are mercury (approximately 33.86 hPa) per deflected to the right, resulting in 1,000 feet. counterclockwise rotation around low- pressure systems and clockwise rotation Pressure Gradient Force (PGF) - is the around high-pressure systems. force that drives air from areas of high pressure to areas of low pressure. This In the Southern Hemisphere - the force is directly proportional to the opposite occurs, with winds deflected to strength of the pressure gradient—larger the left, leading to clockwise rotation differences in pressure over shorter around low-pressure systems and distances result in stronger winds. counterclockwise around high-pressure systems. Coriolis Effect - due to Earth's rotation, moving air is deflected to the right in the Trade Winds - these winds blow from east Northern Hemisphere and to the left in the to west in tropical regions and are deflected Southern Hemisphere, altering its path by the Coriolis Effect, contributing to major from a straight line to a curved trajectory. climatic zones. Cyclones - in low-pressure systems, Jet Stream - high-altitude winds that are tightly packed isobars indicate strong influenced by temperature differences and pressure gradients that lead to intense the Coriolis Effect help direct storm paths winds and storm systems like hurricanes. and influence weather across large areas. Frontal Systems - the interaction between Ocean Currents - the Coriolis Effect also different air masses creates sharp pressure affects ocean currents, causing them to gradients along fronts, leading to flow in circular patterns known as gyres. significant weather changes such as In the Northern Hemisphere, these precipitation and temperature shifts. currents move clockwise, while in the Southern Hemisphere, they move Ascent (Lift) - this refers to the upward counterclockwise. movement of air. As air rises, it expands and cools, which can lead to cloud Hurricanes - the inward flow of air towards formation and precipitation. Ascent is a low-pressure center results in a spiral typically associated with low-pressure pattern due to deflection caused by Earth's systems, where air converges at the rotation. surface and is forced to rise. Geostrophic winds - representing the Subsidence (Descent) - this describes the balance between the pressure gradient downward movement of air. When air force and the Coriolis effect. The wind that descends, it compresses and warms, often flows parallel to isobars (lines of equal resulting in clear skies and stable weather atmospheric pressure) due to a balance conditions. Subsidence is commonly between two primary forces. associated with high-pressure systems, Direction and Speed: Geostrophic winds where air diverges at the surface and blow parallel to isobars, with lower sinks. pressure located to the left of the wind Thermal Instability - warm air is less direction in the Northern Hemisphere and dense than cooler air, causing it to rise. to the right in the Southern Hemisphere. This process often occurs due to solar The speed of geostrophic winds is heating of the Earth's surface, leading to influenced by the strength of the pressure the development of thermals—columns of gradient; closer isobars indicate stronger rising warm air. Conversely, cold air over winds. warm surfaces can also create instability. Location: Geostrophic winds typically Frontal Lifting - when two different air occur at higher altitudes (above about 1 masses meet (e.g., a warm front meets a kilometer) where frictional forces are cold front), the warmer, less dense air is minimal. They are more pronounced in forced to rise over the cooler, denser air. mid-latitude regions and less effective near This lifting mechanism is crucial for storm the equator due to weaker Coriolis effects. development and precipitation. Idealized Conditions: The geostrophic Orographic Lift - when air encounters wind represents an idealized situation mountains or elevated terrain, it is forced where friction is absent. In reality, surface to ascend. As the air rises, it cools friction affects wind flow, particularly at adiabatically, which can lead to cloud lower altitudes, causing actual winds to formation and precipitation on the deviate from geostrophic winds by blowing windward side of the mountain range. slightly towards low-pressure areas. Convergence and Divergence - in areas Vertical Air Motion - refers to the upward where surface winds converge (such as and downward movements of air parcels in low-pressure systems), air is forced the atmosphere. upward, enhancing vertical motion. Thermal circulation - refers to the Conversely, divergence at higher altitudes movement of air driven primarily creates a void that necessitates upward by temperature differences across motion from below to fill it. the Earth's surface. Stable