Trends In Maximum Temperatures Research Articles

Climate Change Impacts on Temperature and Chill Unit Trends for Apple (Malus domestica) Production in Ceres, South Africa

Climate is an essential part of crop production, determining the suitability of a given region for deciduous fruit products such as apples (Malus domestica). It influences the yield and quality of fruits. There is strong evidence of global and regional-scale climate change since the advent of the industrial era. In South Africa, mean surface temperatures have revealed a warming trend over the last century. This study aimed to assess the impact of climate change on temperature and chill unit trends for apple production in Ceres, South Africa. The daily positive Utah chill units (DPCU) model was used as frequent high temperatures can lead to a high negation volume. Historically observed (1981–2010) and future projected (2011–2100) temperatures were obtained from the South African Weather Service (SAWS) and three ensemble members of the Cubic-Conformal Atmospheric Model (CCAM), respectively. The latter employed the RCP8.5 pathway. Linear trends were calculated for temperature and accumulated PCUs for the historical base period. The probability of accumulating specific threshold PCU values for both historical and future periods was assessed from cumulative distribution functions (CDFs). The historical change in minimum temperatures showed no significant trend. Ceres revealed a warming trend in maximum temperatures over the historical period. By the 2080s, the probability of not exceeding a threshold of 1600 PCUs was exceptionally high for all ensemble members. Future projections showed a decline in the accumulated PCUs of 2–5% by the 2020s, 7–17% by the 2050s, and 20–34% towards the end of the 20th century. Based on these results, it is clear that winter chill units are negatively influenced by climate change. The loss in yield and fruit quality of apples due to climate change can negatively impact the export market, leading to significant economic losses for apple production in the Ceres area.

Trend and change point detection in mean annual and seasonal maximum temperatures over Saudi Arabia

Trend and change point detection in mean annual and seasonal maximum temperatures over Saudi Arabia

Acute cold stress: a potential threat to Royle's pika (Ochotona roylii) survival at Central Himalayas of Nepal

Climate change and its threat to human life and biodiversity are under discussion as the major issue of this century. In this study, pika (Ochotona roylii) was taken as a model animal to study the effect of changing climatic parameters in the Central Himalayas of Nepal. The study was carried out for three consecutive years (2011−2013) in the Kyanjing Valley situated at 3900 m asl, Langtang National Park, Nepal. The study focused on the population density of pika, its lowest elevation distribution, and temperature patterns of the pika-burrows and their immediate surroundings. An iButtons Temperature Recorder was installed inside a pika-burrow for acquiring burrow temperature while the ambient temperature data were obtained from the nearby metrological station. The population density of pika decreased compared to those based on the previous studies. Over the last 25 years, there was a significant increase in the minimum temperature (R2 =0.77) that decreased the snow cover which might have reduced the insulation effect and colder winter to animals living inside the burrow. The temperature inside the burrow was recorded below −5°C for nearly 50% time during January alone and 25% time during total winter days. The environment with a temperature below −5°C could be a threat to the survival of pikas suffering from acute cold stress. Neither there was any record of heat stress (above 25°C) recorded nor there was an increasing trend of the ambient maximum temperature within the LNP during the study period. The lowest elevation of the pika's habitat was found to have shifted 200 m upwards over the last 46 years, indicating that the animals had either migrated upwards or facing extinction locally at lower elevations. However, this short-term study is not sufficient to reflect the effects of climate change on the population of pika in the Central Himalayas. Therefore, a long-term study is required to explore the relation between pikas and their vulnerability to the changing climate

Climate Trends at a Hotspot of Chronic Kidney Disease of Unknown Causes in Nicaragua, 1973-2014.

