scholarly journals On the Relationship between Teleconnections and Taiwan's Streamflow: Evidence of Climate Regime Shift and Implications for Seasonal Forecasting

2016 ◽  
Author(s):  
Chia-Jeng Chen ◽  
Tsung-Yu Lee
Keyword(s):  
Large Scale ◽  
Critical Role ◽  
Phase Relationship ◽  
Temporal Variations ◽  
Pacific Basin ◽  
Climate Regime ◽  
Quasi Biennial Oscillation ◽  
Teleconnection Patterns ◽  
Integrated Response ◽  
The Relationship

Abstract. Interannual variations of catchment streamflow represent an integrated response to anomalies in regional moisture transport and atmospheric circulations, ultimately linked to large-scale climate oscillations. This study investigates the relationship between Taiwan's long-term summertime (July to September, JAS) streamflow and manifold teleconnection patterns. Lagged correlation analysis is conducted to calculate how JAS streamflow data derived at 28 upstream and 13 downstream gauges in Taiwan correlate with 14 teleconnection indices in the concurrent or preceding seasons. Out of the many indices, the West-Pacific and Pacific-Japan (PJ) patterns, both of which play a critical role in determining cyclonic activity in the western North Pacific basin, exhibit the highest concurrent correlations (most significant r = 0.48) with the JAS flows in Taiwan. At a one-month lead time, on the other hand, the Quasi-Biennial Oscillation significantly correlate with the JAS flows (most significant r = −0.66), indicating some forecasting utility. By further examining the correlation results using a 20-year moving window, peculiar temporal variations and possible climate regime shifts (CRS) can be revealed. To identify suspicious, abrupt changes in the correlation, a CRS test is employed. The late 1970s and 1990s are identified as two significant change points, and during the intermediate period, a marked in-phase relationship (r ~ 0.9) between Taiwan's streamflow and the PJ index is observed. It is verified that the two shifts are in concordance with the alteration of large-scale circulations in the Pacific basin. Discussion about the changes in pattern correlation and composite maps before and after the change point is carried out, and our results suggest that empirical forecasting techniques should take into account the effect of CRS on predictor screening.

scholarly journals Variations in the correlation between teleconnections and Taiwan's streamflow

2017 ◽  
Vol 21 (7) ◽  
pp. 3463-3481 ◽  
Author(s):  
Chia-Jeng Chen ◽  
Tsung-Yu Lee
Keyword(s):  
Large Scale ◽  
Critical Role ◽  
Phase Relationship ◽  
Temporal Variations ◽  
Pacific Basin ◽  
Quasi Biennial Oscillation ◽  
Intermediate Period ◽  
Before And After ◽  
Composite Maps ◽  
Integrated Response

Abstract. Interannual variations in catchment streamflow represent an integrated response to anomalies in regional moisture transport and atmospheric circulations and are ultimately linked to large-scale climate oscillations. This study conducts correlation analysis to calculate how summertime (July–September, JAS) streamflow data derived at 28 upstream and 13 downstream gauges in Taiwan correlate with 14 teleconnection indices in the current or preceding seasons. We find that the western Pacific (WP) and Pacific–Japan (PJ) patterns, both of which play a critical role in determining cyclonic activity in the western North Pacific basin, exhibit the highest concurrent correlations (most significant r = 0. 50) with the JAS flows in Taiwan. Alternatively, the Quasi-Biennial Oscillation (QBO) averaged over the period from the previous October to June of the current year is significantly correlated with the JAS flows (most significant r = −0. 66), indicating some forecasting utility. By further examining the correlation results using a 20-year moving window, peculiar temporal variations and possible climate regime shifts (CRSs) can be revealed. A CRS test is employed to identify suspicious and abrupt changes in the correlation. The late 1970s and 1990s are identified as two significant change points. During the intermediate period, Taiwan's streamflow and the PJ index exhibit a marked in-phase relationship (r > 0. 8). It is verified that the two shifts are in concordance with the alteration of large-scale circulations in the Pacific basin by investigating the changes in pattern correlation and composite maps before and after the change point. Our results suggest that empirical forecasting techniques should take into account the effect of CRSs on predictor screening.

scholarly journals An Investigation into the Relationship between Teleconnections and Taiwan's Streamflow

2017 ◽  
Author(s):  
Chia-Jeng Chen ◽  
Tsung-Yu Lee
Keyword(s):  
Large Scale ◽  
Critical Role ◽  
Phase Relationship ◽  
Temporal Variations ◽  
Prediction Skill ◽  
Climate Indices ◽  
Pacific Basin ◽  
Linear Regression Models ◽  
Quasi Biennial Oscillation ◽  
The Relationship

