Tropical Design PDF

Step 1 of 4 1.1 Tropical Design and other concepts 4 out of 4 steps passed TROPICAL DESIGN Tropical Design is more about science than art. It is wrongly used to refer to design styles beginning 1800s which focused on 'comfort, relaxation, and resort-like luxury.'1 Tropical design is site-speci...

Step 1 of 4 1.1 Tropical Design and other concepts 4 out of 4 steps passed TROPICAL DESIGN Tropical Design is more about science than art. It is wrongly used to refer to design styles beginning 1800s which focused on 'comfort, relaxation, and resort-like luxury.'1 Tropical design is site-specific therefore, culture-specific and would find most appropriate translation in traditional architecture. In the tropics, traditional housing is rural housing, a design paradox when compared to the variety of materials and technology available in urban areas. But if we regard traditional houses to be responsive to the dictates of nature and the needs of the users then tropical design would be thus. It is the design appropriateness of the 'bahay kubo' which should find wide application in urban settings. Understanding the topics and how to apply nature science in any building, especially in urban areas is the whole content of this course.  Some designers were more explicit in their definition of tropical design as 'passive-cooling tropical' architecture which is a give-away of what design solutions are required for climatic problems. Technically we define tropical design as: The strategic arrangement of elements in buildings and structures to respond to specific conditions of climate prevalent in the tropic region. HELIOTHERMIC PLANNING can be considered the umbrella under which tropical design belongs, which is defined as Site planning that accounts for natural solar heating and cooling processes and their relationship to building shape, orientation, and siting. Although heliothermic planning is not region specific, the science applied in architectural design is the same as in tropical design. Tropical design is not: Green building -- defined as "the practice of (1) increasing the efficiency with which buildings and their sites use energy, water, and materials; (2) reducing building impacts on human health and the environment, through better siting, design, and construction, operation, maintenance, and removal -- the complete building life cycle."2 As a practice, it deals with creating structures and using processes that are environmentally responsible and resource-efficient throughout a building's life cycle.3 Green architecture -- building and structure design philosophy that aims at minimal use of non-renewable and/or polluting materials and resources in the construction and use of a facility. Sustainable architecture -- seeks to minimize the negative environmental impact of buildings by efficiency and moderation in the materials, energy and development space, and the ecosystem at large. Reference: 1. TROPICAL Interiors: What Is It and How to Do it at Home | CUBICOON (https://cubicoon.com/2022/04/15/tropical-interiors-what-is-it-and-how-to-do-it-at- home/#:~:text=A%20design%20style%20that%20takes%20its%20cue%20from,with%20exotic%20decor%2C% 20tropical%20plants%2C%20and%20tropical%20motifs.) 2. Office of Federal Environmental Executive 3. USA-Environmental Protection Agency Instructor disabled comments for this lesson. 10/14/24, 11:33 AM Step 2 – Tropical Design and other concepts – Stepik 1.1 Tropical Design and other concepts 4 out of 4 steps passed Why practice tropical design? 1. Because we cannot set aside nature as the major consideration in architectural design. When we design with nature, we minimize the negative impact our buildings have on the environment. And we are impacted less by the effects of the natural forces on our buildings. 2. Because the issue of climate change should be mainstreamed in all curricula. 3. Because architecture is 'lithic' evidence of how people lived in a particular era, the application of climate science and ethics should be subsumed in all architectural design solutions. https://stepik.org/lesson/773408/step/2?unit=775878 1/2 10/14/24, 11:33 AM Step 2 – Tropical Design and other concepts – Stepik https://stepik.org/lesson/773408/step/2?unit=775878 2/2 10/14/24, 11:39 AM Step 3 – Tropical Design and other concepts – Stepik.1 Tropical Design and other concepts 4 out of 4 steps passed HEATING PASSIVE COOLING Building design and layout AIR MOVEMENT LOW ENERGY BUILDINGS - Space heating or cooling requirement Construction cost Design and operation cost https://stepik.org/lesson/773408/step/3?unit=775878 1/3 10/14/24, 11:39 AM Step 3 – Tropical Design and other concepts – Stepik DESIGN AND OPERATION Temperate Tropical