scholarly journals Seasonal and Annual Trends in Australian Minimum/Maximum Daily Temperatures

2016 ◽  
Vol 10 (1) ◽  
pp. 39-55 ◽  
Author(s):  
W. A. van Wijngaarden ◽  
A. Mouraviev
Keyword(s):  
Temperature Trend ◽  
Daily Temperature ◽  
Maximum Temperature ◽  
Rural Environment ◽  
Maximum Daily Temperature ◽  
Temperature Trends ◽  
Significant Step ◽  
Annual Trends ◽  
Maximum Temperatures ◽  
Minimum Daily Temperature

Seasonal and annual trends in Australian minimum and maximum temperatures were studied. Records of daily minimum and maximum temperatures averaged over each month, extending as far back as 1856 were examined. Over 1/2 million monthly temperature values were retrieved from the Australian Bureau of Meteorology for 299 stations. Each station had an average of 89 years of observations. Significant step discontinuities affected the maximum temperature data in the 19th century when Stevenson screens were installed. The temperature trends were found after such spurious data were removed and averaged over all stations. The resulting trend in the minimum (maximum) daily temperature was 0.67 ± 0.19 (0.58 ± 0.26) oC per century for the period 1907-2014. Decadal fluctuations were evident in the maximum daily temperature with most of the increase occurring in the late 20th century. The minimum and maximum daily temperature trends were also found for the various seasons. The minimum daily temperature trend exceeded the maximum daily temperature trend for all seasons except during June to August. The largest increases in minimum temperature as well as the smallest maximum temperature increases were found for the region north of 30 oS latitude and east of 140 oE longitude. There was also evidence that urban stations had greater increases in maximum daily temperature than those located in a rural environment.

scholarly journals Temperature-related climate extremes in the Potsdam observation record

Geografie ◽  
2008 ◽  
Vol 113 (4) ◽  
pp. 372-382
Author(s):  
Zbigniew W. Kundzewicz ◽  
Damian Józefczyk
Keyword(s):  
Climate Extremes ◽  
Daily Temperature ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Maximum Daily Temperature ◽  
Daily Minimum ◽  
Maximum Temperatures ◽  
Minimum Daily Temperature

This paper examines temperature-related climate extremes in the unique long-term gapfree record at the Secular Meteorological Station in Potsdam. Increasing tendencies in daily minimum temperature in winter and daily maximum temperature in summer, as well as monthly means of daily minimum temperatures in winter months and of daily maximum temperatures in summer months are illustrated. Also the numbers of hot days and of summer days (with maximum daily temperature exceeding 30 °C and 25 °C, respectively) have been increasing. In agreement with warming of winter minimum temperatures, the numbers of frost days (with minimum daily temperature below 0 °C) and of ice days (with maximum daily temperature below 0 °C) have been decreasing. However, low correlation coefficient and huge scatter illustrate strong natural variability, so that the occurrence of extremes departs from the general underlying tendency.

scholarly journals Temperature Changes in Kaski District of Nepal: A Study of Trends (1970-2018)

2019 ◽  
Vol 2 ◽  
pp. 42-53
Author(s):  
Rajendra Prasad Upadhayaya
Keyword(s):  
Climate Change ◽  
Kendall Test ◽  
Rate Of Change ◽  
Temperature Trend ◽  
Maximum Temperature ◽  
Economic Sectors ◽  
Temperature Trends ◽  
Average Maximum ◽  
Average Maximum Temperature ◽  
Maximum Temperatures