Abstract. Interannual variations in catchment streamflow represent an integrated response to anomalies in regional moisture transport and atmospheric circulations and are ultimately linked to large-scale climate oscillations. This study investigates the relationship between Taiwan’s long-term summertime (July to September, JAS) streamflow and manifold teleconnection patterns. Lagged correlation analysis is conducted to calculate how JAS streamflow data derived at 28 upstream and 13 downstream gauges in Taiwan correlate with 14 teleconnection indices in the current or preceding seasons. Of the many indices, the West-Pacific and Pacific-Japan (PJ) patterns, both of which play a critical role in determining cyclonic activity in the western North Pacific basin, exhibit the highest concurrent correlations (most significant r = 0.50) with the JAS flows in Taiwan. Alternately, the Quasi-Biennial Oscillation averaged over the period from the previous October to June of the current year is significantly correlated with the JAS flows (most significant r = −0.66), indicating some forecasting utility. By further examining the correlation results using a 20-year moving window, peculiar temporal variations and possible climate regime shifts (CRSs) can be revealed. To identify suspicious, abrupt changes in the correlation, a CRS test is employed. The late 1970s and 1990s are identified as two significant change points, and during the intermediate period, a marked in-phase relationship (r > 0.8) between Taiwan's streamflow and the PJ index is observed. Linear regression models that incorporate the climate indices into streamflow prediction are found to provide reasonable prediction skill in general, and the models are then used to illustrate the dramatic variations in prediction skill from the pre- to post-regime shift epoch. It is verified that the two shifts are in concordance with the alteration of large-scale circulations in the Pacific basin. The changes in pattern correlation and composite maps before and after the change point are discussed, and our results suggest that empirical forecasting techniques should take into account the effect of CRSs on predictor screening.

scholarly journals Large Scale Solar Magnetic Fields: Temporal Variations

2004 ◽  
Vol 219 ◽  
pp. 552-556 ◽  
Author(s):  
R. Knaack ◽  
J. O. Stenflo
Keyword(s):  
Magnetic Field ◽  
Time Series ◽  
Large Scale ◽  
Solar Magnetic Field ◽  
Temporal Variations ◽  
Solar Photosphere ◽  
Solar Cycles ◽  
Radial Magnetic Field ◽  
Quasi Biennial Oscillation ◽  
Harmonic Decomposition

We have investigated the temporal evolution of the solar magnetic field during solar cycles 20, 21 and 22 by means of spherical harmonic decomposition and subsequent time series analysis. A 33 yr and a 25 yr time series of daily magnetic maps of the solar photosphere, recorded at the Mt. Wilson and NSO/Kitt Peak observatories respectively, were used to calculate the spherical coefficients of the radial magnetic field. Fourier and wavelet analysis were then applied to deduce the temporal variations. We compare the results of the two datasets and present examples of zonal modes which show significant variations, e. g. with a period of approx. 2.0—2.5 years. We provide evidence that this quasi-biennial oscillation originates mainly from the southern hemisphere. Furthermore, we show that low degree modes with odd l — m exhibit periods of 29.2 and 28.1 days while modes with even l — m show a dominant period of 26.9 days. A resonant modal structure of the solar magnetic field (apart from the 22 yr cycle) has not been found.

scholarly journals The relationship between seasonal snow cover in Japan and recent climatic change

1993 ◽  
Vol 18 ◽  
pp. 166-172 ◽  
Author(s):  
Motori Nishimori ◽  
Ryuichi Kawamura
Keyword(s):  
Large Scale ◽  
Correlation Coefficients ◽  
The Sea Of Japan ◽  
Atmospheric Circulation Patterns ◽  
Teleconnection Patterns ◽  
Circulation Patterns ◽  
The Relationship ◽  
Seasonal Snow Cover ◽  
Rotated Empirical Orthogonal Function

Atmospheric circulation patterns associated with snowfall fluctuations in Japan are examined using a rotated empirical orthogonal function (EOF) analysis. We also compute correlation coefficients between the scores of EOF modes in the 500 hPa geopotential height field of the Northern Hemisphere (NH) and amounts of snowfall in Japan on annual, monthly and pentad time scales. It is found that recent variability of snowfall amount in Japan is closely related to the long-term variations of large-scale circulation patterns. It is suggested that the dominance of teleconnection patterns such as Pacific/North American (PNA) and Northern Asian (NA) are responsible for the increase of snowfall in the coastal regions of the Sea of Japan during the cold period for Japan (1977–86).

scholarly journals Assessing the contribution of ENSO and MJO to Australian dust activity based on satellite and ground-based observations

