Central Asia Subtropical Westerly Jet Influences Interannual Variability of Northwest Indian Summer Monsoon rainfall

Central Asia Subtropical Westerly Jet Influences Interannual Variability of Northwest Indian Summer Monsoon rainfall | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Central Asia Subtropical Westerly Jet Influences Interannual Variability of Northwest Indian Summer Monsoon rainfall Nabeela Sadaf, Yanluan Lin, Wenhao Dong This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1255732/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In addition to various factors over the tropics, the interannual variability of northwest Indian summer monsoon (NWISM) rainfall is also regulated by extratropical signals. We defined a subtropical westerly jet index (SWJI) based on the meridional position and intensity of 200-hPa zonal wind within [25-55°N, 40-90°E]. It is found that SWJI exhibits a significant positive correlation with summer rainfall over the NWISM region during 1951-2015. During positive (negative) SWJI years, an upper-level anticyclonic (cyclonic) anomaly over Central Asia along with positive (negative) rainfall anomaly and low-level easterly (westerly) anomalies were observed over the NWISM region. The upper-level anticyclonic (cyclonic) anomaly was accompanied by the descending (ascending) motion and warm (cold) tropospheric temperature anomalies. The anticyclonic (cyclonic) anomaly increased (decreased) the land-ocean thermal contrast by warm (cold) air advection and modified the local meridional circulation. Interannual variability of rainfall over the NWISM region is associated with the meridional position and intensity of the jet that manifest in both upper- and low-level circulation anomalies. Further analysis showed that the interannual variability of SWJI is correlated with Arctic Oscillation (AO). During the positive phase of AO, an upper-level anticyclonic anomaly appeared over Central Asia and favored convection over the NWISM region. westerly jet rainfall interannual variability Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Full Text Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-1255732","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":80114863,"identity":"05b6d1e4-bea8-47a3-96aa-8a18bf93fc1a","order_by":0,"name":"Nabeela 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Westerly Jet Influences Interannual Variability of Northwest Indian Summer Monsoon rainfall","fulltext":[{"header":"Full Text","content":"This preprint is available for \u003ca href='/article/rs-1255732/latest.pdf' target='_blank'\u003edownload as a PDF\u003c/a\u003e."}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"westerly jet, rainfall, interannual variability","lastPublishedDoi":"10.21203/rs.3.rs-1255732/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1255732/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"In addition to various factors over the tropics, the interannual variability of northwest Indian summer monsoon (NWISM) rainfall is also regulated by extratropical signals. We defined a subtropical westerly jet index (SWJI) based on the meridional position and intensity of 200-hPa zonal wind within [25-55°N, 40-90°E]. It is found that SWJI exhibits a significant positive correlation with summer rainfall over the NWISM region during 1951-2015. During positive (negative) SWJI years, an upper-level anticyclonic (cyclonic) anomaly over Central Asia along with positive (negative) rainfall anomaly and low-level easterly (westerly) anomalies were observed over the NWISM region. The upper-level anticyclonic (cyclonic) anomaly was accompanied by the descending (ascending) motion and warm (cold) tropospheric temperature anomalies. The anticyclonic (cyclonic) anomaly increased (decreased) the land-ocean thermal contrast by warm (cold) air advection and modified the local meridional circulation. Interannual variability of rainfall over the NWISM region is associated with the meridional position and intensity of the jet that manifest in both upper- and low-level circulation anomalies. Further analysis showed that the interannual variability of SWJI is correlated with Arctic Oscillation (AO). During the positive phase of AO, an upper-level anticyclonic anomaly appeared over Central Asia and favored convection over the NWISM region.","manuscriptTitle":"Central Asia Subtropical Westerly Jet Influences Interannual Variability of Northwest Indian Summer Monsoon rainfall","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-01-31 15:39:37","doi":"10.21203/rs.3.rs-1255732/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"90c6f32b-19e6-43ee-8011-b03cf77cfd67","owner":[],"postedDate":"January 31st, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2022-03-18T06:50:45+00:00","versionOfRecord":[],"versionCreatedAt":"2022-01-31 15:39:37","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1255732","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1255732","identity":"rs-1255732","version":["v1"]},"buildId":"WrCJVZZCHTDjtuVLN7oU0","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}