Lecture 01 - Earth Climate, AASTMT, Summer 2024 PDF

Arab Academy for Science, Technology, and Maritime Transport (AASTMT) Cairo Campus College of Engineering and Technology UNR1601 Climate Change and Water Management Ch – Earth Climate...

Arab Academy for Science, Technology, and Maritime Transport (AASTMT) Cairo Campus College of Engineering and Technology UNR1601 Climate Change and Water Management Ch – Earth Climate Dr. Hassan Ahmed Construction & Building Department, College of Engineering and Technology, AASTMT, Cairo, Egypt Climate Climate is generally defined as a statistical description in terms of the mean and variability of the atmosphere over a period ranging from months to thousands or millions of years and generally for a specified geographical region. Thus, the mean temperature for the month of May in Cairo is obtained from measurements considered representative for Cairo averaged over the month of May from a record of many years (the classical period is 30 years). 2 Climate The average-state description involves a wide range of variables depending on what is of interest. Temperature and precipitation are the most used; however, the list may include wind, cloudiness and sunshine, pressure, visibility, humidity and elements with noteworthy human impacts such as severe storms, excessively high and low temperatures, fog, snow and hail. 3  Why Study Climate? For several reasons of which: – Determines the type and location of human-managed ecosystems, such as agricultural farmlands. – Affects the weathering of rock, the type of soil that forms, and the rate of soil formation. – Affects people and society – Helps to determine the quantity and quality of water available for human use. – Determines the severity of droughts, storms, and floods. – Largely determines the nature and locations of biomes -major terrestrial ecosystems, defined based on their plant communities. Terrestrial biomes are distinguished primarily by their predominant vegetation and are determined by temperature and rainfall. Differences in temperature or precipitation determine the types of plants that grow in a given area. 4 Weather and Climate Here, it is important to identify the difference between weather and climate. Weather involves the description of the atmospheric condition at a single instant of time for a single occurrence. Climate is an average of weather conditions over a period of time including the probability for distributions from this average. 5  Climate Weather Determined: daily Determined: Over time Measures Looked at by the minutes, Looked at by the years conditions hours, days, week Reported as an average in the Reported as a forecast Depends on the location on Earth atmosphere Climate helps you determine Weather makes up climate the weather 6 Meteorology – the Study of Weather The field of atmospheric science which is most well-known and of practical importance to the public is meteorology, the study of weather. Meteorology is usually concerned only with the lowest region of the atmosphere, the troposphere. The advent of weather-monitoring satellites, and of supercomputers, have greatly facilitated the science and application of meteorology in recent years. 7 Climatology – The Study of Weather Statistics, Patterns, and Trends Climatology, the study of climate, differs from meteorology in that climate is the long-term pattern of temperature, precipitation, wind patterns, etc. at a particular location, over periods of a year or more, while weather is the current (or very near- term) state of affairs at the location or region of interest. For example, the climate in Antarctica is quite different from that in the Sahara http://go3project.com/moodle/file.php/3/climate_monthly_mean_T.gif Desert, or the Amazon river basin. Look for other examples 8 9 Example In Cairo, the hourly temperature in a given day were as presented in the table. Find the daily temperature on this day? Hr Temp (C) Hr Temp (C) 1 19 13 27 2 18 14 26 3 17 15 25 4 16 16 25 5 18 17 24 6 20 18 23 7 21 19 22 8 22 20 21 9 23 21 20 10 24 22 20 11 25 23 19 12 26 24 19 10 Example The following table presents the precipitation gauge records during a given day. Find the daily precipitation on this day? Hr Pr (mm) Hr Pr (mm) 1 0 13 0 2 0 14 1 3 0 15 3 4 0 16 2 5 0 17 5 6 0 18 1 7 1 19 0 8 3 20 0 9 4.2 21 0 10 0 22 1.8 11 0 23 0 12 0 24 0 11  Characteristics of Egypt Climate Climate Type: Arid The monthly variability in rainfall and mean temperature in Egypt for the period 1960–2010. The wettest months are NDJF and the hottest are MJJAS. Spatial variation maximum and minimum temperatures (°C) and annual mean rainfall (mm) over Egypt