Cold Spell Duration Research Articles

EXPERIENCE OF PREDICTING OF EXPECTED EXCESS MORTALITY DUE TO CLIMATE CHANGE: A CASE STUDY IN ARKHANGELSK

A quantitative forecast of expected changes in mortality due to global warming by year 2050 has been developed for the city of Arkhangelsk. The expected changes in the temperature regime for each calendar date were estimated by regionalization of an ensemble of atmosphere-ocean coupled general circulation models. The expected changes in frequency and duration of heat waves and cold spells between the periods 1980-1999 and 2040-2059 were also estimated. Modeling of the temperature-dependent mortality has shown that reduction in the winter mortality overweighed the summer increase. The overall effect will likely be beneficial for public health: total annual mortality will decrease by about 2 %.

The influence of the East Atlantic Oscillation to climate indices based on the daily minimum temperatures in Serbia

In this study, the influence of the East Atlantic Oscillation (EAO) on the climate indices based on the daily minimum temperature at eight stations in Serbia was examined. The following climate indices were analyzed: frost days (FD), cold nights (TN10p), warm nights (TN90p), minimum value of daily minimum temperature (TNn), tropical nights (TR), and cold spell duration indice (CSDI). Analysis of correlation between the East Atlantic Index (EAI) and the geopotential at 500 hPa, as well as between the EAI and climate indices was realized for all seasons and months during the period 1950–2009. Two characteristic situations for the extreme positive and negative values of the EAI were analyzed. Seasonal and monthly trend analyses of climate indices were performed. Decreases of FD and TN10p and increases of TN90p and TR were observed. It was found that the negative correlation prevailed between the EAI and TN10p/FD, and positive one between the EAI and TN90p/TR for all seasons and months. The highest correlation was observed between the EAI and TN90p in February.

Recent changes in daily extremes of temperature and precipitation over the western Tibetan Plateau, 1973–2011

Climate extremes in the Tibetan Plateau may cause serious regional and global consequences, but observation-based research over the western Tibetan Plateau is scarce. In this paper, recent changes in extremes of temperature and precipitation over the western Tibetan Plateau from 1973 to 2011 are investigated. A total of 24 indices that represent extreme climate events are selected and calculated by using daily maximum and minimum temperature and precipitation data. Results demonstrate that most cold-related indices of temperature extremes (frost and ice days, cool nights and cool days, and cold spell duration indicators) show a significant decrease, and that both the coldest night and coldest day have increased during the study period. Warm-related indices of temperature extremes such as summer days, the warmest night and the warmest day, warm nights and warm days, and warm spell duration indicators all have increased. The diurnal temperature ranges show a decreasing trend with statistical significance, whereas growing season lengths have increased significantly. The change trends of precipitation extremes are nonsignificant. Nonsignificant increasing trends are detected for most indices including annual total wet-day precipitation, maximum 1-day and 5-day precipitation, very wet and extremely wet day precipitation, and consecutive wet days. However, nonsignificant decreasing trends are found for the number of heavy precipitation days, consecutive dry days and simple daily intensity index.

Use of “Cold Spell” indices to quantify excess chronic obstructive pulmonary disease (COPD) morbidity during winter (November to March 2000–2007): case study in Porto

The aim of this study was to examine the relationship between the occurrence of cold episodes and excess hospital admissions for chronic obstructive pulmonary disease (COPD) in Porto, Portugal, in order to further understand the effects of cold weather on health in milder climates. Excess COPD winter morbidity was calculated from admissions for November to March (2000-2007) in the Greater Porto Metropolitan Area (GPMA). Cold spells were identified using several indices (Díaz, World Meteorological Organization, Cold Spell Duration Index, Australian Index and Ondas' Project Index) for the same period. Excess admissions in the periods before and after the occurrence of cold spells were calculated and related to the cold spells identified. The COPD seasonal variation admission coefficient (CVSA) showed excess winter admissions of 59%, relative to other months. The effect of cold spell on the aggravation of COPD occurs with a lag of at least 2weeks and differs according to the index used. This study indicates the important role of the persistence of cold periods of at least 2weeks duration in the increase in COPD admissions. The persistence of moderate temperatures (Tmin ≤5°C) for a week can be more significant for increasing COPD admissions than very low temperatures (Tmin ≤ 1.6°C) for just a few days. The Ondas projects' index provides the most accurate detection of the negative impacts of cold persistency on health, while the Diaz index is better at evaluating the consequences of short extreme cold events.

