scholarly journals Quantile Regression–Based Spatiotemporal Analysis of Extreme Temperature Change in China

2017 ◽  
Vol 30 (24) ◽  
pp. 9897-9914 ◽  
Author(s):  
Meng Gao ◽  
Christian L. E. Franzke
Keyword(s):  
Quantile Regression ◽  
Temperature Change ◽  
Long Range ◽  
Large Scale ◽  
Extreme Temperature ◽  
Temperature Series ◽  
Long Range Dependence ◽  
Temperature Extremes ◽  
Mean Temperature ◽  
Cold Extremes

In this study, temporal trends and spatial patterns of extreme temperature change are investigated at 352 meteorological stations in China over the period 1956–2013. The temperature series are first examined for evidence of long-range dependence at daily and monthly time scales. At most stations there is evidence of significant long-range dependence. Noncrossing quantile regression has been used for trend analysis of temperature series. For low quantiles of daily mean temperature and monthly minimum value of daily minimum temperature (TNn) in January, there is an increasing trend at most stations. A decrease is also observed in a zone ranging from northeastern China to central China for higher quantiles of daily mean temperature and monthly maximum value of daily maximum temperature (TXx) in July. Changes of the large-scale atmospheric circulation partly explain the trends of temperature extremes. To reveal the spatial pattern of temperature changes, a density-based spatial clustering algorithm is used to cluster the quantile trends of daily temperature series for 19 quantile levels (0.05, 0.1, …, 0.95). Spatial cluster analysis identifies a few large clusters showing different warming patterns in different parts of China. Finally, quantile regression reveals the connections between temperature extremes and two large-scale climate patterns: El Niño–Southern Oscillation (ENSO) and the Arctic Oscillation (AO). The influence of ENSO on cold extremes is significant at most stations, but its influence on warm extremes is only weakly significant. The AO not only affects the cold extremes in northern and eastern China, but also affects warm extremes in northeastern and southern China.

scholarly journals Regional Climatic Features of the Arabian Peninsula

Atmosphere ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 220 ◽  
Author(s):  
Patlakas ◽  
Stathopoulos ◽  
Flocas ◽  
Kalogeri ◽  
Kallos
Keyword(s):  
Large Scale ◽  
Arabian Peninsula ◽  
Regional Climate ◽  
Atmospheric Model ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Spatial Distance ◽  
Temperature Extremes ◽  
Mean Temperature ◽  
Maximum Temperatures

The climate of the Arabian Peninsula is characterized by significant spatial and temporal variations, due to its complex topography and the large-scale atmospheric circulation. Furthermore, the role of dust in the formation of regional climate is considered to be crucial. In this work, the regional climatology for the Arabian Peninsula has been studied by employing a high resolution state of the art atmospheric model that included sophisticated physical parameterization schemes and online treatment of natural aerosol particles. The simulations covered a 30-year period (1986–2015) with a temporal resolution of 3 h and a spatial distance of 9 km. The main focus was given to the spatial and temporal variations of mean temperature and temperature extremes, wind speed and direction, and relative humidity. The results were evaluated using in situ measurements indicating a good agreement. An examination of possible climatic changes during the present climate was also performed through a comprehensive analysis of the trends of mean temperature and temperature extremes. The statistical significant trend values were overall positive and increased over the northwestern parts of the examined area. Similar spatial distributions were found for the daily minimum and maximum temperatures. Higher positive values emerged for the daily maxima.

scholarly journals Recent trends in daily temperature extremes over northeastern Spain (1960–2006)

2011 ◽  
Vol 11 (9) ◽  
pp. 2583-2603 ◽  
Author(s):  
A. El Kenawy ◽  
J. I. López-Moreno ◽  
S. M. Vicente-Serrano
Keyword(s):  
Land Use Planning ◽  
Crop Yields ◽  
Extreme Temperature ◽  
Daily Temperature ◽  
Maximum Temperature ◽  
Daily Maximum ◽  
Temperature Extremes ◽  
Growing Season Length ◽  
Cold Extremes