for 1979–2013 12 How does climate affect Egypt? For example Sandstorm Fog Heatwave Heavy Rainfall 13 Climate System The climate system is defined as the five components which directly interact with the atmosphere, and which jointly determine the climate of the atmosphere. The five components are listed below: 1. Atmosphere (all air) 2. Hydrosphere (all water) 3. Biosphere (all living things) 4. Geosphere (solid portion of the earth) 5. Cryosphere (frozen water part of the earth) 14 Climate System Interaction Air Ice Water Land Life 15 Earth Climate System 16 17 Earth Climate System The Earth's climate system is a compilation of the following components and their interactions- 1. The atmosphere, includes collection of gases. 2. The hydrosphere, including the oceans and all other reservoirs of water in liquid form, which are the main source of moisture for precipitation and which exchange gases, such as CO2, and particles, such as salt, with the atmosphere. 3. The geosphere, which affects the flow of atmosphere and oceans through their morphology (i.e. topography, vegetation cover and roughness), the hydrological cycle (i.e. their ability to store water) and their radiative properties as matter (solids, liquids, and gases) blown by the winds or ejected from earth's interior in volcanic eruptions. 4. The cryosphere, or the ice component of the climate system, whether on land or at the ocean's surface, that plays a special role in the Earth radiation balance and in determining the properties of the deep ocean. 5. The biosphere - all forms of life - that through respiration and other chemical interactions affects the composition and physical properties air and water. The biosphere is that part of Earth's atmosphere, land, oceans that supports any living plant, animal, or organism. It is the place where plants and animals, including humans, live. Large quantities of carbon dioxide are exchanged between the land-based biosphere and the atmosphere as plants take in carbon dioxide and give off oxygen, and animals inhale oxygen and exhale carbon dioxide. 18 Earth’s Natural Climate Cycle Earth rotates once every 23 hours, 56 minutes and 4 seconds. Earth’s rotation is slowing slightly with time Today is 1.7 ms longer than day one century ago 19 Earth’s Natural Climate Cycle Today, the Earth's axis is tilted 23.5 degrees from the plane of its orbit around the sun. The tilt changes between 22.1 and 24.5 degrees over a cycle of about 40,000 years 20 Earth’s Natural Climate Cycle When Winter is in South, Summer is in North and vice-versa. When Spring in South, Autumn in North As the tilt changes the season shifts 21  Earth’s Natural Climate Cycle The shape of the Earth's orbit varies between nearly circular (lowest eccentricity of 0.000055) and mildly elliptical (highest eccentricity of 0.0679). These variations occurs with a period of 413,000 years. This caused Ice Ages. 22 Global Energy Flows (W/m2) 23 Earth’s Natural Climate Cycle Ocean Circulation has a Large effect on Climate The oceans play a large part in determining the existing climate of the Earth. It seems to have a crucial influence on climate change due to human activities. Ocean and atmosphere are close interactions and have a strong system. Oceans have a high capacity to contain heat compared with the atmosphere driving to gradually raise temperature in the oceans. Oceans redistribute heat throughout the climate system through their internal circulation. 24 Earth’s Natural Climate Cycle Snow and Ice The presence or absence of Changes in snow and ice snow and ice affects cover affect freshwater warming and cooling over availability, air the Earth’s surface, temperatures, sea levels, influencing the Earth’s ocean currents, and storm energy balance. patterns. A reduction in snow cover and ice causes the Earth’s surface to absorb more energy from the sun (decreased albedo), which is a positive feedback, causing stronger warming 25  Earth’s Natural Climate Cycle Since 1976, a series of satellite instruments have measured the energy output of the sun directly. The satellite data show a very slight drop in solar irradiance (which is a measure of the amount of energy the sun gives off) over this time period. 26  Climate Variability Climate variability refers to variations in the mean state and other statistics (such as the occurrence of extremes, etc.) of the climate on all temporal and spatial scales beyond that of individual weather events. Variability may be due to natural internal processes within the climate system (internal variability), or to variations in natural or anthropogenic external forcing (external variability). 27 Thank You ! 28