نشریه پژوهشهای تغییرات آب و هوایی
پیاپی 9 (بهار 1401)

Awareness of vegetation and its health represents the climate of each place. Access to field data is usually difficult and limited to study and monitor vegetation on a global and regional scale. Also, estimating vegetation in the usual way, which includes an overall estimate of vegetation, is both time-consuming and does not provide very accurate information. Therefore, remote sensing is a very useful method by providing a wide view of the area, which is superior to other methods. In this study, the 16-day data of the Normal Vegetation Differential Index (NDVI) of MODIS Aqua Iran were downloaded from the NASA website between 3/20/2003 to 3/20/2019. Then, based on nearly 15 billion pixels, the long-term and annual average of NDVI Iran was calculated. Considering that NDVI values more than 0.2 indicate vegetation, the average annual vegetation of Iran was calculated. Finally, the relationship between vegetation and rainfall in Iran was investigated. The results showed that in 1387, due to water shortage and meteorological drought conditions, Iran's vegetation reached its lowest value, while in 1397, due to heavy rainfall and wet conditions, Iran's vegetation reached the highest amount in the period The study has arrived. The results also showed that in the last two decades, due to increased rainfall, the range of vegetation in Iran has increased.

The impact of climate change on natural resources has become one of the greatest human concerns at the local, regional and global levels in recent years. One of negative impact of climate change is change of aridity index trend and transformation of hydro-ecological conditions in different regions. The main objective of this research is to evaluate the trend of Aridity index (IA) in northern stations of Iran during the period 1982-2009. To do so, the Penman equation was used to calculate the daily potential evaporation. Thereafter, the drought index values were calculated using the precipitation and potential evaporation parameters. Results demonstrate that precipitation values have been decreased during 1982-2019 in northern strip of Iran, so that precipitation has decreased by 300 mm during 2012-2019 in Bandar-e-Anzali station compared to the 10-year period (1982-1991). Temperature values have also increased in the northern stations of the country. Air temperature has increased about 1, 1.7, 0.1, 1.9 and 1.) 5C° ) in Rasht, Ramsar, Gorgan, Babolsar and Bandar-e-Anzali stations respectively. Furthermore, drought index represents a decreasing trend in all studied station during 1982-2019. The trend of Aridity index during 2019-2012 compared to the 10-year period (1982-1991) are -0.178, -0.011, -0.091, -0.142 and -0.420 in Rasht, Ramsar, Gorgan, Babolsar and Anzali stations, respectively.

To understand climate change adaptation in forest management, it is necessary to be examined the general approach of perception and experience with daily behavior to adapt to climate change and the relationships between them. According to the National Center for Drought and Crisis Management, based on the SPEI index, 62.2 percent of the annual and 84.9 percent of decade of the total area of Guilan, respectively, is affected by drought. This study examines the relationship between people's perceptions and experiences of drought as a climate disaster and their daily behavior in terms of adaptation to climate change. Using the theories of world psychology, a questionnaire based on the Theory of Regular Levels (CLT) and Planned Behavior (TPB) was developed and distributed to the teenager generation at the school level in Rudbar city. Then, by using the structural equation model and path analysis, standard beta coefficients and factor loads were estimated using PLS software. For the research variables, convergent validity of AVE was greater than 0.5 and Cronbach's alpha for reliability was greater than 0.7, indicating the validity and reliability of the questionnaire. SEM results showed that drought experiences had an indirect relationship with adaptive behavior, but the two hidden variables of climate change and water saving perception had a direct relationship with adaptive and saving behavior. Significance of these relationships was confirmed by t-test with 95% confidence. The existence of a stronger relationship between the variable of climate change than the variable of perception of water saving implies that people focus less on abstract concepts (high level of CLT structure), while their focus is on objective concepts , like more daily behaviors. Therefore, considering the impact of climate change on climate disasters in Hyrcanian forests, it is necessary to plan climate change adaptive behavior to deal with climate disasters.

