Mean Minimum Temperature Research Articles

Climate Change Prediction Using ARIMA Model

Abstract: It is a challenging task to forecast weather data accurately. The temperature change has important implications for business and economic activity. Effective management of global climate change impacts will depend upon accurate and costeffective forecasts. This paper univariate statistic techniques to model the properties of a world mean temperature dataset to develop a parsimonious forecasting model for managerial decision-making over the short-term horizon and the ARIMAbased prognostication tool has been developed by implementing the ARIMA algorithm in python. Although the model is estimated on global temperature data, the methodology could even be applied to temperature data at more localized levels. The statistical techniques include seasonal and non-seasonal unit root testing with and without structural breaks as well as ARIMA and SARIMA modelling. This paper helps us to predict the air temperature, which is the main problem of global warming. Prediction of the likely impact of climate change on monthly mean maximum and minimum temperature in Tamilnadu. Time-series techniques to develop a parsimonious model of global mean temperature change that can be used to forecast over the short-term horizon (5- 10) years. Keywords: Global warming, Forecasting, temperature

How Well Does the ERA5 Reanalysis Capture the Extreme Climate Events Over China? Part II: Extreme Temperature

The fifth-generation atmospheric reanalysis of the European Center for Medium-Range Weather Forecasts (ERA5) is the latest reanalysis product. However, the reliability of ERA5 to capture extreme temperatures is still unclear over China. Hence, based on conventional meteorological station data, a new criterion (DISO) was used to validate the ERA5 capturing extreme temperature indices derived from the Expert Team on Climate Change Detection and Indices (ETCCDI) across the six subregions of China on different timescales. The conclusions are as follows: the original daily temperatures (mean temperature, maximum temperature, and minimum temperature) can be well reproduced by ERA5 reanalysis over China. ERA5 tends to exhibit more misdetection for the duration of extreme temperature events than extreme temperature intensity and frequency. In addition, ERA5 performed best in the summer and worst in the winter, respectively. The trend of absolute indices (e.g., TXx and TNx), percentile-based indices (e.g., TX90p, TX10p, TN90p, and TN10p), and duration indices (e.g., WSDI, CSDI, and GSL) can be captured by ERA5, but ERA5 failed to capture the tendency of the diurnal temperature range (DTR) over China. Spatially, ERA5 performs well in southeastern China. However, it remains challenging to accurately recreate the extreme temperature events in the Tibetan Plateau. The elevation difference between the station and ERA5 grid point contributes to the main bias of reanalysis temperatures. The accuracy of ERA5 decreases with the increase in elevation discrepancy.

Effects of stand factors on tree growth of Chinese fir in the subtropics of China depends on climate conditions from predictions of a deep learning algorithm: A long-term spacing trial

Stand and climate related variables are the main driving forces controlling individual tree growth. Two machine learning algorithms called deep learning and random forest were used to explore how annual diameter growth varied with stand and climatic variables. Data was obtained from a long-term spacing trail of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations in four provinces of southern China. Results from model comparisons showed the deep learning model with 8 hidden layers and 90 neurons in each hidden layer achieved the best performance, and the RF model ranked 4th among 9 selected models. In addition, sensitivity analysis showed that individual tree growth increased with an increase in Gini coefficient, while growth decreased with an increase in stand age (A) and the basal area of larger trees (BAL). The relationships between diameter growth and summer mean maximum temperature (SMMT), as well as winter mean minimum temperature (WMMT) and annual precipitation (AP) were not constant, which depended on the range of values of each climate factor. BAL had the greatest influence on diameter growth among all the variables. From an interaction analysis, we found that climate factors exacerbated the negative effects of competition on growth. Climate change promoted the growth of younger trees but restrained the growth of older trees. With climate variables considered, tree growth under high and middle stand structural heterogeneity were similar, and observably higher than that with low stand structural heterogeneity. Positive influences of climate tended to promote tree growth under lower competition and older individuals were more vulnerable to WMMT changes. Our findings enhance our understanding of the mechanisms driving individual Chinese fir growth in southern China in the face of future climate uncertainty.

