Hydrology to Precipitation PDF

68.7% - glaciers and ice caps LESSON No. 1 30.1% - groundwater INTRODUCTION TO HYDROLOGY 1.2% - rivers and lakes HYDROLOGY...

68.7% - glaciers and ice caps LESSON No. 1 30.1% - groundwater INTRODUCTION TO HYDROLOGY 1.2% - rivers and lakes HYDROLOGY 3. Atmospheric Water - Branch of physical geography focused on studying water. A small fraction exists as water vapor, but it plays a critical - Hydro – water role in weather and climate systems. - Logy – The study of SOURCES OF WATER No water = No Life 1. Atmospheric Water Precipitation EXISTENCE OF WATER 2. Surface Water 1. Formation Lakes, rivers, seas, oceans Water likely existed on Earth from its early formation, around 4.5 billion years ago, primarily through two 3. Subsurface Water mechanisms: Groundwater Outgassing from Volcanic Activity: When the Earth was still forming, volcanic eruptions released gases, including water vapor, from the planet’s interior. As the earth cooled, this water vapor EARTH’S ATMOSPHERE condensed into liquid water, forming oceans. An envelope of gases surrounding the earth and bound to it Delivery by Comets and Asteroids: permanently by gravitational force Some scientists believe that water could also have been delivered by icy comets or water-rich asteroids that collided with Earth during its early history, Composed of clean dry air, water vapor and impurities contributing additional water. These processes combined with Earth’s position in the “habitable zone” of the Sun, allowed liquid water to exist and METEOROLOGY persist essential for life as we know it. - Science of the atmosphere, weather, and climate. 2. States - Meteoros – things in the sky - Logy – the study of Water exists in three states—solid (ice), liquid (water), and gas (vapor)—thanks to Earth's moderate temperatures and atmospheric pressure. COMPOSITION OF THE EARTH’S ATMOSPHERE 3. Reservoirs 1. Constant Components: Water is stored in oceans, glaciers, rivers, lakes, groundwater, and the atmosphere. Proportions remain the same over time and location Nitrogen (N2) 78.08% DISTRIBUTION OF WATER Oxygen (O2) 20.95% 1. Oceans Argon (Ar) 0.93% 97.5% of Earth’s water is saltwater in oceans, making it Neon, Helium, Krypton trace unsuitable for direct human use. 2. Freshwater Only 2.5% is freshwater. 2. Variable Components:  Amounts vary over time and location - deals with the storage, movement/transport and transformation of water in earth Water Vapor (H2O) 0-4% - Water moves continuously through the hydrological cycle, driven by solar energy and gravity. Carbon Dioxide (CO2) 0.039% - Movement of water through the cycle is erratic both in time and over area o Drought Methane (CH4) trace o Torrential rains o El Niño/La Niña episodes Sulfur Dioxide (SO2) trace Ozone (O3) trace 1. El Niño Nitrogen Oxides (NO, trace A climate phenomenon where sea surface NO2, N2O) temperatures in the central and eastern Pacific Ocean become unusually warm. Effects: Alters global weather patterns, often causing WATER VAPOR drought in some regions (e.g., Southeast Asia, Australia) and heavy rainfall/flooding in others (e.g., - Water in its gas form. South America). - Created when water from oceans, rivers, or other sources evaporates (turns from liquid to gas) or when Cause: Weakening or reversal of trade winds that ice sublimates (turns directly from solid to gas). usually push warm water westward in the Pacific. - Changes phase easily because critical pressure and atmosphere are above atmospheric ranges. 2. La Niña - 0-4% by volume The opposite of El Niño, where sea surface - Agent or medium of heat transfer in the atmosphere. temperatures in the central and eastern Pacific Ocean - Polar regions have lesser distribution compared to the are unusually cool. equatorial regions. Effects: Generally, brings more rainfall to places like Southeast Asia and Australia and can cause drier conditions in parts of South America and the U.S. LAYERS OF ATMOSPHERE Cause: Strengthening of trade winds that intensify 1. Exosphere the upwelling of cold water in the Pacific. >120km altitude: The final layer stretches into space and houses satellites - Water is stored in: 2. Thermosphere o Atmosphere - water vapor o Soil - soil moisture 90-120km altitude: This is the hottest layer because it o Surface waters - seas, oceans, streams, absorbs the sun's radiation. Auroras occur in this layer. lakes, wetlands o Plants and animals 3. Mesosphere o Groundwater 50-90km altitude: The coldest layer which protects us from meteors because they burn up in this layer. 