eChapters

3.1 Introduction

One of the most important functions to the AAS units is to widely disseminate the advisory bulletins among the user community. A unit cannot be considered operational unless its bulletins are reaching the target masses. The dissemination is one way communication which is broadly speaking the process by which human beings share information, knowledge, experience, ideas and motivation. 

ABSTRACT

Presence of mangrove ecosystems on coastline, save lives and property during natural hazards such as cyclones, storm surges and erosion. This study is undertaken to assess the distribution of mangroves in Tamil Nadu. Geographical Information System, Remote Sensing and GPS (Global Positioning System) were used for mapping the mangrove forests. Mangrove wetland map and species zonation maps have been done using didital analysis of Remote Sensing data and ground truth information. The total area of mangroves found in Tamil Nadu and in Puducherry is around 4100ha.

1. INTRODUCTION

Mangroves are typical, tropical specialized trees growing in the saline and brackish water system. Mangrove plants live in muddy and wet saline soils. They are trees associated with shrubs, growing both on the sheltered coast and inland, lining the bank of estuaries and rivers. They are an ecological group of evergreen plant species, belonging to different families, but possessing marked similarities in their physiological characteristics and structural adaptations. Mangrove areas are associated with high leaf production and leaf fall and rapid decomposition of the litter.

Mangrove forests perform multiple ecological functions: They produce woody trees, provide habitat and detritus food for fish and shellfish and act as spawning ground for a variety of fishes, prawns and shellfishes. They harbour a variety of valuable fauna, including migratory birds. They also protect the coasts from storms and tidal waves and help in the formation of land by trapping sediments brought by the coastal community.There are many threats to mangroves. Deforestation is one of the major threats.

1.1 R and R studio

R has become the world-wide language for statistics, predictive analytics, and data visualization. R is not limited to statistics; it has a wide range of tools for spatial analysis and digital image analysis and can handle any process needed for image analysis flexibly. It offers a wide range of methodologies for digital image processing, from the most basic to the most complex. As an open source project, it’s freely available for a range of platforms, including Windows, Mac OS X, and Linux. An integrated development environment (IDE) for R, R Studio, allows interactive execution of R functions with user interface. RStudio is available in two formats - RStudio Desktop and RStudio Server - both available in free and fee-based (commercial) editions.

1.1.1. Download and install R

The R software setup files can be downloaded from any of the widely distributed Comprehensive R Archive Network (CRAN). To download R, please choose your preferred CRAN mirror, a location close to you. Follow the following steps:

Dragon fruit, commonly known as pitaya/pitahya (Hylocereus sp.) is a  climbing perennial cacti belonging to the Cactaceae family and the subfamily Cactoidea of the tribe Cactea (Raveh et al., 1993). It is a perennial climbing cactus plant native to tropical areas of North, Central and South America. Main countries growing dragon fruit are Vietnam, Colombia, Mexico, Costa Rica, Nicaragua, Thailand and Taiwan. Cultivation also occurs in Australia, Israel and Reunion Island. The European Union and Asia, especially China are the largest import markets of dragon fruits (Vinas et al., 2012).

Aerial photography is objective of getting panoramic view of earth surface to analyze the features of earth and their interrelation at particular time period which may be changed in further events. In this concerned, the observation may play a vital role in achieving the goals of photography. Undoubtedly it is widely used in social function and so on, but still awaited for scientific or research use. Drone can measure the geometry of ground surface at lower altitude with more accuracy in the form of visual feature in natural colour. flight height of drone mainly limits the large area coverage due to lower flying and drone can work perfectly at low altitude planning with good quality feature/photography.

The world’s drylands include hyper-arid, arid, semi-arid and dry sub-humid areas where rainfall is highly scanty and variable. Droughts are common in areas / zones where water is the principal limiting factor for agriculture (https:// www.fao.org/3/t0122e/t0122e03.htm) . Dryland soils are characterized by low levels of moisture, organic matter, and biological activity, consequently such soils are very poor in fertility devoid of plant nutrients. When, these soils suffer further degradation in fertility, resulting in erosion, desertification, and salinization when crops are grown on such soils inappropriately without any scientific basis. However, the major factor limiting agricultural production on drylands is the lack of adequate moisture for crop growth or drought.

