Investigation of high and low predictability periods in medium range forecasts.
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Authors
Curtis, John E.
Subjects
Medium range
Predictability
Five day forecasts
NOGAPS
500 MB height fields
Flow characteristics
Error persistence
Predictability
Five day forecasts
NOGAPS
500 MB height fields
Flow characteristics
Error persistence
Advisors
Wash, C.H.
Boyle, J.S.
Date of Issue
1985
Date
December 1985
Publisher
Language
en_US
Abstract
Medium-range five-day forecasts from the U.S. Navy
Operational Global Atmospheric Prediction System (NOGAPS)
are investigated to study high and low predictability
periods from two winter seasons. Northern hemisphere 500 mb
height fields are scored using the anomaly correlation coefficient-
An objective method is used to choose high and low
scoring periods which are analyzed using height tendencies
and wavenumber structure. Results show that it is possible
to objectively determine why some high and low periods
occurred. Flow characteristics leading to high scoring
five-day forecasts include: long wave amplitude decay, transition
from meridional to zonal flow, and more meridionally
extensive flow patterns. This study revealed that persistence
is not a good indicator of model performance, and no
appreciable skill difference exists between good and poor
five-day forecasts at the 48 hour point- However, no single
measure of the flow patterns is found to be a unique indicator
of high or low scoring forecasts.
Type
Thesis
Description
Series/Report No
Department
Meteorology
Organization
Identifiers
NPS Report Number
Sponsors
Funder
Format
Citation
Distribution Statement
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.