scholarly journals Corrigendum to “Spatio‐temporal Variability and Trends in Extreme Temperature Events in Finland over the Recent Decades: Influence of Northern Hemisphere Teleconnection Patterns”

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Masoud Irannezhad ◽  
Hamid Moradkhani ◽  
Bjørn Kløve
Keyword(s):  
Northern Hemisphere ◽  
Extreme Temperature ◽  
Cold Temperature ◽  
Spatiotemporal Variability ◽  
The Arctic ◽  
Temperature Extremes ◽  
Warm Temperature ◽  
Teleconnection Patterns ◽  
The North ◽  
Temperature Indices

Fifteen temperature indices recommended by the ETCCDI (Expert Team on Climate Change Detection and Indices) were applied to evaluate spatiotemporal variability and trends in annual intensity, frequency, and duration of extreme temperature statistics in Finland during 1961–2011. Statistically significant relationships between these high-resolution (10 km) temperature indices and seven influential Northern Hemisphere teleconnection patterns (NHTPs) for the interannual climate variability were also identified. During the study period (1961–2011), warming trends in extreme temperatures were generally manifested by statistically significant increases in cold temperature extremes rather than in the warm temperature extremes. As expected, warm days and nights became more frequent, while fewer cold days and nights occurred. The frequency of frost and icing days also decreased. Finland experienced more (less) frequent warm (cold) temperature extremes over the past few decades. Significant lengthening in warm spells was observed in Finland during 1961–2011, while no clear changes are found in cold spells. Interannual variations in the temperature indices were significantly associated with a number of NHTPs. In general, warm temperature extremes show significant correlations with the East Atlantic and the Scandinavia patterns and cold temperature extremes with the Arctic Oscillation and the North Atlantic Oscillation patterns.

scholarly journals Spatiotemporal Variability and Trends in Extreme Temperature Events in Finland over the Recent Decades: Influence of Northern Hemisphere Teleconnection Patterns

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Masoud Irannezhad ◽  
Hamid Moradkhani ◽  
Bjørn Kløve
Keyword(s):  
Northern Hemisphere ◽  
Extreme Temperature ◽  
Cold Temperature ◽  
Spatiotemporal Variability ◽  
The Arctic ◽  
Temperature Extremes ◽  
Warm Temperature ◽  
Teleconnection Patterns ◽  
The North ◽  
Temperature Indices

Fifteen temperature indices recommended by the ETCCDI (Expert Team on Climate Change Detection and Indices) were applied to evaluate spatiotemporal variability and trends in annual intensity, frequency, and duration of extreme temperature statistics in Finland during 1961–2011. Statistically significant relationships between these high-resolution (10 km) temperature indices and seven influential Northern Hemisphere teleconnection patterns (NHTPs) for the interannual climate variability were also identified. During the study period (1961–2011), warming trends in extreme temperatures were generally manifested by statistically significant increases in cold temperature extremes rather than in the warm temperature extremes. As expected, warm days and nights became more frequent, while fewer cold days and nights occurred. The frequency of frost and icing days also decreased. Finland experienced more (less) frequent warm (cold) temperature extremes over the past few decades. Interestingly, significant lengthening in cold spells was observed over the upper part of northern Finland, while no clear changes are found in warm spells. Interannual variations in the temperature indices were significantly associated with a number of NHTPs. In general, warm temperature extremes show significant correlations with the East Atlantic and the Scandinavia patterns and cold temperature extremes with the Arctic Oscillation and the North Atlantic Oscillation patterns.

scholarly journals Changes in extreme temperature indices over the Peripannonian region of Bosnia and Herzegovina

Geografie ◽  
2019 ◽  
Vol 124 (1) ◽  
pp. 19-40
Author(s):  
Tatjana Popov ◽  
Slobodan Gnjato ◽  
Goran Trbić
Keyword(s):  
Bosnia And Herzegovina ◽  
Extreme Temperature ◽  
The Arctic ◽  
The North ◽  
Expert Team ◽  
Temperature Indices ◽  
Maximum Temperatures ◽  
The Arctic Oscillation ◽  
The North Atlantic Oscillation ◽  
Cold Extremes