An ongoing epidemic of chronic kidney disease of uncertain etiology (CKDu) afflicts large parts of Central America and is hypothesized to be linked to heat stress at work. Mortality rates from CKDu appear to have increased dramatically since the 1970s. To explore this relationship, we assessed trends in maximum and minimum temperatures during harvest months between 1973 and 2014 as well as in the number of days during the harvest season for which the maximum temperature surpassed 35 °C. Data were collected at a weather station at a Nicaraguan sugar company where large numbers of workers have been affected by CKDu. Monthly averages of the daily maximum temperatures between 1996 and 2014 were also compared to concurrent weather data from eight Automated Surface Observing System Network weather stations across Nicaragua. Our objectives were to assess changes in temperature across harvest seasons, estimate the number of days that workers were at risk of heat-related illness and compare daily maximum temperatures across various sites in Nicaragua. The monthly average daily maximum temperature during the harvest season increased by 0.7 °C per decade between 1973 and 1990. The number of days per harvest season with a maximum temperature over 35 °C increased by approximately five days per year between 1974 and 1990, from 32 days to 114 days. Between 1991 and 2013, the number of harvest days with a maximum temperature over 35 °C decreased by two days per year, and the monthly average daily maximum temperature decreased by 0.3 °C per decade. Comparisons with weather stations across Nicaragua demonstrate that this company is located in one of the consistently hottest regions of the country.

Surface air temperature trends in Kathmandu Valley for 2011-2017

In this study, we reviewed the maximum and minimum temperature trends of the Kathmandu valley over the period of 2011-2017. In addition, the average monthly temperature trends were studied annually for the same period, with the data made available from the Department of Hydrology and Meteorology (DHM) of Nepal. The annual temperature trended in the same direction, with winter temperatures being lower and summer temperatures being higher. The annual average minimum and maximum air temperature trends were found to be slightly rising at 0.097˚C/year and 0.04˚C/year, respectively. The mean air temperature in Kathmandu valley is increasing at a rate of 0.06 degrees Celsius per year, with 2016 being the warmest year and 2012 being the least warm, with annual mean temperatures of 19.82˚C and 19.32˚C, respectively. The temperature difference is much smaller in the summer (less than ~12˚C) than in the winter. 
 BIBECHANA 18 (2) (2021) 95-104

Statistical investigation of long-term meteorological data to understand the variability in climate: a case study of Jharkhand, India

The present study was conducted to identify long-term (1901–2002) climatic trends for the state of Jharkhand. The meteorological data utilized in this study included maximum and minimum air temperatures, diurnal temperature (DTR) and rainfall for the state of Jharkhand. This data was evaluated on annual basis as well as for monsoon (June–September), winter (October–January) and summer (February–May) seasons respectively. A nonparametric statistical test (Mann–Kendall test) was employed to statistically analyze the aforementioned meteorological data. Prior to Mann–Kendall test, the time series data was processed using pre-whitening test to remove any serial correlation present in the data. An increasing trend in maximum and minimum temperatures was apparent during winter season and on annual basis for the period of study in Jharkhand at 1%, 5% and 10% significant levels. During monsoon season, all the districts exhibited decreasing trend in DTR at 1%, 5% and 10% significant levels except Giridih district where no trend was apparent at 0.0001% significance level. In winter season, no trend in DTR was apparent for all the districts at 0.0001% significance level except Pashchimi Singhbhum which exhibited decreasing trend at 10% significance level. No trend was observed in the annual DTR for most of districts except Dhanbad, Gumla, Kodarma, Lohardaga, Pashchimi Singhbhum and Ranchi. Rainfall exhibited a decreasing trend during monsoon season for all the district at 1%, 5% and 10% significant levels except Purbi Singhbhum district where the trend was not significant at 0.0001% level. A decreasing trend in annual rainfall was apparent for most of the districts at 1%, 5% and 10% significant levels. However, no significant trend was found in annual rainfall for Pashchimi and Purbi Singhbhum districts, respectively, at 0.0001% significant level. The change point test reveals that break years occured during the 1950 decade for annual maximum temperature and rainfall. Meanwhile, for minimum temperature, break years happened in 1920 decade, whereas a mix behavior was found for DTR. The findings of current study will be useful for the local resource managers and policy makers toward informed decision making.

Have any effect of COVID-19 lockdown on environmental sustainability? A study from most polluted metropolitan area of India.

