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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.
Address
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
Permanent link to this record
Author
Holbach, H.M. ; Uhlhorn, E.W. ; Bourassa, M.A.
Title
Off-Nadir SFMR Brightness Temperature Measurements in High-Wind Conditions
Type
$loc['typeJournal Article']
Year
2018
Publication
Journal of Atmospheric and Oceanic Technology
Abbreviated Journal
J. Atmos. Oceanic Technol.
Volume
35
Issue
9
Pages
1865-1879
Keywords
Tropical cyclones ; Wind ; Air-sea interaction ; Microwave observations ; Remote sensing ; Surface observations
Abstract
Wind and wave-breaking directions are investigated as potential sources of an asymmetry identified in off-nadir remotely sensed measurements of ocean surface brightness temperatures obtained by the Stepped Frequency Microwave Radiometer (SFMR) in high-wind conditions, including in tropical cyclones. Surface wind speed, which dynamically couples the atmosphere and ocean, can be inferred from SFMR ocean surface brightness temperature measurements using a radiative transfer model and an inversion algorithm. The accuracy of the ocean surface brightness temperature to wind speed calibration relies on accurate knowledge of the surface variables that are influencing the ocean surface brightness temperature. Previous studies have identified wind direction signals in horizontally polarized radiometer measurements in low to moderate (0�20 m s−1) wind conditions over a wide range of incidence angles. This study finds that the azimuthal asymmetry in the off-nadir SFMR brightness temperature measurements is also likely a function of wind direction and extends the results of these previous studies to high-wind conditions. The off-nadir measurements from the SFMR provide critical data for improving the understanding of the relationships between brightness temperature, surface wave�breaking direction, and surface wind vectors at various incidence angles, which is extremely useful for the development of geophysical model functions for instruments like the Hurricane Imaging Radiometer (HIRAD).
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Publisher
Place of Publication
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Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
0739-0572
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ rl18 @
Serial
980
Permanent link to this record
Author
Ansong, J.K. ; Arbic, B.K. ; Simmons, H.L. ; Alford, M.H. ; Buijsman, M.C. ; Timko, P.G. ; Richman, J.G. ; Shriver, J.F. ; Wallcraft, A.J.
Title
Geographical Distribution of Diurnal and Semidiurnal Parametric Subharmonic Instability in a Global Ocean Circulation Model
Type
$loc['typeJournal Article']
Year
2018
Publication
Journal of Physical Oceanography
Abbreviated Journal
J. Phys. Oceanogr.
Volume
48
Issue
6
Pages
1409-1431
Keywords
Baroclinic flows ; Internal waves ; Nonlinear dynamics ; Ocean dynamics ; Baroclinic models ; Ocean models
Abstract
The evidence for, baroclinic energetics of, and geographic distribution of parametric subharmonic instability (PSI) arising from both diurnal and semidiurnal tides in a global ocean general circulation model is investigated using 1/12.5° and 1/25° simulations that are forced by both atmospheric analysis fields and the astronomical tidal potential. The paper examines whether PSI occurs in the model, and whether it accounts for a significant fraction of the tidal baroclinic energy loss. Using energy transfer calculations and bispectral analyses, evidence is found for PSI around the critical latitudes of the tides. The intensity of both diurnal and semidiurnal PSI in the simulations is greatest in the upper ocean, consistent with previous results from idealized simulations, and quickly drops off about 5° from the critical latitudes. The sign of energy transfer depends on location; the transfer is positive (from the tides to subharmonic waves) in some locations and negative in others. The net globally integrated energy transfer is positive in all simulations and is 0.5%�10% of the amount of energy required to close the baroclinic energy budget in the model. The net amount of energy transfer is about an order of magnitude larger in the 1/25° semidiurnal simulation than the 1/12.5° one, implying the dependence of the rate of energy transfer on model resolution.
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Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
0022-3670
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
976
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Author
Liu, Y. ; Tan, Z.-M. ; Wu, Z.