Drought is a situation when the demand for water is much greater than the availability of water. Drought is a creeping phenomenon and it is experienced only after it has set in. The scarcity of water compared to demand will have greater impact on every activity of human life including failure of crops, food shortages, decline in ground water table, drying tanks, lakes or reservoirs, acute shortage of drinking water for humans and livestock shortage for cattle etc.

Drought will have very serious impact on economy of households as well as that of nation. There are five different types of droughts depending upon the nature of shortage of water

10.1 Meteorological Drought

Meteorological drought occurs when the water received through rainfall during a given period is much less than long period average rainfall of the area. The meteorological drought is associated with either failure of rain or due to long gap between the successive rainfall events. In India, meteorological drought occurs due to failure of south west monsoon or long breaks in south west monsoon rainfall. In Tamil Nadu the drought occurs due to failure of north east monsoon rainfall during months of October to December.

Drought, a recurring and often devastating feature of climate variability, presents a unique challenge due to its slow onset, complex nature, and farreaching consequences. Unlike hazards with clear event boundaries, drought manifests across diverse spatial and temporal scales and impacts nearly every facet of the environment and human activity. Effectively understanding and managing this phenomenon necessitates an equally comprehensive approach: drought monitoring. This chapter introduces the essential concepts and methodologies underpinning this critical field, highlighting the remarkable breadth required to capture the full picture of drought conditions. • The scope of drought monitoring is inherently vast. Geographically, it spans from tracking localized water stress affecting a single farm or watershed to assessing conditions across entire regions, nations, and continents. Temporally, monitoring efforts must consider short-term deficits unfolding over weeks or months (critical for agriculture) as well as long-term hydrological imbalances developing over seasons, years, or even decades (impacting reservoirs and groundwater). Understanding current conditions crucially relies on comparing them against a deep historical context, requiring decades of baseline data

Drought is a complex and multifaceted issue that affects various aspects of the environment, economy, and society. Its far-reaching consequences underscore the need for a comprehensive and collective approach to mitigate its impacts. 2.1 Drought Prone Area Delineation Drought-prone area delineation involves using scientific criteria like low and erratic rainfall, groundwater potential and agricultural indicators to identify regions susceptible to drought. Modern methods use GIS (Geographic Information Systems) to integrate data from satellite imagery, weather patterns, soil conditions, and vegetation to precisely map drought-vulnerable zones. This spatial analysis allows for targeted interventions such as improved water management techniques and sustainable agricultural practices in the most affected areas. Here are some additional details on the universal nature of drought and the benefits of a global response:

Introduction

Drought is the most common adverse environmental factor which limits crop production in different parts of the world. Often drought is accompanied by relatively high temperatures, which promote evapotranspiration, and hence could accentuate the effects of drought and thereby further reduce crop yields. Since these events occur more frequently in tropical and semitropical regions where most of the developing countries are situated, droughts are often associated with food shortages and an overall setback to developmental activities. Therefore, raising of drought-resistant crops is common sense to achieve stability in production and to enhance the possibility of self-suficiency in food. Consequently, breeding for drought resistance is a major objective of many research programmes in the international and national institutions. This has been so for the past several decades. But, it is disappointing that, there has not been any measurable success in these programmes compared with the success achieved in breeding for yield; or breeding for disease resistance or breeding for quality attributes. In fact, this was amply expressed by Arnon (1980) when he stated “Breeding for drought resistance has been a consistent theme for as long as I remember and probably the greatest source of wasted breeding efforts in the whole field of plant breeding.” However, the fact remains that we do hear of drought resistant varieties in many crops. For example, C-306 in wheat, Lalnakanda in rice and M 35-1 in Sorghum are some of the better known examples in India. It is also claimed that a large number of cultures among the Assam Rice Collection exhibit a considerably high degree of drought tolerance. Many land races and wild relatives of several crop species are said to contain drought resistant traits, which could be profitably utilised in breeding programmes. This situation is not unique to India alone but is a common experience in different parts of the world. However, to afirm a conviction a short questionnaire to assess the current state-of-art on breeding for drought resistance was distributed to 75 distinguished plant breeders and plant physiologists all over the world. The questionnaire and a summary based on the responses is as follows:

