نشریه نیوار
پیاپی 106-107 (پاییز و زمستان 1398)

Temperature is main factors of climate and their variation may lead to change the climate of every region. Due to the direct effects of environmental temperature on water resources. Investigation of temperature trend in different temporal and spatial scales, forms a large part of climatology and water resources management researches. In this study the trend changing of temperature of the karun basin at the three scale namely, monthly, seasonally and annually were investigated using the trend-free pre-whitening mann-kendall (TFPW-MK). The used data includes discharge data of 38 meteorological stations in the period of 29 years (1986-2014). In this study, the slope of the linear trend of data estimated using the theil-sen approach (TSA) and then using trend-free pre-whitening (TFPW) approach the effect of coefficient of self-correlation of data was eliminated. Finally, the trend changing of temperature was examined using Man-Kendall. The results showed that the trend of more than 64 percent of the stations on annual basis are incremental and the increasing trend rates of 13 of the stations are significant at 10% level. On seasonal scale the trend of more than 67 percent of the stations to spring, summer and winter seasons are incremental.On monthly scale, the results showed that the trend of more than 50 percent of the stations on monthly scale are incremental and the increasing trend rates of 26 percent of this stations are significant at 10% level. The results of this study showed that the monthly and annual streamflow of most stations have increasing trend.

The most important issues and challenges facing humanity in the 21st century are the phenomenon of climate change and its effects on increasing the temperature and amount of water consumption. This phenomenon has begun due to the increase in greenhouse gas emissions since the 1850s, following the industrialization of the planet, so that the temperature of the Earth's atmosphere has risen by about 1 degree. This increase in temperature causes changes in other climate variables and in recent decades has had a different impact on systems that are interfacing with or without interacting with the Earth's atmosphere. Therefore, it was necessary for each region to take different measures to reduce greenhouse gases and adaptation strategies for climate change. In this research, by identifying the strengths, weaknesses, opportunities and threats of water resources in the country, their SOWT model and their weighting with the ANP model were determined as the best national strategy for water consumption and adaptation to climate change in Iran. Based on the results, two models can be mentioned. Model No 1, entitled "Control, Reduction and Gradual Decrease in Sustainable and Unhealthy Consumption Volumes", and Model No. 2 "Management, Improvement and Increased Sustainable Water Consumption Resources", stabilize the system of sustainable consumption of water consumption in Iran in order to adapting the climate change in the medium to long term.

Temperature has a key role on human activities and natural processes. Due to Iran's vast and diverse climate and diverse spatial distribution and fluctuations of temperature, defining temperature zones is necessity in different sectors of industry, civil engineering and agriculture. Due to the country's climate variation and existence of different temperature gradients in different regions, in this study, the minimum and maximum temperature evaluation equations were investigated separately in six major agro-climate regions of the Iran. Minimum and maximum temperature data were obtained from 184 synoptic stations (from 2002 to 2016). The pattern used to extract the elevation of the areas (in the country) using the digital elevation data from SRTM satellite products with a precision of 90 meters was used. Maximum and minimum temperature data were used as dependent variable and elevation, latitude, longitude, data were used as independent variable in regression analysis and an independent relationship was established for estimating maximum and minimum temperatures and the calculations were done using SPSS software, multi-variable stepwise regression analysis. It was found that regression equations for maximum temperature modeling have a better performance than the minimum temperature. The equations obtained in each area are applied to the whole area and the peripheral buffer. Finally, with the addition of regions and averaging of buffer zones, maximum and minimum temperature maps were created for the whole country.

this research, the annual rainfall and temperature trends of the country were evaluated using annual rainfall data of 115 synoptic stations during the period of 30 years (2017-1988). The average precipitation of the station and Tissen were calculated for each year. Using the nonparametric statistical method of Kendall-Mean method, the mean rainfall and temperature trend, and the age line slope estimator, the trend line tilt rate were tested. The results showed that there was not a ascendant or significant decrease trend in the mean precipitation in 99% and 95% confidence levels, but this trend was significant at 90% confidence level.However, the average precipitation rate of the country is about 2.1 mm per year, and the average precipitation Tissen of Iran has dropped by about 2.2 mm Also, the results showed that in the time series of the average station temperature and temperature in the country, the incremental temperature of the station is 0,252 ° C per year, which is significant at 95% confidence level. The average temperature of the country has been increased by Tissen at around 0.05 degrees Celsius per year, which is an increase in the 99% confidence level.