The long-term lockdown due to COVID-19 has beneficial impact on the natural environment. India has enforced a lockdown on 24th March 2020 and was subsequently extended in various phases. The lockdown due to the sudden spurt of the COVID-19 pandemic has shown a significant decline in concentration of air pollutants across India. The present article dealt with scenarios of air quality concentration of air pollutants, and effect on climatic variability during the COVID-19 lockdown period in Kolkata Metropolitan Area, India. The result showed that the air pollutants are significantly reduced and the air quality index (AQI) was improved during the lockdown months. Aerosol concentrations decreased by − 54.94% from the period of pre-lockdown. The major air pollutants like particulate matters (PM2.5, PM10), sulphur dioxide (SO2), carbon monoxide (CO) and Ozone (O3) were observed the maximum reduction ( − 40 to − 60%) in the COVID-19 lockdown period. The AQI has been improved by 54.94% in the lockdown period. On the other hand, Sen’s slope rank and the Mann–Kendal trend test showed the daily decreased of air pollutants rate is − 0.051 to − 1.586 μg /m3. The increasing trend of daily minimum, average, and maximum temperature from the month of March to May in this year (2020s) are 0.091, 0.118, and 0.106 °C which is lowest than the 2016s to 2019s trend. Therefore, this research has an enormous opportunity to explain the effects of the lockdown on air quality and climate variability, and it can also be helpful for policymakers and decision-makers to enact appropriate measures to control air pollution.

Temperature trend analysis and extreme high temperature prediction based on weighted Markov Model in Lanzhou

In this study, temporal trend analysis was conducted on the annual and quarterly meteorological variables of Lanzhou from 1951 to 2016, and a weighted Markov model for extremely high temperature prediction was constructed. Several non-parametric methods were used to analyse the trend of meteorological variables. Considering that sequence autocorrelation may affect the accuracy of the trend test, we performed an autocorrelation test and carried out trend analysis for sequences with autocorrelation after removing correlation. The results show that the maximum temperature, minimum temperature and average temperature in Lanzhou all have a significant upward trend and show different performances in each season. In detail, the trend of maximum temperature in the summer is not significant, while the upward trend of minimum temperature in the winter is the most significant, which leads to more and more “warm winter” phenomenon. Finally, we construct a weighted Markov prediction model for extremely high temperature and obtain the conclusion that the prediction results by the model are consistent with the actual situation.

Spatiotemporal Analysis of Maximum and Minimum Temperature within a Basin: A Case Study of West-Flowing River Basin of Kutch, Saurashtra and Marwar, India

India has a vast geographic diversity and accordingly has diverse responses to changing climate. The more than expected variations in the temperature are causing alterations in the water cycle and stressing the regional water availability along with agriculture significantly. With the current climate change conditions with globally evident rising temperatures, India has to face the challenge of sustaining its rapid economic growth along with ensuring food security to its increasing mainly agriculture-dependent population. The purpose of this research was to investigate the spatiotemporal variations in maximum and minimum temperature in terms of monthly and annual trends in west-flowing river basin of Kutch, Saurashtra and Marwar (WFR-KSM basin). The trend was calculated and assessed in ProUCL5.0.00 and ArcMap 10 software using 36-year Indian Meteorological Department (IMD) maximum and minimum temperature grid (1° × 1°) data from 1969 to 2004. The direction and magnitude of annual and monthly trends were calculated for every grid using Mann–Kendall (MK) test and Theil–Sen’s (TS) slope. The trends in annual, maximum and minimum temperature were spatially analyzed annually and for every month from January to December. The majority of the area exhibited increasing trend in minimum and maximum temperature annually and in all the months from January to December. In annual maximum temperature, all grids exhibited positive slope ranging from 0.01 to 0.03 degree Celsius per year. In annual minimum temperature, majority of the grids (81.25%) exhibited positive slope ranging from 0.01 to 0.04 degree Celsius per year and none of the grids exhibited negative slope. Monthwise trend in maximum and minimum temperature also indicated rising trend in majority of the grids, with few grids identified with declining trend mainly along the eastern border of the basin.