Changes in extreme events of temperature and precipitation over Xinjiang, northwest China, during 1960–2009

Based on daily surface air temperature (maximum, minimum and mean values) and precipitation records at 52 meteorological stations over Xinjiang, China, the spatial and temporal distributions of climate extremes are analyzed over the period 1960–2009. Twelve indices of extreme temperature and ten of extreme precipitation are studied. Temperature extremes show patterns consistent with a general warming trend, with most regions showing statistically significant changes for all the temperature-based indices. The regionally averaged occurrence of summer days, growing season length, tropical nights, warm spell duration indicator, warm nights and days have significantly increased by 2.14, 2.74, 1.71, 0.88, 6.23 and 3.59 days/decade, respectively. Over the same period, the occurrence of extreme ice days, frost days, cold spell duration indicator, cold nights and days show statistically significant decreasing trends at rates of −1.61, −3.69, −1.27, −6.57 and −2.6 days/decade, respectively. The diurnal temperature range (DTR) exhibits a decreasing trend of −0.26 °C/decade. With the exception of diurnal temperature range, the other temperature indices are strongly correlated with annual mean temperature. For precipitation indices, most precipitation indices show increasing trends in northern Xinjiang and exhibit decreasing trends in southern Xinjiang. Average maximum with 1-day and 5-day precipitation, very wet and extremely wet day precipitation, number of 10 and 20 mm precipitation days, consecutive wet days and averaged daily rainfall intensity show increasing trends whereas consecutive dry days decrease. In the meantime, annual total precipitation shows positive correlations with precipitation indices except consecutive dry days.

A simulation study on the extreme temperature events of the 20th century by using the BCC_AGCM

Extreme temperature events are simulated by using the Beijing Climate Center Atmospheric General Circulation Model (BCC_AGCM) in this paper. The model has been run for 136 yr with the observed external forcing data including solar insolation, greenhouse gases, and monthly sea surface temperature (SST). The daily maximum and minimum temperatures are simulated by the model, and 16 indices representing various extreme temperature events are calculated based on these two variables. The results show that the maximum of daily maximum temperature (TXX), maximum of daily minimum (TNX), minimum of daily maximum (TXN), minimum of daily minimum (TNN), warm days (TX90p), warm nights (TN90p), summer days (SU25), tropical nights (TR20), and warm spell duration index (WSDI) have increasing trends during the 20th century in most regions of the world, while the cold days (TX10p), cold nights (TN10p), and cold spell duration index (CSDI) have decreasing trends.

Changes in daily temperature and precipitation extremes in the Yellow River Basin, China

