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Author
Ali, M. ; Singh, N. ; Kumar, M. ; Zheng, Y. ; Bourassa, M. ; Kishtawal, C. ; Rao, C.
Title
Dominant Modes of Upper Ocean Heat Content in the North Indian Ocean
Type
$loc['typeJournal Article']
Year
2018
Publication
Climate
Abbreviated Journal
Climate
Volume
6
Issue
3
Pages
71
Keywords
ocean heat content ; tropical cyclone heat potential ; dominant modes ; North Indian Ocean ; SUMMER MONSOON ; INTENSIFICATION ; INTENSITY ; PACIFIC
Abstract
The thermal energy needed for the development of hurricanes and monsoons as well as any prolonged marine weather event comes from layers in the upper oceans, not just from the thin layer represented by sea surface temperature alone. Ocean layers have different modes of thermal energy variability because of the different time scales of ocean-atmosphere interaction. Although many previous studies have focused on the influence of upper ocean heat content (OHC) on tropical cyclones and monsoons, no study thus farparticularly in the North Indian Ocean (NIO)has specifically concluded the types of dominant modes in different layers of the ocean. In this study, we examined the dominant modes of variability of OHC of seven layers in the NIO during 1998-2014. We conclude that the thermal variability in the top 50 m of the ocean had statistically significant semiannual and annual modes of variability, while the deeper layers had the annual mode alone. Time series of OHC for the top four layers were analyzed separately for the NIO, Arabian Sea, and Bay of Bengal. For the surface to 50 m layer, the lowest and the highest values of OHC were present in January and May every year, respectively, which was mainly caused by the solar radiation cycle.
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Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
2225-1154
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ rl18 @
Serial
986
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Author
Ali, M.M. ; Nagamani, P.V. ; Sharma, N. ; Venu Gopal, R.T. ; Rajeevan, M. ; Goni, G.J. ; Bourassa, M.A.
Title
Relationship between ocean mean temperatures and Indian summer monsoon rainfall
Type
$loc['typeJournal Article']
Year
2015
Publication
Atmospheric Science Letters
Abbreviated Journal
Atmos. Sci. Lett.
Volume
16
Issue
3
Pages
408-413
Keywords
ocean mean temperature ; Indian summer monsoon rainfall ; remote sensing ; sea surface height anomaly
Abstract
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Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
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Series Volume
Series Issue
Edition
ISSN
1530261X
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ mfield @
Serial
94
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Author
Bhardwaj, A. ; Misra, V.
Title
Monitoring the Indian Summer Monsoon Evolution at the Granularity of the Indian Meteorological Sub-divisions using Remotely Sensed Rainfall Products
Type
$loc['typeJournal Article']
Year
2019
Publication
Remote Sensing
Abbreviated Journal
Remote Sensing
Volume
11
Issue
9
Pages
1080
Keywords
Indian Summer Monsoon ; GPM ; TRMM satellite precipitation ; meteorological sub-divisions
Abstract
We make use of satellite-based rainfall products from the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) to objectively define local onset and demise of the Indian Summer Monsoon (ISM) at the spatial resolution of the meteorological subdivisions defined by the Indian Meteorological Department (IMD). These meteorological sub-divisions are the operational spatial scales for official forecasts issued by the IMD. Therefore, there is a direct practical utility to target these spatial scales for monitoring the evolution of the ISM. We find that the diagnosis of the climatological onset and demise dates and its variations from the TMPA product is quite similar to the rain gauge based analysis of the IMD, despite the differences in the duration of the two datasets. This study shows that the onset date variations of the ISM have a significant impact on the variations of the seasonal length and seasonal rainfall anomalies in many of the meteorological sub-divisions: for example, the early or later onset of the ISM is associated with longer and wetter or shorter and drier ISM seasons, respectively. It is shown that TMPA dataset (and therefore its follow up Global Precipitation Measurement (GPM) Integrated Multi-satellite Retrievals for GPM (IMERG)) could be usefully adopted for monitoring the onset of the ISM and therefore extend its use to anticipate the potential anomalies of the seasonal length and seasonal rainfall anomalies of the ISM in many of the Indian meteorological sub-divisions. View Full-Text
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Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
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Series Volume
Series Issue
Edition
ISSN
2072-4292
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1026
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Author
Karmakar, N. ; Misra, V.
