{"id":38689,"date":"2023-12-22T03:36:32","date_gmt":"2023-12-21T22:06:32","guid":{"rendered":"https:\/\/vajiramandravi.com\/current-affairs\/?p=38689"},"modified":"2025-04-23T13:27:22","modified_gmt":"2025-04-23T07:57:22","slug":"tn-rainfall","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/current-affairs\/tn-rainfall\/","title":{"rendered":"Tamil Nadu has witnessed heavy rainfall in December"},"content":{"rendered":"<h2>What\u2019s in today\u2019s article?<\/h2>\n<ul>\n<li>Why in news?<\/li>\n<li>What is northeast monsoon?<\/li>\n<li>News Summary: Tamil Nadu has witnessed heavy rainfall in December<\/li>\n<li>Tamil Nadu generally see rain in December<\/li>\n<li>How much did it rain over southern Tamil Nadu this week?<\/li>\n<li>Reasons behind the record rainfall over southern TN<\/li>\n<li>IMD\u2019s forecast<\/li>\n<\/ul>\n<h2>Why in news?<\/h2>\n<ul>\n<li>Tamil Nadu has battled heavy rainfall throughout December.\n<ul>\n<li>In the beginning of the month, parts of Chennai and its neighbourhood experienced massive flooding because of Cyclone Michaung.<\/li>\n<li>Earlier this week, Kalyanapattinum in Thoothukudi district saw excessive amounts of rain, as high as 950mm in 24 hours, leaving a trail of destruction.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h2>Northeast monsoon<\/h2>\n<ul>\n<li>About\n<ul>\n<li>The northeast monsoon is another major and permanent feature of the Indian subcontinent\u2019s climate system.<\/li>\n<li>Its name is derived from the direction of the monsoon winds, which blow from the northeast to the southwest.<\/li>\n<li>During their movement, these winds pick up moisture from the Bay of Bengal.<\/li>\n<li>This moisture is then dumped over the southern states of Tamil Nadu, Andhra Pradesh, Kerala, and even south Telangana and Karnataka.<\/li>\n<li>It is also referred to as the winter monsoon, retreating monsoon, or reverse monsoon.<\/li>\n<\/ul>\n<\/li>\n<li>Period\n<ul>\n<li>It remains active during the three-month period between October and December.<\/li>\n<\/ul>\n<\/li>\n<li>What causes and influences the northeast monsoon?\n<ul>\n<li>One of the primary causes of the northeast monsoon is the southward movement of Inter Tropical Convergence Zone (ITCZ).\n<ul>\n<li>ITCZ is a dynamic region near the Equator where the trade winds of the northern and southern hemispheres come together.<\/li>\n<\/ul>\n<\/li>\n<li>This southward movement of the ITCZ, coupled with the heating up of the Indian Ocean, reverses the direction in which the lower-atmosphere moisture-laden winds blow (from southwest to northeast), thereby triggering the NEM.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h2>News Summary: Tamil Nadu has witnessed heavy rainfall in December<\/h2>\n<ul>\n<li>Since October 1, the rainfall recorded over Tamil Nadu has been 450mm.<\/li>\n<li>Only 14 out of a total of 38 districts have received deficient rainfall during the ongoing season (till December 20).<\/li>\n<\/ul>\n<h2>Tamil Nadu generally see rain in December<\/h2>\n<ul>\n<li>The northeast monsoon is key for Tamil Nadu, Kerala, Puducherry, Karaikal, coastal Andhra Pradesh, Rayalaseema and Yanam in southern India.<\/li>\n<li>Of the total annual rainfall, <u>Tamil Nadu receives nearly 48 per cent (443.3mm) during the October to December months<\/u>, important for rabi cultivation.<\/li>\n<li>Hence, rainfall during these months are normal over Tamil Nadu.<\/li>\n<\/ul>\n<h2>How much did it rain over southern Tamil Nadu this week?<\/h2>\n<ul>\n<li>Three districts of southern Tamil Nadu saw \u2018exceptionally\u2019 heavy rainfall during December 17\u201319.<\/li>\n<li>The India Meteorological Department (IMD) stated that these districts had received about 100 per cent or more surplus rain during these three days over the previous week (December 6 \u2013 13, 2023).<\/li>\n<\/ul>\n<h2>Reasons behind the record rainfall over southern TN<\/h2>\n<ul>\n<li>Northeast monsoon\n<ul>\n<li>The northeast monsoon remained vigorous over Tamil Nadu since the start of this week, brining in steady rainbands, especially over the south Tamil Nadu and neighbouring Kerala.<\/li>\n<\/ul>\n<\/li>\n<li>Development of a cyclonic circulation\n<ul>\n<li>On December 16, a cyclonic circulation developed in the southwest Bay of Bengal, located off the western Sri Lankan coast.<\/li>\n<li>As this system moved westwards and reached southern Tamil Nadu, it gave impetus to the northeast monsoon winds.<\/li>\n<\/ul>\n<\/li>\n<li>Heavy cloud convection\n<ul>\n<li>The above-mentioned system persisted over the southern Tamil Nadu region on December 18 and 19.<\/li>\n<li>A heavy cloud convection was observed here, resulting in exceptionally heavy rainfall (more than 200mm in 24 hours) in these areas.\n<ul>\n<li>Cloud convection is the process by which warm air rises and cool air sinks, transferring heat and mixing within a fluid.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h2>IMD\u2019s forecast<\/h2>\n<ul>\n<li>With the cyclonic circulation having completely moved away from the Indian land mass and currently located over southeast Arabian Sea, <u>there is no significant rainfall forecast or warning over Tamil Nadu<\/u>.<\/li>\n<li>However, the IMD has said that light to moderate intensity (upto 64mm in 24 hours) rainfall will occur in some places in southern Tamil Nadu.<\/li>\n<\/ul>\n<hr \/>\n<h3>Q1)\u00a0What is India Meteorological Department (IMD)?<\/h3>\n<p>The India Meteorological Department (IMD) is a government office and weather forecast agency. The Government of India established the IMD on January 15, 1875. The Ministry of Earth Sciences is the IMD&#8217;s parent organization.<\/p>\n<h3>Q2)\u00a0What is Inter Tropical Convergence Zone (ITCZ)?<\/h3>\n<p>The Intertropical Convergence Zone (ITCZ) is a low-pressure band that circles the Earth near the equator. It is where the trade winds of the Northern and Southern Hemispheres meet, causing frequent thunderstorms and heavy rain.<\/p>\n<hr \/>\n<p><strong>Source:<\/strong> <a href=\"https:\/\/indianexpress.com\/article\/explained\/explained-climate\/why-tamil-nadu-has-witnessed-heavy-rainfall-in-december-9077911\/\" target=\"_blank\" rel=\"nofollow noopener\"><u>Why Tamil Nadu has witnessed heavy rainfall in December<\/u><\/a><u> | <\/u><a href=\"https:\/\/weather.com\/en-IN\/india\/news\/news\/2022-10-28-northeast-monsoon-meaning-cause-importance-for-tamil-nadu-faqs\" target=\"_blank\" rel=\"nofollow noopener\"><u>The Weather Channel<\/u><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The northeast monsoon is key for Tamil Nadu, Kerala, coastal Andhra Pradesh etc. in southern India.<\/p>\n","protected":false},"author":5,"featured_media":38690,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[18],"tags":[],"class_list":{"0":"post-38689","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-upsc-mains-current-affairs","8":"no-featured-image-padding"},"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/38689","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/comments?post=38689"}],"version-history":[{"count":0,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/38689\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media\/38690"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media?parent=38689"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/categories?post=38689"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/tags?post=38689"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}