Abstract. Spatial and temporal characteristics of extreme temperature events in northeastern Spain have been investigated. The analysis is based on long-term, high-quality, and homogenous daily maximum and minimum temperature of 128 observatories spanning the period from 1960 to 2006. A total of 21 indices were used to assess changes in both the cold and hot tails of the daily temperature distributions. The presence of trends in temperature extremes was assessed by means of the Mann-Kendall test. However, the autocorrelation function (ACF) and a bootstrap methodology were used to account for the influence of serial correlation and cross-correlation on the trend assessment. In general, the observed changes are more prevalent in hot extremes than in cold extremes. This finding can largely be linked to the increase found in the mean maximum temperature during the last few decades. The results indicate a significant increase in the frequency and intensity of most of the hot temperature extremes. An increase in warm nights (TN90p: 3.3 days decade−1), warm days (TX90p: 2.7 days decade−1), tropical nights (TR20: 0.6 days decade−1) and the annual high maximum temperature (TXx: 0.27 °C decade−1) was detected in the 47-yr period. In contrast, most of the indices related to cold temperature extremes (e.g. cold days (TX10p), cold nights (TN10p), very cold days (TN1p), and frost days (FD0)) demonstrated a decreasing but statistically insignificant trend. Although there is no evidence of a long-term trend in cold extremes, significant interdecadal variations were noted. Almost no significant trends in temperature variability indices (e.g. diurnal temperature range (DTR) and growing season length (GSL)) are detected. Spatially, the coastal areas along the Mediterranean Sea and the Cantabrian Sea experienced stronger warming compared with mainland areas. Given that only few earlier studies analyzed observed changes in temperature extremes at fine spatial resolution across the Iberian Peninsula, the results of this work can improve our understanding of climatology of temperature extremes. Also, these findings can have different hydrological, ecological and agricultural implications (e.g. crop yields, energy consumption, land use planning and water resources management).

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 Trends in Mediterranean gridded temperature extremes and large-scale circulation influences

2011 ◽  
Vol 11 (8) ◽  
pp. 2199-2214 ◽  
Author(s):  
D. Efthymiadis ◽  
C. M. Goodess ◽  
P. D. Jones
Keyword(s):  
Large Scale ◽  
Eastern Mediterranean ◽  
Temperature Extremes ◽  
Global Trends ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Rate Of Increase ◽  
The Mediterranean ◽  
Large Scale Atmospheric Circulation ◽  
Cold Extremes

Abstract. Two recently-available daily gridded datasets are used to investigate trends in Mediterranean temperature extremes since the mid-20th century. The underlying trends are found to be generally consistent with global trends of temperature and their extremes: cold extremes decrease and warm/hot extremes increase. This consistency is better manifested in the western part of the Mediterranean where changes are most pronounced since the mid-1970s. In the eastern part, a cooling is observed, with a near reversal in the last two decades. This inter-basin discrepancy is clearer in winter, while in summer changes are more uniform and the west-east difference is restricted to the rate of increase of warm/hot extremes, which is higher in central and eastern parts of the Mediterranean over recent decades. Linear regression and correlation analysis reveals some influence of major large-scale atmospheric circulation patterns on the occurrence of these extremes – both in terms of trend and interannual variability. These relationships are not, however, able to account for the most striking features of the observations – in particular the intensification of the increasing trend in warm/hot extremes, which is most evident over the last 15–20 yr in the Central and Eastern Mediterranean.

scholarly journals Characteristics of Observed Atmospheric Circulation Patterns Associated with Temperature Extremes over North America

2012 ◽  
Vol 25 (20) ◽  
pp. 7266-7281 ◽  
Author(s):  
Paul C. Loikith ◽  
Anthony J. Broccoli
Keyword(s):  
North America ◽  
Atmospheric Circulation ◽  
Large Scale ◽  
Climate Models ◽  
Extreme Temperature ◽  
Future Climate Change ◽  
Temperature Extremes ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Patterns And Processes

