Space/time features of the secular variation in 1951-1998 northern 500-hPaheight

Authors
Citation
N. Shin et Zw. Deng, Space/time features of the secular variation in 1951-1998 northern 500-hPaheight, METEOR ATM, 73(1-2), 2000, pp. 35-46
Citations number
32
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
METEOROLOGY AND ATMOSPHERIC PHYSICS
ISSN journal
0177-7971 → ACNP
Volume
73
Issue
1-2
Year of publication
2000
Pages
35 - 46
Database
ISI
SICI code
0177-7971(2000)73:1-2<35:SFOTSV>2.0.ZU;2-B
Abstract
This paper presents a trend coefficient as a characteristic index with whic h to investigate the 1951-1998 secular trend variation (STV) of northern 50 0-hPa height on a seasonal basis. Evidence suggests that low thigh) latitud e 500 hPa geopotential height displays a remarkably positive (negative) tre nd; the positive anomaly of the height is maintained over NW Africa, the we stern Mediterranean Sea and North Africa, mid-Pacific at lower latitudes, L ake Baikal and area to the east and NW North America; the height drops sign ificantly over the Aleutians and North Pacific, the area to the south of th e Greenland and NE North America and the sector to the north of the Arabian Sea. Further, analysis of abrupt change shows that the 500-hPa circulation s experience noticeable sudden change twice, once around the early 1960s an d again in 1976, during which period the height exhibits great differences between the Pacific and Atlantic. In the first period it drops (rises) over the mid-Atlantic at lower latitudes (NW Africa); in the second period the height rises (drops) over the mid-Pacific at lower latitudes and Lake Baika l (the North Pacific). Statistical tests indicate that in the 1976 case the low-Latitude positive abrupt change is even more noticeable compared to th e negative of the North Pacific, thus representing a large-scale jumping ev ent of the northern 500-hPa height.