How changes in the level of Arctic Sea ice can change monsoon patterns in India
September 9, 2024↓Source: This post has been created based on the article “How changes in the level of Arctic Sea ice can change monsoon patterns in India”, published in The Hindu on 9th Sep 2024.
What is the news?
Recent research has shown that fluctuations in Arctic sea ice levels are affecting the Indian summer monsoon rainfall (ISMR), making it more erratic and unpredictable.
About Study
Recently, a study has been published in the journal Remote Sensing of Environment in June.
Participants: Researchers from India’s National Centre for Polar and Ocean Research (NCPOR), under the Ministry of Earth Sciences, and South Korea’s Korea Polar Research Institute.
Key Findings of the Study
Atmospheric Circulations: Changes in Arctic Sea ice impact large-scale atmospheric patterns such as the Rossby waves and Asian jet streams, which affect the distribution and intensity of monsoon rains.
Influence of Arctic Sea Ice: Reduced central Arctic Sea ice leads to lower rainfall in western and peninsular India but higher rainfall in central and northern India. Meanwhile, reduced sea ice in the upper latitudes like Barents-Kara Sea region delays the onset of the monsoon, making it more unpredictable.
Climate Change’s Role: The reduction of Arctic Sea ice due to climate change exacerbates these fluctuations, leading to severe droughts in some areas while causing excessive rainfall and flooding in others.
What are Rosby Waves?
Rossby waves are large-scale atmospheric waves that primarily occur in the mid-latitudes of the Earth’s atmosphere. These are also known as planetary waves.
These waves form in the jet streams—the high-altitude air currents that flow from west to east around the planet. Their meandering patterns influence the weather across regions in both the Northern and Southern Hemispheres.
These waves are most active in regions where there is a significant temperature difference between the equator and the poles, shaping weather patterns and influencing temperature extremes and precipitation levels worldwide.
Significance: They help balance the distribution of heat across the planet, ensuring that polar regions do not become too cold and equatorial regions do not overheat.
Why Global Models Got La Niña Predictions Wrong and Its Impact
September 7, 2024↓Source: The post on Why Global Models Got La Niña Predictions Wrong and Its Impact is based on the article “Why global models went wrong with their La Niña predictions — and what its delay means” published in Indian express on 7th September 24.
What is the News?
Nearly all major global weather agencies had forecasted the onset of La Niña by July 2024. However, the delay in its arrival has rendered the prediction inaccurate.
About El Nino and La Nina
Aspects Description About 1. ENSO is marked by fluctuations in sea surface temperatures in the tropical Pacific Ocean, driven by atmospheric variations.
2. These fluctuations affect global atmospheric circulation and influence weather patterns globally.
3. ENSO has three phases: El Niño (Warm phase), La Niña (Cool phase), Neutral phase.
4. ENSO cycles occur irregularly every two to seven years.
5. Anthropogenic climate change has intensified the effects of both El Niño and La Niña, exacerbating hazards such as high temperatures, heavy rainfall, and droughtsMechanism 1. During El Nino, trade winds weaken, reducing the movement of warm waters to the west. This results in the eastern Pacific becoming warmer than usual.
2. In La Nina, trade winds strengthen, pushing more warm water toward the western Pacific, making the eastern Pacific cooler than usual.
3. During the neutral phase, the eastern Pacific (near the northwestern coast of South America) is cooler than the western Pacific (near the Philippines and Indonesia) due to prevailing east-to-west trade winds.
4. These trade winds move warm surface water westward, and cooler water from below rises to the surface in the east to replace it.Impact on Indian Monsoon El Nino is associated with suppressed monsoon rainfall in India.
La Niña supports enhanced monsoon activity.Reasons for Prediction Errors:
1. Weak La Niña phases are more difficult for weather models to detect than stronger events.
2. Other atmospheric factors, such as inter-seasonal variability and the Madden Julian Oscillation (MJO), added complexity and made predictions harder.
Current Situation: As of September, ENSO-neutral conditions prevail, and La Niña is expected to emerge by late September or early October. La Niña is predicted to peak in November 2024 and last through the winter in the northern hemisphere.
Impact of La Niña Delay on India’s Monsoon
1. La Niña typically enhances the southwest monsoon in India (June to September), but the delay means it won’t directly influence this season’s rainfall.
