Applied Climatology & Urban Climate | Geography Optional for UPSC (Notes) PDF Download

Applied Climatology 

• Climatology's Role in Various Sectors: The growing impact of weather and climate on our day-to-day lives and long-term activities has led to increased attention from climatologists. Since the second world war, there has been a growing awareness of the potential applications of climatology in various areas, such as water resource development and disease eradication.
• Climate and Natural Vegetation: Natural vegetation is an indicator of climate, and their interdependence is vital for understanding their influence on one another. Knowing the optimal climatic conditions for various stages of forest growth is essential for those involved in afforestation, timber production, and watershed management. In silvicultural practices, the interrelationship between forests and climate is considered for maximizing yields.
• Climate and Agriculture: Food is a fundamental human need, and climate and vegetation are closely interconnected. Weather components, such as temperature, precipitation, humidity, and wind, play a significant role in crop production. For example, frost-sensitive crops like coffee, bananas, and sugarcane require specific temperature ranges for optimal growth. In hilly regions, citrus and other sensitive crops are planted on sun-exposed slopes to avoid frost-prone valley areas.
• Climate and Animal Husbandry: Meat and milk products come from animals that rely on pastures and feed crops, which are heavily influenced by climatic factors. Amongst these factors, temperature plays a crucial role in animal productivity. High temperatures can reduce milk production and the overall yield of flesh and fat from animals. Precipitation also affects the availability of grass in pastures, and extreme humidity levels can cause discomfort to animals. To counter these climatic impacts, animal shelters with controlled temperature and protection from adverse weather conditions are used in animal husbandry.
• Climate and Housing: Climatic conditions significantly influence housing types. For example, igloos are built in polar regions as homes for Eskimos, while open houses are found in tropical areas. In building and architectural climatology, micro-climatic conditions are influenced by factors such as local relief, nearby structures, landscaping, water bodies, and industrial waste. Green buildings are designed to maximize the use of natural resources, such as sunlight and wind, and incorporate climate considerations into their design. In tropical countries, double roofs are used to facilitate air movement and minimize heat transfer into the building. Similarly, roof designs in different climatic conditions consider factors such as precipitation and snowfall.

Air Pollution and Health

• Medical climatology is the study of the relationship between human health and climate or weather. Local winds, such as the loo or cold waves, can cause irritability, depression, dizziness, and hypertension. In some areas like Bangalore, a high concentration of pollens in the air can lead to breathing problems. As a result, the local government in Bangalore has restricted the planting of flowering saplings in parks during certain times of the year to reduce pollen levels in the air.
• Cities emit a significant amount of pollutants into the atmosphere, which can transform into acids through chemical reactions and fall as acid rain. Monitoring the atmospheric concentrations of these chemicals can help regulate industries and protect sensitive areas, such as the area surrounding the Taj Mahal in Agra, where vehicular traffic and industry have been banned. Acid rain can also be harmful to plant and marine life.
• Certain diseases are associated with specific climates or seasons. For example, cold seasons can control insect populations by forcing them into hibernation, which is why tropical diseases like dengue and malaria are more prevalent in tropical and subtropical regions. Other diseases, such as pneumonia, influenza, and measles, are closely associated with specific seasons or climates. This association allows governments to issue warnings and take measures to reduce the impact of these diseases. In South Asia, municipal bodies ensure that water does not accumulate in urban areas during monsoon seasons to prevent the spread of malaria and other vector-borne diseases.

Climate and Economy

Climate research plays a crucial role in benefiting various industries, including insurance, tourism, construction, energy, transport, sports, retail food, and retail clothing. By understanding and analyzing climate patterns and extreme weather events, these industries can adapt and make informed decisions to minimize risks and costs.

• Insurance companies, for example, are able to offer financial protection against climate-related damages, such as floods, frost, and wind. Climate research helps insurers quantify the probability of extreme events, provide year-ahead forecasts, and identify vulnerable regions. This information can reduce costs and improve risk management strategies.
• Tourism is directly influenced by climate, as there is often a peak season for tourists in specific destinations based on the local climate. For instance, cold mountainous regions tend to attract more visitors during the summer months. Understanding climate patterns helps the tourism industry better plan and cater to the needs of tourists.
• The energy sector also benefits from climate research, particularly in the development of renewable energy sources like wind and hydroelectric power. Wind atlases and data on water supply from glaciers and rainfall help determine the optimal location and height for wind turbines and hydroelectric plants.
• Transportation industries such as aviation and shipping are directly impacted by weather and climate conditions. Extreme weather events, like fog and cold waves, can disrupt flight schedules, while high-altitude ports may become inaccessible due to freezing during winter. Climate research helps transportation industries better prepare for and adapt to these challenges.
• In addition to these industries, humans and other mammals have evolved internal temperature regulation systems that help maintain stable core body temperatures in different climates. Cultural habits and technologies have also been developed to help people adapt to various climate conditions. For example, people in colder climates may consume more alcohol to increase blood flow and provide a sensation of warmth.
• Technological advancements have enabled researchers to survive in extreme climates, such as the cold Antarctic and Arctic regions or hot tropical areas. Air conditioning, for example, allows people to live comfortably in hot climates. Overall, climate research plays a vital role in helping various industries and individuals adapt and thrive in different climates and weather conditions.