Divergent Tree Growth and the Response to Climate Warming and Humidification in the Tianshan Mountains, China

In recent decades, the global climate has changed significantly. The climate in Northwest China became warm-wet, especially in the Tianshan Mountains. In order to explore the response of tree growth to recent climate change, the two dominant trees species, Picea schrenkiana Fisch. et Mey. and Larix sibirica Ledeb., were studied with the dendrochronological method in the western Tianshan Mountains (WT) and the eastern Tianshan Mountains (ET). Our results showed that: (1) The tree growth of four sample sites in the WT significantly increased in recent decades, while the trees in the three sample sites in the ET significantly decreased. (2) In the WT, except for the Manas site, the tree-ring chronologies of the other three sites were significantly positively correlated with the mean annual minimum temperature. Tree-ring chronologies in the WT, except for Bangfanggou site, were significantly positively correlated with annual precipitation. In the ET, only the tree chronology of L. sibirica in the Balikun site was significantly negatively correlated with the annual temperatures, including the mean minimum, mean and mean maximum temperature. (3) The proportion of trees with a significant upward growth trend at each site decreased from west to east, and the proportion of trees with a significant downward growth trend at each site increased from west to east along the whole Tianshan Mountains. (4) The correlation of tree-ring chronologies with the annual temperature and annual precipitation was not stable during the study period. Warm-humidification promoted the growth of trees in the WT but inhibited tree growth in the ET, which may be exacerbated drought stress in the ET where the increase in precipitation was not enough to offset the increased evapotranspiration potential caused by warming.

Tibetan Plateau greening driven by warming‐wetting climate change and ecological restoration in the 21st century

AbstractHigh altitude areas play an essential role in the global climate system, and their fragile ecosystems sensitively respond to climate change and human activities. An improved understanding of the influences of multiple factors on the spatiotemporal dynamics of vegetation is needed. This study aimed to understand further the impacts of climate, geography, and human on vegetation and disentangle the contributions of climate and humans to vegetation changes using the MOD13Q1 enhanced vegetation index (EVI, 2000–2019). Greening was detected for 70% of the Tibetan Plateau under increased warming and wetting in the 21st century. A rise in temperature of up to 0.66 ± 0.49°C decade−1 occurred over 2/3 of the Tibetan Plateau, while precipitation increased slightly. In particular, significant greening covered 1/4 of the Tibetan Plateau and occurred within the steppe and desert on the northern due to wetting and ecological protection. Browning depended on urbanization, overgrazing, and lake expansion in 1.9% of the total area. Orbicular browning around lakes accounted for 18.4% of significant browning, and significant browning trends were also detected in densely populated cities situated at low‐altitude and flat areas. The EVI was more strongly positively correlated with the annual mean minimum temperature than the annual mean temperature and maximum temperature and was sensitive to extreme low precipitation events. Residual analysis showed that the relative contribution of climate change was 34%, and that of human activities was 66%. A comprehensive description of the vegetation changes on the Tibetan Plateau will help humans to cope with climate change and ecosystem evolution in high altitude.

Climate change, climatic disasters, and adaptation techniques: learnings from the lowlands of Nepal

Nepal is experiencing inevitable consequences of changing climate. Rural communities are badly suffering from these implications. Meanwhile, the rural communities are trying to acclimatize through small–scale adaptation efforts. This study aims to analyze changes in temperature and rainfall trends, identify major climatic disasters, and document current adaptation measures being adopted by rural communities. For this study, we randomly selected 220 households from a total of 4,282 Households, and seven key informants for the questionnaire survey within the study area. Meteorological data from the nearest station were used to analyze changes in temperature and rainfall trends. The study revealed that both mean annual maximum and minimum temperature increased by 0.063 °C/year and 0.072° C/year respectively, between 1991 and 2020. Similarly, mean annual rainfall increased by 12.329 mm/year. Floods, droughts, landslides, hailstorms, and forest fires were major climate disasters experienced by the locals. The adverse impact perceived were loss of crop yield, decrease in water availability, an increase of mosquitoes, and a decline in sightings of the birds and waterfowls in the area. Embankment construction along rivers, changing cropping patterns and cultivation time, forest protection, and maintaining home gardens were major adaptation measures being practiced by the locals. We believe the findings of this study will be helpful for policymakers to develop strategies and programs for communities that will promote resilience against climate– induced disasters at a local level in the lowlands of Nepal.

