Cyclone

1. Low-Pressure System

A low-pressure system is an area where the atmospheric pressure is lower than its surroundings. These systems are associated with rising warm air, which leads to cloud formation and precipitation. They are the primary drivers of weather disturbances like cyclones and storms.

Concept: Warm air rises, creating a region of lower pressure at the surface. As air converges to fill this void, it starts to rotate due to the Coriolis effect.
Example: A monsoon low-pressure system forming over the Bay of Bengal, leading to heavy rains in eastern India.

2. Depression

A depression is a more developed form of a low-pressure system with a well-defined circulation. It brings moderate to heavy rainfall and gusty winds.

Concept: When a low-pressure system intensifies with wind speeds between 31-49 km/h, it is classified as a depression.
Example: The depression over the Arabian Sea that causes heavy rainfall in Mumbai during the monsoon season.

3. Deep Depression

A deep depression is a further intensification of a depression with stronger winds and heavier rainfall.

Concept: A depression becomes a deep depression when wind speeds increase to 50-61 km/h. This stage is a precursor to a tropical storm or cyclone.
Example: A deep depression forming over the Bay of Bengal, later developing into Cyclone Yaas in 2021.

4. Cyclone

A cyclone is a large-scale air mass that rotates around a strong center of low atmospheric pressure. It is classified into different categories based on wind speed.

Concept: A cyclone forms when a deep depression further intensifies, with wind speeds exceeding 62 km/h. Warm ocean waters provide energy, causing rapid intensification.
Types of Cyclones:
- Tropical Cyclones: Form over warm ocean waters (e.g., Cyclone Amphan in 2020).
- Extratropical Cyclones: Occur outside tropical regions and are associated with frontal systems (e.g., Nor'easters in the U.S.).

5. Storm

A storm is a general term for a disturbed state of the atmosphere that can bring strong winds, heavy rain, thunder, lightning, and sometimes snow.

Concept: When wind speeds reach 62-88 km/h, the system is called a "Cyclonic Storm." If it intensifies further, it may become a Severe Cyclonic Storm (89-117 km/h) or even a Super Cyclone (>222 km/h).
Example: Cyclone Fani (2019) was classified as an Extremely Severe Cyclonic Storm with wind speeds exceeding 250 km/h, causing significant destruction in Odisha, India.

Wind Speed Classifications

System Type	Wind Speed (km/h)
Low Pressure	< 31
Depression	31-49
Deep Depression	50-61
Cyclonic Storm	62-88
Severe Cyclonic Storm	89-117
Very Severe Cyclonic Storm	118-165
Extremely Severe Cyclonic Storm	166-221
Super Cyclone	> 222

Comments

CREATION OF SPATIAL DATA

Spatial data creation is the process of generating, organizing, and managing geographically referenced information in a Geographic Information System (GIS). It involves converting maps, satellite images, GPS observations, and field survey data into digital datasets that can be stored, analyzed, and visualized. The quality of GIS analysis depends largely on the accuracy of spatial data creation. 1. Creation of Shapefile and Geodatabase A. Shapefile A Shapefile is one of the most widely used vector data formats developed by Esri for storing geographic features. Definition A shapefile stores the geometry and attributes of geographic features such as points, lines, and polygons. Components of a Shapefile A shapefile consists of several files: .shp – Stores geometry (shape) .shx – Shape index .dbf – Attribute table .prj – Coordinate Reference System (CRS) .sbn/.sbx – Spatial index (optional) Geometry Types Point – W...

Geography of Health or Medical Geography

Health Geography (also known as Medical Geography ) is a sub-discipline of Human Geography that studies the relationships between place, environment, society, and health . It examines how spatial location, environmental conditions, and social and economic factors influence human health, disease patterns, and access to healthcare services. Health geography integrates concepts from geography, epidemiology, medicine, public health, environmental science, sociology, and Geographic Information Systems (GIS) to understand and improve population health. Major Components of Health Geography Health geography is generally divided into two major branches : The Geography of Disease and Ill Health The Geography of Health Care 1. The Geography of Disease and Ill Health This branch studies the spatial distribution, determinants, and diffusion of diseases across different geographical scales, from neighborhoods to global regions. It seeks t...

Nature and Scope of Geography

Geography is the scientific study of the Earth's surface, its physical features, human populations, and the interactions between people and their environment. The word Geography is derived from the Greek words Geo (Earth) and Graphien (to describe or write), meaning "description of the Earth." Modern geography goes far beyond description; it seeks to explain where phenomena occur, why they occur there, how they are spatially distributed, and how they change over time. Geography is regarded as a spatial science , an environmental science , and an integrative discipline because it bridges natural sciences, social sciences, and geospatial technologies. Nature The nature of geography refers to the characteristics and fundamental features that define the discipline. 1. Geography as a Spatial Science Terminology: Spatial Science A discipline concerned with the location, distribution, arrangement, organization, and interaction of phenomena in ...

Historical Development of Geography in the Ancient Period

The Ancient Period marks the earliest stage in the evolution of geographical thought, extending from approximately 3000 BCE to the 5th century CE . During this period, geography evolved from simple descriptions of the Earth's surface to systematic scientific inquiry. Early civilizations developed geographical knowledge to meet practical needs such as navigation, trade, agriculture, military expansion, taxation, and administration . The greatest contributions came from the Mesopotamian, Egyptian, Indian, Chinese, Greek, and Roman civilizations , with the Greeks laying the foundations of scientific geography . Meaning Terminology: Historical Development Historical development refers to the gradual evolution of geographical knowledge, concepts, methods, and theories over time. Concept Geographical knowledge evolved through: Observation of the natural environment Exploration and travel Cartography (map-making) Astronomical observations ...

Development of Health Geography

Health Geography (formerly Medical Geography ) is the branch of geography that studies the relationship between health, disease, environment, place, and healthcare systems . The discipline has evolved over more than 2,500 years through contributions from physicians, geographers, epidemiologists, microbiologists, and public health experts. The development of Health Geography can be divided into the following periods: Ancient Period Medieval Period Renaissance and Pre-Modern Period Nineteenth Century (Pre-World War Era) World War Period Post-World War Period Modern Health Geography 1. Ancient Period (5th Century BC – 500 AD) Characteristics Health closely linked with the natural environment. Diseases explained through climate, water, air, and seasons. No knowledge of microorganisms. Medical observations were descriptive. Major Concepts Environmental Determinism Disease Ecology Climate and Healt...

Vineesh V, Geography

Search This Blog