SNOW COVER AREA ANALYSIS AND ITS RELATION WITH THE TEMPERATURE IN SIBINACOCHA LAKE WATERSHED, PERU, DURING 1984–2019 USING LANDSAT AND ERA5 DATA

ABSTRACT In comparison with many remote parts of the Earth, the watershed Sibinacocha Lake is poorly studied region and the various types of life that habit this region are highly dependent on the waters of this glaciated basin. The present study evaluates the snow cover in this basin associated with changes in air temperatures and precipitation during the period 1984 to 2019. It used the ERA5 high-resolution reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF) and 35 images from the Landsat satellite. The results showed a statistically significant positive trend in maximum air temperatures whose signal is in agreement with previous studies. Seasonal analysis of maximum temperatures showed positive trends in all seasons, indicating that the highest trends occur during winter and the lowest trends during the southern fall. In addition, there was a 26% decrease in snow cover in general in the basin, and it was evidenced that the greater decreases (53%, approximately) occurred in regions below the altitude of 5300 m. In fact, from this contribution of the study comes the need to carry out more research in this region, especially to support decisions covering agriculture, water resources management and biodiversity studies.

Assessment of the Maximum Temperature of Simplified High Heat Radioactive Glass in Interim Storage and Deep Geological Disposal

Ensuring the thermal stability of heat-generating nuclear waste glass canisters in interim storage and the thermal stability of bentonite in the deep geological repository are crucial to preserving the function of the waste form. Yet thermal stability might be challenged by further heated air conditions and excessive heat load in the waste form, such that the maximum temperature would be higher than the glass transition temperature undesirably. The finite element method was carried out for the n × n × 4 (n = 1, 3, 5) multicanister system for the sake of predicting the maximum temperatures of interim storage. The internal heat source amount and exiting air temperature of the system were varied to see different storage environments. The maximum heat load of a 15.8 kW/m3 canister was in a safe range (glass transition temperature of 500°C), whereas an 18.6 kW/m3 canister was not. There is a possibility to extend thermal stability to a system larger than n = 5 for 15.8 kW/m3 based on the converging maximum temperature trends. Besides, the maximum temperature of the canister and bentonite clay in a deep geological repository is potentially below the thermal criterion if the canister cools down for about 65 to 70 years.

Analysis of Maximum and Minimum Temperature in Qilian Mountainous, Northwest China

As one of the key elements of climate change, the temperature changes can affects the energy balance and hydrological cycle. The variations and trend of mean annual maximum temperature (Tmax) and minimum temperature (Tmin) were analyzed by using linear regress for 44 stations inside and surrounding the Qilian Mountains for period of 1960-2017. The results have shown that the variations of mean annual Tmax and Tmin have significant increasing in whole study regions. The warming trend of mean annual Tmix is higher than that of Tmax. Both the trend of mean annual Tmax and Tmin in the southern slope is warmer than those in the northern slope of Qilian Mountains. In spring, the warming trend of Tmax is significantly weaker inside than that outside the Qilian Mountains. For all seasons, the trend of Tmax and Tmin is the highest in winter, and is weakest in spring.

An Investigation of Parent Distributions and Long-Term Trends of Average Maximum and Minimum Temperature in the Limpopo Province of South Africa

An Investigation of Parent Distributions and Long-Term Trends of Average Maximum and Minimum Temperature in the Limpopo Province of South Africa

Evaluation of climate change impact on extreme temperature variability in the Blue Nile Basin, Ethiopia

Abstract. Climate change raises important issues concerning hydrological engineering. The impact of climate change on important river basins should be investigated rigorously. Extreme temperature variability has a direct impact on the hydrological cycle, especially the evaporation component. In this paper, spatial and temporal patterns of changes in extreme temperatures were investigated using 10 meteorological stations' data for the period 1950–2018 in the Blue Nile Basin. Long-term trends in the Blue Nile Basin annual and monthly temperatures were investigated. The statistical significance of the trend was calculated by applying the Mann–Kendall (MK) test. The analysis of data was performed using the coefficient of variance and anomaly index. The results showed that the annual maximum and minimum temperatures were increasing significantly with a magnitude of 0.037 and 0.025 ∘C per decade respectively in the period from 1950 to 2018. The result of the Mann–Kendall analysis test revealed a marked increase in the mean maximum and minimum temperature trends over time during the study period (the minimum temperature rate is more evident than the maximum). The long-term anomalies of mean annual minimum temperature revealed the interannual variability while the trend after 1977 was higher than the long-term average, which is proof of the warming trend's existence during the last two decades of the 20th century.

