Latest news with #RolandMadden
Indian Express
4 days ago
- Science
- Indian Express
Daily subject-wise quiz : Environment and Geography MCQs on Perito Moreno glacier, Madden-Julian Oscillation and more (Week 112)
UPSC Essentials brings to you its initiative of subject-wise quizzes. These quizzes are designed to help you revise some of the most important topics from the static part of the syllabus. Attempt today's subject quiz on Environment and Geography to check your progress. 🚨 Click Here to read the UPSC Essentials magazine for May 2025. Share your views and suggestions in the comment box or at With reference to the Madden-Julian Oscillation (MJO), consider the following statements: 1. It is a moving system of winds, clouds, and pressure that brings rain as it circles around the equator. 2. This system typically travels westward at a speed of 4-8 metres per second. 3. When MJO is in the active phase, it results in drought. How many of the statements given above are correct? (a) Only one (b) Only two (c) All three (d) None Explanation — The southwest monsoon arrived in Kerala on May 24, eight days earlier than usual, although it reached Mumbai two weeks earlier on May 26. This was also the earliest monsoon to arrive in Mumbai on record. — Several large-scale atmospheric-oceanic and local causes contributed to the early monsoon onset, but the Madden-Julian Oscillation (MJO) was a crucial driver, according to the India Meteorological Department (IMD). — The MJO is a moving system of winds, clouds, and pressure that produces rain as it circles the equator. The phenomena is named after Roland Madden and Paul Julian, two scientists who discovered it in 1971 while working at the National Centre for Atmospheric Research in Boulder, Colorado. Hence, statement 1 is correct. — The system normally moves eastward at a speed of 4-8 metres per second. It travels across the world in 30-60 days on average, but can sometimes take 90 days. Hence, statement 2 is not correct. — As it moves, intense MJO activity frequently divides the world into two parts: one in which the MJO is active and produces rainfall, and another in which it suppresses rainfall. MJO causes higher-than-normal rainfall during the active phase, whereas in the suppressed phase, the area receives less than average rainfall. Hence, statement 3 is not correct. Therefore, option (a) is the correct answer. The Perito Moreno glacier was in the news. It is part of: (a) Alps Mountains (b) Himalayas Mountains (c) Andes Mountains (d) Atlas Mountains Explanation — Argentina's most famous glacier, the Perito Moreno glacier, which has a surface area of 250 sq km (lies in the Andes Mountains), is crumbling. It lost a colossal block of ice, equivalent to a 20-story building, plunging 70 m into water below. — Argentina's most famous glacier, the Perito Moreno glacier, which has a surface area of 250 sq km (the total area of Patna, Bihar), is crumbling. Just weeks ago, it lost a colossal block of ice, equivalent to a 20-story building, plunging 70 m into water below. Therefore, option (c) is the correct answer. With reference to the bow echo, consider the following statements: 1. It is a line of storms, also called a squall line. 2. It is used to classify Tsunamis. Which of the statements given above is/are correct? (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2 Explanation — The severe storm that pounded Delhi on Sunday had a unique structure, according to weather radar imagery from the India Meteorological Department (IMD). The storm resembled a crescent or an archer's bow. In technical terminology, such storm presentations are referred to as 'bow echoes'. — A bow echo is a line of storms, also known as a squall line, on radar that resembles a bow. This storm line may occasionally be embedded in a bigger squall line. Hence, statement 1 is correct. — A bow echo can range from 20 to 100 kilometres and last three to six hours. — Ted Fujita, a Japanese-American meteorologist who developed the tornadoes classification system, coined the word in the 1970s. Hence, statement 2 is not correct. Therefore, option (a) is the correct answer. Consider the following statements: Statement 1: Western Disturbances also impact the weather outside the winter season. Statement 2: In the last 70 years, Western Disturbances have become more common in May, June, and July, months where they were previously rare. Which one of the following is correct in respect of the above statements? (a) Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation for Statement 1. (b) Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation for Statement 1. (c) Statement 1 is correct but Statement 2 is incorrect. (d) Statement 1 is incorrect but Statement 2 is correct. Explanation — Western Disturbances are rain-bearing wind systems that begin east of Afghanistan and Iran and pick up moisture from the Mediterranean, Black, Caspian, and Arabian Seas. — These are examples of extratropical cyclones caused by low-pressure zones created by the interplay of polar and tropical winds. Western Disturbances are embedded in the subtropical westerly jet stream, which is a high-altitude, fast-moving air movement that runs from west to east in the Earth's atmosphere and passes over the Himalayan and Tibetan highlands. — They are most abundant during the boreal winter months (December to March) and have an impact on the weather in India, notably the northwest, Pakistan, Afghanistan, and Tajikistan. — Western Disturbances are also now impacting the weather outside the winter season. In the last 70 years, they have become more common in May, June, and July, months where they were previously rare, according to the 2024 study. One reason for this trend could be the 'delayed northward retreat of the subtropical jet, which historically has occurred before the onset of the summer monsoon.' Hence, statements 1 and 2 are correct. Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation for Statement 1. Therefore, option (a) is the correct answer. Karreguttalu Hill (KGH) region — a known stronghold of Naxalite groups was in the news. It is located in: (a) Telangana-Chhattisgarh region (b) Chhattisgarh-Madhya Pradesh region (c) Maharashtra-Karnataka region (d) Karnataka-Telangana region Explanation — The Centre stated that incidences of violence by Left Wing Extremism (LWE) have decreased to 374 in 2024 from its maximum number of 1936 in 2010. — While LWE-related violence has decreased by 81 per cent, 'the total number of deaths, including civilians and security forces, has also reduced by 85 per cent — from 1005 deaths in 2010 to 150 in 2024,' according to a government news statement. — The news release continued: 'Recently, in one of the biggest anti-Naxal operations in the country's history, security forces achieved a major breakthrough in the fight against LWE along the Chhattisgarh-Telangana border.' — It stated that a huge operation was carried out between April 21 and May 11, 2025, in the Karreguttalu Hill (KGH) region, which is a renowned stronghold of Naxalite organisations. Therefore, option (a) is the correct answer. Sorry for the inconvenience caused. All remaining questions and answers are correctly marked. Daily Subject-wise quiz — History, Culture, and Social Issues (Week 112) Daily subject-wise quiz — Polity and Governance (Week 112) Daily subject-wise quiz — Science and Technology (Week 112) Daily subject-wise quiz — Economy (Week 112) Daily subject-wise quiz — Environment and Geography (Week 111) Daily subject-wise quiz – International Relations (Week 111) Subscribe to our UPSC newsletter and stay updated with the news cues from the past week. Stay updated with the latest UPSC articles by joining our Telegram channel – IndianExpress UPSC Hub, and follow us on Instagram and X.
Indian Express
7 days ago
- Climate
- Indian Express
This Word Means: Madden-Julian Oscillation
While the southwest monsoon arrived in Kerala on May 24, eight days earlier than the normal onset date, it reached Mumbai two weeks in advance on May 26. This was also the earliest the monsoon arrived in Mumbai on record. Several large-scale atmospheric-oceanic and local factors developed and favoured the early monsoon onset but one of the key drivers was the Madden-Julian Oscillation (MJO), according to the India Meteorological Department (IMD). What is MJO? The MJO is a moving system of winds, cloud, and pressure that brings rain as it circles around the equator. The phenomenon takes its name from the two scientists who identified it in 1971 — Roland Madden and Paul Julian, who then worked at the National Centre for Atmospheric Research in Boulder, Colorado. The system typically travels eastward at a speed of 4-8 metres per second. It goes around the globe in 30-60 days on average, but can sometimes take 90 days. As it moves, strong MJO activity often splits the planet into two parts — one in which the MJO is in active phase and brings rainfall, and the other in which it suppresses rainfall. In the active phase, MJO results in higher-than-average rainfall for that time of the year, while in the suppressed phase, the area receives less than average rainfall. An active phase is generally followed by a weak or suppressed phase, in which there is little MJO activity. The effect of the MJO is witnessed mainly in the tropical region, in the band between 30 degrees North and 30 degrees South of the equator, even though the mid-latitude regions in both hemispheres also feel its impact. India falls in this band. As the MJO cycle lasts only 30-60 days, there can be multiple MJO events in a season. There is some evidence that the MJO and El Niño — the unusual warming of sea-surface Pacific waters off the South American coast — are correlated. Thus, strong MJO activity, like this year, is witnessed in a year of strong El Niño. However, the correlation is not exclusive: a strong El Niño year — the strength being a measure of the increase of temperature of sea surface water — is generally associated with a bad monsoon. How did the MJO contribute to the early monsoon onset? In the tropics, MJO in its active phase brings frequent cyclonic activity, and can initiate the onset of the monsoon. For instance, in June 2015, the MJO resulted in about 20 days of very good rainfall in most parts of the country. This is what could have happened this year as well. That is because around May 22, the MJO, which had originated in the Indian Ocean, was in Phase 4 with an amplitude greater than 1, which is indicative of strong rainfall and storms, according to IMD's extended range forecast.