In this paper, marine meteorological and oceanic characteristics of Persian Gulf and Oman Sea were simulated using coupled numerical weather prediction model WRF and numerical oceanic model ROMS. At first, WRF model was operated over the sea and its results were analyzed and verified, and then numerical model ROMS operated and assessed on the sea by considering meteorological forcing. The major phenomena for analyzing WRF model was Indian Ocean summer Monsoon. For the model ROMS, transferring seawater form Indian Ocean to Oman Sea and Persian Gulf was studied. Oceanic numerical model was operated for a 7 years period and its results were compared by satellite images. The results show that considering interaction of atmosphere and ocean (by coupling) lead to more real results.

To quantify the uncertainty exists in the weather forecasting, and producing the probabilistic forecasting of diurnal maximum and minimum temperature, two important methods named Ensemble Model Output Statistics (EMOS) and Bayesian Model Averaging (BMA) are used to estimate the forecast probabilistic density function. In this study, the ensemble system has two members consisting of 1 to 5 ahead forecasting of diurnal maximum and minimum temperature over synoptic stations of Iran provinces from 10 November 2017 to 31 May 2018. These members are the outputs of the WRF model with two different physical configurations. Results show that the deterministic post-processed forecasts have improved the root mean squared error (RMSE) of deterministic raw forecast, 37% and 7% for mximum and minimum temperature, respectively. Generally, raw forecasts of minimum temperature have less error than maximum temperature, but they are not be improved considerably after post-processing.

In this study, the forecast data are the accumulated 24 hours precipitation forecasts generated by the WRF model. Initialization time is 12 UTC during the period from 1st September of 2011 through 26th February of 2012. The initial conditions for forecasts are provided by the Global Forecast System (GFS) forecasts with 1- degree horizontal resolution. WRF is run with two nested domains. The large domain has a 45 km and the small domain has a 15 The small domain has a horizontal resolution of 15 horizontal resolution. Observational data used in this study consist of the cumulative precipitation observations measured at 0600 UTC in 306 irregularly spaced synoptic meteorological stations spread across Iran. To assess the performance of the ENSWM method, the data are divided into two sets of training and test period. The training period starts from September 1st through November 30th of 2011, and the test period include all the days between December 1st of 2011 and February 26th of 2012. The ensemble forecasts are generated using different configurations of the WRF model. Nine different configurations for the WRF model are used to build members of the system of consciousness.

Drought caused by abnormal dry period which its continuation makes unbalance hydrologic system in a region, if some prevention countermeasures are taken against drought, its damages will be declined. In order to Drought monitoring and management by use of some indices, 33 meteorological stations which belongs to ministry of Energy in Mazandaran province were selected. Thus required data were collected and statistically analyzed. To reconstruct and statistical prolongation of incomplete station, differential and ratios method are applied. Run test was used for homogeneity assessment of data. Finally, based on available data analysis, 35 year data series from 1976 to 2000 as a research statistical period was used. Then, drought indices includes Standardized Precipitation Index (SPI), Normal Percentage(PN), Chinese Z(CZI), Modified Chinese Z(MCZI), Z- Score Index(ZSI), Deciles Index(DI) on 1 year time scale in all stations was calculated and related curves were drawn. Based on Correlation test, pair significance of these indices was satisfied at 5% level in all stations. PN, ZSI and SPI with maximum average correlations and least standard errors respect to others, had better results, but MCZI with minimum correlation had the worst results. Maximum correlation between annual precipitation and each one of indices belongs to PN, ZSI, SPI, CZI, DI, MCZI with determination coefficient of 0.998, 0.99, 0.986, 0.942, 0.908 and 0.057 respectively. Results show that for study and investigation of meteorological drought in Mazandaran province, PN, ZSI and SPI indices has the same status and prior to other indices.

This research was developed to assess future climatic changes in the south of Ahwaz using General Circulation Models (GCM) based on IPCC-AR5. Temperature and precipitation data were extracted from 6 models in AR5. Then, EC-EARTH and CESM1-CAM5 for temperature and EC-EARTH and BNU-ESM for precipitation were used in LARS WG for downscaling. The results showed the temperature increase of 0.5 to 4 °C in winter and spring and 2 to 3 °C in summer and autumn. Precipitation will decrease in all months in the period of 2016–2035. This case study predicted the reduction of precipitation in most of the months. Investigation of the number of rainy days showed that this parameter had increased in all patterns. The results of the Mann-Kendall test also revealed that the precipitation didn’t have statistically significant trend.. Only EC-EARTH2.6 had an increasing trend for summer. This increase was significant at the 90% confidence level. In the case of the temperature parameter, the EC-EARTH8.5 pattern was increased in spring and summer and it was statistically significant at the 95% level. This increase was significant at the 99% confidence level for the summer season. CESM-CAM5-2.6 had an increasing trend significant at the 95% confidence level in summer. CESM-CAM5-8.5 had an increasing trend significant at 95% confidence level in autumn and winter. In the annual scale, the temperature parameter had an increasing trend significant at the 90% confidence level. Key words: AR5, Man Kendall, Temperature, Precipitation

