Records
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.
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
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
Permanent link to this record
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
2019
Publication
Climate
Abbreviated Journal
Climate
Volume
6
Issue
71
Pages
1 – 8
Keywords
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 far—particularly 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.
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
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 @ user @
Serial
1030
Permanent link to this record
Author
Liu, M. ; Lin, J. ; Wang, Y. ; Sun, Y. ; Zheng, B. ; Shao, J. ; Chen, L. ; Zheng, Y. ; Chen, J. ; Fu, T.-M. ; Yan, Y. ; Zhang, Q. ; Wu, Z.
Title
Spatiotemporal variability of NO2 and PM2.5 over Eastern China: observational and model analyses with a novel statistical method
Type
$loc['typeJournal Article']
Year
2018
Publication
Atmospheric Chemistry and Physics
Abbreviated Journal
Atmos. Chem. Phys.
Volume
18
Issue
17
Pages
12933-12952
Keywords
TROPOSPHERIC NITROGEN-DIOXIDE ; PROVINCIAL CAPITAL CITIES ; CRITERIA AIR-POLLUTANTS ; BOUNDARY-LAYER ; NORTH CHINA ; HILBERT SPECTRUM ; UNITED-STATES ; TIME-SERIES ; OZONE ; EMISSIONS
Abstract
Eastern China (27-41 degrees N, 110-123 degrees E) is heavily polluted by nitrogen dioxide (NO2), particulate matter with aerodynamic diameter below 2.5 mu m (PM2.5), and other air pollutants. These pollutants vary on a variety of temporal and spatial scales, with many temporal scales that are nonperiodic and nonstationary, challenging proper quantitative characterization and visualization. This study uses a newly compiled EOF-EEMD analysis visualization package to evaluate the spatiotemporal variability of ground-level NO2, PM2.5, and their associations with meteorological processes over Eastern China in fall-winter 2013. Applying the package to observed hourly pollutant data reveals a primary spatial pattern representing Eastern China synchronous variation in time, which is dominated by diurnal variability with a much weaker day-to-day signal. A secondary spatial mode, representing north-south opposing changes in time with no constant period, is characterized by wind-related dilution or a buildup of pollutants from one day to another. We further evaluate simulations of nested GEOS-Chem v9-02 and WRF/CMAQ v5.0.1 in capturing the spatiotemporal variability of pollutants. GEOS-Chem underestimates NO2 by about 17 mu g m(-3) and PM2.5 by 35 mu g m(-3 )on average over fall-winter 2013. It reproduces the diurnal variability for both pollutants. For the day-to-day variation, GEOS-Chem reproduces the observed north-south contrasting mode for both pollutants but not the Eastern China synchronous mode (especially for NO2). The model errors are due to a first model layer too thick (about 130 m) to capture the near-surface vertical gradient, deficiencies in the nighttime nitrogen chemistry in the first layer, and missing secondary organic aerosols and anthropogenic dust. CMAQ overestimates the diurnal cycle of pollutants due to too-weak boundary layer mixing, especially in the nighttime, and overestimates NO2 by about 30 mu g m(-3) and PM2.5 by 60 mu g m(-3). For the day-to-day variability, CMAQ reproduces the observed Eastern China synchronous mode but not the north-south opposing mode of NO2. Both models capture the day-to-day variability of PM2.5 better than that of NO2. These results shed light on model improvement. The EOF-EEMD package is freely available for noncommercial uses.
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
1680-7324
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
946
Permanent link to this record
Author
Venugopal, T. ; Ali, M.M. ; Bourassa, M.A. ; Zheng, Y. ; Goni, G.J. ; Foltz, G.R. ; Rajeevan, M.
Title
Statistical Evidence for the Role of Southwestern Indian Ocean Heat Content in the Indian Summer Monsoon Rainfall
Type
$loc['typeJournal Article']
Year
2018
Publication
SCIENTIFIC REPORTS
Abbreviated Journal
Sci Rep
Volume
8
Issue
1
Pages
12092
Keywords
SEA-SURFACE TEMPERATURE ; EL-NINO ; EQUATORIAL PACIFIC ; IMPACT ; PREDICTION ; ENSO ; DIPOLE ; REGION ; SST
Abstract
This study examines the benefit of using Ocean Mean Temperature (OMT) to aid in the prediction of the sign of Indian Summer Monsoon Rainfall (ISMR) anomalies. This is a statistical examination, rather than a process study. The thermal energy needed for maintaining and intensifying hurricanes and monsoons comes from the upper ocean, not just from the thin layer represented by sea surface temperature (SST) alone. Here, we show that the southwestern Indian OMT down to the depth of the 26 degrees C isotherm during January-March is a better qualitative predictor of the ISMR than SST. The success rate in predicting above- or below-average ISMR is 80% for OMT compared to 60% for SST. Other January-March mean climate indices (e.g., NINO3.4, Indian Ocean Dipole Mode Index, El Nino Southern Oscillation Modoki Index) have less predictability (52%, 48%, and 56%, respectively) than OMT percentage deviation (PD) (80%). Thus, OMT PD in the southwestern Indian Ocean provides a better qualitative prediction of ISMR by the end of March and indicates whether the ISMR will be above or below the climatological mean value.
