Angular Momentum, Length of Day and Monsoonal Low Frequency Mode

Krishnamurti, T. N.; Sinha, M. C.; Krishnamurti, Ruby; Oosterhof, D.; Comeaux, Joseph

doi:10.2151/jmsj1965.70.1b_131

Cited by 19 publications

(7 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure indicates that the active and break composites from the RCOAM simulation are reasonably well captured when compared with the corresponding observations. The active spell is characterized by 850 hPa wind anomalies that reinforce the climatological southwesterly flow across the sub‐continent and the establishment of monsoon low over Central India (Krishnamurti et al ., ) as seen in the observations (Figure (a)) is represented reasonably well in the RCOAM simulation (Figure (b)). It may be noted, however, that the intraseasonal precipitation anomalies over the Bay of Bengal in the RCOAM simulation is comparatively weak (Figure (b)).…”

Section: Resultsmentioning

confidence: 99%

High‐resolution regional‐coupled ocean–atmosphere simulation of the Indian Summer Monsoon

Misra

Mishra

Bhardwaj

2017

Intl Journal of Climatology

View full text Add to dashboard Cite

A 23‐year integration of a Regional‐Coupled Ocean–Atmosphere Model (RCOAM) centred over the Indian monsoon region is validated with observations and analysis for its seasonal climatology, evolution, and variability at intraseasonal and interannual scales. The RCOAM has the Regional Spectral Model (RSM) as its atmospheric component and Regional Ocean Model System (ROMS) as its oceanic component. They are both coupled at 15 km grid spacing with identical grids, without applying any form of flux correction and are forced with global fields of atmospheric and oceanic reanalysis. The verification indicates that the RCOAM simulation simulates the mean Indian Summer Monsoon (ISM) rainfall climatology and SST in the neighbouring oceans reasonably well with finer details apparent along the orography (e.g. Western Ghats, Himalaya) and along the upwelling regions of the coastal oceans. In addition the evolution of the ISM at its onset and its devolution around the time of demise in the RCOAM simulation both in the atmosphere and the ocean conform to its well known features and reinforce the coupled ocean–atmosphere phenomenon of the ISM. The intraseasonal variations in the RCOAM simulation also adhere to the observed composite of dry and wet spells of the ISM, with the low‐level flow in the latter (former) counteracting (enhancing) the low‐level atmospheric ISM climatological flow. The interannual variations in relation to the remote ENSO variations are also validated with respect to the observations. It is also shown that the variations of the length of the ISM to the seasonal anomalies of the ISM both in the RCOAM simulation and observations is largely a result of the ENSO teleconnection. However, significant systematic bias in surface fluxes, cloud fraction, SST, and precipitation of the RCOAM simulation of the ISM is also noted.

show abstract

Section: Resultsmentioning

confidence: 99%

High‐resolution regional‐coupled ocean–atmosphere simulation of the Indian Summer Monsoon

Misra

Mishra

Bhardwaj

2017

Intl Journal of Climatology

View full text Add to dashboard Cite

show abstract

“…As the MJO wave traverses east from Africa to Asia, takes a northward swing during the northern hemisphere summer season at which point it has been associated with the Indian monsoonal Intraseasonal Oscillation (ISO) [ Yasunari , 1980; Sikka and Gadgil , 1980; Krishnamurti and Subrahmanyam , 1982; Waliser , 2006]. Recent reviews [e.g., Waliser , 2006; Krishnamurti et al , 1992] addresses the relationship among MJO and ISO. The MJO wave carries its largest amplitude in the equatorial latitude in roughly 20 to 60 days.…”

Section: Introductionmentioning

confidence: 99%

“…The ISO is a meridionally propagating wave that seems to originate in the southern equatorial through (which is located near 5°S and can be seen in the sea level pressure data sets). Two meridionally propagating components one moving north and another moving south originating from the southern equatorial trough can be mapped on latitude‐time diagram [ Krishnamurti et al , 1992], where it was noted that arrival of an active part of an MJO wave over the equatorial Indian Ocean often seem to trigger the ISO wave. The dynamics of this coupling of MJO and ISO is not clear at the present time.…”

Section: Introductionmentioning

confidence: 99%

Passage of intraseasonal waves in the subsurface oceans

Krishnamurti

Chakraborty

Krishnamurti

et al. 2007

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

[1] This study exploits the coverage of ARGO (Array for Real-time Geostrophic Oceanography) float data sets towards identifying passage of intraseasonal waves over the subsurface global oceans. ARGO, a new observing system, has provided an unprecedented data coverage and impact. The assimilation of ARGO data reveals that the subsurface ocean temperature carry signatures on the passage of the intraseasonal waves. This vast oceanic data sets provided an opportunity to explore the usefulness of coupled assimilation for seasonal forecasts on the passage of these waves. The results suggest that the inclusion of subsurface ARGO profiler data sets can be useful for prediction of the intraseasonal waves in the atmosphere/ oceans. These improved forecasts hold the promise for improved seasonal outlook projections for the dry and wet spells of the monsoon. We also demonstrate improved phase relationship on the passage of zonal wind anomalies of the intraseasonal waves and the monsoon rainfall.

show abstract

“…Such change of phase is absent over the higher latitudes. This is what we mean by the more baroclinic structure for the MJO time Krishnamurti et al 1992a) scale over the tropics and a more barotropic structure in the extratropics. The MJO is intimately connected to organized tropical convection that prefers a lower pressure in the lower troposphere and a higher pressure aloft.…”

Section: Observational Aspectsmentioning

confidence: 74%

“…Shaded area denotes negative values. The interval of analysis is shown on the top right of each panel (AfterKrishnamurti et al 1992a) …”

mentioning

confidence: 99%

Tropical Meteorology

Krishnamurti¹,

Stefanova²,

Misra³

2013

Springer Atmospheric Sciences

View full text Add to dashboard Cite

Angular Momentum, Length of Day and Monsoonal Low Frequency Mode

Abstract: In this paper some global aspects of the intraseasonal oscillations on the time scale of 30 to 50 days are explored.

Cited by 19 publications

References 39 publications

High‐resolution regional‐coupled ocean–atmosphere simulation of the Indian Summer Monsoon

High‐resolution regional‐coupled ocean–atmosphere simulation of the Indian Summer Monsoon

Passage of intraseasonal waves in the subsurface oceans

Tropical Meteorology

Contact Info

Product

Resources

About