Climate change is one of the most complex and crucial issues in the world. It has impacted environmental, social, and economic sectors of our planet. Unsurprisingly, Nepal is not immune to climate change. In fact, it is one of the most susceptible countries to climate change. One of the most impacted variables in Nepal due to climate change is the maximum temperature. The rate of change of temperature per year, in Nepal is ever-increasing. This paper examines the temperature trend and how it has affected environmental, social, and economic sustainability of Kaski District in Nepal. The paper utilizes the maximum temperature trend of Kaski District during 1970-2018. The monthly minimum and maximum temperatures are obtained from the Department of Hydrology and Meteorology (DHM). The study is done based on the data obtained from Pokhara Airport and Lumle stations. The paper uses three statistical tools alongside descriptive statistics to analyze the data. First, the Man-Kendall test is used to figure out the trend of temperature. Second, Sen’s slope is used to find the magnitude of a trend. Third, the Time series model has been used for forecasting temperature trends. Finally, SPSS and R software were used to calculate the results. The trend of maximum temperature has been significantly increased in Kaski District. The maximum temperature in Kaski during 1970-2018, recorded, was 24.99°C in 2005 and was closely followed by 24.66°C temperature in 2010. The average maximum temperature during the 1970-2018 period was 23.49°C. The maximum variation of maximum temperature during 1970-2018 was in 1992 with a standard deviation of 5.94°C. The minimum temperature during 1970-2018 was 21.12°C in 1978 and was closely followed by 22.19°C in 1997. There is an increasing trend of maximum temperature in Kaski District. In addition, the trend of maximum temperature is higher and faster after 1998 in Kaski District of Western Nepal during 1970-2018.

scholarly journals Determinants of thermal regime influence of small dams

2019 ◽  
Author(s):  
André Chandesris ◽  
Kris Van Looy ◽  
Yves Souchon
Keyword(s):  
Time Series ◽  
Water Temperature ◽  
Surface Area ◽  
Residence Time ◽  
Thermal Regime ◽  
Daily Temperature ◽  
Maximum Daily Temperature ◽  
Small Dams ◽  
Maximum Temperatures ◽  
Minimum Daily Temperature

Abstract. The purpose of this study was to quantify the downstream impacts of different types of small dams on summer water temperature in lowland streams. We examined: (i) temperature regime upstream and downstream dams of different structural characteristics; (ii) relationships between stream temperature anomalies and climatic variables, watershed area, dam height, impoundment length and surface and residence time; (iii) the more significant variables explaining the different thermal behaviours, in order to account for dam diversity and functioning in future regional stream temperature models. Water temperature loggers were installed upstream and downstream 11 dams in the Bresse Region (France) and monitored at 30 min intervals during summer period (June to September), from 2009 to 2016 depending on the sites (2 sites were monitored during 2 summers, others only 1 summer, resulting in 13 time-series), with the opportunity to compare cold and hot summers. The small dams altered the downstream thermal regime for 23 % of the time-series with a > 1 °C elevation of the maximum daily temperature; for 77 % the range was in between −1 °C and +1 °C. The mean increase of the minimum daily temperature was 1 °C, with 85 % of the time-series showing an increase > 0.5 °C. The sites are grouped in three main types with specific responses of different temperature variables (maximum daily temperature (T max), minimum daily temperature (T min) and daily temperature amplitude). Two main types of impact were identified: an increase in the daily minimum temperatures associated with stability and even a slight reduction of the daily maximum temperatures for impoundments of low volume (residence time shorter than 0.7 day and an impoundment surface area smaller than 35 000 m2); and an increase of the daily minimum and maximum temperatures in the same orders of magnitude when the surface area of the impoundment is larger than 35 000 m2 and the residence time is longer than 0.7 day. This increase can reach 2.4 °C at certain structures and could impact the structure of aquatic communities and the functioning of the aquatic ecosystem. These determinants are candidate to generalize results, but this would necessitate the gathering of more precise information than the current dam descriptors in public databases.

Effect of heat and precipitation on pea yield and reproductive performance in the field

2015 ◽  
Vol 95 (4) ◽  
pp. 629-639 ◽  
Author(s):  
Rosalind A. Bueckert ◽  
Stacey Wagenhoffer ◽  
Garry Hnatowich ◽  
Thomas D. Warkentin
Keyword(s):  
Reproductive Performance ◽  
Crop Growth ◽  
Daily Temperature ◽  
Growth And Yield ◽  
Maximum Temperature ◽  
Future Research ◽  
Yield Reduction ◽  
Weather Factors ◽  
Reproductive Growth ◽  
Maximum Daily Temperature