Address
Ministry of Earth Sciences, Government of India, New Delhi, India
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
2045-2322
ISBN
Medium
Area
Expedition
Conference
Funding
strtoupper('3').strtolower('0108244'); strtoupper('P').strtolower('MC6092415')
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
972
Permanent link to this record
Author
Zheng, Y. ; Ali, M.M. ; Bourassa, M.A.
Title
Contribution of Monthly and Regional Rainfall to the Strength of Indian Summer Monsoon
Type
$loc['typeJournal Article']
Year
2016
Publication
Monthly Weather Review
Abbreviated Journal
Mon. Wea. Rev.
Volume
144
Issue
9
Pages
3037-3055
Keywords
Abstract
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
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 @ mfield @
Serial
60
Permanent link to this record
Author
Zheng, Y. ; Bourassa, M. A. ; Dukhovskoy, D. S.
Title
Upper-Ocean Processes Controlling the Sea Surface Temperature in the Western Gulf of Mexico
Type
$loc['typeAbstract']
Year
2018
Publication
American Geophysical Union
Abbreviated Journal
AGU
Volume
Fall Meeting
Issue
Pages
Keywords
4299 General or miscellaneous, OCEANOGRAPHY: GENERAL
Abstract
This study examines the upper-ocean processes controlling the mixed layer temperature in the western Gulf of Mexico (GOM) through estimating the contributing terms in the heat equation, with an emphasis on eddies' role. The major heat contributing terms for the upper GOM were estimated using two ocean reanalysis datasets: an eddy-resolving HYbrid Coordinate Ocean Model (HYCOM) and a Simple Ocean Data Assimilation (SODA). Analysis of net surface heat fluxes from four datasets reveals that the long-term mean net surface heat flux cools the northern GOM and warms the southern GOM. Two regions are focused for analysis: an eddy-rich region where LCEs are energetic, and the southwestern Gulf where eddy activity is relatively weak and the features of near surface temperature differ from the eddy-rich region. An eddy-rich region in the western GOM is defined based on the eddy kinetic energy derived from satellite sea surface heights. The long-term mean horizontal heat advection causes a weak warming over most of the eddy rich region, partly attributed to the flow-temperature configuration that the long-term and seasonally mean flow is nearly parallel to the corresponding mean isotherms. By contrast, the temporal mean vertical heat advection causes a strong warming in the eddy rich region, partly balancing the cooling caused by net surface heat flux. The temporal mean eddy heat flux convergence in the western GOM, whose positive and negative values are not small at some locations, appears heterogeneous in space, resulting in a small term for the western GOM when area averaged. The persistent warm water in the southwestern Gulf is primarily caused by the net warming from net surface heat flux rather than from eddies and heat advection.
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1007
Permanent link to this record
Author
Zheng, Y. ; Bourassa, M.A. ; Ali, M.M. ; Krishnamurti, T.N.
Title
Distinctive features of rainfall over the Indian homogeneous rainfall regions between strong and weak Indian summer monsoons
Type
$loc['typeJournal Article']
Year
2016
Publication
Journal of Geophysical Research: Atmospheres
Abbreviated Journal
J. Geophys. Res. Atmos.
Volume
121
Issue
10
Pages
5631-5647
Keywords
Abstract
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
2169897X
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ mfield @
Serial
61
Permanent link to this record
Author
Zheng, Y. ; Bourassa, M.A. ; Hughes, P.
Title
Influences of Sea Surface Temperature Gradients and Surface Roughness Changes on the Motion of Surface Oil: A Simple Idealized Study
Type
$loc['typeJournal Article']
Year
2013
Publication
Journal of Applied Meteorology and Climatology
Abbreviated Journal
J. Appl. Meteor. Climatol.
Volume
52
Issue
7
Pages
1561-1575
Keywords
Air-sea interaction ; Boundary conditions ; Diagnostics ; Local effects ; Societal impacts ; Wind effects
Abstract
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
1558-8424
ISBN
Medium
Area
Expedition
Conference
Funding
GoMRI, OVWST
Approved
$loc['no']
Call Number
COAPS @ mfield @
Serial
229
Permanent link to this record
Author
Zheng, Y. ; Lin, J.-L. ; Shinoda, T.
Title
The equatorial Pacific cold tongue simulated by IPCC AR4 coupled GCMs: Upper ocean heat budget and feedback analysis
Type
$loc['typeJournal Article']
Year
2012
Publication
Journal of Geophysical Research: Oceans
Abbreviated Journal
J. Geophys. Res.
Volume
117
Issue
C5
Pages
Keywords
Abstract
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
0148-0227
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ mfield @
Serial
250
Permanent link to this record
Author
Zheng, Y. ; Shinoda, T. ; Lin, J.-L. ; Kiladis, G.N.
Title
Sea Surface Temperature Biases under the Stratus Cloud Deck in the Southeast Pacific Ocean in 19 IPCC AR4 Coupled General Circulation Models
Type
$loc['typeJournal Article']
Year
2011
Publication
Journal of Climate
Abbreviated Journal
J. Climate
Volume
24
Issue
15
Pages
4139-4164
Keywords
Abstract
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
0894-8755
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ mfield @
Serial
297
Permanent link to this record