Passive heating Passive cooling Energy storage Energy storage Insulation Insulation Air tightness Openness Space heating Ventilation Lighting Lighting = daylighting ENERGY AND COMFORT https://stepik.org/lesson/773408/step/3?unit=775878 2/3 10/14/24, 11:39 AM Step 3 – Tropical Design and other concepts – Stepik REFERENCES de Dear, R.J. and Schiller-Brager, G. 1998: Developing an adaptive model of thermal comfort and preference, ASHRAE Trans, V.104(1) Fanger, P. O. 1970: Thermal Comfort: Danish Technical Press Humphreys, M. A. 1976: Field studies of thermal comfort compared and applied: Building Services Engineer 44 Humphreys, M. A. 1978: Outdoor temperatures and comfort indoors: Building Research and Practice Vol. 6 (2) https://stepik.org/lesson/773408/step/3?unit=775878 3/3 10/14/24, 11:39 AM Step 1 – Atmospheric Circulation – Stepik 2.1 Atmospheric Circulation 1 out of 1 step passed ATMOSPHERIC SCIENCES A combination of physics+chemistry that focuses on the structure and dynamics of Earth's atmosphere. It is divided into 3 areas: a) Meteorology - the study and forecasting of weather; hourly and daily changes in weather within the lower stratosphere and troposphere. b) Climatology - the study of long-term atmospheric patterns and their influences. Climatology attempts to describe the interaction of the atmosphere with the bodies of water, land, and glaciers. c) Aeronomy - the study of the physics and chemistry of the upper atmosphere, from the stratosphere outward. Focused on the propagatio of electromagnetic communications, such as shortwave radio transmissions. ATMOSPHERIC CIRCULATION Air flows from hot to cold. Air moves from high pressure to low pressure. Air expands when heated, and gets compressed when cooled. Air has mass. The general circulation of the atmosphere of the pattern of planetary winds depends on the latitudes, pressure belts and their migration, distribution of continents and oceans, and the earth's rotation. The Earth's 23.5-degree tilt provided surplus solar energy about the equator and a deficit at the poles. The atmosphere resolves this through the general troposphere circulation that transfers energy from the equator to the poles. https://stepik.org/lesson/779362/step/1?unit=781878 1/7 10/14/24, 11:39 AM Step 1 – Atmospheric Circulation – Stepik https://stepik.org/lesson/779362/step/1?unit=781878 2/7 10/14/24, 11:39 AM Step 1 – Atmospheric Circulation – Stepik adiabatic lapse rate = easterly = coming from the east = westward = going west 1. HADLEY CIRCULATION, also known as the Hadley cell (after George Hadley, 1735), is a global tropical atmospheric circulation pattern transporting energy from the tropics to the subtropics as a response to intense solar heating about the equator. It is the area where the northeast an southeast trade winds meet (intertropical convergence zone or ITCZ) near the earth's surface and their rise on the convective cell. Because the equator receives more heat energy, the air turns warm and moist (warm air has more moisture than cold air). Warm air rises at 10-15 kilometers altitude and flows eastward toward 30 degrees north and south, where it cools and collides with a colder air mass from the poles going down, and then flows back toward the equator. In short, the Hadley cell is an atmospheric heat transport. 0deg = equator = doldrums 30deg N&S = horse latitudes Hadley cell is responsible for the formation of desert lands. Watch the video to learn more: Where are deserts formed and why? - The Hadley cell, rain shadows and continental interiors - YouTube 2. FERREL CIRCULATION, aka Ferrel cell (after William Ferrel, 1856). It is the mid-latitude winds that are opposite to that of the Hadley cell. Air flows eastward toward the poles near the surface as part of the sinking air mass at 30 degrees latitude. The air travels towards 60 degrees north/southwards where they meet cold air from the poles. The air masses from 30 degrees (warm) and 60 degrees (cold) latitudes rise when they meet causing low pressure at the surface and mid-latitude depressions (wet and windy weather). https://stepik.org/lesson/779362/step/1?unit=781878 3/7 10/14/24, 11:39 AM Step 1 – Atmospheric Circulation – Stepik 3. POLAR CIRCULATION (aka Polar cell) is a transient weather system residual. Cold, dense air sinks at the poles forming the polar highs (high-pressure) with the south polar high as the stronger high-pressure area due to the Antarctic land mass. Surface winds in the polar cell move westward to the mid-latitudes and diverge outward from the polar highs. The horizontal distribution of pressure is drawn as isobars (lines connecting places with equal pressure taken at sea level). Closely spaced isobars indicate a strong