Current Affairs 26th June 2023 for UPSC Prelims Exam

Flash Floods

Context: Flash floods triggered by a cloudburst in Himachal Pradesh’s Solan have damaged crops, homes and vehicles, and washed away livestock.

What are Flash Floods?

Definition: Flash floods are floods which occur within 6 hours of the beginning of heavy rainfall.
- Flash Floods are usually associated with cloud bursts, storms and cyclones requiring rapid localized warnings and immediate response if damage is to be mitigated.
  - Cloudburst is a sudden, very heavy rainfall, usually local in nature and of brief duration.
Causes:
- A flash flood is often the result of a heavy or excessive rainfall.
  - Whenever it rains, the soil acts as an absorber, and absorbs the precipitation.
  - However, in cases of heavy rain, the soil may be saturated to capacity and unable to absorb any more water.
- Flooding can also occur after a drought, when the soil is too dry and hardened to absorb the precipitation. This is why, flash floods are a common scene in desert landscapes after heavy rainfalls.
- The other reason of flash floods is cloudburst or thunderstorm. It is common in places such as hilly, not too hilly regions and sloping lands.
- Sudden release of waters from upstream reservoirs, breaches in landslide dams and embankments on the banks of the rivers can also lead to disastrous floods.
- Flash floods may also begin to take place after wildfires.
  - This is because wildfires destroy forests and other vegetation, which in turn weakens the soil and makes it less permeable for water to seep through.
Area: Flash flooding commonly happens more where rivers are narrow and steep, so they flow more quickly.
- They can occur in urban areas located near small rivers, since hard surfaces such as roads and concrete do not allow the water to absorb into the ground.
Flash Floods in India: India is the worst flood-affected country in the world after Bangladesh and accounts for one-fifth of the global death count due to floods.
- In India, flash floods are often associated with cloudbursts.
- The young Himalayan Mountain range is highly prone to flash floods owing to overflowing glacial lakes formed due to the melting of glaciers.
- Depression and cyclonic storms in the coastal areas of Orissa, West Bengal, Andhra Pradesh cause flash floods.
  - Depressions, sometimes called mid-latitude cyclones, are areas of low pressure located between 30° and 60° latitude.
- States of Arunachal Pradesh, Assam, Orissa, Himachal Pradesh, Uttarakhand, the Western Ghats in Maharashtra and Kerala are more vulnerable to flash floods caused by cloud bursts.
- Floods in Assam, Bihar, Uttar Pradesh, Orissa and Andhra Pradesh are generally caused by breaches in embankments.

Uttarakhand Floods, 2013

The state of Uttarakhand and the adjoining areas received heavy rainfall in June 2013, which was about 375% more than the benchmark rainfall in a normal monsoon.
The major reason for the flash flood was extreme rainfall, melting of Chorabari Glacier and eruption of the Mandakini River.
Reasons for Flash Floods in India:
- As per data from the National Disaster Management Authority, nearly 75% of the total Indian rainfall is concentrated over a short monsoon season of four months (June to September).
  - As a result, the rivers witness a heavy discharge during these months.
- About 40 million hectares of land in the country are liable to floods according to the National Flood Commission.
- An average of 18.6 million hectares of land are affected annually by floods.
Impact of Flash Floods:
- Floods destroy valuable crops every year.
- They also damage physical infrastructure such as roads, rails, bridges and human settlements.
- Millions of people are rendered homeless and are also washed down along with their cattle in the floods.
- Spread of diseases like cholera, gastro-enteritis, hepatitis and other water-borne diseases spread in the flood-affected areas.
Dealing with Flash Floods: The need to have strict implementation of the Flood Plain Zoning Act which can regulate the constructions within the flood plain of a river.
- Landslide risk zonation mapping be completed on priority. Development and enforcement of guidelines, regulations and codes for landslides is critical.
- Construction of flood protection embankments in the flood-prone areas, construction of dams, afforestation should be done.
- Effective stabilization of slopes in weak zones be undertaken using scientific techniques available at national/international levels.
- Blasting for developmental activities be avoided as it may destabilize the weak rocks in mountainous regions.
- The existing emergency communication system be reviewed regularly to ensure last mile connectivity during disasters.
- Investments in infrastructure development related to weather, glacial lakes, river flow monitoring, etc. are fundamental for improving the accuracy of risk mapping.
- Tourism related development should not be allowed along the riverbanks.
- An effective pilgrim control and regulatory body should be constituted for control and management of pilgrims/tourists.