Bueckert, R. A., Wagenhoffer, S., Hnatowich, G. and Warkentin, T. D. 2015. Effect of heat and precipitation on pea yield and reproductive performance in the field. Can. J. Plant Sci. 95: 629–639. Pea (Pisum sativum L.) is important globally as a cool season crop. Pea cultivars are heat-sensitive so our goal was to investigate how weather impacted growth and yield in recent cultivars in the Co-operative pea yield trials (2000 to 2009) for a dryland (Saskatoon) and an irrigated (Outlook) location. We explored relationships between days to maturity, days spent in reproductive growth (flowering to maturity), yield and various weather factors. Yield and the length of reproductive growth increased with seasonal precipitation. Pea was sensitive to heat but heat units did not satisfactorily describe growth and yield in all environments. Strong relationships were observed between crop growth and mean maximum daily temperature experienced during reproductive growth, and between crop growth and mean minimum temperature. The greater the mean maximum temperature (>25.5°C), the fewer the number of days (<35) spent in reproductive growth at the dryland location. At Outlook, 35 to 40 d in reproductive growth occurred in a much wider temperature range from 24.5 to 27°C, and irrigation mitigated some reduction in yield. For dryland pea, more than 20 d in the season above 28°C were associated with less time in reproductive growth and less yield. The threshold maximum temperature for yield reduction in the field was closer to 28°C than 32°C from published studies, and above 17.5°C mean seasonal daily temperature. Western Canadian cultivars currently have short lifecycles, which make them heat sensitive. Heat tolerance could be improved by earlier flowering and a longer duration of flowering via an indeterminate habit. Future research will investigate pea nodal development, flowering and abortion patterns in a range of pea cultivars in field conditions.

The increasing of maximum lake water temperature in lowland lakes of central Europe: case study of the Polish Lakeland

2019 ◽  
Vol 55 ◽  
pp. 6 ◽  
Author(s):  
Mariusz Ptak ◽  
Mariusz Sojka ◽  
Michał Kozłowski
Keyword(s):  
Cluster Analysis ◽  
Water Temperature ◽  
Warming Trend ◽  
Maximum Temperature ◽  
Average Value ◽  
Temperature Trends ◽  
Air Temperatures ◽  
Maximum Water Temperature ◽  
Maximum Water ◽  
Maximum Temperatures

The paper presents the results of time-related changes in maximum temperatures in lakes. The analysis was carried out on the basis of 9 lakes located in the northern part of Poland. The analysis was based on daily water and air temperatures in the period 1971–2015. Mann–Kendall's and Sen's tests were applied to determine the directions and rates of change of maximum air and water temperatures. The average increase of maximum water temperature in analysed lakes was found to be 0.39 °C dec–1, while the warming trend of the maximum air temperature was 0.48 °C dec–1. Cluster analysis (CA) was used to group lakes characterised by similar changes of maximum water temperature. The first group included five lakes in which the values of the maximum temperature trends were 0.41 °C dec–1. In the second cluster the average value of maximum water temperature increase was smaller than in the first cluster (0.36 °C dec–1). Comparing the results of cluster analysis with morphometric data show that in the first cluster lakes are having a greater average depth, maximum depth and water transparency in comparison to the lakes of the second cluster.

scholarly journals Maximum Temperatures and Heat Waves in Mexicali, Mexico: Trends and Threshold Analysis

2016 ◽  
Vol 9 ◽  
pp. ASWR.S32778 ◽  
Author(s):  
Polioptro F. Martínez Austria ◽  
Erick R. Bandala
Keyword(s):  
Climate Change ◽  
Heat Wave ◽  
Heat Waves ◽  
Decision Makers ◽  
Maximum Temperature ◽  
Climate Trends ◽  
Intergovernmental Panel ◽  
Temperature Trends ◽  
Maximum Temperatures ◽  
The City

Maximum temperature trends and the corresponding heat wave thresholds in the northwestern city of Mexicali, Mexico, were analyzed using historical data from the site. We found that there seems to be an upward trend in temperature in the past decades, along with an increased number of days reaching maximum temperatures considered as heat waves. Despite the difficulty of establishing heat wave parameters, the trends of the analyzed field data clearly show their presence, mainly during July and August. This trend is also supported by the analysis of the number of admissions and casualties registered in hospitals in the city of Mexicali. This work is a warning on the frequency and duration of a very important climate change-related effect capable of jeopardizing the health of the population in the region and requiring more attention by decision makers and stakeholders. It also helps to document observed climate trends, as requested by the Intergovernmental Panel for Climate Change.