pressure difference but which is not permanent because of the movement of the sun. Pressure difference moves air and the horizontal movement of air is called wind. To learn more about high-pressure to low-pressure air movement, watch this: https://www.youtube.com/watch?time_continue=223&v=zBU23ZM6EO8&feature=emb_logo Westward winds from the poles are dry and cold coming from the polar highs. Winds move to low-pressure areas in the mid-latitudes but cold ai and warm air do not mix because of density variance and the boundary separating them is called a front. The cold front causes dramatic weather https://stepik.org/lesson/779362/step/1?unit=781878 4/7 10/14/24, 11:39 AM Step 1 – Atmospheric Circulation – Stepik changes and they move fast. This is because the cold front stays under the warm front, lifting it up. If the warm air is moist, water vapor begins to condense and clouds will form. The cold front has the most hazardous weather conditions because precipitation is always present and wind gustiness is more than 90kph. 4. WALKER CIRCULATION, aka Walker cell (after Gilbert Walker, 1904), is the conceptual model for the longitudinal (east-west) circulation across the equatorial Pacific which is also affected by the temperature and pressure gradients. High-pressure areas (eastern Pacific) are over cooler pacific waters and low pressure on the warmer pacific (western Pacific). Near-surface equatorial winds cross the Pacific east to west as par of the trade winds, pushing the warm surface water to the west. Warm air over the west Pacific rises to make clouds, and precipitate creating drier a then completes the loop by going back towards the eastern Pacific. The cool air converges with cool continental air and sinks along the eastern Pacific coast. There are fewer rainstorms in the eastern Pacific because the air is cool and dry. The Walker cell also flows over the Indian Ocean an the equatorial Atlantic Ocean. https://stepik.org/lesson/779362/step/1?unit=781878 5/7 10/14/24, 11:39 AM Step 1 – Atmospheric Circulation – Stepik Vocabulary: https://stepik.org/lesson/779362/step/1?unit=781878 6/7 10/14/24, 11:39 AM Step 1 – Atmospheric Circulation – Stepik Low-pressure area = a storm; it begins from the collision of air from 2 regions that are forced upward so a vacuum is created as the air rises so a zone of low pressure is lowest at the center of the storm. In a low-pressure area, the air pressure is lower than in the surrounding areas. A falling barometer reading is an indication of rain. High-pressure area = anticyclone, where the air is sinking; it is a region where the atmospheric pressure is greater than the surrounding environment so it keeps stormy and rainy weather out. Or it is a dry sinking air behind a departing storm. Winds flow out from the higher pressure areas towards the low-pressure areas, and they flow clockwise in the northern hemisphere. Intertropical convergence zone (ITCZ) = the zone in the equator where the trade winds converge. Convection cell (aka Bénard cell) = fluid flow pattern where a rising body of fluid loses heat due to encountering a colder surface. Reference: atmospheric science | Britannica Types of Winds: Permanent, Secondary & Local Winds - PMF IAS Climate Signals | Hadley Cell Expansion Hadley Cells: The Foundations of Atmospheric Circulation | Musings of a Meteorologist (psu.edu) What is high pressure? - Internet Geography Intertropical Convergence Zone - Wikipedia Models Of The General Circulation - Climates and Weather (briangwilliams.us) https://stepik.org/lesson/779362/step/1?unit=781878 7/7 10/14/24, 11:42 AM Step 1 – Climate of the Philippines – Stepik https://stepik.org/lesson/779812/step/1?unit=782386 3/5 10/14/24, 11:42 AM Step 1 – Climate of the Philippines – Stepik By Impact Assessment and Applications Section, Climatology and Agrometeorology Division, Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) - http://bagong.pagasa.dost.gov.ph/information/climate-philippines, Publi Domain, https://commons.wikimedia.org/w/index.php?curid=90153815 Climate types The Philippine climate has 4 types based on the distribution of rainfall. The country has 2 seasons based on the amount of rainfall: wet and dry seasons. Based on temperature, March until October are the warmest months with their peak around May. The rainy months of winter monsoon are from November to February with January as the coolest month. The country's location across the typhoon belt grants us dangerous storms from July through October, averaging 28 storms/typhoons entering the Philippine area of responsibility (PAR) in a year. https://stepik.org/lesson/779812/step/1?unit=782386 4/5 10/14/24, 11:42 AM Step 1 – Climate of the Philippines – Stepik