Drought Early Warning Systems (DEWS) form the essential foundation for effective and proactive drought management strategies. These systems are crucial in facilitating a fundamental shift from reactive approaches, where responses are implemented after the onset of a crisis, to proactive risk reduction measures that aim to anticipate and mitigate the adverse effects of drought before they fully materialize. By providing timely and accurate information about impending drought conditions, DEWS empower governments, communities, and individuals to make informed decisions and take preemptive actions, thereby minimizing the potential economic, social, and ecosystem losses associated with these events (Fig.6.1). Recognizing the risks posed by drought in a timely manner is of paramount importance for ensuring an effective and comprehensive response that can alleviate suffering and reduce overall vulnerability. The implementation of robust drought early warning systems plays a critical role in minimizing the negative consequences of drought and building longterm resilience to this recurring natural hazard.

Imagine the lifeblood of a nation’s energy grid thinning to a trickle. This is the stark reality when prolonged droughts grip regions heavily reliant on the oncemighty force of hydroelectric power. While the allure of clean, renewable energy from flowing water has positioned hydropower as a cornerstone of electricity generation globally, its dependence on a consistent and abundant water supply renders it exceptionally vulnerable to the increasingly frequent and intense droughts sweeping the planet. This chapter embarks on a critical exploration of the intricate and often strained relationship between these two forces: the essential need for water in sustaining hydroelectric power and the devastating impact of its absence during drought conditions Moving beyond a simple definition, we will delve into the multifaceted ways in which droughts cripple hydroelectric facilities, from dwindling reservoir levels that starve turbines to the cascading effects on energy security, economic stability, and ecological balance. We will traverse the globe, examining compelling case studies from drought-stricken regions, revealing the tangible consequences for communities and industries. Furthermore, this chapter will unpack the complex interplay of factors that exacerbate

Drought, characterized by prolonged periods of abnormally low rainfall, is a recurring and devastating natural phenomenon with profound implications for global agriculture. Among the sectors most vulnerable to the adverse impacts of drought is livestock production. This chapter, “Droughts and Livestock Production,” delves into the intricate relationship between these two critical elements, exploring the multifaceted challenges and consequences that drought poses to livestock farming across diverse geographical contexts The chapter will examine how water scarcity, a hallmark of drought, disrupts the delicate balance of feed availability, animal health, and overall productivity within livestock systems. It will further analyze the varied impacts of drought on different livestock species, considering their unique physiological needs and vulnerabilities. Beyond the immediate 

The 21st century has ushered in an era of unprecedented drought challenges, with far-reaching implications for global ecosystems, economies, and human societies. The increased frequency, severity, and duration of droughts worldwide have pushed water resources, agricultural systems, and communities to the brink, underscoring the pressing need for comprehensive understanding and proactive management. • One of the most striking aspects of modern droughts is their capacity to affect vast geographic areas, transcending national borders and impacting multiple sectors simultaneously. The 2012 drought in the United States, for instance, affected over 80% of the country, leading to significant economic losses in agriculture and beyond. Similarly, the 2018 Cape Town water crisis brought the city to the edge of “Day Zero,” where the taps would run dry, highlighting the devastating potential of droughts on urban water systems. • The impacts of droug

The concept of climate-resilient agriculture encompasses a range of approaches, including climate-smart agriculture, conservation agriculture, and agroforestry. These approaches recognize that agricultural development and growth are inextricably linked to climate change, and that farmers, policymakers, and other stakeholders must work together to promote climate-resilient agriculture practices. The dynamics of development and growth engineering in the context of climate-resilient agriculture are complex and multifaceted. They involve understanding the interactions between climate change, agricultural productivity, and rural livelihoods, as well as the role of institutions, policies, and technologies in promoting climate-resilient agriculture practices. Several driving factors are influencing the dynamic development of climate-resilient agriculture (Fig. 7.1). These include:
Increased awareness of climate change impacts on agriculture, leading to growing demand for climate-resilient agriculture practices.
• Advances in climate information and early warning systems, enabling farmers and policymakers to make more informed decisions.
• Growing recognition of the importance of soil health, biodiversity, and ecosystem services in promoting climate-resilient agriculture.
• Increased investment in climate-resilient agriculture research and development, leading to the development of new technologies and practices.
• Effective governance for growth is critical for promoting climate-resilient agriculture. This requires:
• Strong institutions and policies that support climate-resilient agriculture, including laws, regulations, and incentives.
• Inclusive coordination and collaboration among stakeholders, including farmers, researchers, policymakers, and private sector actors.
• Investment in climate information and early warning systems, as well as climate-resilient agriculture research and development.
• Support for capacity building and extension services, enabling farmers to access and adopt climate-resilient agriculture practices.
• Agricultural insurance and risk management mechanisms, enabling farmers to manage climate-related risks and uncertainties. By understanding the driving factors and governance requirements for climate-resilient agriculture, policymakers, researchers, and practitioners can work together to promote dynamic development and growth in the agricultural sector, enhancing food security, sustainability, and climate resilience.