Prophesying the stream flow and perpetrating the performance of Halele-Werabessa reservoirs of Ethiopia using HEC-HMS and HEC-ResSim

Purpose To assess the impacts of climate change on stream flow and evaluation of reservoir performances, reliability, resilience and vulnerability (RRV) indices are contemplated. Precipitation, temperature (Tmax, Tmin), relative humidity and solar radiation are the hydrological and meteorological data which have been used extensively. Climate data like RCP2.6, RCP4.5 and RCP8.5 were evaluated for the base period 1976–2005 and future climate scenario for 2021–2050 and 2051–2080 as per the convenience. Design/methodology/approach The hydrologic engineering center hydrologic modeling system (HEC-HMS) model was used to simulate the current and future inflow volume into the reservoir. The model performance resulted as 0.76 Nash-Sutcliffe efficiency (NSE), 0.78 R2 and −3.17 D and during calibration the results obtained were 0.8 NSE, 0.82 R2 and 2.1 D. The projected climate scenario illustrates an increasing trend for both maximum and minimum temperature though a decreasing trend was documented for precipitation. The average time base reliability of the reservoirs was less than 50% without reservoir condition and greater than 50% for other conditions but volumetric reliability and resilience varies between 50% and 100% for all conditions. The vulnerability result of reservoirs may face shortage of flow ranging from 5.7% to 33.8%. Findings Evaluating reservoir simulation and hydropower generation for different climate scenarios by HEC-ResSim model, the energy generated for upper dam ranges from 349.4 MWhr to 331.2 MWhr and 4045.82 MWhr and 3946.74 MWhr for short and long-term future scenario, respectively. RCP for Tmax and Tmin goes on increasing whereas precipitation and inflow to reservoir decreases owing to increase in evapotranspiration. Under diverse climatic conditions power production goes on varying simultaneously. Originality/value This paper is original and all the references are properly cited.

Seasonal temperature trends on the Spanish mainland: A secular study (1916–2015)

AbstractTrends in seasonal mean values of maximum and minimum temperature are analysed in the Spanish mainland from the new MOTEDAS_century database. This new data set has been developed combining the digitalized archives from the Spanish Meteorological Agency (AEMET) with information retrieved from Annual Books published by the former Meteorological Agency dating back to 1916, and covers the period 1916–2015. In all four seasons, mean seasonal temperature of maximum (Tmax) and minimum (Tmin) increased. The raising occurred in two main pulses separated by a first pause around the middle of the 20th century, but differed among seasons and also between maximum and minimum temperature. Analysis of the percentage of land affected by significant trends in maximum temperature reveals two increasing phases in spring and summer for Tmax, and in spring, summer, and autumn for Tmin. However, winter Tmax only rose during the recent decades, and autumn Tmax in the first decades. Negative significant trends were found in extended areas in spring Tmax, and in spring, autumn, and summer Tmin, confirming the first pause around the 1940's–1960's. Trends of seasonal mean values of Tmax and Tmin are not significant for at least the last 25–35 years of the study period, depending on the season. The areas under significant positive trend are usually more extended for Tmin than Tmax at any season and period. Areas with significant trend expand and contract in time according to two spatial gradients: south‐east to north‐west (east‐west) for Tmax, and west to east for Tmin. We hypothesize a relationship between atmospheric prevalent advection and relief as triggering factors to understand spatial and temporal differences in seasonal temperatures at regional scale during the 20th century in the Iberian Peninsula.

ANÁLISIS DEL REGISTRO DE TEMPERATURA LOCAL EN EL SURESTE DE MÉXICO

Durante los últimos años, el planeta se ha visto envuelto en un proceso de calentamiento global, lo que lleva a la necesidad conocer más sobre variaciones de temperatura. El objetivo de esta investigación fue identificar las tendencias anuales de temperatura máxima (variable 1) y mínima (variable 2) en el sur de México en el periodo de registro de 1960 a 2000. Las estaciones de los estados de Campeche, Quintana Roo, Tabasco y Yucatán presentaron rangos de temperatura similares, mientras que Chiapas presenta variaciones asociadas a la orografía del estado. Los resultados para ambas mostraron una tendencia positiva en la mayoría de las estaciones. Tenían en común que gran parte de éstas, se localizan en zonas urbanizadas o con nula o muy poca vegetación. Esto puede asociarse a la manifestación de islas de calor debido a la urbanización.