The paper analyzes changes in extreme temperature indices over the Peripannonian region of Bosnia and Herzegovina. Data on daily minimum and maximum temperatures during the period 1961–2016 from four meteorological stations were used for the calculation in the RClimDex (1.0) sopware trends in 16 indices recommended by the Expert team on climate change detection and indices. The estimated significant upward tendency in indices of warm extremes and downward in cold-related indices confirm that warming is present. The highest trend values were obtained for indices TXx, TNn, TN90p, TX90p, SU25, SU30 and WSDI. The results indicate significant distributional changes in the period 1987−2016 compared to the period 1961−1990. A significant positive (negative) correlation between the East-Atlantic pattern and indices of warm (cold) extremes was determined throughout the year. In winter and spring, significant links to the North Atlantic Oscillation and the Arctic Oscillation, respectively, were also found.

Midlatitude Winter Extreme Temperature Events and Connections with Anomalies in the Arctic and Tropics

2021 ◽  
Vol 34 (10) ◽  
pp. 3733-3749 ◽  
Author(s):  
Irina Rudeva ◽  
Ian Simmonds
Keyword(s):  
Wave Propagation ◽  
North America ◽  
Northern Hemisphere ◽  
Large Scale ◽  
Extreme Temperature ◽  
The Arctic ◽  
Temperature Extremes ◽  
Arctic Seas ◽  
Temperature Anomalies ◽  
Wave Trains

AbstractFor the last few decades the Northern Hemisphere midlatitudes have seen an increasing number of temperature extreme events. It has been suggested that some of these extremes are related to planetary wave activity. In this study we identify wave propagation regions at 300 hPa using the ERA-Interim dataset from 1980 to 2017 and link them to temperature extremes in densely populated regions of the Northern Hemisphere. Most studies have used background flow fields at monthly or seasonal scale to investigate wave propagation. For a phenomenon that is influenced by threshold incidents and nonlinear processes, this can distort the net Rossby wave signal. A novel aspect of our investigation lies in the use of daily data to study wave propagation allowing it to be diagnosed for limited but important periods across a wider range of latitudes, including the polar region. We show that winter temperature extremes in the midlatitudes can be associated with circulation anomalies in both the Arctic and the tropics, while the relative importance of these areas differs according to the specific midlatitude region. In particular, wave trains connecting the tropical Pacific and Atlantic may be associated with temperature anomalies in North America and Siberia. Arctic seas are markedly important for Eurasian regions. Analysis of synoptic temperature extremes suggests that pre-existing local temperature anomalies play a key role in the development of those extremes, as well as amplification of large-scale wave trains. We also demonstrate that warm Arctic regions can create cold outbreaks in both Siberia and North America.

scholarly journals How Predictable Are the Arctic and North Atlantic Oscillations? Exploring the Variability and Predictability of the Northern Hemisphere

2018 ◽  
Vol 31 (3) ◽  
pp. 997-1014 ◽  
Author(s):  
Daniela I. V. Domeisen ◽  
Gualtiero Badin ◽  
Inga M. Koszalka
Keyword(s):  
Time Scales ◽  
Northern Hemisphere ◽  
North Atlantic ◽  
Prediction Models ◽  
The Arctic ◽  
Ensemble Prediction ◽  
Atmospheric Conditions ◽  
Short Term ◽  
The North ◽  
The North Atlantic Oscillation