Early Warning Systems (EWS) have evolved from simple, rudimentary alert mechanisms into complex, multi-hazard, data-driven networks that play a critical role in disaster risk management and climate adaptation. In today’s rapidly changing climate, timely and accurate information is essential not only for saving lives but also for protecting livelihoods, reducing economic losses, and enhancing community resilience. The application of EWS varies significantly by region, geography, type of disaster, and across diverse sectors such as agriculture, aquaculture, horticulture, animal husbandry, fisheries, and allied sciences. Global initiatives - led by organizations such as the United Nations - aim to ensure that every person, particularly the most vulnerable, is equipped with lifesaving early warnings by 2027 (Fig.11.1). Complementary partnerships, such as that between the World Meteorological Organization (WMO) and the Food and Agriculture Organization (FAO), further strengthen these systems by integrating cutting edge forecasting with actionable advisories for critical sectors. A particularly groundbreaking effort is the United Nations’ Early Warnings for All (EW4ALL) initiative, launched in 2022 by UN Secretary General António Guterres, which seeks to provide comprehensive early warning coverage for hazardous weather, water, and climate events to every person on Earth. Underpinning these global efforts is Weather Intelligence - a transformative approach that harnesses advanced data analytics, real time monitoring, and machine learning techniques to refine forecasts and deliver precise, context specific alerts. By integrating diverse data streams and tailoring

The dynamic layer surrounding the earth above its surface containing various gases, moisture, aerosols, etc. is called atmosphere. Atmosphere can be defined as the gaseous envelope surrounding the earth. It is retained by earth’s gravity.

The atmosphere protects life on earth by absorbing ultraviolet solar radiation, warming the surface through heat retention and reducing temperature extremes between day and night. The common name given to the atmospheric gases used in breathing and photosynthesis is air. The atmosphere has a mass of about 5.15 × 10¹⁸ kg, three quarters of which is within about 11 km of the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. The imaginary ‘Karman line’ lies at an altitude of 100 km above the earth’s sea level, and commonly represents the boundary between the earth’s atmosphere and outer space. The study of earth’s atmosphere and its processes is called atmospheric science or ‘aerology’.

Earth’s atmosphere is a dynamic and complex system that plays a crucial role in supporting life as we know it. This chapter explores into the fascinating world of this gaseous envelope that surrounds our planet, exploring its composition, structure, and the processes that drive both our daily weather and long-term climate. It includes:
• Composition and Structure: It will begin by examining the unique blend of gases that make up the atmosphere, including nitrogen, oxygen, argon, and trace amounts of others. It will also be explored how the atmosphere is structured into distinct layers (troposphere, stratosphere, mesosphere, thermosphere, and exosphere), each with its own characteristics and role.
• Weather: Weather refers to the short-term conditions of the atmosphere at a specific time and place. We’ll discuss the key elements of weather, such as temperature, pressure, humidity, wind, and precipitation, and how they interact to create the ever-changing weather patterns we experience.
• Climate: In contrast to weather, climate describes the long-term average of atmospheric conditions in a particular region. We’ll investigate the factors that influence climate, including latitude, altitude, proximity to oceans, and atmospheric circulation patterns. We’ll also explore the different climate zones found across the globe.
• Interconnectedness: A key focus of this chapter understands how weather and climate are interconnected. Daily weather patterns are influenced by the same fundamental atmospheric processes that shape long-term climate. For example, the way the sun’s energy interacts with the atmosphere drives both daily temperature variations and global climate patterns.