Simulation of the Indian summer monsoon onset-phase rainfall using a regional model

Handle URI:
http://hdl.handle.net/10754/579817
Title:
Simulation of the Indian summer monsoon onset-phase rainfall using a regional model
Authors:
Srinivas, C. V.; Hari Prasad, D.; Bhaskar Rao, D. V.; Baskaran, R.; Venkatraman, B.
Abstract:
This study examines the ability of the Advanced Research WRF (ARW) regional model to simulate Indian summer monsoon (ISM) rainfall climatology in different climate zones during the monsoon onset phase in the decade 2000–2009. The initial and boundary conditions for ARW are provided from the NCEP/NCAR Reanalysis Project (NNRP) global reanalysis. Seasonal onset-phase rainfall is compared with corresponding values from 0.25° IMD (India Meteorological Department) rainfall and NNRP precipitation data over seven climate zones (perhumid, humid, dry/moist, subhumid, dry/moist, semiarid and arid) of India to see whether dynamical downscaling using a regional model yields advantages over just using large-scale model predictions. Results show that the model could simulate the onset phase in terms of progression and distribution of rainfall in most zones (except over the northeast) with good correlations and low error metrics. The observed mean onset dates and their variability over different zones are well reproduced by the regional model over most climate zones. It has been found that the ARW performed similarly to the reanalysis in most zones and improves the onset time by 1 to 3 days in zones 4 and 7, in which the NNRP shows a delayed onset compared to the actual IMD onset times. The variations in the onset-phase rainfall during the below-normal onset (June negative) and above-normal onset (June positive) phases are well simulated. The slight underestimation of onset-phase rainfall in the northeast zone could be due to failure in resolving the wide extent of topographic variations and the associated multiscale interactions in that zone. Spatial comparisons showed improvement of pentad rainfall in both space and quantity in ARW simulations over NNRP data, as evident from a wider eastward distribution of pentad rainfall over the Western Ghats, central and eastern India, as in IMD observations. While NNRP under-represented the high pentad rainfall over northeast, east and west coast areas, the ARW captured these regional features showing improvement upon NNRP reanalysis, which may be due to the high resolution (30 km) employed. The onset-phase rainfall characteristics during the contrasting ISM of 2003 and 2009 are well simulated in terms of the variations in the strength of low-level jet (LLJ) and outgoing long-wave radiation (OLR).
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Citation:
Simulation of the Indian summer monsoon onset-phase rainfall using a regional model 2015, 33 (9):1097 Annales Geophysicae
Publisher:
Copernicus GmbH
Journal:
Annales Geophysicae
Issue Date:
11-Sep-2015
DOI:
10.5194/angeo-33-1097-2015
Type:
Article
ISSN:
1432-0576
Additional Links:
http://www.ann-geophys.net/33/1097/2015/
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorSrinivas, C. V.en
dc.contributor.authorHari Prasad, D.en
dc.contributor.authorBhaskar Rao, D. V.en
dc.contributor.authorBaskaran, R.en
dc.contributor.authorVenkatraman, B.en
dc.date.accessioned2015-10-18T14:34:43Zen
dc.date.available2015-10-18T14:34:43Zen
dc.date.issued2015-09-11en
dc.identifier.citationSimulation of the Indian summer monsoon onset-phase rainfall using a regional model 2015, 33 (9):1097 Annales Geophysicaeen
dc.identifier.issn1432-0576en
dc.identifier.doi10.5194/angeo-33-1097-2015en
dc.identifier.urihttp://hdl.handle.net/10754/579817en
dc.description.abstractThis study examines the ability of the Advanced Research WRF (ARW) regional model to simulate Indian summer monsoon (ISM) rainfall climatology in different climate zones during the monsoon onset phase in the decade 2000–2009. The initial and boundary conditions for ARW are provided from the NCEP/NCAR Reanalysis Project (NNRP) global reanalysis. Seasonal onset-phase rainfall is compared with corresponding values from 0.25° IMD (India Meteorological Department) rainfall and NNRP precipitation data over seven climate zones (perhumid, humid, dry/moist, subhumid, dry/moist, semiarid and arid) of India to see whether dynamical downscaling using a regional model yields advantages over just using large-scale model predictions. Results show that the model could simulate the onset phase in terms of progression and distribution of rainfall in most zones (except over the northeast) with good correlations and low error metrics. The observed mean onset dates and their variability over different zones are well reproduced by the regional model over most climate zones. It has been found that the ARW performed similarly to the reanalysis in most zones and improves the onset time by 1 to 3 days in zones 4 and 7, in which the NNRP shows a delayed onset compared to the actual IMD onset times. The variations in the onset-phase rainfall during the below-normal onset (June negative) and above-normal onset (June positive) phases are well simulated. The slight underestimation of onset-phase rainfall in the northeast zone could be due to failure in resolving the wide extent of topographic variations and the associated multiscale interactions in that zone. Spatial comparisons showed improvement of pentad rainfall in both space and quantity in ARW simulations over NNRP data, as evident from a wider eastward distribution of pentad rainfall over the Western Ghats, central and eastern India, as in IMD observations. While NNRP under-represented the high pentad rainfall over northeast, east and west coast areas, the ARW captured these regional features showing improvement upon NNRP reanalysis, which may be due to the high resolution (30 km) employed. The onset-phase rainfall characteristics during the contrasting ISM of 2003 and 2009 are well simulated in terms of the variations in the strength of low-level jet (LLJ) and outgoing long-wave radiation (OLR).en
dc.language.isoenen
dc.publisherCopernicus GmbHen
dc.relation.urlhttp://www.ann-geophys.net/33/1097/2015/en
dc.rightsThis work is distributed under the Creative Commons Attribution 3.0 License.en
dc.titleSimulation of the Indian summer monsoon onset-phase rainfall using a regional modelen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalAnnales Geophysicaeen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionRadiological Safety Division, Radiological Safety {&} Envrionment Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Indiaen
dc.contributor.institutionCentre for Atmospheric Science, KL University, Vaddeswaram 522502, AP, Indiaen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorHari Prasad, D.en
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