ABSTRACT The North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO) describe the dominant part of the variability in the Northern Hemisphere extratropical troposphere. Because of the strong connection of these patterns with surface climate, recent years have shown an increased interest and an increasing skill in forecasting them. However, it is unclear what the intrinsic limits of short-term predictability for the NAO and AO patterns are. This study compares the variability and predictability of both patterns, using a range of data and index computation methods for the daily NAO and AO indices. Small deviations from Gaussianity are found along with characteristic decorrelation time scales of around one week. In the analysis of the Lyapunov spectrum it is found that predictability is not significantly different between the AO and NAO or between reanalysis products. Differences exist, however, between the indices based on EOF analysis, which exhibit predictability time scales around 12–16 days, and the station-based indices, exhibiting a longer predictability of 18–20 days. Both of these time scales indicate predictability beyond that currently obtained in ensemble prediction models for short-term predictability. Additional longer-term predictability for these patterns may be gained through local feedbacks and remote forcing mechanisms for particular atmospheric conditions.

scholarly journals The Impact of North Atlantic–Arctic Multidecadal Variability on Northern Hemisphere Surface Air Temperature

2010 ◽  
Vol 23 (21) ◽  
pp. 5668-5677 ◽  
Author(s):  
Vladimir A. Semenov ◽  
Mojib Latif ◽  
Dietmar Dommenget ◽  
Noel S. Keenlyside ◽  
Alexander Strehz ◽  
...  
Keyword(s):  
Climate Variability ◽  
Northern Hemisphere ◽  
North Atlantic ◽  
The Arctic ◽  
Decadal Climate Variability ◽  
Multidecadal Variability ◽  
The North ◽  
Hemisphere Surface ◽  
The North Atlantic ◽  
Decadal Climate

Abstract The twentieth-century Northern Hemisphere surface climate exhibits a long-term warming trend largely caused by anthropogenic forcing, with natural decadal climate variability superimposed on it. This study addresses the possible origin and strength of internal decadal climate variability in the Northern Hemisphere during the recent decades. The authors present results from a set of climate model simulations that suggest natural internal multidecadal climate variability in the North Atlantic–Arctic sector could have considerably contributed to the Northern Hemisphere surface warming since 1980. Although covering only a few percent of the earth’s surface, the Arctic may have provided the largest share in this. It is hypothesized that a stronger meridional overturning circulation in the Atlantic and the associated increase in northward heat transport enhanced the heat loss from the ocean to the atmosphere in the North Atlantic region and especially in the North Atlantic portion of the Arctic because of anomalously strong sea ice melt. The model results stress the potential importance of natural internal multidecadal variability originating in the North Atlantic–Arctic sector in generating interdecadal climate changes, not only on a regional scale, but also possibly on a hemispheric and even a global scale.

scholarly journals Temporal Trends and Spatial Patterns of Temperature and Its Extremes over the Beijing-Tianjin Sand Source Region (1960–2014), China

2018 ◽  
Vol 2018 ◽  
pp. 1-26
Author(s):  
Wei Wei ◽  
Baitian Wang ◽  
Kebin Zhang ◽  
Zhongjie Shi ◽  
Genbatu Ge ◽  
...  
Keyword(s):  
Source Region ◽  
Temporal Trends ◽  
Extreme Temperature ◽  
Spatiotemporal Variability ◽  
Mountain Area ◽  
Increasing Trend ◽  
Cold Tolerant ◽  
Temperature Indices ◽  
Slope Estimator ◽  
Sand Source

In order to examine temperature changes and extremes in the Beijing-Tianjin Sand Source Region (BTSSR), ten extreme temperature indices were selected, categorized, and calculated spanning the period 1960–2014, and the spatiotemporal variability and trends of temperature and extremes on multitimescales in the BTSSR were investigated using the Mann-Kendall (M-K) test, Sen’s slope estimator, and linear regression. Results show that mean temperatures have increased and extreme temperature events have become more frequent. Annual temperature has recorded a significant increasing trend over the BTSSR, in which 51 stations exhibited significant increasing trends (p<0.05); winter temperature recorded the most significant increasing trend in the northwest subregion. All extreme temperature indices showed warming trends at most stations; a higher warming slope in extreme temperature mainly occurred along the northeast border and northwest border and in the central-southern mountain area. As extreme low temperature events decrease, vegetation damage due to freezing temperatures will reduce and low cold-tolerant plants may expand their distribution range northward to revegetate barren areas in the BTSSR. However, in water-limited areas of the BTSSR, increasing temperatures in the growing season may exacerbate stress associated with plants relying on precipitation due to higher temperatures combining with decreasing precipitation.