The purpose of this research is to establish a long time series of Shiraz through geometric analysis of Shiraz rain measurement stations, which has been displaced four times. The precipitation statistics of three old Shiraz stations (British Consulate, Moshir St. and Army III streets) were collected from a water company affiliated to the Water Organization during the period from 1302 to 1345. Since 1345, rainfall statistics are measured by two water and synoptic stations in Shiraz. The method used was that the geometric analysis criterion was considered for horizontal displacement up to a maximum of 5 km and a vertical displacement up to a maximum of 75 meters. In this case, the link between two series of times becomes meaningful. Two Ran and Mann-Whitney tests were performed for the time series. The results show that the statistics of the three old Shiraz stations can be considered as an interconnected time series because it meets the criterion of geometric analysis. Also, the statistics of the Water Organization Station can be linked to the statistics of the three old Shiraz stations and built the 90-year series of Shiraz during the period from 1302 to 1392. The Ran test showed that data was generated randomly. The Mann-Whitney nonparametric test was also used to determine the difference between the two old and new meanings of rainfall measurement and showed that there is no statistical difference between the two series.

In this research, we attempted to identify the cause for occurrence of the heat wave in April 2008 as one of the most significant and most comprehensive heat waves. Since deep recognition of such phenomena is not possible only by ground data, so, it is necessary to study synoptic conditions and effective atmospheric factors more than before. To study synoptic of how the heat wave occurs, the geopotential height, sea level pressure, air temperature, as well as the meridian and orbital component of the wind data at various levels with a resolution of 2.5 to 2.5 degrees, were obtained and the mean maps and anomalies of geopotential pressure and height at different levels, hot air flow and thickness map were plotted using GrADS software. The synoptic results showed that the existence of thermal low pressure in sea level and settlement of the subtropical high pressure was a major cause of this heat wave. The formation of a thermal low pressure center in the lower level of the atmosphere, on Sudan and the expansion from the south and southwest on Iran, causes the hot and dry weather of the desert areas, such as Saudi Arabia and Iraq move towards Iran. On the other hand the subtropical high pressure with hot core, when formed at the intermediate levels of the troposphere, causes a considerable increase in temperature due to air subsidence inside it.

Developing atmospheric General Circulation Models (GCMs) and, in particular, their dynamical cores are important steps towards future model improvements. For this reason, most GCMs of the atmosphere are developed in various vertical coordinates and grids. The diabatic contour-advective semi-Lagrangian method (DCASL) is an algorithm based on the use of contour representation for a fundamental dynamic quantity such as a potential vorticity. Previously, DCASL algorithms have been constructed for the shallow-water and multilayer Boussinesq primitive equations and also multilayer non-Boussinesq equations on the sphere using a hybrid terrain-following–isentropic (Sigma-Theta) vertical coordinate on the Charney-Philips grid (CP-grid). In this research, the results of the dynamical core constructed based on the DCASL algorithm are presented for the hybrid terrain-following–pressure (Sigma-P) vertical coordinate and compared with the results in the previously constructed model in coordinate. Also in this study, the performance of the coordinate models constructed using the CP-grid and the Lorenz grid (L-grid) are compared. For assessment and comparison of the dynamical cores in representations of different fields, we have used the baroclinic instability test case introduced by Jablonowski and Williamson in 2006. Qualitative and quantitative comparisons have been made with the results of four dynamical cores of global reference models (three hydrostatic dynamical cores that are parts of NCAR’s Community Atmosphere Model version 3 (CAM3) and also the dynamical core of the operational weather forecast model GME at the German Weather Service (DWD)). The comparisons show that the initialization problem present in the Sigma-Theta vertical coordinate in this test case is removed by the use of the Sigma-P vertical coordinate and thus results become ever closer to the references solutions. Also results of the Sigma-P vertical coordinate in the Lorenz grid for this dynamical core have the least difference with the reference results in the first 15 days of the test case.