بررسی اثرات تغییر اقلیم بر زمان رخداد آستانۀ زیستی و مرحلۀ گُل‏ دهی درخت انگور در ایران

Introduction
Climate change and global warming will endanger the production of agricultural products and food security in the world. The horticulture sector and fruit trees are affected by the climate because of the long distance to the production. Any changes in temperature patterns will change the length of the growth season and dates of the phonological and physiological stages. Air temperature is often considered as the main factor affecting the phonological phases of fruit trees in temperate climates. The increase in the Earth's surface temperature due to greenhouse gas emissions has created a phenomenon called climate change. The perceived effects of climate change on the daily lives of communities around the world have raised the public's attention to climate change. The transformation of the climate and its consequences from different aspects on the planet are not covered by anyone. Today, the challenge of climate change and its effects is the most important challenge facing the country. Fruit trees are subjected to climate change as one of the main sources of agricultural economics and employment in the country. Given the importance of grape product in the country's economy, it is essential to study the effects of climate change on this tree in Iran. Therefore, the present study aimed at revealing the effects of climate change on the time of phonological stages of Grape tree in Iran based on the output of new CMIP5 models and representative concentration pathways scenarios (RCP).
Materials and methods
The realm of this research is the cultivation of grape tree in Iran. The major areas of grape tree cultivation in Iran are located in the northern, western, and eastern regions of cold weather. In the present study, two types of data were used to analyze the process using statistical-analytical method. The data of the baseline or past period have been extracted from IRIMO by the actual statistics of 55 meteorological stations in vineyard cultivation areas. These observation data include the statistical period (1985-2005). Future data as simulated data are based on the output of CMIP5 models. These data have been processed in two routings RCP8.5 and RCP4.5 from 2020 to 2090. In the upcoming period, the models (BCC-CSM1.1, MRI.CGCM3, GFDL-CM3, MIROC-ESM and (GISS-E2-R from the CMIP5 models of the MarksimGCM database were used in the RCP8.5 and RCP4.5 scenarios). The results showed that the MRI.CGCM3 model has a higher ability to simulate the future than other models.
Results and discussion
The results showed that the MRI.CGCM3 model, with the higher weight, than the other general circulation models proposed, has a higher ability to simulate temperature and precipitation behavior in the future period relative to the base period. The model has the minimum, maximum and precipitation temperature for weight of 0.40, 0.39 and 0.29, respectively. Therefore, from the model data, in-built comparison model of the CMIP5 is based on RCP radiative forcing scenarios. It was used to assess and detect the effects of climate change in the upcoming period. The results showed that the air temperature in the pessimistic and middle run pattern of RCP8.5 and RCP4.5, respectively, would increase compared with the baseline period. This increase in the pessimism pattern was higher than the midterm pattern. The changes in the far future period (2056-2090) will be greater than the upcoming mid-term (2020-2055). The magnitude of these changes in the RCP8.5 induction trajectory in the period (2020-2055) and (2056-2090) at the selected station level was 1.6 and 2.4 degrees Celsius, respectively, and in the RCP4.5 induction line , Is 1.2 and 2.3 degrees Celsius, respectively, relative to the base period.
Conclusion
Output of the overall model of the MRI.CGCM3 has less simulation abilities in illustrating the climate change of the upcoming period. It has errors that are more than those of the observation period or the baseline period. The results showed that in the most pessimistic case in the middle and distant future, 1.6 and 4.2 degrees Celsius, the minimum temperature would increase compared to the baseline period. The results showed that the most changes occur during the occurrence of phonological stages in cold regions and high latitudes of vineyard cultivations. Due to the increase in the temperature of the air in the future period, it will also alter the date of occurrence of the phonological stages of the grapevine. Due to the increase in the air temperature of the future period, the threshold of biota will occur ahead, and as a result, the vinegrowing period will begin earlier than the previous period. Therefore, in a pessimistic evolutionary pattern, the threshold of biota timing will be ahead in the middle of the future, 8 to 16 days, and the flowering time will be 7 days to 16 days. Therefore, one of the major effects of climate change on fruit trees will evolve in the form of a change in the time of occurrence of the phonological stages. In the future period, the deviation from the optimal temperature conditions of the phonological stages of the grapevine will be increased. In the futures period, the amount of deviations and temperature anomalies will increase significantly from the optimum temperature range over the base period. The regions of northwest and northeast will have the highest deviation from optimal temperature conditions. The range of areas with high temperature deviation was observed at the phonological stage of germination and flowering. The flowering stage shows the highest deviation from optimal temperature conditions. The amount of deviation from optimal temperature conditions will be increased from the south to the north of the grapevine area .
Changes and displacement of the threshold times of the grapevine biomass increase the risk of possible dangers of frost and late frost in most vineyard cultivation areas, especially in the northern half. It is important to select species and varieties resistant to and adapted to the climatic conditions of each region. In the future period, the range of cultivars of the grapevine will decrease. In the future, the final area of the grapevine area will be limited to 12.64824123 hectares. In fact, due to the rising air temperature in the future, areas susceptible to Ango cultivation in the southern, central, and eastern regions of the grapevine area will lose their climate capability.