2. Other factors also contribute to a robust monsoon, with India recording 16% surplus rainfall in August and the IMD forecasting 109% above-normal rainfall in September.
3. India has received 8% more rainfall than usual for the season, though regional variations persist, with deficient rainfall in the east and northeast, and surplus rainfall in central and southern India.
4. La Niña’s influence could extend to the northeast monsoon (October-December), but it generally doesn’t favor enhanced rainfall during this period.
5. Regions like Tamil Nadu, coastal Andhra Pradesh, and Kerala may experience normal or lower rainfall, though there have been exceptions in the past.
UPSC Syllabus: World Geography
Nazca Ridge
September 2, 2024↓Source- This post on Nazca Ridge has been created based on the article “Ocean World Exploration: A New Seamount And Previously Unknown Species Discovered” published in “Astrobiology” on 2nd September 2024.
Why in News?
Recently, a team of oceanographers identified and charted a new seamount on the Nazca Ridge, located 900 miles off the coast of Chile in international waters.
About Nazca Ridge
Source: Hakai Magazine 1. Location: The Nazca Ridge is a prominent submarine geological feature located in the southeastern Pacific Ocean.
2. Area: It extends over 1,100 kilometers (about 680 miles) from the coast of Peru towards the west.
3. Geology: The ridge is part of the Nazca Plate, which is an oceanic tectonic plate that underlies much of the southeastern Pacific Ocean.
4. Formation: The Nazca Ridge formed over a hotspot, where rising magma created volcanic islands and underwater mountains made mostly of basalt.
6. Geologically, the Nazca Ridge is notable for its interaction with the South American Plate. As the Nazca Plate moves eastward, it subducts beneath the South American Plate along the Peru-Chile Trench.
This subduction influences regional earthquakes, volcanic activity, and the uplift of the Andes. The ridge’s presence also affects the subduction angle, leading to unique geological phenomena.
7. The unique underwater topography of the ridge creates a range of habitats for marine life, supporting diverse ecosystems. It is home to a variety of marine species, including many that are unique to the area.
About Nazca plate
Source: erinbennettrilling.wixsite.com| 1. It is located in the eastern Pacific Ocean, near the western coast of South America. It interacts with the South American Plate.
2. Its collision with the South American Plate contributes to the creation of the Andes Mountains. This interaction also leads to significant volcanic activity in the region.
3. The Nazca Plate is being pushed under the South American Plate in a process called subduction. This subduction affects the region’s geology, including earthquakes and volcanic eruptions.
UPSC Syllabus: World Geography
Shiveluch Volcano
August 22, 2024↓Source- This post on Shiveluch Volcano has been created based on the article “Shiveluch volcano erupts after 7.0 magnitude earthquake strikes off eastern Russian coast” published in “ANI” on 22 August 2024.
Why in News?
The Shiveluch volcano in Russia recently erupted following a 7.0-magnitude earthquake that occurred off the country’s eastern coast.
About Shiveluch Volcano
Source: Copyright infringement not intended 1. About: It is a stratovolcano characterized by its composition of alternating layers of solidified ash, hardened lava, and volcanic rocks.
2. Location: It is the northernmost active volcano in Kamchatka Krai, Russia.
3. Shiveluch is one of Kamchatka’s most active volcanic structures, with at least 60 significant eruptions recorded during the Holocene period. Its current phase of activity began around 900 BC and continues to this day, with frequent eruptions.
4. Eruptions from Shiveluch often produce volcanic ash emissions that can disrupt air traffic, particularly on routes connecting Asia and North America.
5. In 2024, Shiveluch experienced a major eruption following a powerful 7.0 magnitude earthquake off the east coast of Kamchatka. This event is part of the ongoing active phase of the volcano.
About Kamchatka Peninsula
1. It is situated in the far eastern part of Russia. It is bounded by the Sea of Okhotsk to the west and the Pacific Ocean to the east.
2. The peninsula stretches about 1,250 kilometers (780 miles) in length.
3. It is home to over 160 volcanoes, 29 of which are active. Notable volcanoes include Klyuchevskaya Sopka (the tallest) and Kronotsky (famous for its cone shape).