Current Affairs 24th June 2023 for UPSC Prelims Exam

Implosion of Titan

Context: The Titan submersible is believed to have imploded.

Background

The Titan submersible vessel which was on a tourism expedition to explore the wrecks of the Titanic, went missing off the coast of Canada.
Many reports referred to the vessel as a submarine, Titan is actually a submersible and those terms are not completely interchangeable.

What is Titan Submersible?

Titan Submersible: As a submersible, Titan was designed to be launched and recovered with the help of a surface vessel.
- Made of carbon fibre and titanium, and weighing 10,432 kg, Titan was built with “off-the-shelf” components.
Submarine: Submarine is any naval vessel that is capable of propelling itself beneath the water as well as on the water’s surface. This is a unique capability among warships, and submarines are quite different in design and appearance from surface ships.
Submersible: A submersible is a watercraft, and it operates like a submarine.
- It is fitted with cameras outside, and it has a viewport.
- The passengers inside the submersible can watch through this viewport and can have a view of the nearby outside world.
- A submersible is generally used for research and exploration.
- It can also be used for searching the wreckage of the ship and documenting the underwater environment.
- Submersibles are generally connected to a mother vessel through a tether.
Difference Between Submarine & Submersible:
- A submarine is a large and manned vessel designed for military operations.
- Most submarines can generate their own oxygen and might stay submerged for a few months at a time.
  - A submarine has enough power to leave port and come back to port under its own power. This means that a submarine can drive independently to the bottom of the ocean and come back.
- A submersible has no crew, and it is controlled and operated from outside.
  - Submersibles are very small and simply constructed and are only equipped for short-term dives.
  - Submersibles need oxygen supply in tanks.
  - A submersible has very limited power reserves so it needs a mother ship that can launch it and recover it. This means it does not, unlike a submarine, have the power to drive down to the bottom of the ocean and come back under its own steam.

What caused Implosion of Titan?

Experts have questioned the use of titanium and carbon fiber for deep diving, as they have different properties.
Titanium is elastic and can adapt to ranges of stresses and pressures without permanent strain on the material.
Carbon fiber on the other hand is stiffer and non-elastic, often prone to cracking.
The differences in the materials could have created a defect in the hull, triggering an instantaneous implosion due to the underwater pressure.
Within less than one second, the vessel being pushed down on by the weight of a 3,800m column of water would have immediately crumpled in from all sides.

Climate Shift Index (CSI)

Context: A deadly heatwave over Uttar Pradesh has claimed as many as 100 lives. According ‘Climate Shift Index’ (CSI), the present heatwave in India is caused by climate change.

Background

Researchers at Climate Central have found that the three-day extreme heat event over parts of UP from June 14 to June 16 was made at least two times more likely by climate change.
As per the India Meteorological Department (IMD), a heat wave is a condition of air temperature which becomes fatal to [the] human body when exposed to it.
The IMD defines a heat wave as occurring if temperatures depart by 4.5°C to 6.4°C more than normal (above different temperature levels for hills and plains), and a severe heat wave when the temperature rises to more than 6.4°C.

What is Climate Shift Index (CSI)?

Definition: Climate Shift Index (CSI) is a model developed by a reputed U.S. nonprofit called Climate Central.
- The CSI uses a categorical five-point scale to show how climate change makes daily average temperatures more or less likely around the world.