Awareness of the effect of soils on the dynamics of water resources is extremely important to improve management in the face of stress; In recent years, concerns about climate change have led to concerns about preserving the soil bed and regulating activities that are least harmful; Therefore, in a recent study aimed at quantifying the spatio-temporal sensitivity of soil during the Quaternary period due to fluctuations in vegetation index and water resources to the importance of soils and zoning of ecological response to changes, in this regard using the Kendall (nonparametric) time series method. Vegetation and irrigation changes on Quaternary soils compared to other soils in Iran were studied. In the study, Modis data and MERA version 2 model in the period 2018 to 2021 were used for 36 months. The results of the study showed; The average volume of water stored in Iranian soils is 345 ml / m2. According to the results of water reserves in Quaternary regions with extremely humid climate 20% and semi-humid regions 18% and also Mediterranean regions 8% - semi-arid regions + 12%, arid regions + 21% and desert regions with + 25% relative to the same climate They themselves have a change in volume. Also, the shores of Lake Urmia and Khuzestan province have the effect of soil type on cover and water resources with high sensitivity and an area of 650,000 hectares. There are 22,000 hectares in Golestan plain under threat and it shows high sensitivity. Recent results indicate the high sensitivity and fragility of Quaternary soil areas in the face of climate change, so planning and studying the country's planning with respect to soil potentials is extremely important.

In the present study, in order to monitor and project the impact of global warming on household energy consumption pattern, a comparative study was conducted between the Middle East and Eurasia as two different climates.Tehran as a cold semi-arid climate and Moscow as a humid continental climate have been evaluated. In this study, two-time series of climate data have been used to model the residential energy demand. This paper contained the basic data from 1990 to 2010, and the CMIP5 climate models have been used to project climate data (radiation, temperature, wind speed, and relative humidity) from the outputs of CanEMS2 model, which its values have been dynamically downscaled using the RegCM4.6 for the period from 2020 to 2049. In addition, RCP4.5 scenario was used in this study.The results of this study demonstrated that the mean annual temperature for the period 2020–2049 as compared with the current decade would be increased 3.27°C and 4.71°C for Tehran and Moscow, respectively. On the other hand, relative humidity changes in future compared to base period would be decreased 4% for Tehran and increased 10.5% for Moscow. The total assessment on climate change in the coming decades would be led to a change in energy demand pattern for both study areas. Although heating energy demand is reduced in both study areas, the rate of decrease in Tehran was 12.75 percent, and it was in Moscow one percent, compared to the base period. On the other hand, the rate of increase in cooling energy in Tehran was 12.74 percent, and it was in Moscow One percent, compared to the base period. In general, the percentage of increased cooling energy demand compared to the reduced heating energy for both stations was high, which would be resulted in more emissions of CO2 (carbon dioxide) from these buildings.

In climatic and environmental studies, we sometimes encounter data gap or deficiency, so using other sources for creating reliable meteorological data at different spatiotemporal scales, becomes crucially important. For this, various research groups around the world have been collecting multiple meteorological data from different terrestrial and satellite sources and combining them to provide regular global data at different scales. In this study, the applicability of AgMERRA as a gauge-satellite database was evaluated in order to fill meteorological data gap, using goodness of fit measures and probability distribution functions. This was completed with the ultimate goal of producing reliable climatic data to study Hamoun International Wetland.We studied three major synoptic stations of Sistan plain in southeast of Iran: Zabol, Zahak and Zahedan. The observed daily maximum, minimum and average temperatures and precipitation data were collected through Iran meteorological Organization (IMO). AgMERRA Data was downloaded through NASA website and extracted with OPEN NCfile software. Then five goodness of fit were calculated at three spatiotemporal scales (daily, 14 days, monthly) to define correlation between the observed and simulated data.We found that AgMERRA has good ability to fill temperature data deficiency in the three studied stations. RMSE, NRMSE, MBE and d showed good and high correlation between the observed and modeled temperature data. Also R2 was high for temperature data at three temporal scales. However, correlation coefficient for daily and 14-day precipitation was <0.5 and <0.6 respectively, which is low. At the three stations, R2 was higher than 0.7 for the monthly precipitation. Results showed that AgMERRA has an acceptable potential to simulate meteorological data of the study area especially for temperature and could be used to fill the data gap. The generated data will be used to check the status of the Hamoon International Wetland.