4. It is also home to the Valley of Geysers which is one of the largest geothermal fields in the world. It is also UNESCO World heritage site.
5. Climate: It is characterized by long, cold winters and short, cool summers. Coastal areas have milder temperatures, while the interior experiences more extreme cold. Heavy snowfall and frequent fog are common over there. Rivers and streams are abundant with Pacific salmon.
6. Flora and Fauna: It is rich in biodiversity. It is dominated by Coniferous forests with tundra landscapes in the northern areas.
7. It is famous for its large population of brown bears, especially during the salmon spawning season. Marine animals such as seals, sea lions, and whales are also found there.
8. Cultural and Historical Significance: The area is inhabited by indigenous peoples like the Itelmen, Koryaks, and Evens for thousands of years. The first Russian settlement established in the late 17th century. It also served as a strategic military region during the Soviet era.
UPSC Syllabus: World Geography
St Martin’s Island
August 16, 2024↓Source- This post on St Martin’s Island has been created based on the article “What is Bangladesh’s St Martin’s Island, under spotlight after Sheikh Hasina’s resignation?” published in “Indian Express” on 14 August 2024.
Why in News?
Recently, Sajeeb Wazed, son of former Bangladesh PM Sheikh Hasina, has dismissed the report claiming that Sheikh Hasina could have stayed in power by handing over Bangladesh’s St. Martin’s Island to America.
About St Martin’s Island
Source:Researchgate Aspects Description About 1. St Martin’s Island is situated in the northeastern region of the Bay of Bengal, near the border between Bangladesh and Myanmar.
2. It is located nine kilometers from the southern tip of Bangladesh’s Cox’s Bazar-Teknaf peninsula.
3. The island is 7.3 km long and flat. It has an elevation of 3.6 meters above sea level.
4. It is Bangladesh’s only coral island, surrounded by reefs located 10-15 km to the west-northwest.History 1. In the 18th Century, Arab merchants were among the first to settle on the island.
2.They initially named it “Jazira” (meaning “the island”) and later changed it to “Narikel Jinjira” or “Coconut Island.”
3. The island was annexed by British India during a land survey in 1900. During this time, the island became known as St Martin’s Island, reportedly named after the then Deputy Commissioner of Chittagong, Martin.Submersion and Resurfacing 1. It was originally part of the Teknaf peninsula. However, the island was submerged into the sea around 5,000 years ago.
2. The southern part resurfaced about 450 years ago, with the northern parts rising above sea level in the following century.Population and Tourism 1. The island has a permanent population of approximately 10,000 people.
2. St Martin’s Island is a popular tourist spot, with an average of 10,000 tourists visiting and staying on the island daily.Strategic Importance The island’s proximity to both Bangladesh and Myanmar. It’s position in the Bay of Bengal, makes it strategically important in regional geopolitics. Cultural Significance The island has a mixed cultural heritage, with influences from both Bengali and Rakhine communities, as well as the early Arab settlers. Environmental Significance St Martin’s Island holds significant environmental importance as it is both a coral island and a breeding ground for sea turtles. UPSC Syllabus: World Geography
Tungabhadra Reservoir
August 13, 2024↓Source- This post on Tungabhadra Reservoir has been created based on the article “Broken crest gate of Tungabhadra reservoir washes away hopes of farmers in command area” published in “The Hindu” on 13 August 2024.
Why in News?
Recently, Tungabhadra reservoir filled up due to a good monsoon in the Sahyadri range.
About Tungabhadra Reservoir
Source: Photographic Print Aspects Description About 1. The Tungabhadra Reservoir, also known as the Tungabhadra Dam is a multipurpose dam located near Hospet in the Bellary district of Karnataka, India.
2. It was built across the Tungabhadra River, a major tributary of the Krishna River.Construction and Design 1. The Tungabhadra Dam was constructed in 1953 as a joint venture between Karnataka and Andhra Pradesh.
2. The dam is constructed using stone and earth, extending approximately 2.4 kilometers in length and standing 49.39 meters tall.Purpose It was designed primarily to store water for irrigation, power generation, and flood control. Capacity and Storage 1. The reservoir has a gross storage capacity of around 3.7 billion cubic meters (131 TMC ft).