Taking China's Temperature: Daily Range, Warming Trends, and Regional Variations, 1955–2000

2004 ◽  
Vol 17 (22) ◽  
pp. 4453-4462 ◽  
Author(s):  
Binhui Liu ◽  
Ming Xu ◽  
Mark Henderson ◽  
Ye Qi ◽  
Yiqing Li
Keyword(s):  
Atmospheric Aerosols ◽  
Solar Irradiance ◽  
Cloud Cover ◽  
Maximum Temperature ◽  
Daily Maximum ◽  
Climate Data ◽  
Temperature Range ◽  
Temperature Trends ◽  
Air Temperatures ◽  
Maximum Temperatures

Abstract In analyzing daily climate data from 305 weather stations in China for the period from 1955 to 2000, the authors found that surface air temperatures are increasing with an accelerating trend after 1990. They also found that the daily maximum (Tmax) and minimum (Tmin) air temperature increased at a rate of 1.27° and 3.23°C (100 yr)−1 between 1955 and 2000. Both temperature trends were faster than those reported for the Northern Hemisphere, where Tmax and Tmin increased by 0.87° and 1.84°C (100 yr)−1 between 1950 and 1993. The daily temperature range (DTR) decreased rapidly by −2.5°C (100 yr)−1 from 1960 to 1990; during that time, minimum temperature increased while maximum temperature decreased slightly. Since 1990, the decline in DTR has halted because Tmax and Tmin increased at a similar pace during the 1990s. Increased minimum and maximum temperatures were most pronounced in northeast China and were lowest in the southwest. Cloud cover and precipitation correlated poorly with the decreasing temperature range. It is argued that a decline in solar irradiance better explains the decreasing range of daily temperatures through its influence on maximum temperature. With declining solar irradiance even on clear days, and with decreases in cloud cover, it is posited that atmospheric aerosols may be contributing to the changing solar irradiance and trends of daily temperatures observed in China.

scholarly journals An analysis of Skukuza climate data

Koedoe ◽  
2002 ◽  
Vol 45 (1) ◽  
Author(s):  
A.C. Kruger ◽  
L.B. Makamo ◽  
S. Shongwe
Keyword(s):  
Minimum Temperature ◽  
Negative Temperature ◽  
Temperature Trend ◽  
Maximum Temperature ◽  
Experimental Program ◽  
Climate Data ◽  
Temperature Trends ◽  
Diurnal Range ◽  
Climate Station

Data from the climate station at Skukuza, which has been open from 1912 to the present, are analysed. This exercise was done to provide the South African Regional Science Initiative (SAFARI-2000) experimental program with long-term climate statistics and trends. Climate parameters analysed are rainfall, temperature, humidity and sunshine. In the case of rainfall and temperature, the data was first tested for homogeneity and in only three out of 36 monthly cases, the data proved not to be homogeneous. No monthly rainfall trends proved to be significant (at the 5 % level), with five months indicating slightly negative trends and seven slightly positive. Only the monthly maximum temperature series for June proved to be non-homogeneous. The June maximum temperature trend and the February, March, May, July and December minimum temperature trends were significantly positive. The annual time series for minimum temperature were also significantly positive. The monthly results were reiterated by the seasonal results, with the winter maximum temperature trend and the autumn and summer minimum temperature trends significantly positive. Ten months showed negative temperature diurnal range trends with only March being significant. All long-term statistics of rainfall, temperature, humidity and sunshine were found to be typical of a savanna type climate in the southern hemisphere, although average monthly sunshine hours were somewhat less than the norm, due to frequent influx of moist air from the Mozambique Channel.

Assessing several downscaling methods for daily minimum and maximum temperature in a mountainous area. Are we able to statistically simulate a warmer climate in the Pyrenees?