Spatiotemporal changes in climatic extremes in the Yellow River Basin from 1959 to 2008 were investigated on the basis of a suite of 27 climatic indices derived from daily temperature and precipitation data from 75 meteorological stations with the help of the Mann–Kendall test, linear regression method and GIS technique. Furthermore, the changes in the probability distribution of the extreme indices were examined. The results indicate: (1) The whole basin is dominated by significant increase in the frequency of warm days and warm nights, and dominated by significant decrease in the frequency of cold days and cold nights. Although trends in absolute temperature indices show less spatial coherence compared with that in the percentile-based temperature indices, overall increasing trends can be found in Max Tmax (TXx), Min Tmax (TXn), Max Tmin (TNx) and Min Tmin (TNn). (2) Although the spatial patterns and the number of stations with significant changes for threshold and duration temperature indices are also not identical, general positive trends in warm indices (i.e., summer days (SU25), tropical nights (TR20), warm spell duration indicator and growing season length) and negative trends in cold indices (i.e., frost days, ice days and cold spell duration indicator) can be found in the basin. Annual nighttime temperature has increased at a faster rate than that in daytime temperature, leading to obvious decrease in diurnal temperature range. (3) The changes in precipitation indices are much weaker and less spatially coherent compared with these of temperature indices. For all precipitation indices, only few stations are characterized by significantly change in extreme precipitation, and their spatial patterns are always characterized by irregular and insignificant positive and negative changes. However, generally, changes in precipitation extremes present drying trends, although most of the changes are insignificant. (4) Results at seasonal scale show that warming trends occur for all seasons, particularly in winter. Different from that in other three seasons, general positive trends in max 1-day precipitation (Rx1DAY) and max 5-day precipitation (Rx5DAY) are found in winter. Analysis of changes in probability distributions of indices for 1959–1983 and 1984–2008 indicate a remarkable shift toward warmer condition and a less pronounced tendency toward drier condition during the past decades. The results can provide beneficial reference to water resource and eco-environment management strategies in the Yellow River Basin for associated policymakers and stakeholders.

Changes in Extreme Climate Indices for the Northeastern United States, 1870–2005

Abstract The northeastern United States is one of the most variable climates in the world, and how climate extremes are changing is critical to populations, industries, and the environment in this region. A long-term (1870–2005) temperature and precipitation dataset was compiled for the northeastern United States to assess how the climate has changed. Adjustments were made to daily temperatures to account for changes in mean, variance, and skewness resulting from inhomogeneities, but precipitation data were not adjusted. Trends in 17 temperature and 10 precipitation indices at 40 stations were evaluated over three time periods—1893–2005, 1893–1950, and 1951–2005—and over 1870–2005 for a subset of longer-term stations. Temperature indices indicate strong warming with increases in the frequency of warm events (e.g., warm nights and warm summer days) and decreases in the frequency of cold events (e.g., ice days, frost days, and the cold spell duration indicator). The strongest warming is exhibited in the decrease in frost days and the increase in growing season length. Although maximum temperatures indices showed strong warming trends over the period 1893–1950, subsequent trends show little change and cooling. Few significant trends were present in the precipitation indices; however, they displayed a tendency toward wetter conditions. A stepwise multiple linear regression analysis indicated that some of the variability in the 27 indices from 1951 to 2002 was explained by the North Atlantic Oscillation, Pacific decadal oscillation, and Pacific–North American pattern. However, teleconnection patterns showed little influence on the 27 indices over a 103-yr period.

Observed changes in extreme weather indices in Hong Kong

AbstractPast trends of the occurrences of extreme temperature and rainfall events in Hong Kong from 1885 to 2008 were examined using a suite of 27 extreme indices adopted from the core indices developed by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI) under the auspices of the World Meteorological Organization (WMO), with appropriate modification to suit the sub‐tropical climate of Hong Kong. Results showed that the extreme daily maximum and minimum temperatures, annual numbers of very hot days (daily maximum temperature ≥ 33.0 °C) and hot nights (daily minimum temperature ≥ 28.0 °C) as well as the warm spell duration index (WSDI) in Hong Kong exhibited statistically significant long‐term rising trends, whereas the annual number of cold days (daily minimum temperatures ≤ 12.0 °C) and cold spell duration (CSDI) index had a statistically significant decreasing trend. Regarding rainfall, the frequency of occurrence of extreme hourly, 2‐ and 3‐hourly rainfall amounts increased significantly. The fraction of annual total precipitation due to events exceeding the daily 95th percentile of the climatological normal (1971–2000) increased by 22 mm per decade in the same period, indicating that the contribution of heavy rain to the annual rainfall amount was increasing with time. However, the maximum length of dry spell in the summer months from April to September increased at a rate of 0.3 days per decade from 1885 to 2008. Using the time‐dependent generalized extreme value (GEV) distribution technique, the return period for the daily minimum temperature of 4 °C or lower had significantly lengthened from 6 years in 1900 to 163 years in 2000. The return period for an hourly rainfall of 100 mm or more had shortened from 37 years in 1900 to 18 years in 2000. Copyright © 2010 Royal Meteorological Society

