scholarly journals Long-term trends in precipitation and temperature in the Norwegian Arctic: can they be explained by changes in atmospheric circulation patterns?

1998 ◽  
Vol 10 ◽  
pp. 143-153 ◽  
Author(s):  
I Hanssen-Bauer ◽  
EJ Førland
Keyword(s):  
Atmospheric Circulation ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Long Term Trends ◽  
Precipitation And Temperature

scholarly journals Recent Trends in the Recurrence of North Atlantic Atmospheric Circulation Patterns

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Pascal Yiou ◽  
Julien Cattiaux ◽  
Aurélien Ribes ◽  
Robert Vautard ◽  
Mathieu Vrac
Keyword(s):  
Atmospheric Circulation ◽  
North Atlantic ◽  
Atmospheric Circulation Patterns ◽  
The North ◽  
Emerging Trends ◽  
Circulation Patterns ◽  
Long Term Trends ◽  
Recent Trends ◽  
The Stability ◽  
Climate Events

A few types of extreme climate events in the North Atlantic region, such as heatwaves, cold spells, or high cumulated precipitation, are connected to the recurrence of atmospheric circulation patterns. Understanding those extreme events requires assessing long-term trends of the atmospheric circulation. This paper presents a set of diagnostics of the intra- and interannual recurrence of atmospheric patterns. Those diagnostics are devised to detect trends in the stability of the circulation and the return period of atmospheric patterns. We detect significant emerging trends in the winter circulation, pointing towards a potential increased predictability. No such signal seems to emerge in the summer. We find that the winter trends in the dominating atmospheric patterns and their recurrences do not depend of the patterns themselves.

Hail Day Frequency Trends and Associated Atmospheric Circulation Patterns over China during 1960–2012

2016 ◽  
Vol 29 (19) ◽  
pp. 7027-7044 ◽  
Author(s):  
Mingxin Li ◽  
Qinghong Zhang ◽  
Fuqing Zhang
Keyword(s):  
Tibetan Plateau ◽  
Atmospheric Circulation ◽  
Southern China ◽  
East Asian ◽  
Northern China ◽  
The Tibetan Plateau ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Change In Mean

Abstract Based on a comprehensive collection of hail observations and the NCEP–NCAR reanalyses from 1960 to 2012, the long-term trends of hail day frequency in mainland China and the associated changes in atmospheric circulation patterns were analyzed. There was no detectable trend in hail frequency from 1960 to the early 1980s, but a significant decreasing trend was apparent in later periods throughout most of China and in particular over the Tibetan Plateau from the early 1980s and over northern and northwestern China from the early 1990s. Hail frequency in southern China did not decrease as significantly as in other regions over the last couple of decades. An objective classification method, the obliquely rotated T-mode principal component technique, was used to investigate atmospheric circulation patterns. It was found that 51.85% of the hail days occurred during two major circulation types, both of which were associated with cold frontal systems in northern China. More specifically, the synoptic trough in East Asia, signified by the meridional circulation at 850 hPa, became considerably weaker after 1990. This change in the synoptic pattern is consistent with a weakening trend in the East Asian summer monsoon, the primary dynamic forcing of moisture transport that contributes to the generation of severe convection in northern China. The long-term variability of hail day frequency over the Tibetan Plateau was more strongly correlated with the change in mean freezing-level height (FLH) than the strength of the East Asian monsoon.

scholarly journals Trends in atmospheric patterns conducive to seasonal precipitation and temperature extremes in California

2016 ◽  
Vol 2 (4) ◽  
pp. e1501344 ◽  
Author(s):  
Daniel L. Swain ◽  
Daniel E. Horton ◽  
Deepti Singh ◽  
Noah S. Diffenbaugh
Keyword(s):  
Thermal Expansion ◽  
Atmospheric Circulation ◽  
Temperature Extremes ◽  
Seasonal Precipitation ◽  
Cool Season ◽  
Sea Level Pressure ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Northeastern Pacific ◽  
Precipitation And Temperature

Recent evidence suggests that changes in atmospheric circulation have altered the probability of extreme climate events in the Northern Hemisphere. We investigate northeastern Pacific atmospheric circulation patterns that have historically (1949–2015) been associated with cool-season (October-May) precipitation and temperature extremes in California. We identify changes in occurrence of atmospheric circulation patterns by measuring the similarity of the cool-season atmospheric configuration that occurred in each year of the 1949–2015 period with the configuration that occurred during each of the five driest, wettest, warmest, and coolest years. Our analysis detects statistically significant changes in the occurrence of atmospheric patterns associated with seasonal precipitation and temperature extremes. We also find a robust increase in the magnitude and subseasonal persistence of the cool-season West Coast ridge, resulting in an amplification of the background state. Changes in both seasonal mean and extreme event configurations appear to be caused by a combination of spatially nonuniform thermal expansion of the atmosphere and reinforcing trends in the pattern of sea level pressure. In particular, both thermal expansion and sea level pressure trends contribute to a notable increase in anomalous northeastern Pacific ridging patterns similar to that observed during the 2012–2015 California drought. Collectively, our empirical findings suggest that the frequency of atmospheric conditions like those during California’s most severely dry and hot years has increased in recent decades, but not necessarily at the expense of patterns associated with extremely wet years.

scholarly journals Spectral Ocean Wave Climate Variability Based on Atmospheric Circulation Patterns

2014 ◽  
Vol 44 (8) ◽  
pp. 2139-2152 ◽  
Author(s):  
Antonio Espejo ◽  
Paula Camus ◽  
Iñigo J. Losada ◽  
Fernando J. Méndez
Keyword(s):  
Climate Variability ◽  
Atmospheric Circulation ◽  
Wave Energy ◽  
Ocean Waves ◽  
Wave Climate ◽  
Future Climate Change ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Basin Scale

Abstract Traditional approaches for assessing wave climate variability have been broadly focused on aggregated or statistical parameters such as significant wave height, wave energy flux, or mean wave direction. These studies, although revealing the major general modes of wave climate variability and trends, do not take into consideration the complexity of the wind-wave fields. Because ocean waves are the response to both local and remote winds, analyzing the directional full spectra can shed light on atmospheric circulation not only over the immediate ocean region, but also over a broad basin scale. In this work, the authors use a pattern classification approach to explore wave climate variability in the frequency–direction domain. This approach identifies atmospheric circulation patterns of the sea level pressure from the 31-yr long Climate Forecast System Reanalysis (CFSR) and wave spectral patterns of two selected buoys in the North Atlantic, finding one-to-one relations between each synoptic pattern (circulation type) and each spectral wave energy distribution (spectral type). Even in the absence of long-wave records, this method allows for the reconstruction of long-term wave spectra to cover variability at several temporal scales: daily, monthly, seasonal, interannual, decadal, long-term trends, and future climate change projections.

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