Introduction: The phenomenon of climate change can have different effects on different systems. Due to the vital role of water in human life, the study of its negative effects on the occurrence, severity and duration of drought is of particular importance. In this study, the effects of climate change on droughts on the southern shores of the Caspian Sea in future periods will be evaluated Material and methods: The region under study covers three northern provinces of Gilan, Mazandaran, which Golestan and covers four percent in terms of area and 12 percent in terms of population of the whole Iran. In this study, the effects of climate change on droughts on the southern shores of the Caspian Sea in future periods will be evaluated. For this purpose, precipitation data from the HadCM3-A2 general circulation model for future periods (2099-2070, 2069-2040, 2039-2010) have been scaled statistically and while considering the uncertainty of climate fluctuations in the 20 series. At first, daily precipitation was produced. Then the standardized precipitation index was calculated for the monitoring period and future periods. Finally, the downscaled variables of the region were compared with the observed variables and after ensuring the ability of the HadCM3 model in downscaling temperature and precipitation variables of the region, observed daily time series of precipitation and temperature and large-scale variables from HadCM3 model in the periods of 2010-2039, 2040-2069, and 2070-2099) were fed to the SDSM model. Results and discussion: The results obtained from the output of this index in the monitoring period and future periods with different time scales show that the intensity of drought in the coming decades will increase compared to the monitoring period. This increase is more severe for the east of the Caspian Sea, so that the intensity of the drought in the 2080s will be three times the observation period. The results indicated that the climate change results in an increase in the frequency and severity of drought in the studied region. Findings of the present research indicate that in spite of the existence of variability in the SPI lower than 9 months, it has increased 25 and 23. 5% in longer periods of 1 to 2 year periods in comparison with the historical period. The incompatibility of drought simulated in the future with observation period in Gorgan station with four remaining stations of the southern regions of the Caspian Sea should be noted. This situation may be due to differences in the resources of precipitation in the eastern and western coasts of the Caspian Sea and different response of two regions against the global warming. Different studies such as Alijani (1991) indicated that the Caspian Sea west coasts are more affected by the northerly flows of Siberian high pressure system than its east coasts, and in case of the establishment of the high pressure over Caspian Sea, precipitations in the west of the Caspian Sea will be higher than its eastern region. The phenomenon of global warming has resulted in weakening the Siberian high pressure system in general. Therefore, the degree of the reduction in precipitations in central and western regions of the Caspian Sea will be relatively higher than in its eastern regions such as Gorgan station. Conclusion: Occurrence of successive droughts and increasing drought intensity in the coming decades of the southern Caspian coastal areas will reduce water resources and the region-based economy will face a more severe crisis, in which case water resources management and development of strategic irrigation document and cultivation pattern a region compatible with socio-economic and climatic trends seems absolutely necessary.

Global warming leads to changes in precipitation patterns, temperature, and other climatic variables. These impacts affect the risk of thermal stresses in cropping systems. This study was carried out to evaluate the effect of climate change on the cold stress variation of potato plants in the tropical regions of Kerman province. To this end, changes in the occurrence of cold stress in the observation data of Jiroft, Kahnouj, and Manoajan stations were analyzed(from 1981 to 2005) and the future period (from 2011to2100). The future course data, using general circulation model CanESM2 with respect torcp26, rcp45 and RCP 85 scenarios were quantified by SDSM software. For this, the climactic indices were used to evaluate the changes in cold stress of potatoes by the tolerance thresholds of potatoes and based on the average of long-term climate data and the probability of its occurrence during the growth period. The results showed that in the Jiroft station, the probability of occurrence of early and late temperature below 5º decreased to 83% and 63% respectivelydintheKahnoj and Manoajan stations the probability of occurrence of early and late temperature below 5º in the future period decreased and increased, respectively. Also, the date of the beginning and end of cold stress was shifted to the beginning and end of the cold season. The statistical analysis of data indicated that the days of cold stress (5≤ T≤ 0) will increase from 2011to2040 in the Jiroft station, and from 2071to2100 in the Manojan station but it showed a decreasing in the Kahnouj station. The results show that the days with freezing stress will increase in the future in the Jiroft, Kahnoj, and Manojan stations, as a result, date of early and late cold stress will happen 10 days earlier and 14 days later compared to long term average of climate in the study area.

Due to climate changes, precipitation forecasting and precipitation estimation, one of the most important climatic parameters in the field of water resources management, is of particular importance. Therefore, in this research, the application of SDSM model in precipitation estimation was investigated. In this research, the data related to Ahvaz, Abadan and Dezful synoptic stations were used. The forecast time frame for the future period (climate scenarios) is also 30 years between 2031 and 2060. The outputs of the HadCM3 model, under the A2 and B2 scenarios and the CanECM2 model, under the RCP26, RCP45 and RCP85 scenarios, were micro scaled by applying the SDSM statistical exponential micro scale model in the prediction of the precipitation parameter, also using statistical and graphical methods. Micro scaled and basic data were analyzed and then calibrated. Base period modeling was done with higher accuracy in CanESM2 data compared to HadCM3 data. The results indicated that in the coming years, the total rainfall will increase in all three stations and the maximum amount of rainfall will decrease in all three stations. According to the modeling results, it seems that the climate of Khuzestan will have a wetted winter climate and drier summers in the near future.