Variability of extreme temperature and precipitation in Iran during recent decades

AbstractWe examined extreme temperature and precipitation as indicative climatic variables to determine recent climatic changes over Iran. We present the results from 27 synoptic stations which have been quality controlled, tested for homogeneity and have less missing data. For each station, 27 indicative climatic indices recommended by the joint World Meteorological Organization CCL/CLIVAR/JCOMM Expert Team on Climate Change Detection and Indices (ETCCDI) were calculated.Marked negative trends for indices like frost days (FD), ice days (ID), cool days (TX10p), cool nights (TN10p) and diurnal temperature range (DTR) were found over most regions of Iran. Conversely, positive trends were found for summer days (SU25), warm days (TX90p) and tropical nights (TR20) over most regions of the country. For indices such as Cold Spell Duration Index (CSDI) and Warm Spell Duration Index (WSDI), both positive and negative trends were obtained.We found negative trends in consecutive dry days (CDD) over most of the country. A negative trend was observed for about two‐thirds of the country for annual total wet days precipitation (PRCPTOT). Positive trends in the Simple Daily Intensity Index (SDII) were found for the northern half of the country, and concurrently negative trends in total wet days for many places within the same region. We observed a negative trend in very wet days exceeding the 95th percentile (R95p) over the eastern and western regions, and a positive trend over the central region of the country, although a clear negative trend was observed for extremely wet days exceeding the 99th percentile (R99p) over most of the country. No similar trends in either the maximum 1‐day precipitation (Rx1DAY) or maximum 5‐day precipitation (Rx5DAY) were found over the country. Copyright © 2008 Royal Meteorological Society

Associations between low frequency variability modes and winter temperature extremes in Canada

Relationships between patterns of low frequency climate variability including the El Niño‐Southern Oscillation (ENSO), the Arctic Oscillation (AO) and the Quasi‐Biennial Oscillation (QBO), and the occurrence of Canadian winter temperature extremes are examined for the 1950–98 period. Composite analyses reveal that ENSO plays a dominant role in the frequency and duration of both cold and warm spells. In particular, the warm phase of ENSO is associated with a significant increase (decrease) in the occurrence of warm (cold) spells and the number of extreme warm (cold) days across most of Canada. The findings are generally the opposite for the cold ENSO phase. The singular value decomposition (SVD) technique further shows that ENSO‐like interdecadal sea surface temperature variability plays a significant role in the variability of winter cold and warm spells over Canada. Differences between the high and low index phases of the AO show a significantly higher frequency and duration of cold spells over eastern Canada during positive AO winters, while the frequency of winter warm spells increases over the Canadian Prairies. These results are also confirmed by the SVD analysis using northern hemisphere 1000‐hPa circulation. The QBO, as determined by the phase of the stratospheric winds, has an effect on the spatial pattern of Canadian extreme temperatures that is similar to that of the AO. The most significant result involves increases in the frequency of warm spells and the number of extreme warm days over the southern Prairies during the westerly phase of the QBO. The diagnostic results from this study improve the understanding of the imapact of the low frequency variability modes on temperature extremes over Canada. They may also assist in the attribution of past trends and variability in extremes, and potentially, provide insight into future changes to extreme temperature events.