Monsoons are breezes created when the land temperature is warmer or cooler than the ocean temperature. Habagat or southwest monsoon (summer monsoon) produces large amounts of rain due to water vapor condensation. Amihan from the northeast is responsible for drought because it diverges/subsides. Monsoon rains are from May to October. Reference: PAGASA, Philippine Atmospheric, Geophysical and Astronomical Services Administration https://stepik.org/lesson/779812/step/1?unit=782386 5/5 10/14/24, 11:40 AM Step 1 – Ocean Circulation – Stepik 2.2 Ocean Circulation 1 out of 1 step passed OCEAN CIRCULATION Ocean currents move in large circular systems for warm waters in the equator to reach the poles and back. Ocean currents affect the temperatur and the amount of precipitation over an area. 1. SURFACE WATER - Ocean currents are influenced by the prevailing winds on the surface (Walker circulation) and the general atmospheric circulation which are also deflected by the Coriolis force. Warm water in the tropics can travel to the cold polar regions even if every ocean has its own pattern of currents. https://stepik.org/lesson/779363/step/1?unit=781879 1/3 10/14/24, 11:40 AM Step 1 – Ocean Circulation – Stepik 2. THERMOHALINE CIRCULATION or the Global Ocean Conveyor or Great Ocean Conveyor Belt. Aside from pressure and temperature thermohaline is also affected by water salinity. The vertical water movement makes sure that seawater at the deep end of the ocean is replaced with surface water in the continuous rise and fall. Big volumes of water are moved which transport heat, nutrients, and other materials to varying depths in a slow process that takes about 1,200 years. Know more about thermohaline circulation in this video: https://gpm.nasa.gov/education/sites/default/files/videos/thermohaline_conveyor_30fps.mp4 https://stepik.org/lesson/779363/step/1?unit=781879 2/3 10/14/24, 11:40 AM Step 1 – Ocean Circulation – Stepik Reference: Ocean currents - Atmosphere and climate - Edexcel - GCSE Geography Revision - Edexcel - BBC Bitesize https://stepik.org/lesson/779363/step/1?unit=781879 3/3 10/14/24, 11:41 AM Step 1 – Climate regions and classifications – Stepik 2.3 Climate regions and classifications 3 out of 3 steps passed Climate Climate (klima, Greek) is the pattern of temperature and precipitation of a specific location over a long period which could be 30 years or more. Temperature, wind and light conditions define the climate of a region. Climate is the average of weather events happening in an ecosystem. It is influenced by geography: hot regions are near the equator while cold regions are near the poles. In between the equator and the poles are the temperate regions. The type of climate determines the flora and fauna in an area because organisms require specific conditions to live. It is now accepted that manmade factors also contribute to the conditions that influence climate, which include land use and consumption of natural resources affecting both local and even global changes in climate. https://stepik.org/lesson/773477/step/1?unit=775945 1/3 10/14/24, 11:41 AM Step 1 – Climate regions and classifications – Stepik CLIMATE REGIONS The world's climate was divided into 5 categories by a German climate scientist named Wladimir Koppen in the early 1900s. Koppen based his climate grouping based on latitude, temperature, amount, and frequency of precipitation in a year. The 5 main climate types are: A: Tropical. In this hot and humid zone, the average temperatures are greater than 64°F (18°C) year-round and there are more than 59 inches of precipitation each year. B: Dry. These climate zones are so dry because moisture is rapidly evaporated from the air and there is very little precipitation. C: Temperate. In this zone, there are typically warm and humid summers with thunderstorms and mild winters. D. Continental. These regions have warm to cool summers and very cold winters. In the winter, this zone can experience snowstorms, strong winds and very cold temperatures—sometimes falling below -22°F (-30°C)! E: Polar. In the polar climate zones, it’s extremely cold. Even in summer, the temperatures here never go higher than 50°F (10°C)! https://stepik.org/lesson/773477/step/1?unit=775945 2/3 10/14/24, 11:41 AM Step 1 – Climate regions and classifications – Stepik Reference: What Are the Different Climate Types? | NOAA SciJinks – All About Weather https://stepik.org/lesson/773477/step/1?unit=775945 3/3 10/14/24, 11:41 AM Step 2 – Climate regions and classifications – Stepik 2.3 Climate regions and classifications 3 out of 3 steps passed CLIMATE SUB-REGIONS TROPICAL WET This subregion has little variation in temperature over the year—it is always hot, with an average