Atmosphere: In a stable Local Thermal Circulation - these are environment, vertical motion is small-scale circulations that occur due to suppressed. This occurs when warmer air localized heating. overlays cooler air (temperature inversion), Land-Sea Breezes - during the day, land preventing rising air from continuing its heats up faster than water, causing air ascent. Stable conditions are often over the land to rise and creating a low- associated with clear skies and calm pressure area. Cooler air from over the sea weather. moves in to replace it, generating a sea Unstable Atmosphere: An unstable breeze. At night, the process reverses as atmosphere encourages vertical motion. If land cools more quickly than water, an ascending parcel of air remains warmer leading to a land breeze. than its surroundings as it rises (often due Valley and Mountain Breezes: In to heating from below), it will continue to mountainous regions, during the day, rise until it reaches a more stable layer or warm air rises from valleys (valley breeze), loses its buoyancy. Unstable conditions while at night, cooler air descends from are conducive to thunderstorms and mountains (mountain breeze). severe weather. Global Thermal Circulation - this refers Neutral Stability - In this state, vertical to larger-scale patterns that involve motion neither occurs nor is suppressed; significant portions of the Earth’s parcels will remain at their new altitude if atmosphere. displaced. Hadley Cell: This is a prominent feature of Dry Adiabatic Lapse Rate (DALR) - The global thermal circulation located between rate at which dry (unsaturated) air cools as approximately 0° and 30° latitudes. Warm it rises is approximately 3°C per 1,000 feet air rises near the equator due to intense (or about 1°C per 100 meters). solar heating, creating a low-pressure Saturated Adiabatic Lapse Rate (SALR) - area. The rate at which saturated (moist) air Ferrel Cell and Polar Cell: These are cools as it rises is lower than that of dry additional components of the three-cell air, typically around 1.5°C per 1,000 feet. model of atmospheric circulation. The This difference occurs because latent heat Ferrel cell exists between 30° and 60° is released during condensation when latitudes, where air moves poleward aloft water vapor in the rising parcel condenses and returns equatorward at the surface. into liquid water. The Polar cell operates between 60° latitudes and the poles, where cold air Katabatic Winds: These are cold winds sinks at the poles and flows toward lower that flow downhill due to gravitational latitudes. forces acting on dense, cold air that has accumulated at higher elevations. They Local wind systems - are atmospheric can be particularly strong in mountainous phenomena that occur over relatively small regions and can lead to rapid temperature areas, typically influenced by local drops. geographical features, temperature differences, and pressure gradients. Anabatic Winds: Conversely, these warm winds ascend slopes during daytime Sea Breeze: This wind occurs during the heating. As air is heated by contact with day when the land heats up faster than the warm surfaces, it becomes buoyant and sea. The warm air over the land rises, rises along mountain slopes. creating a low-pressure area, while cooler air from over the sea moves in to replace it. Foehn winds - are warm, dry winds that Sea breezes typically develop in coastal descend on the leeward side of mountains areas and can moderate temperatures on after passing over a barrier. As moist air land. rises on the windward side, it cools and loses moisture through precipitation; when Land Breeze: At night, the process it descends on the leeward side, it warms reverses as the land cools more quickly adiabatically, leading to dry conditions. than the sea. The cooler, denser air over the land creates high pressure, causing air Monsoons - are seasonal wind systems to flow from the land to the sea. Land characterized by a significant shift in wind breezes are generally weaker than sea direction associated with changes in breezes and affect smaller areas, usually temperature between land and ocean extending only a few kilometers offshore. surfaces. In summer, moist air from oceans moves onto warmer land masses, Valley Breeze: During the day, sunlight leading to heavy rainfall; in winter, the heats the air in valleys, causing it to rise as pattern reverses. it becomes less dense. This upward movement creates a valley breeze that Wind Speed: The rate at which air moves flows up the slopes of mountains. horizontally past a fixed point. It is typically measured in units such as meters Mountain Breeze: At night, the air along per second (m/s), kilometers per hour mountain slopes cools rapidly due to (km/h), or knots (nautical miles per