Due to climate changes, precipitation forecasting and precipitation estimation, one of the most important climatic parameters in the field of water resources management, is of particular importance. Therefore, in this research, the application of SDSM model in precipitation estimation was investigated. In this research, the data related to Ahvaz, Abadan and Dezful synoptic stations were used. The forecast time frame for the future period (climate scenarios) is also 30 years between 2031 and 2060. The outputs of the HadCM3 model, under the A2 and B2 scenarios and the CanECM2 model, under the RCP26, RCP45 and RCP85 scenarios, were micro scaled by applying the SDSM statistical exponential micro scale model in the prediction of the precipitation parameter, also using statistical and graphical methods. Micro scaled and basic data were analyzed and then calibrated. Base period modeling was done with higher accuracy in CanESM2 data compared to HadCM3 data. The results indicated that in the coming years, the total rainfall will increase in all three stations and the maximum amount of rainfall will decrease in all three stations. According to the modeling results, it seems that the climate of Khuzestan will have a wetted winter climate and drier summers in the near future.

In this paper, we explore the numerical analysis of the microscale heat equation. We present the characteristics of numerical solutions obtained through both semi- and fully-discrete linear finite element methods. We establish a priori estimates and error bounds for both semi-discrete and fully-discrete finite element approximations. Additionally, the existence and uniqueness of the semi-discrete and fully-discrete finite element ap-proximations have been confirmed. The study explores error bounds in various spaces, comparing the semi-discrete to the exact solutions, the semi-discrete against the fully-discrete solutions, and the fully-discrete solutions with the exact ones. A practical algorithm is introduced to address the sys-tem emerging from the fully-discrete finite element approximation at every time step. Additionally, the paper presents numerical error calculations to further demonstrate and validate the results.

Background and ObjectivesGlobal warming is one of the challenges that has attracted more and more public opinion in recent years, and if wrong behavior continues, including excessive use of fossil fuels, it can become a serious threat to human life. One of the effects of global warming is climate change. The phenomenon of global warming and the resulting climate change, with changes in temperature and precipitation, have significant effects on various systems such as water resources, agriculture, and the environment. In such a way that it can be considered as a big threat to water systems all over the world. These threats are different for different regions of the world. The industrialization of societies and increasing greenhouse gases have caused climate change and seriously threaten human life. Change in rainfall is one of the important effects of climate change. Changes in precipitation have affected surface runoff and underground water sources, and in such conditions, water resources management becomes more difficult and complicated. The most reliable tool for investigating the effects of climate change on different systems is the use of climate variables simulated by coupled atmosphere-ocean general circulation models. These models can simulate climate parameters (temperature, precipitation, etc.) for future periods. But the main weakness of these models is their low spatial resolution and the simplifications they consider for climate processes. Microscale exponentials are used to cover the weakness of spatial resolution. The aim of this research is to evaluate the climate change on temperature and precipitation and its effect on the runoff entering the Nahand dam reservoir.MethodologyIn this research, the daily temperature and precipitation data of Nahand basin during the period (1360-1384) were used as the base period to evaluate climate changes using the CanESM2 climate model and RCPs emission scenarios in future periods. And SDSM statistical model was used for the microscopic scale.By applying the output of the CanESM2 general circulation model, using the SDSM model under RCP 2.6, RCP 4.5 and RCP 8.5 emission scenarios, and with the help of the IHACRES conceptual integrated model, the impact of climate change on the runoff entering Nahand Dam was evaluated.Nahand Dam is one of the drinking water sources of Tabriz. Therefore, determining the incoming runoff to the tank can help to manage the system optimally. Also, to simulate the runoff entering the reservoir in future periods, the conceptual integrated model of IHACRES was used to simulate rainfall-runoff. The main goal of IHACRES model is to determine the hydrological behavior of the basin using a small number of parameters.FindingsBased on the results of the temperature assessment in both the near future (2021-2060) and the far future (2061-2100) and under all emission scenarios, it is increasing and the temperature increase in the far future is more than the near future. The lowest and highest temperature increase is respectively related to the RCP 2.6 scenario in the near future period of 0.17°C and the RCP 8.5 scenario in the far future period to the extent of 1.01°C compared to the base period (1981-2005). By examining the trend of changes in the average precipitation in the coming periods, it can be seen that the precipitation, contrary to the temperature, is decreasing in all scenarios, so that the lowest and the highest decrease, respectively, related to the RCP 2.6 scenario in the future period is close to 7.23 mm and The RCP 4.5 scenario will be 25.77 mm in the far future period compared to the base period. Runoff will decrease in future periods under all scenarios. The lowest and highest decrease in the order of the near future (2021-2060) under the RCP 2.6 scenario is 0.08 m3s-1 (8.51%) and the far future (2061-2100) under the RCP 4.5 scenario is 0.08 m3s-1 It is 0.18 (19.15%).ConclusionIn this study, the effects of climate change on the runoff entering the Nahand dam were investigated using general atmospheric circulation models (GCM) and the fifth report (AR5) of the International Panel on Climate Change (IPCC) with the CanESM2 climate model under RCPs emission scenarios. The results of the climate change study on the entrance to Nahand Dam show that the runoff will decrease under the influence of this phenomenon, so that under the RCP 4.5 scenario, the runoff will decrease by 19.15% in the far future period.

In this paper, the vibrations of thin plate in modified couple stress thermoelastic medium by using Kirchhoff- Love plate theory has been investigated. The governing equations of motion and heat conduction equation for Lord Shulman (L-S) [1] theory are written with the help of Kirchhoff- Love plate theory. The thermoelastic damping of micro-beam resonators is analyzed by using the normal mode analysis. The solutions for the free vibrations of plates under clamped-simply supported (CS) and clamped-free (CF) conditions are obtained. The analytical expressions for thermoelastic damping of vibration and frequency shift are obtained for couple stress generalized thermoelastic and coupled thermoelastic plates. A computer algorithm has been constructed to obtain the numerical results. The thermoelastic damping and frequency shift with varying values of length and thickness are shown graphically in the absence and presence of couple stress for (i) clamped-simply supported, (ii) clamped-free boundary conditions. Some particular cases are also presented.