Title
The Relation of Intraseasonal Variations With Local Onset and Demise of the Indian Summer Monsoon
Type
$loc['typeJournal Article']
Year
2019
Publication
Journal of Geophysical Research: Atmospheres
Abbreviated Journal
J. Geophys. Res. Atmos.
Volume
124
Issue
5
Pages
2483-2506
Keywords
hydroclimatic, Indian Summer Monsoon, Intraseasonal Oscillations, eastern Indiawestward propagating
Abstract
Two of the most important hydroclimatic features of the Indian Summer Monsoon (ISM) rainfall are its onset/demise and Intraseasonal Oscillations (ISOs) manifested by the active‐break cycles. In this study, we aim to understand the quantitative association between these two phenomena. An objective definition of local onset/demise of the ISM based on more than a century‐long India Meteorological Department (IMD) rain‐gauge observation is taken into consideration. Using multichannel singular spectrum analysis (MSSA) we isolate northward propagating low‐ (20–60 days; LF‐ISO) and northwestward propagating high‐ (10–20 days; HF‐ISO) frequency ISOs from the daily ISM rainfall. Our results suggest that a large number of local onset (59%) and demise (62%) events occur during positive developing phases and positive decaying phases of two ISOs, respectively, with phase‐locking between LF‐ISO and HF‐ISO being particularly important. Local onset is largely associated with favorable phases of ISOs across India except for LF‐ISO over eastern India and HF‐ISO over western Ghats and central India (CI). We find that local demise is more coherent with the ISO phases, especially with HF‐ISO across the domain. We performed a case study to understand large‐scale association with the onset of the ISM over CI. In 44 of total 58 cases (1948–2005), when CI onset occurred during favorable LF‐ISO or HF‐ISO phase, they are either linked with a northward propagation of convection from the equator in LF‐ISO timescale (28 cases) or westward propagating structures from the western Pacific in HF‐ISO timescale (27 cases).
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Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
2169-897X
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1014
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Author
Misra, V. ; Bhardwaj, A.
Title
Defining the Northeast Monsoon of India
Type
$loc['typeJournal Article']
Year
2019
Publication
Monthly Weather Review
Abbreviated Journal
Mon. Wea. Rev.
Volume
147
Issue
3
Pages
791-807
Keywords
Indian Summer Monsoon, intraseasonal,Climate models, variability, NEM, rainfall
Abstract
This study introduces an objective definition for onset and demise of the Northeast Indian Monsoon (NEM). The definition is based on the land surface temperature analysis over the Indian subcontinent. It is diagnosed from the inflection points in the daily anomaly cumulative curve of the area-averaged surface temperature over the provinces of Andhra Pradesh, Rayalseema, and Tamil Nadu located in the southeastern part of India. Per this definition, the climatological onset and demise dates of the NEM season are 6 November and 13 March, respectively. The composite evolution of the seasonal cycle of 850hPa winds, surface wind stress, surface ocean currents, and upper ocean heat content suggest a seasonal shift around the time of the diagnosed onset and demise dates of the NEM season. The interannual variations indicate onset date variations have a larger impact than demise date variations on the seasonal length, seasonal anomalies of rainfall, and surface temperature of the NEM. Furthermore, it is shown that warm El Niño�Southern Oscillation (ENSO) episodes are associated with excess seasonal rainfall, warm seasonal land surface temperature anomalies, and reduced lengths of the NEM season. Likewise, cold ENSO episodes are likely to be related to seasonal deficit rainfall anomalies, cold land surface temperature anomalies, and increased lengths of the NEM season.
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Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
English
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
0027-0644
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ rl18 @
Serial
999
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