hour). radiative cooling. The denser cold air then flows down into the valley, creating a Wind Direction: The direction from which mountain breeze. This circulation can lead the wind is blowing, measured relative to to localized weather changes, such as true north. For example, an easterly wind temperature inversions. blows from the east (90 degrees), while a northerly wind blows from the north (0 particles to determine wind speed and degrees). direction over large areas. Gusts: Short-lived peaks in wind speed Lidar (Light Detection and Ranging): that can cause significant damage during Uses laser pulses to measure atmospheric storms. Wind gusts are often defined by properties, including wind profiles at the maximum three-second average wind various altitudes. speed occurring within a specified period. Direct Measurement: Involves using Anemometers - the primary instruments instruments like anemometers and vanes for measuring wind speed. to obtain real-time data on wind speed and direction at specific locations. Cup Anemometers: Consist of three or four cups mounted on a vertical spindle. Indirect Measurement: Involves The rotation speed of the cups is estimating wind speed based on secondary proportional to wind speed. These are parameters such as pressure differentials commonly used at weather stations due to or temperature gradients. their reliability and accuracy. Remote Sensing: Allows for measuring Sonic Anemometers: Utilize ultrasonic wind over large geographic areas without sound waves to measure wind speed and requiring physical instruments on-site, direction without moving parts. They work providing valuable data for meteorological by measuring the time it takes for sound research and operational forecasting. pulses to travel between transducers, Global circulation - refers to the large- allowing for precise measurements even in scale movement of air in the Earth's harsh conditions. atmosphere, driven primarily by the Propeller Anemometers: Combine an uneven heating of the Earth's surface by anemometer with a wind vane, using a solar radiation. propeller to measure wind speed and a Hadley Cell - operates between the vane to determine direction. equator and approximately 30° latitudes in Wind Vanes: Instruments used to both hemispheres. At the equator, intense determine wind direction. A typical vane solar heating causes warm air to rise, consists of a horizontal arm with a vertical creating a low-pressure zone known as the plate that aligns with the wind direction. Intertropical Convergence Zone (ITCZ). As Wind vanes are often paired with this air ascends, it cools and loses anemometers to provide comprehensive moisture, resulting in heavy rainfall typical data on both speed and direction. of tropical rainforests. Doppler Radar: Measures the frequency Ferrel Cell - situated between 30° and 60° shift of radar waves reflected off moving air latitudes, the Ferrel cell is influenced by both the Hadley and Polar cells. In this region, warm air from the tropics moves climate phenomena, including the El Niño- poleward while cold air from polar regions Southern Oscillation (ENSO), seasonal moves equatorward. weather patterns, and long-term climate variability. Polar Cell - exists from about 60° latitudes to the poles. Cold air sinks at the poles, Heat Exchange: The ocean absorbs solar creating high-pressure areas that result in radiation and stores heat, which can be dry conditions. The descending air flows transferred to the atmosphere through toward lower latitudes at the surface as processes such as evaporation and polar easterlies. sensible heat flux. This exchange influences atmospheric temperature and Jet stream - is a narrow band of strong pressure, affecting wind patterns and winds located in the upper levels of the precipitation. atmosphere, typically between 5 to 7 miles (approximately 8 to 12 kilometers) above Wind Stress: Atmospheric winds exert the Earth's surface. These winds stress on the ocean surface, influencing predominantly blow from west to east. ocean currents and mixing. Changes in wind patterns can alter SSTs, which in Polar Jet Stream: Located at mid- turn affect atmospheric circulation. latitudes, this jet stream forms at the boundary between cold polar air and Feedback Loops: Ocean-atmospheric warmer subtropical air. It is strongest coupling often involves positive feedback during winter when temperature gradients mechanisms. For example, an increase in are most pronounced. SST can enhance evaporation, leading to more moisture in the atmosphere, which Subtropical Jet Stream: Found closer to can further warm the air and increase the equator, this jet stream operates at SSTs. higher altitudes and is generally less variable than the polar jet stream. It is El Niño-Southern Oscillation (ENSO): is