An assessment of data requirements for quasigeostrophic nowcasts and hindcasts of a mesoscale eddy field in the California Current System with application to fall transition
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Authors
Johnson, John Edward.
Subjects
Mesoscale Ocean Models
Fall Transition
AVHRR
Data Requirements
California Current System
GEOSAT Altimetry
Fall Transition
AVHRR
Data Requirements
California Current System
GEOSAT Altimetry
Advisors
Mooers, Christopher N.K.
Date of Issue
1990-03
Date
March 1990
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
An extensive Ocean Prediction Through Observation, Modeling, and Analysis (OPTOMA) domain, off Northern and Central California, was surveyed in November 1986, during OPTOMA 23. Surface dynamic height (SDH), sea surface temperature (SST), and other fields were mapped with a Gandin objective analysis (OA) model; stream function nowcasts and hindcasts of the mesoscale oceanic field were generated by a quasigeostrophic (QG) model, initialized and updated with OA fields of dynamic topography. The westward propagation, at 5-to-10 km/day, of an anticyclone was the predominant mesoscale event; cyclonic features were quasi-stationary. The Generalized Digital Environmental Model had accurate averages and ranges of values, but was not representative of the mesoscale field, Because the mesoscale field did not change much over the ten-day period, persistence fields scored well. QG hindcasts were most sensitive to data density, The transition in the autumn of 1986 in the California Current System was a chronic event; winds favorable for upwelling fluctuated and diminished in late Oct. but occurred during short periods through Dec. A balance of alongshore pressure gradient and wind stress at Monterey shifted from a maximum southward in late Nov. to maximum northward two weeks later. The northward nearshore flow was observed in satellite imagery, SDH and SSH OA fields, and in QG hindcasts.
Type
Thesis
Description
Series/Report No
Department
Oceanography
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
Format
xxiii, 345 p. ; ill.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Approved for public release; distribution is unlimited.
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.