Analysis of cold spells in the Greek region

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 27:211-223 (2004) - doi:10.3354/cr027211 Analysis of cold spells in the Greek region C. Pappas, N. Hatzianastassiou*, B. D. Katsoulis Laboratory of Meteorology, Department of Physics, University of Ioannina, 45110, Ioannina, Greece *Corresponding author. Email: nhatzian@cc.uoi.gr ABSTRACT: The extreme phenomenon of cold-spell events in the Greek region was investigated in this study by using a combined deterministic-stochastic model, along with 31 yr daily minimum temperature data from 16 meteorological stations of the Hellenic National Meteorological Service (HNMS). Trend analysis and the spatio-temporal distribution of cold spells were investigated by applying linear regression and Fourier analysis. The frequency, duration, distribution, timing and intensity of cold spells were successfully fitted with Poisson, Gauss and exponential distributions. The features of cold spells were found to vary widely, due to the effect of physicogeographical parameters such as latitude, longitude, altitude, and continentality, as well as to the synoptic weather situations prevailing in the various Greek sub-areas. The relative importance of the physicogeographical peculiarities was assessed: latitude and altitude were evaluated as the most important parameters for determining the features of cold spells in Greece. The highest probability of cold spells in the Greek peninsula exists when a persistent NW European and/or Siberian anticyclone reaches its highest intensity during winter and extends high-pressure ridges to the Balkans, and particularly to the Greek area. KEY WORDS: Extreme events · Cold spell · Frequency · Timing · Magnitude · Statistical distributions Full article in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 27, No. 3. Online publication date: December 08, 2004 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2004 Inter-Research.

An Assessment of Changes in Winter Cold and Warm Spells over Canada

The recent Third Assessment Report (TAR) of the Intergovernmental Panel onClimate Change (IPCC) indicated that observed 20th century changes in severalclimatic extremes are qualitatively consistent with those expected due to increasedgreenhouse gases. However, a lack of adequate data and analyses make conclusiveevidence of changing extremes somewhat difficult, particularly, in a global sense.In Canada, extreme temperature events, especially those during winter, can havemany adverse environmental and economic impacts. In light of the aforementionedIPCC report, the main focus of this analysis is to examine observed trends andvariability in the frequency, duration, and intensity of winter (Jan–Feb–Mar) cold and warm spells over Canada during the second half of the 20th century. Cold spell trends display substantial spatial variability across the country. From1950–1998, western Canada has experienced decreases in the frequency, duration, and intensity of cold spells, while in the east, distinct increases in the frequency and duration have occurred. These increases are likely associated with morefrequent occurrences of the positive phase of the North Atlantic Oscillation (NAO)during the last several decades. With regard to winter warm spells, significantincreases in both the frequency and duration of these episodes were observedacross most of Canada. One exception was found in the extreme northeasternregions, where warm spells are becoming shorter and less frequent. The resultsof this study are discussed within the context of climate warming expectations.

Are non-migrant white storks ( Ciconia ciconia) able to survive a cold-induced fast?

Northwestern European populations of White Storks ( Ciconia ciconia) have been restored by settling young birds which, after having been maintained captive for 3 years, do not migrate when released. Since they are still supplied with food, the question we address here is how settled White Storks would cope with a fast resulting from a cold spell if food were no longer available. We therefore measured daily body mass loss, nitrogen excretion and daily energy expenditure under natural photoperiod and climatic conditions in six captive White Storks exposed to 5 days of food deprivation during winter. Daily ambient temperature ranged between −10 and 17°C. After an initial decrease in both daily body mass loss and nitrogen excretion during the first day of fasting, these two parameters stabilized at low values. Lipids were the main fuel energy source (91%) and body proteins accounted for the remainder (9%). The rate of CO 2 production, measured with the doubly labeled water method, decreased significantly ( P<0.001) during fasting when compared to the ad libitum value. Our data show that the metabolic adjustments of White Storks facing starvation are similar to those found in birds well-adapted to long-term fasting. From the determination of lipid and protein stores and of lipid and protein depletion rates, we conclude that White Storks would be able to survive at least during 4 weeks, a period of time twice as long as the duration of cold spells usually occurring in the Alsace region.

Home Range, Habitat Use, and Mortality of Black Bears in North-Central Florida

Home Range, Habitat Use, and Mortality of Black Bears in North-Central Florida