associated with tropical air masses and a significant climate pattern characterized does not typically interact with surface by periodic fluctuations in SSTs across the weather fronts. central and eastern Pacific Ocean. During El Niño events, warmer SSTs lead to Equatorial Jet Stream: This jet stream altered atmospheric circulation, resulting flows intermittently east to west across in widespread climatic impacts, such as equatorial regions and is strongest during increased rainfall in some regions and summer months. droughts in others. Ocean-atmospheric coupling - is a Conversely, La Niña events are associated fundamental concept in climate dynamics with cooler SSTs and typically bring that describes the interactions between the opposite effects to those of El Niño. ocean and the atmosphere. This coupling is essential for understanding various Monsoons - are heavily influenced by Eyewall: Surrounding the eye, this region ocean-atmospheric coupling. For instance, contains the most intense winds and the Indian monsoon is driven by seasonal heaviest rainfall. It consists of a ring of variations in SSTs over the Indian Ocean, cumulonimbus clouds where which affect wind patterns and thunderstorms are most organized. precipitation over South Asia. Rainbands: These are spiral bands of Tropical Cyclones: The intensity and clouds and precipitation that extend frequency of tropical cyclones are closely outward from the eyewall. They can linked to SSTs. Warmer ocean waters produce heavy rain and strong winds well provide more energy for storm outside the main storm structure. development, while cooler waters can Global climate change - refers to weaken storms. significant and lasting changes in the Hurricane - is a powerful tropical cyclone Earth's climate, particularly those driven characterized by organized thunderstorms by human activities that alter the and sustained winds exceeding 74 miles composition of the atmosphere. per hour (mph) or 64 knots (kts). These Amihan - known as the Northeast storms form over warm ocean waters and Monsoon, typically occurs from October are known for their potential to cause to March. It is characterized by cooler and significant damage through high winds, drier air flowing from the northeast, heavy rainfall, and storm surges. originating from high-pressure systems "Hurricane" - is used in the North Atlantic, over Siberia and northern China. This Caribbean Sea, Gulf of Mexico, and the season brings moderate temperatures, eastern North Pacific Ocean. lower humidity, and generally clear skies. Rainfall during Amihan is minimal, In the Northwest Pacific, they are primarily affecting the eastern parts of the called typhoons, while in the South Pacific Philippines with light drizzles or squalls. and Indian Ocean, they are referred to as tropical cyclones. Habagat, or the Southwest Monsoon, typically spans from May to October. It is Saffir-Simpson Hurricane Wind Scale - characterized by warm, humid air flowing categorizes hurricanes based on their from the southwest, driven by low- maximum sustained wind speeds. pressure systems over Southeast Asia. Eye: The calm center of the hurricane, This season brings heavy rainfall, high typically about 20-40 miles wide, humidity, and often leads to severe characterized by clear skies and light weather events such as typhoons. Habagat winds. The eye forms as air descends and is responsible for significant precipitation warms in the center of the storm. across many regions of the Philippines, particularly in July and August. Tropical weather - refers to the flow eastward toward the Americas. This atmospheric conditions that prevail in shift disrupts normal oceanic and tropical regions, characterized by atmospheric circulation patterns. consistently high temperatures and high La Niña - is characterized by cooler-than- humidity throughout the year. average sea surface temperatures in the Tropical Cyclones - are intense storm central and eastern tropical Pacific Ocean. systems that form over warm ocean waters Like El Niño, it occurs irregularly every few when conditions are favorable for years and can last for several months to a development. They are classified as few years. hurricanes in the Atlantic and typhoons in La Niña - trade winds strengthen, pushing the Northwest Pacific. warm water further west toward Asia and Thunderstorms - common in tropical allowing cold water from the depths of the regions due to high humidity and heat. ocean to upwell along the coasts of the They often occur in clusters or complexes Americas. This process enhances nutrient known as "tropical disturbances" or availability in these regions but also leads "tropical waves," which can develop into to cooler sea surface temperatures. more organized systems. Air mass - defined as a significant