scholarly journals Trend in temperature extreme indices over Mongolia and associated large-scale circulations

2020 ◽  
Author(s):  
Baljinnyam Nyamjantsan ◽  
Changhyun Yoo
Keyword(s):  
Large Scale ◽  
Extreme Temperature ◽  
The Arctic ◽  
Gobi Desert ◽  
Temperature Extremes ◽  
Temperature Extreme ◽  
East Atlantic ◽  
Rate Of Increase ◽  
June July ◽  
Extreme Indices

Abstract Employing the percentile-based indices, TN10p, TX10p, TN90p, and TX90p during 1961–2018, we evaluate temporal and spatial trends in extreme temperature at 54 stations over Mongolia. Statically significant changes in temperature extremes in the warm (TN90p and TX90p) and cool indices (TN10p and TX10p) are found. The rate of increase in the number of warm nights and days are respectively 1.5 and 1.9 days decade− 1, while the cool nights and days show a declining trend of -0.8 and − 1.5 days decade− 1, respectively. Despite the fact that the trends are most vigorous during June-July-August, seasonal variations can be seen. Also, spatial distributions of the trends reveal weakest magnitudes in Gobi Desert, while strongest in the west and north of Mongolia. The large-scale atmospheric circulations account for changes in the temperature extreme indices. The East Atlantic, East Atlantic/western Russian, and Scandinavian patterns, and the Arctic Oscillation is found to contribute the most to the interannual variation in the temperature extremes.

scholarly journals A Climatology of Northern Hemisphere Blocking

2006 ◽  
Vol 19 (6) ◽  
pp. 1042-1063 ◽  
Author(s):  
David Barriopedro ◽  
Ricardo García-Herrera ◽  
Anthony R. Lupo ◽  
Emiliano Hernández
Keyword(s):  
Conceptual Model ◽  
Northern Hemisphere ◽  
Additional Information ◽  
Teleconnection Patterns ◽  
The North ◽  
Blocking Mechanisms ◽  
The Individual ◽  
Dynamical Connection

Abstract In this paper a 55-yr (1948–2002) Northern Hemisphere blocking climatology is presented. Traditional blocking indices and methodologies are revised and a new blocking detection method is designed. This algorithm detects blocked flows and provides for a better characterization of blocking events with additional information on blocking parameters such as the location of the blocking center, the intensity, and extension. Additionally, a new tracking procedure has been incorporated following simultaneously the individual evolution of blocked flows and identifying coherently persistent blocked patterns. Using this method, the longest known Northern Hemisphere blocking climatology is obtained and compared with previous studies. A new regional classification into four independent blocking sectors has been obtained based on the seasonally preferred regions of blocking formation: Atlantic (ATL), European (EUR), West Pacific (WPA), and East Pacific (EPA). Global and regional blocking characteristics have been described, examining their variability from the seasonal to interdecadal scales. The global long-term blocking series in the North Hemisphere showed a significant trend toward weaker and less persistent events, as well as regional increases (decreases) in blocking frequency over the WPA (ATL and EUR) sector. The influence of teleconnection patterns (TCPs) on blocking parameters is also explored, being confined essentially to wintertime, except in the WPA sector. Additionally, regional blocking parameters, especially frequency and duration, are sensitive to regional TCPs, supporting the regional classification obtained in this paper. The ENSO-related blocking variability is evident in blocking intensities and preferred locations but not in frequency. Finally, the dynamical connection between blocking occurrence and regional TCPs is examined through the conceptual model proposed by Charney and DeVore. Observational evidence of a dynamical link between the asymmetrical temperature distributions induced by TCPs and blocking variability is provided with a distinctive contrast “warm ocean/cold land” pattern favoring the blocking occurrence in winter. However, the conceptual model is not coherent in the WPA sector, suggesting different blocking mechanisms operating in this sector.