Minimum temperature during the growing season limits the radial growth of timberline Schrenk spruce (P. schrenkiana)

Representing the altitudinal limit of typical vegetation, the alpine timberline is a unique natural landscape that is also a sensitive indicator of the well-being of alpine ecosystems. Schrenk spruce (P. schrenkiana) is a tree species unique to arid Central Asia. In this study, we found that the P. schrenkiana can grow at elevations of up to 3600 m. To better understand how this species survives at such high elevations, we used tree-ring samples to analyze the relationship between climate and the radial growth of P. schrenkiana at the alpine timberline. Our results suggest that the mean minimum temperature during the growing season is the main factor limiting the radial growth of timberline P. schrenkiana. The limiting effect of temperature on radial growth has been significant and stable over the past 60 years. However, the influence of precipitation on tree growth has increased due to rapid warming. Continued warming may further complicate the response of P. schrenkiana radial growth to climate at the timberline in arid Central Asia.

Simulation and Evaluation of Hydrothermal Conditions in Crop Growth Period: A Case Study of Highland Barley in the Qinghai-Tibet Plateau

WXGEN, a weather generator model based on stochastic process theory and mathematical statistics, was widely used in hydrological monitoring models, crop yield estimation models and derived fields of meteorological data. In this study, we used WXGEN to evaluate the simulation accuracy of hydrothermal conditions in the highlands of the Qinghai–Tibet Plateau. Results showed that: (1) The Markovian chain transfer parameters P(W|D) and P(W|W) of each station were between 0.03–0.30 and 0.12–0.74, which was basically consistent with the temporal and spatial distribution of actual precipitation; (2) In the thermal data simulation, more than 96% of the meteorological stations passed the 0.05 level in three different significance tests of monthly mean minimum and maximum temperature and solar radiation, and the measured deviations of simulated annual mean temperature and solar radiation were 0.686 °C and 1.65 MJ/m2, respectively. In all, 94% of the stations in the hydrological simulation passed the monthly precipitation significance test; (3) The simulated vs. measured deviations of annual precipitation, heavy rain days and wet days were 8.04 mm, 1.023 d and 8.374 d, respectively; (4) The simulation of extreme hydrothermal conditions that may affect the yield of highland barley was very close to the measured situation, and the R2 of simulation and measured value was all above 0.85. The simulation of freezing damage was less accurate, but also higher than 0.85.

Association of the incidence of atopic dermatitis until 3 years old with climate conditions in the first 6 months of life: Japan Environment and Children's Study (JECS).

To determine the climate conditions that affect the incidence of atopic dermatitis from infancy to 3 years old. We analyzed 100,303 children born from 2011 to 2014 for follow-up until 3 years old using cohort data from the Japan Environment and Children's Study. The study included 15 Regional Centers, including 19 prefectures across Japan. We used meteorological data of the Japan Meteorological Agency. We calculated the hazard ratio (HR) of the standard deviation and low vs. high mean values of several climate conditions in children in their first 6 months of life to determine the incidence of atopic dermatitis. The Kaplan-Meier curve showed that children born in the months of October to December had the highest incidence of atopic dermatitis. Among climate conditions, a one standard deviation increase in the temperature (HR = 0.87), minimum temperature (HR = 0.87), and vapor pressure (HR = 0.87) showed the lowest HRs for the incidence of atopic dermatitis. These results were confirmed by an analysis by strata of the birth season. A low vapor pressure (HR = 1.26, p<0.0001) and the combination of a low mean temperature or low mean minimum temperature and low vapor pressure (HR = 1.26, p<0.0001) were associated with the highest incidence of atopic dermatitis. These results were consistent when they were adjusted for a maternal and paternal history of allergy and the prefecture of birth. Among climate conditions, a low vapor pressure is the most strongly associated with a high incidence of atopic dermatitis. Measuring vapor pressure may be useful for preventing atopic dermatitis.