temperature of 80°F. The days begin sunny but b afternoon have clouded up, and rain falls almost daily. The average amount of rain in a year is more than 80 inches. Tropical wet climates are found Central and South America as well as Africa and Southwest Asia. TROPICAL WET AND DRY https://stepik.org/lesson/773477/step/2?unit=775945 1/3 10/14/24, 11:41 AM Step 2 – Climate regions and classifications – Stepik This climate is called “tropical wet and dry” because the subregion has a rainy season in summer and a dry season in winter. Temperatures are cooler in the dry season and warmer in the wet season. Rainfall is less than in the tropical wet climate subregion and occurs mostly in the wet seaso Tropical wet and dry climates are found next to tropical wet climates in Africa, South and Central America, and parts of Asia. SEMIARID This climate subregion does receive precipitation, just not very much: about 16 inches per year. Summers are hot. Winters are mild to cold, and some semiarid locations can produce snow. The climate is found in the interior of continents or in a zone around deserts. The region contains some of the most productive agricultural lands in the world. DESERT Some people think a desert is nothing but sand dunes. However, deserts are categorized according to the amount of rainfall, rather than by landforms, and can be hot or cool/cold. Deserts receive less than ten inches of rain per year. Hot deserts, like the Sahara and the Arabian Desert, regularly have low humidity and high temperatures during the day. At night, temperatures drop because the dry air cannot hold heat well. Cool/cold deserts are found in the mid-latitudes mostly in the Northern Hemisphere, often in the rain shadow of nearby mountain ranges. Summe temperatures are warm to hot, and winter temperatures range from quite cool to below freezing. MEDITERRANEAN This climate subregion is named for the land around the Mediterranean where it is located. It also exists elsewhere, such as on the west coast of the US and parts of Australia. Its summers are dry and hot, and its winters cool and rainy. This climate region supports a dense population and rich agricultural activity. MARINE WEST COAST This climate subregion, which is located close to the ocean, is frequently cloudy, foggy, and damp. The winds over the warm ocean moderate the temperatures and keep them relatively constant. Parts of the west coast of the United States and Canada and most of Western Europe experience this climate. Precipitation in marine west coast climate regions is evenly distributed throughout the year. Industrial regions with a marine west coast climate may have smog (a mixture of smoke and fog). HUMID SUBTROPICAL Long periods of summer heat and humidity characterize the humid subtropics. These areas are found on the east coast of continents and are often subject to hurricanes in late summer and autumn. The southeastern part of the United States and large areas of China are examples. Winters are mild to cool, depending on latitude. The climate is very suitable for raising crops, especially rice. HUMID CONTINENTAL https://stepik.org/lesson/773477/step/2?unit=775945 2/3 10/14/24, 11:41 AM Step 2 – Climate regions and classifications – Stepik A great variety in temperature and precipitation characterizes this climate, which is found in the mid-latitude interiors of Northern Hemisphere continents. For example, Winnipeg, Manitoba, in Canada is located deep in the North American continent. It has a humid continental climate. Air masses chilled by Arctic ice and snow flow south over these areas and frequently collide with tropical air masses, causing changing weather conditions. These areas experience four seasons. However, the length of each season is determined by the region's latitude. SUBARCTIC Evergreen forests called taiga cover the lands in the subarctic subregion, especially in Canada and Russia. Huge temperature variations occur i this subregion between summer and winter. Although the summers are short and cool, the winters are always very cold. Temperatures at freezing or below freezing last five to eight months of the year. TUNDRA The flat, treeless lands forming a ring around the Arctic Ocean are called tundra. The climate subregion is also called tundra. It is almost exclusively located in the Northern Hemisphere. Very little precipitation falls here, usually less than 15 inches per year. The land has permafrost—tha is, the subsoil is constantly frozen. In the summer, which lasts for only a few weeks, the temperature may reach slightly above 40°F. ICECAP Snow, ice, and permanently freezing temperatures characterize the region, which is so cold that it rarely snows. These subregions are sometime