2020 ◽  
Author(s):  
Yan Yu ◽  
Paul Ginoux
Keyword(s):  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
Regional Climate ◽  
Critical Role ◽  
Temporal Variations ◽  
Austral Spring ◽  
Maximum Enhancement ◽  
Eastern Australia

Abstract. Despite Australian dust's critical role in the regional climate and surrounding marine ecosystems, the controlling factors of the spatio-temporal variations of Australian dust are not fully understood. Here we assess the connections between observed spatial-temporal variations of Australian dust with key modes of large-scale climate variability, namely the El Niño-Southern Oscillation (ENSO) and Madden-Julian Oscillation (MJO). Multiple dust observations from Aerosol Robotic Network (AERONET), weather stations, and satellite instruments, namely the Moderate Resolution Imaging Spectroradiometer (MODIS) and Multi-angle Imaging SpectroRadiometer (MISR) are examined. The assessed multiple dust observations consistently identify the natural and agricultural dust hotspots in Australia, including the Lake Eyre Basin, Lake Torrens Basin, Lake Frome Basin, Simpson Desert, Barwon-Darling Basin, Riverina, Barkly Tableland, and lee side of the Great Diving Range, as well as a country-wide, austral spring-to-summer peak in dust activity. Our regression analysis of observed dust optical depth (DOD) upon an ocean Niño index confirms previous model-based finding on the enhanced dust activity in southern and eastern Australia during the subsequent austral spring and summer dust season following the strengthening of austral wintertime El Niño. Our analysis further indicates the modulation of the ENSO-dust relationship with the MJO phases. During sequential MJO phases, the dust-active center moves from west to east associated with the eastward propagation of MJO, with maximum enhancement in dust activity at about 120° E, 130° E, and 140° E corresponding to MJO phases 1–2, 3–4, and 5–6, respectively. MJO phases 3–6 are favorable for enhanced ENSO modulation of dust activity, especially the occurrence of extreme dust events, in southeastern Australia, currently hypothesized to be attributed to the interaction between MJO-induced anomalies in convection and wind and ENSO-induced anomalies in soil moisture and vegetation.

scholarly journals The Relationship between the Wintertime Cold Extremes over East Asia with Large-Scale Atmospheric and Oceanic Teleconnections

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 813 ◽  
Author(s):  
Ye Yang ◽  
Naru Xie ◽  
Meng Gao
Keyword(s):  
East Asia ◽  
Large Scale ◽  
Southern Oscillation ◽  
Low Frequency ◽  
Surface Air Temperature ◽  
Boreal Winter ◽  
Key Factors ◽  
Teleconnection Patterns ◽  
The Relationship ◽  
Cold Extremes

The influence of large-scale teleconnection patterns, Western Pacific (WP), Arctic Oscillation (AO) and El Niño-Southern Oscillation (ENSO), on the minimum surface air temperature (Tmin) anomalies and extremes over East Asia during the boreal winter from 1979 to 2017 were investigated by the composite analysis in terms of atmospheric and oceanic processes. The relationship between the Tmin and the geopotential height at 500 hPa (Z500) as well as sea surface temperature (SST) were first examined. Then we explored and estimated the contribution of the teleconnection patterns to the occurrence of extremely cold days and months quantitatively, and discussed other key factors in relation to the cold extremes. The WP and AO patterns play an important part in the prevalence of significant Tmin variability, whereas the effect of ENSO is relatively weak. Most of the cold extremes tend to appear in the negative phase of teleconnections, while there some extremes that occur in the opposite phase. In addition, the extreme months are more related to the preferred phase of the dominant pattern when compared to days. We conclude that the daily extremes are primarily triggered by the local-synoptic atmospheric circulations embedded in the large-scale teleconnection patterns, while the monthly extremes have a closer relationship with these low-frequency patterns.

scholarly journals Hydrological alteration of the upper Yangtze River and its possible links with large-scale climate indices

2019 ◽  
Vol 50 (4) ◽  
pp. 1120-1137
Author(s):  
Qianjin Dong ◽  
Debin Fang ◽  
Jian Zuo ◽  
Yongqiang Wang
Keyword(s):  
Yangtze River ◽  
Water Resource Management ◽  
Large Scale ◽  
Phase Relationship ◽  
Wavelet Coherence ◽  
Climate Indices ◽  
Hydrological Alteration ◽  
Upper Yangtze River ◽  
The Relationship ◽  
The Upper Yangtze River