Title
Noninstantaneous Wave-CISK for the Interaction between Convective Heating and Low-Level Moisture Convergence in the Tropics
Type
$loc['typeJournal Article']
Year
2019
Publication
Journal of the Atmospheric Sciences
Abbreviated Journal
J. Atmos. Sci.
Volume
76
Issue
7
Pages
2083-2101
Keywords
Convection ; Diabatic heating ; Moisture ; moisture budget
Abstract
The interaction between tropical convective heating and thermally forced circulation is investigated using a global dry primitive-equation model with the parameterization of wave-conditional instability of the second kind (CISK). It is demonstrated that deep convective heating can hardly sustain itself through the moisture convergence at low levels regardless of the fraction of immediate consumption of converged moisture. In contrast, when the fraction is large, shallow convective heating and its forced circulation exhibit preferred growth of small scales. As the “CISK catastrophe” mainly comes from the instantaneous characters of moisture-convection feedback in the conventional wave-CISK, a noninstantaneous wave-CISK is proposed, which highlights the accumulation-consumption (AC) time scale for the convective heating accumulation and/or the converged moisture consumption. In the new wave-CISK, once moisture is converged, the release of latent heat takes place gradually within an AC time scale. In this sense, convective heating is not only related to the instantaneous moisture convergence at the current time, but also to that which occurred in the past period of the AC time scale. The noninstantaneous wave-CISK could guarantee the occurrence of convective heating and/or moisture convergence at larger scales, and then favor the growth of long waves, and thus solve the problem of CISK catastrophe. With the new wave-CISK and AC time scale of 2 days, the simulated convective heating-driven system bears a large similarity to that of the observed convectively coupled Kelvin wave.
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Publisher
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Summary Language
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Series Editor
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Series Volume
Series Issue
Edition
ISSN
0022-4928
ISBN
Medium
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Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1065
Permanent link to this record
Author
Maloney, E.D. ; Gettelman, A. ; Ming, Y. ; Neelin, J.D. ; Barrie, D. ; Mariotti, A. ; Chen, C.-C. ; Coleman, D.R.B. ; Kuo, Y.-H. ; Singh, B. ; Annamalai, H. ; Berg, A. ; Booth, J.F. ; Camargo, S.J. ; Dai, A. ; Gonzalez, A. ; Hafner, J. ; Jiang, X. ; Jing, X. ; Kim, D. ; Kumar, A. ; Moon, Y. ; Naud, C.M. ; Sobel, A.H. ; Suzuki, K. ; Wang, F. ; Wang, J. ; Wing, A.A. ; Xu, X. ; Zhao, M.
Title
Process-Oriented Evaluation of Climate and Weather Forecasting Models
Type
$loc['typeJournal Article']
Year
2019
Publication
Bulletin of the American Meteorological Society
Abbreviated Journal
Bull. Amer. Meteor. Soc.
Volume
100
Issue
9
Pages
1665-1686
Keywords
Abstract
Realistic climate and weather prediction models are necessary to produce confidence in projections of future climate over many decades and predictions for days to seasons. These models must be physically justified and validated for multiple weather and climate processes. A key opportunity to accelerate model improvement is greater incorporation of process-oriented diagnostics (PODs) into standard packages that can be applied during the model development process, allowing the application of diagnostics to be repeatable across multiple model versions and used as a benchmark for model improvement. A POD characterizes a specific physical process or emergent behavior that is related to the ability to simulate an observed phenomenon. This paper describes the outcomes of activities by the Model Diagnostics Task Force (MDTF) under the NOAA Climate Program Office (CPO) Modeling, Analysis, Predictions and Projections (MAPP) program to promote development of PODs and their application to climate and weather prediction models. MDTF and modeling center perspectives on the need for expanded process-oriented diagnosis of models are presented. Multiple PODs developed by the MDTF are summarized, and an open-source software framework developed by the MDTF to aid application of PODs to centers' model development is presented in the context of other relevant community activities. The paper closes by discussing paths forward for the MDTF effort and for community process-oriented diagnosis.
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Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
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Series Volume
Series Issue
Edition
ISSN
0003-0007
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1088
Permanent link to this record
Author
Hoffman, R.N. ; Privé, N. ; Bourassa, M.