called polar deserts since they receive less than ten inches of precipitation a year. The coldest temperature ever recorded, 128.6°F below zero, was on the ice cap at Vostok, Antarctica. HIGHLANDS The highlands climate varies with latitude, elevation, other topography, and continental location. In rugged mountain areas such as the Andes of South America, climates can vary based on such factors as whether a slope faces north or south and whether it is exposed to winds carrying moisture. https://stepik.org/lesson/773477/step/2?unit=775945 3/3 10/14/24, 11:43 AM Step 1 – Climate factors – Stepik 2.5 Climate factors 8 out of 8 steps passed Factors Affecting Climate The major factors influencing the climate of a region are latitude, wind, and ocean currents which were already discussed. Additionally, the elevation and topography of the area also play a role. 4. Elevation Elevation or altitude is the distance of an area as measured above sea level. It is a common misconception that the high elevated areas are warmer because of their seeming proximity to the sun. The opposite happens as air temperature becomes cooler by about 3.5 degrees F every 1,000 feet (300 meters) so, the mountainous areas have colder air. Regions located above 12,000 feet have cold air temperatures like those in the poles, with snow and ice like Mt Kilimanjaro in East Africa which has year-long snow. Therefore high elevations have lower temperatures are greate precipitation. 5. Topography Climate is also affected by landforms, especially mountains and other high elevated areas. Because cool air is moisture-bearing, it can release rain or snow on the windward side but becomes dry and warmer on the leeward. The type of ground cover or vegetation of specific landforms is based on the amount of precipitation they receive. https://stepik.org/lesson/773478/step/1?unit=775946 1/2 10/14/24, 11:43 AM Step 1 – Climate factors – Stepik https://stepik.org/lesson/773478/step/1?unit=775946 2/2 10/14/24, 11:44 AM Step 3 – Climate factors – Stepik 2.5 Climate factors 8 out of 8 steps passed The Daily Energy Cycle The ground warms from solar radiation after sunrise and heats the adjacent air. The incoming solar energy peaks around noon (solar gain > loss and falls until just after sunset (energy loss > gain). The diurnal (daily) energy cycle is illustrated below: Diurnal Temperature and Energy Rate https://stepik.org/lesson/773478/step/3?unit=775946 1/7 10/14/24, 11:44 AM Step 3 – Climate factors – Stepik Diurnal temperature changes are affected by the same factors influencing global/regional temperatures, namely: latitude, surface type, elevation aspect, proximity to large bodies of water, and cloud cover. https://stepik.org/lesson/773478/step/3?unit=775946 2/7 10/14/24, 11:44 AM Step 3 – Climate factors – Stepik https://stepik.org/lesson/773478/step/3?unit=775946 3/7 10/14/24, 11:44 AM Step 3 – Climate factors – Stepik Adiabatic Cooling and Warming Adiabatic ("not passable through", Greek) means that cooling and warming do not happen from the addition or extraction of heat into the system. Adiabatic cooling and warming occur from the change in volume and/or pressure of the air. The less pressure there is on air, the more it ca expand. The farther air molecules are, the lesser the friction so heat becomes less. When you compress air, the molecules get tighter so friction increases and they heat up. Rising Air Parcel Adiabatic cooling and warming are more experienced in the atmosphere. Because the earth's temperature is not isothermal, the temperature decreases with height. The higher the air travels the colder it gets because of the lower pressure (and not from the removal of heat). When air descends it gets warmer due to high air pressure (not from the addition of heat). The air just feels colder above because the molecules are far apart. Conversely, dry air feels warmer because it is more compressed. Environmental Lapse Rate (ELR) - The decrease in temperature of the atmosphere as we go up. The rate of decrease is 6.5 degrees/1000 meters. Dry Adiabatic Lapse Rate (DALR) - It is the decrease in temperature of air parcels with height. The rate is 10 degrees / 1000 meters (constant). The air is considered dry because it has not reached a saturation point and/or has not condensed. To better explain the adiabatic cooling, the following statements should be remembered: A rising air column always expands because atmospheric pressure decreases upward. https://stepik.org/lesson/773478/step/3?unit=775946 4/7 10/14/24, 11:44 AM Step 3 – Climate factors – Stepik A rising air column always cools because its energy is in expansion. The rate of cooling is 10 degrees Centigrade per kilometer for an unsaturated (RH