Abstract The relationship between hydrological alteration and climate variability in the upper Yangtze River is not fully understood. In this paper, the periodicity features and the intercorrelation of annual and seasonal eco-flow metrics at the Yichang gauge station are analyzed for the period 1882 to 2013. Analysis is carried out to explore the formation of the eco-flow metrics and the possible linkages between eco-flow metrics and selected climate indices, using the cross-wavelet and wavelet coherence methods on data from 1948 to 2013. The results show that the variation of eco-flow metrics correlates well with some selected climate indices, but changes in different eco-flow metrics are complex. Most annual and seasonal eco-flow metrics correlate well with the Northern Hemisphere (N.H) and Indian Ocean Dipole (IOD) and have a significant common power in the two to four years band. In addition, most annual eco-flow metrics have an obvious phase relationship with the selected climate indices. However, the seasonal eco-flow metrics have no significant phase relationship with the selected climate indices. These findings provide a better understanding of how hydrological alterations of the streamflow and better water resource management can ensure ecosystem sustainability for the Yangtze River.

scholarly journals The relationship between seasonal snow cover in Japan and recent climatic change

1993 ◽  
Vol 18 ◽  
pp. 166-172 ◽  
Author(s):  
Motori Nishimori ◽  
Ryuichi Kawamura
Keyword(s):  
Large Scale ◽  
Correlation Coefficients ◽  
The Sea Of Japan ◽  
Atmospheric Circulation Patterns ◽  
Teleconnection Patterns ◽  
Circulation Patterns ◽  
The Relationship ◽  
Seasonal Snow Cover ◽  
Rotated Empirical Orthogonal Function

Atmospheric circulation patterns associated with snowfall fluctuations in Japan are examined using a rotated empirical orthogonal function (EOF) analysis. We also compute correlation coefficients between the scores of EOF modes in the 500 hPa geopotential height field of the Northern Hemisphere (NH) and amounts of snowfall in Japan on annual, monthly and pentad time scales. It is found that recent variability of snowfall amount in Japan is closely related to the long-term variations of large-scale circulation patterns. It is suggested that the dominance of teleconnection patterns such as Pacific/North American (PNA) and Northern Asian (NA) are responsible for the increase of snowfall in the coastal regions of the Sea of Japan during the cold period for Japan (1977–86).

Relationship between total plasma homocysteine and the risk of aneurysms – a meta-analysis

VASA ◽  
2020 ◽  
pp. 1-6
Author(s):  
Hanji Zhang ◽  
Dexin Yin ◽  
Yue Zhao ◽  
Yezhou Li ◽  
Dejiang Yao ◽  
...  
Keyword(s):  
Large Scale ◽  
Meta Analysis ◽  
Single Species ◽  
Total Plasma ◽  
Control Groups ◽  
Randomized Controlled ◽  
Randomized Controlled Studies ◽  
The Difference ◽  
The Relationship ◽  
Healthy Participants

Summary: Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.

Nursing professionals’ attitudes toward use of physical restraints in Styrian nursing homes Austria

Pflege ◽  
2019 ◽  
Vol 32 (1) ◽  
pp. 57-63
Author(s):  
Hannes Mayerl ◽  
Tanja Trummer ◽  
Erwin Stolz ◽  
Éva Rásky ◽  
Wolfgang Freidl
Keyword(s):  
Nursing Homes ◽  
Large Scale ◽  
Critical Role ◽  
Physical Restraint ◽  
Care Practice ◽  
Physical Restraints ◽  
Convenience Sample ◽  
Restraint Use ◽  
Positive Attitudes ◽  
Nursing Professionals

Abstract. Background: Given that nursing staff play a critical role in the decision regarding use of physical restraints, research has examined nursing professionals’ attitudes toward this practice. Aim: Since nursing professionals’ views on physical restraint use have not yet been examined in Austria to date, we aimed to explore nursing professionals’ attitudes concerning use of physical restraints in nursing homes of Styria (Austria). Method: Data were collected from a convenience sample of nursing professionals (N = 355) within 19 Styrian nursing homes, based on a cross-sectional study design. Attitudes toward the practice of restraint use were assessed by means of the Maastricht Attitude Questionnaire in the German version. Results: The overall results showed rather positive attitudes toward the use of physical restraints, yet the findings regarding the sub-dimensions of the questionnaire were mixed. Although nursing professionals tended to deny “good reasons” for using physical restraints, they evaluated the consequences of physical restraint use rather positive and considered restraint use as an appropriate health care practice. Nursing professionals’ views regarding the consequences of using specific physical restraints further showed that belts were considered as the most restricting and discomforting devices. Conclusions: Overall, Austrian nursing professionals seemed to hold more positive attitudes toward the use of physical restraints than counterparts in other Western European countries. Future nationwide large-scale surveys will be needed to confirm our findings.

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