7 MAJOR PROCESSES IN HYDROLOGY CYCLE (ETCPRIG) 4. Stratosphere 1. Evaporation 10-50km altitude: The ozone is found in this layer protecting us from UV rays. Water transports from free water surfaces or land surfaces 5. Troposphere to the atmosphere (liquid to gas). 0-10km altitude: The layer in which we live and weather 2. Transpiration occurs. Water transports from plants and animals to the atmosphere. MOVEMENT OF WATER 3. Condensation HYDROLOGIC CYCLE Water is converted from gas to liquid.  4. Precipitation - Usually expressed in terms of temperature, air pressure, humidity, wind, precipitation, and Water transports from the atmosphere to land and/or cloudiness. water surfaces. - Localized (city or region) 5. Run Off Water flows on land surface or subsurface. METEOROLOGY 6. Infiltration - The scientific study of atmospheric phenomena and short-term weather patterns. Water enters soil surface. - Forecasting and understanding weather events such as storms, rain, and temperature changes. 7. Groundwater Flow - Real-time data such as temperature, humidity, wind speed, and pressure. Water flows beneath soil surface and stored in rock formations. CLIMATE Water is transformed: - This is the average condition of the atmosphere over a longer period of time. (Ex: hot and humid) LIQUID TO GAS - evaporation and transpiration. - The climate defines the types of weather you can expect in an area. GAS TO LIQUID - rainfall. - Long-term (takes very long time to change, decades or centuries) (~30 years) GAS TO SOLID - solid forms of precipitation. - Broader area (country or global). SOLID TO LIQUID - snowmelt. CLIMATOLOGY - The scientific study of climate, focusing on long-term atmospheric trends and patterns. - Used for studying climate change, global warming, and regional climate adaptations. - Historical and long-term data, including precipitation patterns, temperature trends, and carbon dioxide levels. PHILIPPINE ATMOSPHERIC, GEOPHYSICAL AND ASTRONOMICAL SERVICES ADMINISTRATION - PAGASA, one of the attached agencies of the Department of Science and Technology (DOST) under its Scientific and Technical Services Institutes - mandated to “provide protection against natural Lesson No. 2 calamities and utilize scientific knowledge as an effective instrument to ensure the safety, well-being WEATHER AND CLIMATE and economic security of all the people, and for the promotion of national progress.” WEATHER FACTORS AFFECTING WEATHER (SECTHRAW) - The condition of the atmosphere at a particular place over a short period of time (Ex: sunny, rainy, windy) 1. Solar Radiation - Short-term (can change within a few minutes or 2. Greenhouse Gases hours). 3. Evaporation 4. Temperature  5. Humidity 6. Rainfall/Precipitation 7. Atmospheric Pressure 8. Wind Pressure 1. Solar Radiation Energy emitted by the sun. Determines weather and climate. Measured using a radiometer. Greenhouse Gases Greenhouse gases are gases that trap/ produce heat in Earth causing global warming. Refers to the fraction of the sky obscured by clouds o Water vapor – most abundant greenhouse gas when observed from a particular location. in the atmosphere. OKTAS is the usual unit of measurement of the cloud o Carbon dioxide – burning of fossil fuels. cover (0-9 OKTAS) o Methane – produced from decaying plant or Cloud cover regulates Earth's temperature by animal matter. reflecting solar radiation (cooling) or trapping heat o Chlorofluorocarbons – used as refrigerant in (warming). refrigerator and air-conditioning units. It remains in the atmosphere for a lifetime over 100 years. o Nitrous oxide – also called as laughing gas, i. Clear Sky: [Symbol 0] nitrous oxide has been used in surgical and Represented by a circle or a blank space on dental procedures for years because of its the weather chart. anesthetic and analgesic properties. There are no clouds present, and the sky is Produced by microbial processes in soil and completely clear. water. ii. Partly Cloudy [Symbol 1, 2, 3] Sky with a mixture of clouds and clear areas. Combination of clear sky and a cloud symbol, indicating that there are some clouds in the sky, but they are not completely covering the sun. iii. Scattered Clothes [Symbol 4, 5] Few cloud symbols with visible clear areas in between. Isolated clouds present but not enough to significantly obscure the sun. 2. Evaporation Amount of water that is returned to air from liquid to gaseous state. It affects humidity levels and contributes to cloud iv. Mostly Cloudy [Symbol 6, 7] formation, influencing precipitation and Sky where a significant portion is covered by temperature. clouds. Measured using an evaporation pan. Layer of cloud symbols i.e., clouds are covering a large portion of the sky, leaving minimal clear areas visible. 