Urban Climate 

Urban regions around the world exhibit a unique climate that differs from the typical regional patterns. This is because the process of urbanization modifies the physical environment, leading to changes in energy, moisture, and air movement near the surface. The concentration of buildings in urban areas can impact wind and atmospheric conditions as much as a large forest.

• An urban area alters various aspects of the atmosphere, such as air composition, temperature, and precipitation patterns. Wind speeds tend to be lower in cities compared to open areas due to the obstructive nature of urban structures. The actual impact depends on factors such as street design, season, and time of day. Winds usually flow down streets parallel to their general direction, especially in cities with high-rise buildings and canyon-like streets. In contrast, streets at right angles to the wind may experience strong lee effects. During the day, wind speeds in cities are significantly lower than in surrounding areas, but at night, turbulence over the city reduces the contrast. Rural-urban differences are more pronounced during strong winds, making the effects more noticeable in winter than in summer.
• Urban areas typically absorb less water per area than rural regions, as much of the city is covered with pavement or buildings. In some cases, this necessitates specific measures to reduce the risk of localized flooding during heavy rainfall. Construction activities in flood-prone areas can increase the duration and intensity of flooding. Cities generally have lower humidity than rural or forested areas due to factors such as rapid surface runoff, lower vegetation density, and the absence of water bodies. However, under certain conditions, the thermal and turbulence effects over cities may trigger precipitation or thunderstorms. Many cities experience more light rain and thunder than surrounding areas, resulting in a slight increase in total precipitation.

Urban Heat Island: An "urban heat island" (UHI) refers to built-up areas that are warmer than nearby rural areas due to human activities. This phenomenon was first studied and documented by Luke Howard in the 1810s. The temperature difference is usually greater at night than during the day and is most noticeable when winds are weak. The average temperature difference can be several degrees between the city center and surrounding fields, sometimes reaching as high as 10°C.

Urban Heat Islan

There are three main factors behind the urban heat island effect:

1. Direct production of heat in cities from fires, industry, and homes.
2. Heat-conserving properties of the bricks and materials used in building cities.
3. The blanketing effect of atmospheric pollution on outgoing radiation.

Heat trapped in concrete buildings and pavements during the day is released slowly in the form of long-wave radiation, making the cooling process slow. Additionally, cities have less vegetation, which means they lose the shade and cooling effect of trees, the low albedo of their leaves, and the removal of carbon dioxide. Tall buildings in urban areas also provide multiple surfaces for reflecting and absorbing sunlight, increasing the heating efficiency. Furthermore, these buildings inhibit cooling by convection and prevent pollution from dissipating. Chemicals emitted by cars and industries often trap sunshine, creating more heat. All these factors change the energy balance of an urban area.

As a city grows, its area and average temperature tend to increase. For example, Los Angeles has experienced an average temperature rise of approximately 0.5°C every decade since World War II. Other cities have seen increases of 0.1°-0.4°C each decade. The urban heat island effect varies for each city based on its structure, as parks and greenbelts reduce temperatures while central business districts, commercial areas, and suburban housing tracts are warmer.

Urban heat islands impact city residents by increasing discomfort, raising energy consumption for cooling purposes, and decreasing air and water quality. They also enhance photochemical reactions, which contributes to the formation of smog and clouds.
To counteract the urban heat island effect, several strategies can be employed:

• Use light-colored or reflective materials in construction to increase albedo. Dark surfaces can be up to 21°C hotter than light surfaces, which contributes to increased cooling needs. By switching to light-colored roofs, buildings can use 40% less energy.
• Implement green roofs, where a building's roof is partially or completely covered with vegetation and a growing medium over a waterproofing membrane. Rooftop ponds can also be used to treat grey-water. Green roofs serve multiple purposes, such as absorbing rainwater, providing insulation, creating wildlife habitats, and helping to lower urban air temperatures. They also offer financial benefits, such as reduced energy usage, tax incentives, and an increased lifespan for the roof.

Green Roof

• Green Building is a construction approach that emphasizes resource efficiency and environmental sustainability. This method involves optimizing the use of sunlight within the building, which helps to reduce its overall energy consumption and thus, minimizes the impact of Urban Heat Island (UHI) effect.
• Another strategy to mitigate the UHI effect is to increase the presence of well-maintained vegetation, particularly trees. Studies have shown that the cooling potential per area is significantly higher in streets with a higher density of trees. This is because trees increase evapotranspiration, which in turn lowers the air temperature. As a result, trees can contribute to reducing energy costs by 10-20%.
• Heat island mitigation is usually incorporated into a community's efforts towards energy conservation, air quality improvement, water management, or overall sustainability. Mitigation activities can vary from voluntary initiatives, such as demonstrating the use of cool pavements, to policy-driven actions like enforcing cool roof requirements through building codes. Most of these mitigation measures offer multiple benefits, including cleaner air, enhanced human health and comfort, reduced energy expenses, and decreased greenhouse gas emissions.