Title
Comments on “Reanalyses and Observations: What's the Difference?”
Type
$loc['typeJournal Article']
Year
2017
Publication
Bulletin of the American Meteorological Society
Abbreviated Journal
Bull. Amer. Meteor. Soc.
Volume
98
Issue
11
Pages
2455-2459
Keywords
GEOPHYSICAL DATA ; marine surface winds ; energy and water cycles
Abstract
Are there important differences between reanalysis data and familiar observations and measurements? If so, what are they? This essay evaluates four possible answers that relate to: the role of inference, reliance on forecasts, the need to solve an ill-posed inverse problem, and understanding of errors and uncertainties. The last of these is argued to be most significant. The importance of characterizing uncertainties associated with results—whether those results are observations or measurements, analyses or reanalyses, or forecasts—is emphasized.
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Publisher
Place of Publication
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Summary Language
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Series Editor
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Series Volume
Series Issue
Edition
ISSN
0003-0007
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ rl18 @
Serial
990
Permanent link to this record
Author
Smith, S.R. ; Briggs, K. ; Bourassa, M.A. ; Elya, J. ; Paver, C.R.
Title
Shipboard automated meteorological and oceanographic system data archive: 2005-2017
Type
$loc['typeJournal Article']
Year
2018
Publication
Geoscience Data Journal
Abbreviated Journal
Geosci Data J
Volume
5
Issue
2
Pages
73-86
Keywords
data stewardship ; marine meteorology ; open data access ; quality control ; thermosalinograph
Abstract
Since 2005, the Shipboard Automated Meteorological and Oceanographic System (SAMOS) initiative has been collecting, quality-evaluating, distributing, and archiving underway navigational, meteorological, and oceanographic observations from research vessels. Herein we describe the procedures for acquiring ship and instrumental metadata and the one-minute interval observations from 44 research vessels that have contributed to the SAMOS initiative from 2005 to 2017. The overall data processing workflow and quality control procedures are documented along with data file formats and version control procedures. The SAMOS data are disseminated to the user community via web, FTP, and Thematic Real-time Environmental Distributed Data Services from both the Marine Data Center at the Florida State University and the National Centers for Environmental Information, which serves as the long-term archive for the SAMOS initiative. They have been used to address topics ranging from air-sea interaction studies, the calibration, evaluation, and development of satellite observational products, the evaluation of numerical atmospheric and ocean models, and the development of new tools and techniques for geospatial data analysis in the informatics community. Maps provide users the geospatial coverage within the SAMOS dataset, with a focus on the Essential Climate/Ocean Variables, and recommendations are made regarding which versions of the dataset should be accessed by different user communities.
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
2049-6060
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ rl18 @
Serial
979
Permanent link to this record
Author
Yu, B. ; Seed, A. ; Pu, L. ; Malone, T.
Title
Integration of weather radar data into a raster GIS framework for improved flood estimation
Type
$loc['typeJournal Article']
Year
2019
Publication
Atmospheric Science Letters
Abbreviated Journal
Atmos. Sci. Lett.
Volume
6
Issue
1
Pages
Keywords
Abstract
We present in this paper the interannual variability of seasonal temperature and rainfall in the Indian meteorological subdivisions (IMS) for boreal winter and summer seasons that take in to account the varying length of the seasons.Our study reveals that accounting for the variations in the length of the sea-sons produces stronger teleconnections between the seasonal anomalies of surface temperature and rainfall over India with corresponding sea surface temperature anomalies of the tropical Oceans (especially over the northern Indian and the equatorial Pacific Oceans) compared to the same teleconnections from fixed length seasons over the IMS. It should be noted that the IMS show significant spatial heterogeneity in these teleconnections
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
1530-261X
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1069
Permanent link to this record
Author
Luecke, C.A. ; Arbic, B.K. ; Bassette, S.L. ; Richman, J.G. ; Shriver, J.F. ; Alford, M.H. ; Smedstad, O.M. ; Timko, P.G. ; Trossman, D.S. ; Wallcraft, A.J.