Long-term nationwide spatiotemporal changes of freshwater temperature in Japan during 1982–2016

We analyzed freshwater temperature data from 1982 to 2016 throughout Japan to better understand how waters are warming in Japan. We used linear regression to determine the temperature change rate and Mann–Kendall tests to identify significant temporal trends in the annual maximum and mean temperatures. Among 11,240 monitoring sites screened, 159 with fewer missing values were selected for analysis. On the basis of this analysis, we identified and ranked the sites showing significant temporal increasing or decreasing trends for future management. At nearly half (42%) of the analyzed sites, the annual mean freshwater temperature was increasing; thus, in the future, adverse impacts from warm temperatures may increase in those aquatic ecosystems. The temperature change rate of fresh water was higher than that of air, indicating that the observed increases in freshwater temperature were not due to atmospheric warming only. Among individual sites, the annual maximum freshwater temperature change rate ranged from −1.27 to 1.91 °C/decade, and the annual mean rate ranged from −1.13 to 1.28 °C/decade. Few other studies have reported decreasing temperatures for fresh water. We expect our results will improve understanding of how freshwater temperatures are changing at a large scale, enhance understanding of human impacts on the aquatic environment, support effective management of ecosystems experiencing temperature changes, and help to minimize the loss of biodiversity over the next half century.

Assessing the Impacts of Climate Change and Variability on Maize (Zea mays) Yield over Tanzania

This study aimed at understanding the impacts of the seasonal hydroclimatic variables on maize yield and developing of statistical crop model for future maize yield prediction over Tanzania. The food security of the country is basically determined by availability of maize. Unfortunately, agriculture over the country is mainly rain fed hence highly endangered by the detrimental consequences of climate change and variability. Observed climate data was acquired from Tanzania Meteorological Authority (TMA) and Maize yield data from Food and Agriculture Organization (FAO). The study used the Mann-Kendall test and Sen’s slope for trend and magnitude detection in minimum, maximum temperature and rainfall at the 95% confidence level. The results have shown that rainfall is decreasing over the country and especially during the growing season but increasing during short rains season. Characteristics of seasonal climatic variables, cycle during growing period were linked to maize yield, and high (low) yield was reported during anomalous wet (dry) growing seasons. This portrays seasonal dependence of maize production. Statistical crop model was built by aggregating spatial regions that have statistically significant relation with maize yield. Results show that, 58.8% of yield variance is linked to seasonal hydroclimate variability. Rainfall emerged as the dominant predictor variable for maize yield since it accounts for 44.1% of yield variance. The modeled and observed yields exhibit statistically substantial relationship (r = 0.78) hence depicting high credence of the built statistical crop model. Also, the results revealed a decreasing trend in Maize yield with further Lessing trend is projected to proceed in the future. This calls for adaptation and implementation of appropriate regional measures to raise maize production in order to feed the burgeoning human population amidst climate change.

Trend Analysis of the Variations of Ambient Temperature Using Mann-Kendall Test and Sen’s Estimate in Calabar, Southern Nigeria

Studies have been made to understand the fluctuations of temperature in regions around the world because of an ever changing variation due mostly to man’s anthropogenic activities. This study is focused on analysing the temperature variations in Calabar, Southern Nigeria for 20 years (1998 – 2018) using the Mann-Kendall trend test and Sen’s slope estimator. Results from the Mann-Kendall test shows that the annual trends of the maximum and average ambient temperature are both increasing after showing positive Kendall Z-values (1.04 and 0.10 respectively). The minimum ambient temperature annual trend was observed to be decreasing after having a negative Kendall Z-value (-0.32); the estimations from Sen’s slope agreed with these results. The p-values were calculated to be 0.745, 0.299, and 0.922 for the minimum, maximum, and average ambient temperature trend respectively; these values were all found to be less than all significant levels used 0.1% (0.001), 1% (0.01), 5% (0.05), and 10% (0.1). This shows that the trends were not increasing or decreasing significantly, hence there is “no significant trend”. This may be due to the almost unchanging weather condition in the region arising from its closeness to the Atlantic Ocean.