Temperature Change Characteristics in Gansu Province of China

The applicability of reanalysis data has been widely addressed in climate and hydrology studies over the past two decades. In this study, we analyzed spatiotemporal variations in ERA-Interim temperature data from four climate zones within Gansu Province from 1979 to 2017 by using linear regression model and Mann-Kendall mutation test. Results showed that: (1) The highest temperature was found in the subtropical monsoon climate zone, and the lowest in the plateau mountain climate zone. Temperatures in high-elevation regions were lower than those in low-elevation regions; (2) The annual mean temperature increased across Gansu Province from 1979 to 2017. The lowest warming rates of annual mean, annual maximum, and annual minimum temperatures were found in the subtropical monsoon climate zone, and these were 0.334, 0.300, and 0.336 °C/10a, respectively. The highest warming rates of annual mean and annual minimum temperature were found in the temperate monsoon climate zone, and these were 0.420 and 0.464 °C/10a, respectively. The highest warming rate of annual maximum temperature was found in the temperate continental climate zone (0.471 °C/10a); (3) The Mann-Kendall analysis showed that the mutation times of annual mean temperature of the subtropical monsoon, temperate monsoon, and temperate continental climate zones in Gansu Province were all in 1997. The mutation times of annual maximum temperature were found in the subtropical monsoon climate zone (1997) and temperate monsoon climate zone (1997). The mutation times of annual minimum temperature were found in the temperate continental climate zone (1997) and plateau mountain climate zone (1994). ERA-Interim reanalysis data are reliable for capturing mutation time of temperature, especially in the high-elevation areas with rare meteorological station. This study can provide a reference when analyzing climate change at different climatic zones using reanalysis data.

Impact of ambient temperature, precipitation and seven years of experimental warming and nutrient addition on fruit production in an alpine heath and meadow community

Alpine and polar regions are predicted to be among the most vulnerable to changes in temperature, precipitation, and nutrient availability. We carried out a seven-year factorial experiment with warming and nutrient addition in two alpine vegetation communities. We analyzed the relationship between fruit production and monthly mean, maximum, and min temperatures during the fall of the pre-fruiting year, the fruiting summer, and the whole fruit production period, and measured the effects of precipitation and growing and thawing degree days (GDD & TDD) on fruit production. Nutrient addition (heath: 27.88 ± 3.19 fold change at the end of the experiment; meadow: 18.02 ± 4.07) and combined nutrient addition and warming (heath: 20.63 ± 29.34 fold change at the end of the experiment; meadow: 18.21 ± 16.28) increased total fruit production and fruit production of graminoids. Fruit production of evergreen and deciduous shrubs fluctuated among the treatments and years in both the heath and meadow. Pre-maximum temperatures had a negative effect on fruit production in both communities, while current year maximum temperatures had a positive impact on fruit production in the meadow. Pre-minimum, pre-mean, current mean, total minimum, and total mean temperatures were all positively correlated with fruit production in the meadow. The current year and total precipitation had a negative effect on the fruit production of deciduous shrubs in the heath. GDD had a positive effect on fruit production in both communities, while TDD only impacted fruit production in the meadow. Increased nutrient availability increased fruit production over time in the high alpine plant communities, while experimental warming had either no effect or a negative effect. Deciduous shrubs were the most sensitive to climate parameters in both communities, and the meadow was more sensitive than the heath. The difference in importance of TDD for fruit production may be due to differences in snow cover in the two communities.

Evaluating area-specific adaptation strategies for rainfed maize under future climates of India

This study investigates the spatio-temporal changes in maize yield under projected climate and identified the potential adaptation measures to reduce the negative impact. Future climate data derived from 30 general circulation models were used to assess the impact of future climate on yield in 16 major maize growing districts of India. DSSAT model was used to simulate maize yield and evaluate adaptation strategies during mid (2040-69) and end-centuries (2070-99) under RCP 4.5 and 8.5. Genetic coefficients were calibrated and validated for each of the study locations. The projected climate indicated a substantial increase in mean seasonal maximum (0.9–6.0 °C) and minimum temperatures (1.1–6.1 °C) in the future (the range denotes the lowest and highest change during all the four future scenarios). Without adaptation strategies, climate change could reduce maize yield in the range of 16% (Tumkur) to 46% (Jalandhar) under RCP 4.5 and 21% (Tumkur) to 80% (Jalandhar) under RCP 8.5. Only at Dharwad, the yield could remain slightly higher or the same compared to the baseline period (1980–2009). Six adaptation strategies were evaluated (delayed sowing, increase in fertilizer dose, supplemental irrigation, and their combinations) in which a combination of those was found to be effective in majority of the districts. District-specific adaptation strategies were identified for each of the future scenarios. The findings of this study will enable in planning adaptation strategies to minimize the negative impact of projected climate in major maize growing districts of India.