scholarly journals Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles

2019 ◽  
Vol 32 (9) ◽  
pp. 2591-2603 ◽  
Author(s):  
Emily Hogan ◽  
Robert E. Nicholas ◽  
Klaus Keller ◽  
Stephanie Eilts ◽  
Ryan L. Sriver
Keyword(s):  
United States ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Extreme Temperature ◽  
The United States ◽  
Temperature Extremes ◽  
Warm Temperature ◽  
Climate Model Ensembles ◽  
Model Ensembles

Abstract Extreme temperature events can have considerable negative impacts on sectors such as health, agriculture, and transportation. Observational evidence indicates the severity and frequency of warm extremes are increasing over much of the United States, but there are sizeable challenges both in estimating extreme temperature changes and in quantifying the relevant associated uncertainties. This study provides a simple statistical framework using a block maxima approach to analyze the representation of warm temperature extremes in several recent global climate model ensembles. Uncertainties due to structural model differences, grid resolution, and internal variability are characterized and discussed. Results show that models and ensembles differ greatly in the representation of extreme temperature over the United States, and variability in tail events is dependent on time and anthropogenic warming, which can influence estimates of return periods and distribution parameter estimates using generalized extreme value (GEV) distributions. These effects can considerably influence the uncertainty of model hindcasts and projections of extremes. Several idealized regional applications are highlighted for evaluating ensemble skill and trends, based on quantile analysis and root-mean-square errors in the overall sample and the upper tail. The results are relevant to regional climate assessments that use global model outputs and that are sensitive to extreme warm temperature. Accompanying this manuscript is a simple toolkit using the R statistical programming language for characterizing extreme events in gridded datasets.

scholarly journals Trends in Thailand’s Extreme Temperature Indices during 1955-2018 and Their Relationship with Global Mean Temperature Change

2020 ◽  
pp. 94-107
Author(s):  
Atsamon Limsakul
Keyword(s):  
Global Warming ◽  
Extreme Temperature ◽  
Local Scale ◽  
Maximum Temperature ◽  
Temperature Extremes ◽  
Global Mean Temperature ◽  
Temperature Distributions ◽  
Mean Temperature ◽  
Temperature Indices ◽  
Global Mean

Trends in Thailand’s extreme temperature indices and their relationship with global mean temperature (GMT) change are analyzed, based on longer quality controlled temperature data during 1955–2018. Widespread significant trends of extreme temperature indices with a clear warming evident in all indices are observed, consistent with the earlier results and general global warming. Changes associated with the upper tails of the minimum and maximum temperature distributions are the dominant feature of Thailand’s extreme temperature indices accounting for more than 65% of the total variance. Analysis of the probability distribution functions (PDFs) of combined extreme temperature indices further shows significant shifts in their distributions toward warmer conditions in the recent decades. The results suggest that daytime and nighttime temperatures in Thailand have become more extreme and that the changes are related to shifts in multiple aspects of the daily temperature distributions. With long-term temperature records, this study provides more confident and robust evidence of trends in Thailand’s temperature extremes occurred since the second half of 20th century. Another noteworthy finding is that most of Thailand’s extreme temperature indices show a distinct linear relationship with GMT, indicating that local-scale changes in temperatures and its extreme at local scale are related almost linearly to GMT change. The extrapolated values of the indices with strong linearity with GMT show substantial distinction with nearly 50% increase between 2 global warming levels set by Paris Agreement, highlighting that half a degree increase in GMT will lead to greatly increase in Thailand’s temperature extremes.

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