volume Intertropical Convergence Zone (ITCZ) - of air, typically extending hundreds or characterized by low pressure where trade thousands of square miles, with relatively winds converge. It plays a vital role in uniform properties of temperature and driving tropical weather patterns by moisture at any given altitude. promoting convection and cloud formation. Continental (c): Air masses that form over Global warming - refers to the long-term land and are typically dry. increase in Earth's average surface Maritime (m): Air masses that form over temperature due to human activities, oceans and are usually moist. particularly the emission of greenhouse gases (GHGs) such as carbon dioxide (CO₂), Tropical (T): Warm air masses originating methane (CH₄), and nitrous oxide (N₂O). from low latitudes. El Niño - refers to the periodic warming of Polar (P): Cold air masses originating from sea surface temperatures in the central higher latitudes. and eastern tropical Pacific Ocean. The Arctic (A): Extremely cold air masses from phenomenon typically occurs every two to polar regions. seven years and can last from nine months to several years. Equatorial (E): Very warm and humid air masses from equatorial regions. El Niño - the trade winds weaken or reverse direction, allowing warm water that mT: Maritime Tropical (warm and moist) typically resides in the western Pacific to cT: Continental Tropical (hot and dry) prolonged cloudy conditions and light precipitation if moisture is present. mP: Maritime Polar (cool and moist) Occluded front - occurs when a cold front cP: Continental Polar (cold and dry) overtakes a warm front. This results in the cA: Continental Arctic (very cold) lifting of warm air off the ground as it becomes trapped between two colder air mA: Maritime Arctic (cool and moist) masses. Occluded fronts can produce Cold front - occurs when a cold air mass complex weather patterns that may pushes into a warm air mass, often leading include both warm front and cold front to thunderstorms. characteristics. Warm front - occurs when warm air rises Weather fronts form when different air over a cold air mass, resulting in gradual masses meet due to prevailing winds. The cloud formation and precipitation. density differences between warm and cold Weather front - is defined as a transition air lead to varying behaviors at the zone between two air masses that have boundary. different properties, such as temperature, As one air mass pushes against another, it humidity, and density. creates lift along the frontal boundary. This Cold front - occurs when a colder air mass lift causes cooling and condensation, advances into a warmer air mass. The cold leading to cloud formation and air is denser and pushes under the warm precipitation. air, causing it to rise rapidly. Cold fronts Tornado - is defined as a narrow, violently are typically associated with cumulus rotating column of air that is in contact cloud formation and can lead to with both the surface of the Earth and a thunderstorms and heavy precipitation. cumulonimbus cloud or, in rare cases, the Warm front - forms when a warmer air base of a cumulus cloud. mass moves into a cooler air mass. The Supercell thunderstorms - which are warm air gradually rises over the denser characterized by a rotating updraft known cold air. Warm fronts are usually as a mesocyclone. These storms can characterized by widespread cloudiness produce severe weather, including large and light to moderate precipitation that hail and damaging winds. can last for extended periods. Landspouts - are another type of non- Stationary front - occurs when neither supercell tornado that forms from weakly the warm nor cold air mass is advancing. organized thunderstorms without The boundary remains relatively fixed over significant rotation aloft. They typically an area. Weather along stationary fronts have narrower funnels and are less can be variable; they may produce intense. Waterspouts are similar to landspouts but occur over water; they can sometimes move inland and become tornadoes. Thunderstorm - is defined as a rain- bearing cloud that produces lightning and thunder. It typically forms in warm, humid, and unstable atmospheric conditions. Lightning: A hallmark of thunderstorms, lightning is caused by the discharge of electrical energy that accumulates within storm clouds. This discharge heats the air rapidly, producing shock waves that we hear as thunder. Thunder: The sound produced by the rapid expansion of heated air due to lightning. Thunder can vary in intensity from a sharp crack to a low rumble depending on the distance and atmospheric conditions. Precipitation: Thunderstorms can produce varying amounts of precipitation, ranging from light rain to heavy downpours. They may also generate hail and strong winds.