2. The catchment area feeding the reservoir spans approximately 28,177 square kilometers.
3. The reservoir supports the irrigation of over 1.2 million acres of farmland across Karnataka and Andhra Pradesh.Hydroelectric Power Generation 1. The dam houses a hydroelectric power station with an installed capacity of 72 MW.
2. The generated electricity supports nearby regions, contributing to their electrification and industrial development.Environmental and Social Impact 1. The reservoir plays a critical role in the agrarian economy by providing water for the cultivation of crops such as rice, sugarcane, and cotton.
2. The large water body supports diverse flora and fauna, contributing to the local ecosystem. However, the construction led to the displacement of communities and environmental changes in the region.Tourism and Cultural Significance 1.The reservoir is a popular tourist destination, attracting visitors with its scenic beauty and proximity to the historic Vijayanagara ruins at Hampi.
2. The serene waters, lush greenery, and surrounding hills make it an ideal spot for picnics and relaxation.Challenges and Future Prospects 1. The reservoir faces challenges such as siltation and water management issues.
2. There is a need to modernize the irrigation infrastructure to ensure the long-term sustainability of the reservoir and its benefits to the region.UPSC Syllabus: Geography
Lake Turkana
August 10, 2024↓Source- This post on Lake Turkana has been created based on the article “Lake Turkana: First comprehensive survey in 50 years highlights key findings” published in “UNESCO” on 10 August 2024.
Why in News?
The first comprehensive survey of Lake Turkana in 50 years, led by UNESCO and WFP, has revealed significant findings about the lake’s high fish potential, particularly in its central and northern regions.
About Lake Turkana
Source: kanaga.com Aspects Description About 1. Lake Turkana is also known as Lake Rudolf or the Jade Sea.
2. It is a vast, shallow lake located in the arid northern region of Kenya, with its northernmost section extending into Ethiopia.
3. It ranks as Africa’s 4th largest lake by surface area and holds the title of the world’s largest permanent desert lake.
4. Lake Turkana is Africa’s largest saline lake by volume and the 4th largest in the world.
5. The lake and its surrounding areas are known as Lake Turkana National Parks are recognized as World Heritage Sites.River Three rivers Omo, Turkwel, and Kerio flow into Lake Turkana. The Omo River is the only perennial river, contributing 90% of the lake’s annual water inflow. Climate 1. Lake Turkana is located in Kenya’s hot, arid region with sparse vegetation.
2. The climate is characterized by low annual rainfall (less than 250 mm), high temperatures, and strong winds.
3. Due to intense heat, the lake loses more water through evaporation than it gains from precipitation.Flora 1. Intense heat and strong winds limit plant life around Lake Turkana, with thorn bushes as the dominant vegetation.
2. Dry grasslands appear during the wet season (March to May) and vanish in the dry months.
3. The lake supports abundant plankton, including cyanobacteria and microalgae.Fauna 1. Lake Turkana hosts 50 fish species, with 12 endemic, such as cichlids, barbs, catfish, and robber tetras; other species include tilapia, Nile perch, African knifefish, and African arowana.
2. Bird species around the lake include the little stint, common sandpiper, wood sandpiper, and white-breasted cormorant.
3. Mammals in the region include giraffes, zebras, rhinos, elephants, and cheetahs.UPSC Syllabus: World Geography
Standardised Precipitation Index’ (SPI)
August 5, 2024↓Source- This post on Standardised Precipitation Index (SPI) has been created based on the article “Environmental hazards in the North-Eastern States” published in PIB on 5 August 2024.
Why in News?
The India Meteorological Department (IMD) has recently analyzed precipitation and drought trends using the ‘Standardised Precipitation Index’ (SPI).
About Standardised Precipitation Index (SPI)
1. Purpose: The SPI is used to estimate wet or dry conditions based on precipitation data.
2. Calculation: The calculation of the SPI is based on long-term precipitation records for a particular location, with a long-term period of over 30 years being desirable for accurate calculation.
3. The index is negative for drought conditions and positive for wet conditions. As the dry or wet conditions become more severe, the index values become more negative or positive, respectively.
