Characteristics of Daily and Extreme Temperatures over Canada

Bonsal, Barrie; Zhang, X.; Vincent, Lucie A.; Hogg, W. D.

doi:10.1175/1520-0442(2001)014<1959:codaet>2.0.co;2

Cited by 374 publications

(287 citation statements)

References 21 publications

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“…There was no evidence to suggest changes in the frequency of heavy precipitation events (daily rainfall/snowfall larger than a threshold value which is exceeded by an average of three events per year) across Canada [Zhang et al, 2000b], but significant trends have been identified in extreme temperatures (daily temperatures larger than 95 or less than 5 percentiles). The increasing trend in spring temperature has also resulted in earlier starting dates of both frost-free period and growing season [Bonsal et al, 2000] during the last half of the twentieth century. Such changes in both flow categories and were least prevalent in the annual maximum category.…”

Section: Introductionsupporting

confidence: 91%

Trends in Canadian streamflow

Zhang¹,

Harvey²,

Hogg³

et al. 2001

Water Resources Research

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647

460

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Abstract. This study presents trends computed for the past 30-50 years for 11 hydroclimatic variables obtained from the recently created Canadian Reference Hydrometric Basin Network database. It was found that annual mean streamflow has generally decreased during the periods, with significant decreases detected in the southern part of the country. Monthly mean streamflow for most months also decreased, with the greatest decreases occurring in August and September. The exceptions are March and April, when significant increases in streamflow were observed. Significant increases were identified in lower percentiles of the daily streamflow frequency distribution over northern British Columbia and the Yukon Territory. In southern Canada, significant decreases were observed in all percentiles of the daily streamflow distribution. Breakup of river ice and the ensuing spring freshet occur significantly earlier, especially in British Columbia. There is also evidence to suggest earlier freeze-up of rivers, particularly in eastern Canada. The trends observed in hydroclimatic variables are entirely consistent with those identified in climatic variables in other Canadian studies.

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Section: Introductionsupporting

confidence: 91%

Trends in Canadian streamflow

Zhang¹,

Harvey²,

Hogg³

et al. 2001

Water Resources Research

Self Cite

647

460

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show abstract

“…In Switzerland, in the 90s of the 20 th century, there were approximately 50 fewer days with frost than in the 30s. Similar changes were not only observed in Europe, but also in Canada [32], China [33] and the USA [34,35]. The greatest threat, with regard to plant development, is from May frosts.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

Frost periods and frost-free periods in Poland and neighbouringcountries

2015

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Abstract:The main objective of this article is to analyse the multiannual variability of frost occurrence and the length of the frost-free period in Poland and neighbouring countries between 1971 and 2010. A frost day was dened as a day on which the minimum temperature was below 0°C and the maximum temperature was above 0°C. On average, between March and November, there were 30 frost days in Poland and neighbouring countries, and their number ranged between 12 and 61. In the analysed multiannual period, there was a statistically signi cant tendency for the last spring frost to be earlier. Conversely, the rst autumn frost occurred increasingly late, although the changes were not statistically signi cant. All but three stations (Augsburg, Kaliningrad, Olsztyn) recorded an increase in the length of frost-free periods, which was statistically signi cant in 51% of stations. The pressure condition conducive to the occurrence of frosts was anticyclonic circulation, as con rmed by the SLP and z500 hPa maps which were drawn up, and the Grosswetterlagen (GWL) classi cation types which were distinguished.

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“…For example, Linderholm et al (2008) found a clear trend towards increasing growing season length (defined by 5°C threshold) around the Baltic Sea for the twentieth century, with rates ranging from 0.9 to 3.4 days decade -1 , mainly due to significant changes in spring. Comparable results were also found over Canada (for the period 1900-1998, (Bonsal et al 2001) and in the United States (for the period 1895-2000, Kunkel et al 2004) by analyzing changes in the frost-free season length (defined by 0°C threshold). In particular, Kunkel et al (2004) pointed out that larger changes had occurred in the western U.S. (1.9 days decade -1 ) than in the eastern U.S. (0.3 days decade -1 ), similar to the present results as expressed in Fig.…”

Section: Changes In Local Growing Season 1960-1999mentioning

confidence: 94%

Multidecadal variability in local growing season during 1901–2009

Xia

Zeng

2012

Clim Dyn

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Global warming exerts a lengthening effect on the growing season, with observational evidences emerging from different regions over the world. However, the difficulty for a global overview of this effect for the last century arises from limited availability of the long-term daily observations. In this study, we find a good linear relationship between the start (end) date of local growing season (LGS) and the monthly mean temperature in April (October) using the global gridded daily temperature dataset for 1960-1999. Using homogenized daily temperature records from nine stations where the time series go back to the beginning of the twentieth century, we find that the rate of change in the start (end) date of the LGS for per degree warming in April (October) mean temperature keeps nearly constant throughout the time. This enables us to study LGS changes during the last century using global gridded monthly mean temperature data. The results show that during the period 1901-2009, averaged over the observation areas, the LGS length has increased by a rate of 0.89 days decade -1 , mainly due to an earlier start (-0.58 days decade -1 ). This is smaller than those estimates for the late half of the twentieth century, because of multidecadal climate variability (MDV). A MDV component of the LGS index series is extracted by using Ensemble Empirical Mode Decomposition method. The MDV exhibits significant positive correlation with the Atlantic Multi-decadal Oscillation (AMO) over most of the Northern Hemisphere lands, but negative in parts of North America and Western Asia for start date of LGS. These are explained by analyzing differences in atmospheric circulation expressed by sea level pressure departures between the warm and cool phases of AMO. It is suggested that MDV in association with AMO accelerates the lengthening of LGS in Northern Hemisphere by 53 % for the period 1980-2009.

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Characteristics of Daily and Extreme Temperatures over Canada

Cited by 374 publications

References 21 publications

Trends in Canadian streamflow

Trends in Canadian streamflow

Frost periods and frost-free periods in Poland and neighbouringcountries

Multidecadal variability in local growing season during 1901–2009

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