3. Cloud Cover/State of the Sky  v. Overcast [Symbol 8] High pressure system usually leads to fair, calm Sky is completely covered with clouds (cloud weather. cover greater than 90%). Common units of measure are: Solid layer of cloud symbols without any o 1 atm visible clear areas. o 1013 millibars A significant absence of sunlight and is often o 101 325 Pa associated with gloomy and rainy conditions. o 760 mm Hg o 760 Torr o 14.7 psi vi. Obscure Sky [Symbol 9] Used in weather charts to represent an obscured sky is a cross line, filled in circle. 8. Wind Something is blocking both the view of the Air in motion. sky and the clouds. Has magnitude and direction. This could be dust, haze (pollution), smoke, Measured using anemometer and wind vane or aero volcanic ash or even heavy rain and snow. vane. 4. Temperature FACTORS AFFECTING CLIMATE OF THE PHILIPPINES A measure of the heat energy in the atmosphere. Terms: MAX, MIN, MEAN, NORMAL 1. Topography and location Measured using a thermometer. Common units are 2. Trade winds degree Celsius, Fahrenheit, Kelvin, Rankine 3. Intertropical Convergence Zone (ITCZ) 4. Easterly waves 5. Monsoon winds 6. Weather fronts Max Temperature: the highest temperature recorded 7. Tropical Cyclones over a specific period (e.g., a day, a month, or a year). Min Temperature: the lowest temperature recorded over a specific period. 1. Philippine Geography and Topography Mean Temperature: the average temperature has varied geographical and topographic features that calculated by adding up all the temperature readings bring a variety of climatic conditions and influence over a specific period and dividing by the number of the type of rainfall. readings. divided in to two seasons (based on rainfall and Normal Temperature: the average temperature for a temperature) specific location over a long period, typically 30 o Rainy Season (June-Nov) years. o Dry Season (Dec-May) ▪ Cool dry season (Dec-Feb) ▪ Hot dry season (Mar-May) 5. Humidity Water vapor content of the atmosphere. Indicates likelihood of precipitation, dew or fog. 2. Trade Winds Amount of humidity in % is measured by Hygrometer Steady winds that blow from east to west near the Earth's equator. These winds are consistent and were historically used by sailors to navigate trade routes, which is how they got their name. 6. Rainfall/Precipitation o Northeast (NE) trade winds Amount of water that is released from the o Southeast (SE) trade winds atmosphere. Measured in mm by using a rain gauge. 3. Intertropical Convergence Zone (ITCZ) A region near the equator where trade winds 7. Atmospheric Pressure converge, causing heavy rainfall and thunderstorms, The force exerted by the weight of the atmosphere. especially during the wet season. Measured using a Barometer. Low pressure systems usually lead to cloudiness, wind and precipitation.  4. Easterly Waves Consists of a spherical glass mounted on a stand. Weather patterns where the wind moves in a wavelike When the sun rays fall on the glass, a strip of prepared shape from east to west, typically in tropical regions. paper held in a grove at the focus length starts Small disturbances that can lead to storms. burning. Easterly waves are more localized. They occur over a smaller area but can still cause significant weather changes, such as heavy rain or storms, especially in tropical regions. 2. Radiometer They are common in places like the Atlantic Ocean Device used for measuring radiant flux of and the western Pacific. electromagnetic radiation. 5. Monsoon Winds 3. Stevenson Screen seasonal winds that change direction. Standard shelter (from rain, snow and high winds, but Two types of Monsoon winds: also leaves and animals) for meteorological o Northeast (NE) monsoon (amihan: cool, instruments, particularly wet and dry bulb dry air) - brings cooler and drier weather. thermometers used to record humidity and air o Southwest (SW) monsoon (habagat: temperature. warm, moist air) – brings heavy rains. WEATHER INSTRUMENTS (TEMPERATURE) 6. Fronts Boundaries between warm and cold air. 1. Minimum and Maximum Thermometer Caused by the collision of warm and cold air masses. Consists of two horizontally placed thermometers. Types of fronts: warm front and cold front. One records the minimum temperature of the day and the other records the maximum temperature of the day. WEATHER INSTRUMENTS (HUMIDITY) 1. Sling Psychrometer instrument is swung freely in the air or is aerated by a fan, the loss of heat required to evaporate water from the wet bulb will cause it to show lower temperature reading 2. Hygrometer this device uses a human or animal hair under tension. 