4. The SPI includes timescales of 1, 2, 3, 6, 9, 12, 24, 36, 48, 60, and 72 months.
About India Meteorological Department (IMD)
Aspects Description About The India Meteorological Department was established in 1875 and serves as the National Meteorological Service of India. Nodal Ministry The IMD operates under the Ministry of Earth Sciences (MoES). Headquarters The headquarters of the India Meteorological Department is located in New Delhi. Regional Centers There are six Regional Meteorological Centres located in Mumbai, Chennai, New Delhi, Calcutta, Nagpur, and Guwahati, each headed by a Deputy Director General. Mandate 1. The IMD provides meteorological observations and forecasts to optimize weather-sensitive activities such as agriculture, irrigation, shipping, aviation, and offshore oil exploration.
2. It issues warnings for severe weather events like tropical cyclones, dust storms, heavy rains, snow, cold waves, and heat waves, to protect life and property.
3. The IMD supplies essential meteorological data for agriculture, water resource management, industries, and oil exploration, and promotes research in meteorology and related disciplines.UPSC Syllabus: Geography
Kerala Floods
July 31, 2024↓Source- This post on the Kerala Floods has been created based on the article “Kerala landslide: a look at the extreme weather events in India recently” published in “Indian Express” on 31 July 2024.
Why in the news?
Recently, multiple landslides occurred in Wayanad district, Kerala.
Causes and Contributing Factors of landslide
i) Heavy Rainfall: Wayanad received over 140 mm of rain in 24 hours, significantly exceeding normal levels. Some areas recorded more than 300 mm of rainfall.
ii) Fragile Ecology: The region’s hilly terrain with sharp slopes is highly susceptible to landslides, especially during heavy rains.
iii) Soil and Rock Interaction: The local geology features a layer of soil over hard rocks. Heavy rain saturates the soil, weakening its bond with the rocks and triggering landslides.
Predictive Measures and Mitigation
i) Forecasting and Prediction: The Indian Meteorological Department (IMD) had predicted the possibility of landslides due to expected heavy rains.
ii) Mitigation Strategies: Experts call for developing detailed susceptibility and route maps to better predict and manage landslide risks. Current susceptibility maps exist, but more precise route maps are needed to identify safe areas.
Future Recommendations
i) Implementing stricter regulations on land use in vulnerable areas.
ii) Establishing more effective systems for monitoring rainfall and soil saturation to predict and prevent landslides.
iii) Increasing public awareness about landslide risks and emergency preparedness.
UPSC Syllabus: Disaster management
Bohai Gulf
July 30, 2024↓Source- This post on the Bohai Gulf has been created based on the article “New Chinese Migratory Bird Sanctuaries Added To UNESCO World Heritage List” published in “TimesNow” on 30 July 2024.
Why in the news?
UNESCO has recently added China’s Migratory Bird Sanctuaries along the Yellow Sea-Bohai Gulf (Phase II) to its World Heritage List.
About Bohai Gulf
Source: Wikipedia 1. Location: The Bohai Gulf is the innermost part of the Yellow Sea, situated on the northeastern coast of China. It is also known as the Bohai Sea or Bo Hai. Historically, it was called the Gulf of Chili or the Gulf of Pechili.
2. It covers an area of approximately 78,000 square kilometers. Due to its proximity to Beijing, it is one of the busiest seaways in the world.
3. The gulf is bordered by the Liaodong Peninsula to the northeast and the Shandong Peninsula to the south.
4. Key cities around the Bohai Gulf include Dalian and Tianjin. The gulf’s shores include Liaodong Bay, Bohai Bay, and Laizhou Bay.
5. The Yellow River, China’s second-longest river, flows into the gulf.
6. The area has significant petroleum deposits, oil refineries, and various industries.
Key Facts about the Yellow Sea
1.The Yellow Sea is a marginal sea of the western Pacific Ocean.
2. It is located between mainland China to the west and north, the Korean Peninsula to the east, and the Shandong and Liaodong Peninsulas to the south. It connects to the Bohai Sea to the northwest.
3. The Yellow Sea is one of the largest shallow areas of continental shelf in the world, with an average depth of 44 meters and a maximum depth of 152 meters.
4. Major rivers such as the Yellow River and the Yangtze River flow into the Yellow Sea. The sea has many islands, with notable ones including Jeju Island (South Korea), the Shandong Peninsula islands (China), and Ganghwa Island (South Korea).
UPSC Syllabus: World geography
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