Atmospheric Pollution Over Cities 

• Air pollution refers to any substance introduced into the atmosphere by humans that negatively impacts living organisms and the environment. In urban areas, air pollution typically consists of soot, ash, gases, fumes, smoke, and oxides of sulfur, carbon, and nitrogen. Carbon dioxide and other greenhouse gases, such as methane, are the primary pollutants responsible for global warming.
• Sulfur dioxide and related chemicals are primarily known for causing acid rain. These pollutants can increase a city's albedo, or the amount of sunlight reflected back into space, by forming a blanket of radiation over the city. Additionally, they can act as condensation nuclei, which are particles on which water vapor condenses to form clouds.
• Under normal circumstances, much of this pollution would be dispersed upwards by turbulence and removed by stronger winds at higher altitudes. However, tall buildings in cities can obstruct the free movement of these particles, leading to higher concentrations of pollution. The highest levels of pollution occur when there are low wind speeds, temperature inversions, and high relative humidity.
• Addressing air pollution in cities requires a multifaceted approach, involving both civil society and individual residents. On a larger scale, governments can implement legislation, tax incentives, and other initiatives to reduce air pollution. Civil society can contribute by raising environmental awareness among citizens and promoting activities such as urban forestry.

In summary, atmospheric pollution in cities is a complex issue caused by various human activities, resulting in the release of harmful substances into the atmosphere. These pollutants can have severe consequences for both the environment and human health. Addressing this issue requires collaborative efforts from governments, civil society, and individuals to implement effective strategies to reduce air pollution in urban areas.

Urban Climate and Global Climate Change 

• Urban climate changes are closely connected to global climate change. Cities, as hubs for socioeconomic activities, generate significant amounts of greenhouse gases, primarily CO2, due to human activities such as transportation, construction (e.g., concrete production), and energy consumption for heating and cooling purposes. Cities are the primary consumers of energy, which is primarily produced using fossil fuels.
• Many urban areas are susceptible to the anticipated impacts of climate change, such as rising sea levels, temperature fluctuations, alterations in precipitation patterns, and increased storm frequency. This vulnerability is due to factors such as their location along or near coastlines, the presence of distinct urban heat islands, and the production of atmospheric pollution.

Conclusion

The study of applied climatology and urban climate is crucial for understanding the impacts of climate change on various sectors, such as agriculture, animal husbandry, housing, health, and economy. The urban heat island effect and atmospheric pollution in cities further contribute to global climate change, exacerbating its negative consequences. Addressing these issues requires concerted efforts from governments, civil society, and individuals to implement effective strategies and adopt sustainable practices to mitigate climate change and improve the quality of life in urban areas.

Frequently Asked Questions (FAQs) of Applied Climatology & Urban Climate

What is the role of climatology in various sectors, such as agriculture and housing?

Climatology plays a crucial role in various sectors by helping them understand and adapt to different climate and weather conditions. For example, in agriculture, weather components like temperature, precipitation, and humidity can impact crop production, while in housing, climatic conditions can influence building design and materials used to maximize energy efficiency and comfort.

How does urban climate differ from the regional climate, and what factors contribute to the urban heat island effect?

Urban climate differs from regional climate due to the unique features of urban areas, such as the concentration of buildings, paved surfaces, and human activities. The urban heat island effect occurs when built-up areas are warmer than nearby rural areas due to factors like heat production from human activities, heat-conserving properties of building materials, and the blanketing effect of atmospheric pollution on outgoing radiation.

What are some strategies to mitigate the urban heat island effect and reduce air pollution in cities?

Some strategies to mitigate the urban heat island effect include using light-colored or reflective materials in construction to increase albedo, implementing green roofs or rooftop gardens, and increasing the presence of well-maintained vegetation, particularly trees. To reduce air pollution in cities, governments can implement legislation and incentives to reduce emissions, while civil society can raise environmental awareness and promote activities such as urban forestry.

How are urban climate changes connected to global climate change, and how are cities vulnerable to the impacts of climate change?

Urban climate changes are connected to global climate change because cities generate significant amounts of greenhouse gases due to human activities like transportation, construction, and energy consumption. Cities are vulnerable to the impacts of climate change due to factors such as their location along coastlines, the presence of urban heat islands, and the production of atmospheric pollution.

What measures can governments and individuals take to address atmospheric pollution in urban areas?

Governments can implement legislation, tax incentives, and other initiatives to reduce air pollution in urban areas. They can also invest in renewable energy sources and promote public transportation. Individuals can contribute by using energy-efficient appliances, reducing their use of private vehicles, and participating in urban forestry or other environmental initiatives.