Title
The Global Mesoscale Eddy Available Potential Energy Field in Models and Observations: GLOBAL LOW-FREQUENCY EDDY APE
Type
$loc['typeJournal Article']
Year
2017
Publication
Journal of Geophysical Research: Oceans
Abbreviated Journal
J. Geophys. Res. Oceans
Volume
122
Issue
11
Pages
9126-9143
Keywords
eddy available potential energy ; mesoscale eddies ; mixing ; model‐ ; data comparison ; ocean energy reservoirs ; Argo
Abstract
Global maps of the mesoscale eddy available potential energy (EAPE) field at a depth of 500 m are created using potential density anomalies in a high‐resolution 1/12.5° global ocean model. Maps made from both a free‐running simulation and a data‐assimilative reanalysis of the HYbrid Coordinate Ocean Model (HYCOM) are compared with maps made by other researchers from density anomalies in Argo profiles. The HYCOM and Argo maps display similar features, especially in the dominance of western boundary currents. The reanalysis maps match the Argo maps more closely, demonstrating the added value of data assimilation. Global averages of the simulation, reanalysis, and Argo EAPE all agree to within about 10%. The model and Argo EAPE fields are compared to EAPE computed from temperature anomalies in a data set of “moored historical observations” (MHO) in conjunction with buoyancy frequencies computed from a global climatology. The MHO data set allows for an estimate of the EAPE in high‐frequency motions that is aliased into the Argo EAPE values. At MHO locations, 15–32% of the EAPE in the Argo estimates is due to aliased motions having periods of 10 days or less. Spatial averages of EAPE in HYCOM, Argo, and MHO data agree to within 50% at MHO locations, with both model estimates lying within error bars observations. Analysis of the EAPE field in an idealized model, in conjunction with published theory, suggests that much of the scatter seen in comparisons of different EAPE estimates is to be expected given the chaotic, unpredictable nature of mesoscale eddies.
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
2169-9275
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ rl18 @
Serial
992
Permanent link to this record
Author
Savage, A.C. ; Arbic, B.K. ; Alford, M.H. ; Ansong, J.K. ; Farrar, J.T. ; Menemenlis, D. ; O'Rourke, A.K. ; Richman, J.G. ; Shriver, J.F. ; Voet, G. ; Wallcraft, A.J. ; Zamudio, L.
Title
Spectral decomposition of internal gravity wave sea surface height in global models: INTERNAL GRAVITY WAVE SEA SURFACE HEIGHT
Type
$loc['typeJournal Article']
Year
2017
Publication
Journal of Geophysical Research: Oceans
Abbreviated Journal
J. Geophys. Res. Oceans
Volume
122
Issue
10
Pages
7803-7821
Keywords
high-frequency motions ; atmospheric pressure ; dynamic height
Abstract
Two global ocean models ranging in horizontal resolution from 1/128 to 1/488 are used to study the space and time scales of sea surface height (SSH) signals associated with internal gravity waves (IGWs). Frequency-horizontal wavenumber SSH spectral densities are computed over seven regions of the world ocean from two simulations of the HYbrid Coordinate Ocean Model (HYCOM) and three simulations of the Massachusetts Institute of Technology general circulation model (MITgcm). High wavenumber, high-frequency SSH variance follows the predicted IGW linear dispersion curves. The realism of high-frequency motions (>0:87 cpd) in the models is tested through comparison of the frequency spectral density of dynamic height variance computed from the highest-resolution runs of each model (1/258 HYCOM and 1/488 MITgcm) with dynamic height variance frequency spectral density computed from nine in situ profiling instruments. These high-frequency motions are of particular interest because of their contributions to the small-scale SSH variability that will be observed on a global scale in the upcoming Surface Water and Ocean Topography (SWOT) satellite altimetry mission. The variance at supertidal frequencies can be comparable to the tidal and low-frequency variance for high wavenumbers (length scales smaller than 50 km), especially in the higher-resolution simulations. In the highest-resolution simulations, the high-frequency variance can be greater than the low-frequency variance at these scales.
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
2169-9275
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ rl18 @
Serial
993
Permanent link to this record