Abstract Motivated by a desire to understand the physical mechanisms involved in future anthropogenic changes in extreme temperature events, the key atmospheric circulation patterns associated with extreme daily temperatures over North America in the current climate are identified. The findings show that warm extremes at most locations are associated with positive 500-hPa geopotential height and sea level pressure anomalies just downstream with negative anomalies farther upstream. The orientation, physical characteristics, and spatial scale of these circulation patterns vary based on latitude, season, and proximity to important geographic features (i.e., mountains, coastlines). The anomaly patterns associated with extreme cold events tend to be similar to, but opposite in sign of, those associated with extreme warm events, especially within the westerlies, and tend to scale with temperature in the same locations. Circulation patterns aloft are more coherent across the continent than those at the surface where local surface features influence the occurrence of and patterns associated with extreme temperature days. Temperature extremes may be more sensitive to small shifts in circulation at locations where temperature is strongly influenced by mountains or large water bodies, or at the margins of important large-scale circulation patterns making such locations more susceptible to nonlinear responses to future climate change. The identification of these patterns and processes will allow for a thorough evaluation of the ability of climate models to realistically simulate extreme temperatures and their future trends.

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.

Change in mean temperature as a predictor of extreme temperature change in the Asia-Pacific region

2005 ◽  
Vol 25 (10) ◽  
pp. 1301-1330 ◽  
Author(s):  
G. M. Griffiths ◽  
L. E. Chambers ◽  
M. R. Haylock ◽  
M. J. Manton ◽  
N. Nicholls ◽  
...  
Keyword(s):  
Temperature Change ◽  
Extreme Temperature ◽  
Asia Pacific ◽  
Pacific Region ◽  
Asia Pacific Region ◽  
Mean Temperature ◽  
Change In Mean

Changes in patterns of extreme temperature distribution across different regions in India

2021 ◽  
Author(s):  
Angana Borah ◽  
Udit Bhatia
Keyword(s):  
Large Scale ◽  
Indian Subcontinent ◽  
Extreme Temperature ◽  
Maximum Temperature ◽  
Temperature Extremes ◽  
Climate Projections ◽  
Extreme Temperatures ◽  
Regional Patterns ◽  
Cold Temperatures ◽  
Annual Minimum Temperature

<p>Global studies of extreme temperature suggest that in recent times there has been an increase in frequency and intensity for hot temperature and decrease for cold temperatures  while a few others show an increase in both warm and cold extremes in the last decade of the twentieth century. Previous research on large scale climate projections show an amplified increase in the highest percentile of maxima and minima, with respect to the lowest percentiles of temperature extremes. The indices recommended by the Expert Team for Climate Change Detection Monitoring and Indices (ETCCDMI) to analyse trends of extreme climate are pertinent to policy and decision making with regard to impact and adaptation studies. While literature is abundant with large scale evaluation of trends in extreme temperatures, there is a want of studies in the regional patterns and distribution of temperature extremes in India. Although India is widely known as a tropical country, the diversities found in the topography of the regions from north to south and east to west, renders microclimate unique to each region leading to disparate inter-annual temperature ranges across the country. So, it is important to explore how regional trends in the different climatic zones of the Indian subcontinent correspond with each other in view of its unique climatic regimes. A comprehensive analysis of temperature extremes in the urban agglomerates and their suburban and rural counterparts is relatively unexplored for India. The results offer insights on the change in the percentile based indices recommended by the IPCC as well as summer and winter maximas and minimas for the entire India over the last several decades. The frequency and intensity of extreme temperatures characterised by number of days less than 10th percentile and more than 90th percentile, and minimum annual minimum temperature and maximum annual maximum temperature respectively, of the distribution over the last six decades have been assessed. The findings of this study suggests that warmer extremes follow an increasing trend, while the colder extremes exhibit no significant trend. However, the trends appear to be spatially coherent irrespective of the extent of urbanization.   Additionally, change in maximum and minimum percentiles of summer and winter temperatures are assessed between the first half of the last century and  the later half of the last century, for the entire country. It was found that change in highest percentiles in both summer and winter minima is more pronounced than lowest percentiles, while increase in highest percentile is more amplified for summer and winter maxima. </p><p> </p>

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.

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