Assessing Impact of Projected Climate Change on Sali Rice in a Representative District of Upper Brahmaputra Valley Zone of Assam

Three years of field trial along with DSSAT v4.6 CERES-Rice model-based simulation experiment was carried out to study the impact of climate change on Sali rice yield under various Representative Concentration Pathways (RCPs) in the agro-climatic conditions of Jorhat, Assam. Field experiments were conducted during kharif, 2017, 2018 and 2019 at the Instructional-Cum-Research (ICR) farm of Assam Agricultural University, Jorhat with three varieties viz., Mahsuri (150 days), Swarna Sub-1 (140-145 days) and TTB-404 (140-145 days); transplanted under three different micro-climatic regimes created by manipulating date of transplanting i.e., 26th June (early), 11th July (mid) and 26th July (late) under split plot experimental design with four replications. The validated model showed a good agreement for estimation of days required to attain different phenological stages with RMSE value 3.5, 2.9 and 2.9 days for Swarna sub-1; 2.4, 3.3 and 4.1 days for Mahsuri and 3.7, 2.6 and 2.4 days for TTB-404, respectively for panicle initiation, anthesis and physiological maturity. The overall d-stat value varied within 0.53 to 0.85 for phenology and 0.68 to 0.79 for grain yield. The ensemble weather data under four RCPs revealed an increase in mean maximum (0.3 to 3.0°C) and minimum (0.8 to 3.5°C) temperatures along with rainfall (11.8 to 43.4%) during the crop growing period compared to experimentation period (i.e. 2017-19) in three projected years. The grain yield of Sali rice showed positive deviation in all four RCPs and projected years under successive transplanting dates. The overall results reveal an increase in mean temperature up to 3°C during the crop growing period has no substantial adverse impact on grain yield of Sali rice under the agro-climatic condition of Jorhat, Assam.

Significant climatic differences in the period 1991-2020 and analysis of its representativeness for climatic characterization in the Center Region of Jalisco

The objective of the current research was to compare statistically on a monthly and annual scale, the climatologies 1961-1990 and1991-2020 in the Central Region of Jalisco, in order to determine (in case there are) differences between both climatologies and thatway be able to conclude on the adequate data period to characterize the current climatology of the region. Climatic informationfrom six meteorological stations with data for the period 1961-2020 was analyzed, which was divided into the sub-periods 1961-1990 and 1991-2020, and then carried out a comparative statistical analysis that included a data normality test, correlation analysis,and Tukey HSD test. The results of the correlation analysis but also the Tukey tests, show the presence of numerous evidence thatthe climate has changed during the last 30 years both on a monthly and annual scale and in diverse areas of the Central Region. Theannual mean maximum and minimum temperatures are changing significantly over the years. The changes found in the regionalclimate patterns are more evident in the temperature regime than in the precipitation regime, since in more than 61% of the monthlydata of mean maximum temperature and more than 55% of the monthly data of mean minimum temperature, a significant changewas found in the 1991-2020 climatology. According to the results, the current climatology in the study region must be characterizedby a time series of the last three decades or one that does not go beyond the first years of the 1980s, a period of time in whichclimate change began to manifest itself evidently. For that reason, the suggested options are the period 1991-2020 or 1985-2020.Climate series older than 40 years can be used to characterize extreme or irregular climatic events, and their return periods.

Influence of soil moisture on mean daily maximum and minimum temperatures over India

Influence of soil moisture on mean daily maximum and minimum temperatures over India

Phenology, cold injury and growth of American chestnut in a Range-Wide provenance test

