نوع مقاله : پژوهشی
نویسندگان
1 دانشجوی دکتری علوم و مهندسی آبخیزداری، گروه احیاء مناطق خشک و کوهستانی، دانشکدة منابع‌طبیعی، دانشگاه تهران، تهران، ایران
2 استاد گروه احیاء مناطق خشک و کوهستانی، دانشکدة منابع‌طبیعی، دانشگاه تهران، تهران، ایران
3 دانشیار گروه احیاء مناطق خشک و کوهستانی، دانشکدة منابع‌طبیعی، دانشگاه تهران، تهران، ایران
4 استادیار گروه احیاء مناطق خشک و کوهستانی، دانشکدة منابع‌طبیعی، دانشگاه تهران، تهران، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction and Goal
Evaporation is one of the important parameters in hydrology that plays a significant role in the water cycle. This parameter, in addition to various spatial distributions, with having altitude distribution causes the complexity of evaporation modeling The aim of this research is to present a new approach for spatio-temporal modeling of evaporation changes, which can be used in rain-runoff models.
Materials and Methods
In order to carry out this research, monthly evaporation data over a 20-years period (2002-2021) were used from the Maroun evaporation monitoring station located in the Paskouhak catchment, 27 km west of Shiraz, as well as three stations surrounding Paskouhak catchment including Shiraz, Ghalat, and Dasht Arjan stations. Initially, by using regression modeling and determining the relationship between evaporation and elevation above sea level for each month, monthly evaporation raster maps were drawn for the study area. Then, using the proposed approach of using the ratio equations method, the initial spatio-temporal model of evaporation changes was prepared. Due to the dynamic nature and sensitivity of the evaporation parameter, the impact of various factors on the intensity of evaporation was simulated and the initial raster maps were corrected to a large extent. For this purpose, correction coefficients obtained in the form of raster maps or numerical coefficients were used. These coefficients included the correction coefficient of evaporation intensity due to the ratio of water depth at the target surface to the water depth in the evaporation pan, the effect of different days of the year on the conversion coefficient of the evaporation pan, and the correction coefficient based on changes in elevation from the ground surface. All stages of the research were performed in the SNAP and MATLAB software. Finally, the final result was obtained in the ArcGIS software.
Results and Discussion
The results showed that using the linear regression model and elevation parameters above sea level, it is possible to obtain the spatial distribution of evaporation with high accuracy (R2=0.81 in December and R2=0.99 in March and October) in the form of a regular pixel grid (in this study 100 m2). In addition, the final spatio-temporal distribution model of evaporation showed that there is a noticeable difference between the results of the initial and the final evaporation models in some areas of the study region (pixels). This highlights the need for more corrective coefficients.
Conclusion and Suggestions
In this study, using the proposed approach, it is possible to model the spatiotemporal distribution of evaporation in the study area at time steps corresponding to the time series of data available at the evaporation monitoring stations. It is recommended to apply this model under various climatic and topographic conditions and to evaluate its results.
کلیدواژه‌ها [English]
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