7. Tropical Cyclones Hair is hygroscopic, its length changes with humidity a large vortex of air (usually 25 km) spiraling inwards and the length change may be magnified by a towards the center where the pressure is at a mechanism and indicated on a dial or scale. minimum number of tropical cyclones that enter PAR (based from 1948-2000 data) average -20 per year; minimum -11 per year (1998); maximum -32 per year (1993) WEATHER INSTRUMENTS (ATMOSPHERIC PRESSURE) affect the Philippines from June to December (although the rest of the year is not entirely free from 1. Barometer cyclones) Measures atmospheric pressure. Identifies high- or low-pressure systems for weather forecasting. WEATHER INSTRUMENTS (SOLAR RADIATION) 1. Campbell Stoke Sunshine Recorder 2. Barograph Continuous record of bright sunshine hour is obtained Tracks and records pressure changes over a period of by sunshine recorder; time, giving a visual representation.  - Primary input quantity to the hydrologic cycle. - Begins after water vapor (which has condensed in the WEATHER INSTRUMENTS (WIND) atmosphere) - Becomes too heavy to remain in atmospheric air 1. Aerovane currents and falls. indicates both the wind direction and wind speed or - ¼ of the total precipitation on continental areas – simply the wind velocity. seas by direct runoff and underground. It is shaped like an airplane. The nose of the plane - Rainfall pattern in the Philippines – affected by the points to the direction from which the wind blows and major air streams (movement of the ITCZ) and by the the rotation of the propeller measures the wind speed cyclonic disturbances. - 2,360 mm of rainfall every year (Philippines) o Not evenly distributed over time and space. - Mean annual number of about 175 rainy days 2. Anemometer (Philippines) - A large majority of the stations in the eastern coastal used for the measurement of wind speed. areas have mean annual of rainy days more than the Either three or four metal hemispheres are mounted average for the Philippines while the majority of the on arms which rotate freely about a vertical axis. stations in the western coastal areas have values less than the average. WEATHER INSTRUMENTS (RAINFALL/PRECIPITATION) CONDENSATION PRECIPITATION Deposition of liquid water 1. Rain Gauge droplets and ice particles device used for measuring the amount of rainfall. It is that are formed in the 8 in. in diameter. The process of water atmosphere and grow to a The rainfall collected is being measured with the use changing from a vapor to a sufficient size so that they liquid. of a dipstick with a measurement on it. returned to the Earth’s surface by gravitational setting. 2. Tipping Bucket Recorder and Rain Gauge Water vapor in the air rises rainfall entering the funnel collector is directed to the mostly by convention (warm, humid air rise, while May be solid or liquid. tipping bucket assembly. cooler air will flow When the incremental amount of precipitation has downward) been collected, the buckets assembly tips and activates a magnetic reed switch. The sample is As the warmer air rises, the discharged through the base of the gauge. water vapor will lose energy, causing its temperature to drop. WEATHER INSTRUMENTS (EVAPORATION) The water vapor then has a change of state into liquid. is a device which measures the amount of water evaporated in certain time from a surface. It consists of a round reservoir with a diameter of 47.5 inches and depth of ten inches. The tank is filled with GENERAL PRINCIPLE OF PRECIPITATION FORMATION water up to two and half inches from the top. The decrease by noting the level of water with the help of Warm moist air rises by one of the three lifting a vernier scale. mechanisms convective, cyclonic, or orographic. The moist air is cooled. The relative humidity increases. When dew point temperature is reached, LESSON No. 3 condensation begins. o Dew point – temperature at which air must PRECIPITATION be cooled to reach 100% relative humidity. - Discharge of water out of atmosphere (onto land or water surface) - Used to designate the quantity of water that is HYDROMETEOR precipitated.  Any product of condensation of atmospheric water 7. Hail vapor in the free air at earth’s surface. Precipitation in the form of balls of ice, produced in All precipitation is a type of hydrometeor, but not convective clouds. all hydrometeors are precipitation. HYDROMETEOR IN THE PHILIPPINES FORMS OF PRECIPITATION - Rain 1. Drizzle - Drizzle 2. Rainfall - Fog 3. Glaze - Hail (less common) 4. Rime - Snow (rare) 5. Snow - Dew 6. Sleet - Frost (rare) 7. Hail HOW HYDROMETEOR FORMS 1. Drizzle (Mist) Consists of tiny liquid water droplets, 0.1 to 0.5 m in *Fahrenheit diameter, it falls at a rate of