The primary factor limiting the distribution and growth of American chestnut (Castanea dentata (Marsh.) Borkh.) in eastern North America is tolerance to chestnut blight that is caused by the introduced fungal pathogen Cryphonectria parasitica (Murr.) Barr. However, a better understanding of how genetics and the environment influence American chestnut physiology and growth will also be needed to guide restoration as blight-tolerant growing stock becomes available. Here we describe patterns of phenology, cold injury and radial growth for American chestnut from 13 seed sources that represent three temperature zones (warm, moderate and cold) grown together in a unique provenance test in Vermont, USA. Temperature zones were established using data on the mean minimum winter temperatures over 10–30 years for weather stations nearest seed source locations; these averages were −5 °C and above for the warm temperature zone, −5 to −10 °C for the moderate temperature zone, and below −10 °C for the cold temperature zone. There was a consistent trend for trees from the warm temperature zone to break bud and leaf out earlier, and experience greater spring leaf frost damage and shoot winter injury than trees from other temperature zones. After initial establishment, woody growth (approximately 6 years of ring counts) was robust and tended to be greatest among moderate temperature zone sources and lowest for cold zone sources. Especially for trees from the warm zone, earlier budbreak was associated with greater growth. Foliar frost injury was not associated with altered growth, whereas winter shoot damage was associated with lower growth – especially following significant shoot loss. Even though warm temperature zone sources experienced more winter injury than trees from cold temperature zones, the growth of cold temperature zone sources tended to underperform that for warm and moderate zone sources – this suggests that, at least for the limited time that we evaluated growth, greater protection from the cold may come at the cost of greater growth potential. Although American chestnut is considered to be a relatively drought-tolerant species and growth was assessed during a period of historically high precipitation, higher moisture availability the year before, and occasionally during, the year of ring formation was broadly associated with greater growth across the temperature zones. Despite the negative influences of winter shoot injury on growth, the overall productivity of trees was exceptional, even at the northern edge of the species’ range provided that moisture availability was adequate.

Northward expansion leads to cold tolerance? Investigating thermal adaptation of the non-native pike killifish (Belonesox belizanus) in Florida

For an introduced species to expand its range, individuals must be able to adapt to novel stressors (biotic and abiotic) that they may encounter. Florida has a distinct temperature gradient and rapid climate zone transitions from warmer subtropical regions to cooler temperate regions. Mean minimum temperatures are thought to prohibit northward movement of introduced fish species in south Florida. As the introduced Belonesox belizanus (pike killifish) expands its introduced range northward, it may be gaining cold tolerance. This study sought to compare thermal tolerances and cessation of feeding between adult B. belizanus from southern (initial, introduced population) and northern (spreading, fringe edge population) populations from its introduced range. To compare thermal tolerances between locations, southern individuals and northern individuals were acclimated to three temperatures (20, 25, and 30 °C) and their upper and lower lethal temperatures and cessation of feeding temperatures were measured. Two-way ANOVAs revealed that lower lethal temperatures and cessation of feeding temperatures were significantly different between northern and southern populations, with northern individuals having a lower lethal temperature approximately 0.5 °C lower and a cessation of feeding temperature approximately 2 °C lower compared with southern individuals. Directional selection may be influencing this non-native species’ thermal tolerance and feeding ability benefitting their continued effort to disperse from subtropical to temperate environments within Florida. This study indicates that B. belizanus may be gaining cold tolerance as it continues to spread northward in its introduced range.

Comparison of Early-Twentieth-Century Arctic Warming and Contemporary Arctic Warming in the Light of Daily and Subdaily Data

AbstractA review of many studies published since the late 1920s reveals that the main driving mechanisms responsible for the early-twentieth-century Arctic warming (ETCAW) are not fully recognized. The main obstacle seems to be our limited knowledge about the climate of this period and some forcings. A deeper knowledge based on greater spatial and temporal resolution data is needed. The article provides new (or improved) knowledge about surface air temperature (SAT) conditions (including their extreme states) in the Arctic during the ETCAW. Daily and subdaily data have been used (mean daily air temperature, maximum and minimum daily temperature, and diurnal temperature range). These were taken from 10 individual years (selected from the period 1934–50) for six meteorological stations representing parts of five Arctic climatic regions. Standard SAT characteristics were analyzed (monthly, seasonal, and yearly means), as were rarely investigated aspects of SAT characteristics (e.g., number of characteristic days, day-to-day temperature variability, and the onset, end, and duration of thermal seasons). The results were compared with analogical calculations done for data taken from the contemporary Arctic warming (CAW) period (2007–16). The Arctic experienced warming between the ETCAW and the CAW. The magnitude of warming was greatest in the Pacific (2.7°C) and Canadian Arctic (1.9°C) regions. A shortening of winter and lengthening of summer were noted. Furthermore, the climate was also a little more continental (except the Russian Arctic) and less stable (greater day-to-day variability and diurnal temperature range) during the ETCAW than during the CAW.Significance StatementIt is well established that human activity (particularly increased greenhouse gas emissions) is the primary driving mechanism of the recent dramatic warming in the Arctic. However, the causes of a similar warming here in the first half of the twentieth century remain uncertain. The limited knowledge about the climate of that period—which mainly results from the low resolution of data—is a significant obstacle to a definitive determination of the forcing mechanisms. Therefore, the main aim of our paper is to improve our understanding of specific aspects of weather and climate (including extremes) using long-term series of daily and subdaily data that have rarely been applied for this purpose. This new, more comprehensive knowledge about the historical Arctic climate should allow the scientific community (particularly climate modelers) to better validate both climate models and reanalysis products and, consequently, to more precisely identify the causes of the early-twentieth-century Arctic warming.