Key Finding: As per Climate Central, the fact that these extreme temperatures occurred along with high humidity is unusual and contributed to the severity of the event.
- In addition to UP, most locations across India experienced significant CSI levels during the same period.
Determination of Climate Change: An exercise to determine climate change’s influence on a weather event involves two exercises: detection and attribution.
- A heatwave is defined based on the normal temperature of a region; ‘normal’ in turn is defined based on long-term historical data.
- The temperatures in Uttar Pradesh during the June 14-16 period met the definition of a heatwave. A heatwave was detected.
- In terms of Attribution, the CSI implies that the heatwave was made twice as likely due to global warming.
  - An attribution exercise compares real conditions that have occurred with a so-called counterfactual world, a hypothetical world where climate change has not occurred.
  - Scientists create counterfactual worlds for these weather events using historical weather data and model simulations.
  - The observations are constrained by limitations and the models are never accurate.
Shortcomings of the CSI:
- Lack of Multiple Natural Weather Conditions: Attributions do not account for the confluence of multiple natural weather conditions as well as human decisions that led to a heatwave being so deadly.
- Lack of Reliable Data: Even though India has some of the best rainfall data among the world’s countries, there is dearth of data with sufficient spatial and temporal coverage.
- Impact of Cyclone not Considered in Model:
  - Warming of the northern Indian Ocean from January onwards and the cyclones and typhoons during May and June have disrupted the normal march of the southwest monsoon in 2023.
  - World’s transition from a La Niña winter in 2022-2023 to the emerging El Niño summer of 2023 also has a significant impact.
  - The number and intensities of tropical cyclones as well as the El Niños and the La Niñas are also likely being affected by climate change, but the models do not agree on some of these estimates.
- Lack of Inclusion of Local Weather Systems: Natural variations in the climate always adds to or subtracts from the effects of climate change at the local level.
  - For example, South India can have its hottest summer and in the same season Chennai can have its coolest day in June. The attribution approach that the CSI has taken does not consider such local weather systems.
  - Studies have found that even irrigation can affect heatwaves, but neither the attribution data nor the models in the Uttar Pradesh case represent such effects.
  - So, a 360-degree view of such claims is needed, especially considering their potential deficiencies.
  - Event-by-event attribution on a daily timescale is neither possible with sufficient accuracy nor is it practically valuable. It can also divert resources away from other, more worthy efforts, such as improving early-warning systems.

Chandrayaan 3

Context: India’s third moon exploration mission, Chandrayaan-3, slated for a mid-July launch, will share the names associated with the 2019 Chandrayaan-2 lunar adventure.

Background

The Indian Space Research Organisation (ISRO) plans to retain the names of the Chandrayaan-2 lander and rover for their Chandrayaan-3 equivalents as well.
- This means, the Chandrayaan-3 lander will bear the name ‘Vikram’ (after Vikram Sarabhai, the father of the Indian space programme) and the rover, ‘Pragyan’.

What is Chandrayaan-3 Mission?

Definition: Chandrayaan-3 is a planned 3rd lunar exploration mission by the Indian Space Research Organization to demonstrate end-to-end capability in:
- Safe landing through the lander Vikram, and
- Roving through the rover Pragyan on the lunar surface.
Orbiter: Unlike Chandrayaan-2, Chandrayaan-3 will not have an orbiter and its propulsion module will behave like a communications relay satellite.
Module: Chandrayaan-3 interplanetary mission has three major modules:
- Propulsion module
- Lander module and
- Rover.
Payloads for Chandrayaan-3:
- Propulsion Module Payload: It has Spectro-polarimetry of Habitable Planet Earth (SHAPE) payload to study the spectral and polarimetric measurements of Earth from lunar orbit.
- Lander Payload: It will have 4 payloads –
  - Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere (RAMBHA) to study the temporal evolution of electron density in the Lunar ionosphere.
  - Chandra’s Surface Thermophysical Experiment (ChaSTE) to measure the thermal conductivity and temperature.
  - Instrument for Lunar Seismic Activity (ILSA) for measuring the seismicity around the landing site.
  - Langmuir Probe (LP) to estimate the plasma density and its variations.
- Rover Payloads: Alpha Particle X-ray Spectrometer (APXS) and Laser Induced Breakdown Spectroscope (LIBS) for deriving the elemental composition in the vicinity of the landing site.
Implementation of the Mission:
- A propulsion module will carry the lander-rover configuration to a 100-km lunar orbit.
- Once the ‘Vikram’ lander module makes it safely to the moon, it will deploy ‘Pragyan’.
- Pragyan will carry out in-situ chemical analysis of the lunar surface during its mobility.
Launch: ISRO plans to launch the third moon mission in mid-July aboard the LVM3 (formerly GSLV Mk-III) rocket from Sriharikota.