---

The aim of the current research is to show the potential areas for autumn sugar beet cultivation in Golestan province according to temperature and precipitation parameters. For this purpose, temperature (daily) and precipitation (annual) statistics were used for a statistical period of 15 years (2006-2020). In order to analyze the data, the methods of thermal potential diagrams, deviation from optimal conditions, phenology and zoning of Golestan province in terms of the amount of irrigation during growth were used from the annual rainfall data. The results of temperature evaluation using the thermal potential method based on the thermal threshold showed zero, 4 and 10 degrees Celsius at the level of stations in Golestan province; Inche Brun station has the highest cumulative thermal unit and Aliabad Katul station has the lowest cumulative thermal unit. Examining the date of the probability of late spring frost at the level of 95% showed that due to its occurrence at the end of April in the center, east, north, northeast and west of Golestan province, it coincides with the phenological stage of root bulking and sugar accumulation. Also, based on the deviation from the optimal conditions in Golestan province, Inche Brun station was calculated to have the lowest deviation (-20.64). Also, in terms of phenology, in the stage of budding, six leaves, root bulking and sugar accumulation and full ripening of the autumn sugar beet plant in Golestan province, the favorable areas for autumn sugar beet cultivation in Golestan province were determined, including Gonbadkavus, Bandar Turkman, Kalaleh, Inche Brun and Bandar Gaz. Also, the evaluations in terms of rainfall according to the annual rainfall zoning map of Golestan province, it can be concluded that in terms of rainfall and water supply required for autumn sugar beet, there is not much limitation towards Golestan province, however, considering the recent multi-year droughts, the cultivation of this plant in the province needs additional irrigation for growth.

---

Flood is one of the most destructive natural phenomena. Every year it brings extensive losses to the country’s financial and human resources. In our country, major parts of Iran’s provinces are always at risk of flooding. The Gorgan and Atrak catchments have also become more important, as several floods have occurred in Golestan province in recent years, causing many deaths and economic losses. The purpose of this study was to investigate the synoptic and thermodynamic conditions of the March 2019 flood event in Golestan province in order to atmospheric system that lead to such floods. This study includes statistical analysis of provincial stations (Gorgan, Gonbadkavus, Aliabadkatol, Hashemabad, Kalale, Maravetape and Bandaretokman), calculating of the return period of precipitation during the available statistical period of each station, analysis of synoptic maps on the day of the flood event, the analysis of satellite images of the days involved in the flood, and calculation of instability indices of the Gorgans’s station. Statistical results showed that Gorgan and Gonbadkavus stations, with the highest amount of rainfall in March 2019, had a return period with 800 and 400 years respectively. Also the highest amount index of Gorgan with values of K=26°c, PW= 0.27 cm and TT= 48 was obtained with high relative humidity (about 80%). The analysis of the synoptic maps showed the severe sea level pressure and mid- level height drop with a deep trough in the study area, which led to extreme rainfall.
Key words: Flood, return period, Synoptic maps, instability indices, Golestan province.