Monitoring climate extremes using standardized evapotranspiration index and future projection of rainfall and temperature in the wettest parts of southwest Ethiopia

Ethiopia is categorized as one of the most vulnerable countries to climate extremes. A better understanding of climate extremes at short and long timescales is therefore crucial to minimize the potential impacts of these extremes. The present study aimed to characterize the frequency and severity of agricultural and hydrological drought in southwestern parts of Ethiopia over the period 1971 to 2020. Satellite blended/gridded and historical observed monthly rainfall, maximum temperature and minimum temperature data of nine stations (Arjo, Bako Tibe, Bedele, Didessa Dildey, Gedo, Gimbi, Sekoru, Serbo and Nekemte) were obtained from Ethiopia National Meteorological Agency. We used standardized evapotranspiration index (SPEI) to calculate the dry and wet condition at 3-, 6-, and 12-months timescales. Besides, past climate change analysis, future rainfall and temperature were projected under four representative concentration pathways (RCPs) of CMIP5 for the near and mid-term (2041-2060) and end of the twenty-first century (2081-2100). Our results showed that the frequency of drought in the short timescales is much higher than that of the longer timescales. In the present study, a total of 108 and 111 drought months were observed at Bedele and Nekemte, respectively at SPEI 3 and both stations recorded a total of 101 at SPEI 6. An increase in projected mean minimum and maximum temperature by 1.2°C was observed by the end of 21st century comparative to the reference time (1986-2005) under a high emission scenario (RCP8.5). Projected changes in rainfall showed a slight increase over the periods 2041-2060 and 2081-2100 under RCP4.5, RCP6.0 and RCP8.5, while projected trends under RCP2.6 indicated a slight decrease. The results of this study will be useful to design effective climate resilience agriculture in the study area. Moreover, it provides evidences for policy makers towards climate change adaptation and mitigation in the southwestern parts of the country.

Geospatial and Temporal Studies on Climatic Parameters and Their Impact on Inland Fish Production: A Case Study

Climate change threatening the word food security including fisheries production. The current study aimed to find the relationship between different climatic variables and fish production by generating spatial maps. The climatic parameters data viz., mean maximum temperature; mean minimum temperature; total rainfall, and mean wind speed were plotted in GIS (Geographical Information System) platform and thematic mapping of it’s for all the districts of Maharashtra for the year 1975 and 2017 on quarter basis was done using QGIS 3.6.1. The thematic maps of the percentage change in parameters of all the quarters of the year 2017 and 1975 were done for all the zone of Maharashtra. In addition, the thematic maps of the percentage change in parameters along with fish production of all the quarters of the year 2017–18 for the year 2012 were done for all the zone. The sensitivity analysis of climatic parameters with inland fish production for Maharashtra state and all the seven zones were done using GAM (Generalized Additive Model). The mean maximum temperature (MMAX) and total monthly rainfall (TMRF) were found to the most significant factors in the prediction of inland fish production. The average increase in MMAX during the 2nd and 3rd quarters (April to September) was less than the average increase in MMAX during the 1st and 4th quarters, whereas, in case of rainfall an average decrease was estimated during the 2nd and 3rd quarter. The current study found that Nagpur and Pune were the two highest fish-producing regions, and Konkan and Aurangabad were the two least productive regions.