2020 ◽  
Author(s):  
Marc Lemus-Canovas ◽  
Swen Brands
Keyword(s):  
Climate Change ◽  
Decision Making ◽  
Regression Models ◽  
Temporal Correlation ◽  
Daily Temperature ◽  
Maximum Temperature ◽  
Mountainous Area ◽  
Present Contribution ◽  
Mountain Areas ◽  
Maximum Daily Temperature

&lt;p&gt;Mountain areas are one of the most vulnerable areas to climate change, due to the large amount of natural resources they contribute to society. Moreover, the announced increase in temperature for the next few decades may have uncertain consequences for the ecosystems and landscapes of such territories. To face this challenge, it is necessary to test the capacity to simulate the climate of warm periods using observed data. In the present contribution, different perfect prog (PP) downscaling methods were evaluated to simulate the minimum and maximum daily temperature in a 1x1 km grid in the Pyrenees (Spain, France &amp; Andorra) for the period 1985-2015. To obtain the results, several combinations of predictors, different geographical domains of such predictors, as well as different reanalysis databases were used, to check how much they can influence the prediction skill. In addition, different metrics were calculated to evaluate the bias, the similarity in the observed and predicted distributions, the temporal correlation, etc.&lt;/p&gt;&lt;p&gt;The results obtained reflect that the regression models better represent the warm periods using the observed data, as well as a lower bias. The present study will facilitate the decision making on which method of downscaling PP is more useful to reproduce the future temperature in the Pyrenees.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Keywords: &lt;/strong&gt;Statistical downscaling, perfect prog, Pyrenees, daily temperature.&lt;/p&gt;

scholarly journals Small dams alter thermal regimes of downstream water

2019 ◽  
Vol 23 (11) ◽  
pp. 4509-4525 ◽  
Author(s):  
André Chandesris ◽  
Kris Van Looy ◽  
Jacob S. Diamond ◽  
Yves Souchon
Keyword(s):  
Water Temperature ◽  
Surface Area ◽  
Residence Time ◽  
Structural Characteristics ◽  
Daily Temperature ◽  
Aquatic Communities ◽  
Maximum Daily Temperature ◽  
Small Dams ◽  
Thermal Regimes ◽  
Minimum Daily Temperature

Abstract. The purpose of this study was to quantify the downstream impacts of different types of small dams on summer water temperature in lowland streams. We examined (1) temperature regimes upstream and downstream of dams with different structural characteristics, (2) relationships between stream temperature anomalies and climatic variables, watershed area, dam height, impoundment length and surface area, and residence time, (3) the most significant variables explaining the different thermal behaviors, and (4) the dam thermal effect considering a biological threshold of 22 ∘C, with a calculation of both the number of days with a temperature above this threshold and the average hourly duration above this threshold. Water temperature loggers were installed upstream and downstream of 11 dams in the Bresse region (France) and monitored at 30 min intervals during summer (June to September) over the 2009–2016 period, resulting in 13 paired water temperature time series (two sites were monitored for two summers, allowing the opportunity to compare cold and hot summers). At 23 % of the dams, we observed increased downstream maximum daily temperatures of more than 1 ∘C; at the remaining dams we observed changes in the maximum daily temperature of −1 to 1 ∘C. Across sites, the mean downstream increase of the minimum daily temperature was 1 ∘C, and for 85 % of the sites this increase was higher than 0.5 ∘C. We hierarchically clustered the sites based on three temperature anomaly variables: upstream–downstream differences in (1) maximum daily temperature (ΔTmax), (2) minimum daily temperature (ΔTmin), and (3) daily temperature amplitude (ΔTamp). The cluster analysis identified two main types of dam effects on thermal regime: (1) a downstream increase in Tmin associated with Tmax either unchanged or slightly reduced for impoundments of low volume (i.e., a residence time shorter than 0.7 d and a surface area less than 35 000 m2), and (2) a downstream increase of both Tmin and Tmax of the same order of magnitude for impoundments of larger volume (i.e., a residence time longer than 0.7 d and a surface area greater than 35 000 m2). These downstream temperature increases reached 2.4 ∘C at certain structures with the potential to impair the structure of aquatic communities and the functioning of the aquatic ecosystem. Overall, we show that small dams can meaningfully alter the thermal regimes of flowing waters, and that these that these effects can be explained with sufficient accuracy (R2=0.7) using two simple measurements of small dam physical attributes. This finding may have importance for modelers and managers who desire to understand and restore the fragmented thermalscapes of river networks.

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