جستجوی مقالات مرتبط با کلیدواژه "دمای سطح زمین" در نشریات گروه "زمین شناسی"

Urbanization and the increase of impermeable materials cause significant changes in the thermal properties of the region, which leads to the creation of urban thermal islands, on the other hand, the change of use caused by human activities leads to adverse effects on the region's environment. Plains areas are a clear example of these phenomena. The purpose of this study is to analyze the spatial and temporal changes of land use/land cover and its effects on the surface temperature of the plains of Dezful city. Landsat images in 2000-2020 were used to analyze the changes of (LU/LC) and its thermal bands to investigate LST using remote sensing techniques. Significant changes in land use were observed in this fertile plain during the study period. The highest percentage of land use change was related to the change of barren to agriculture and gardening, the second percentage land use change of water use to agriculture and gardening. During the monitoring period of 151,189, water areas decreased to half of 66,712 hectares. urban areas increased almost twice from 97,462 to 174,713. The Land surface temperature has increased during the monitoring period, the average temperature has increased in all classes of land use, but temperature increase in urban and barren classes are more than agricultural and gardening classes. The vegetation cover index increased during the monitored period, but this increase was not enough to prevent the temperature increase.

Split-window algorithm is the effective method for determination of land surface temperature. The results of temperature pattern show that the Gach salt dome has a higher temperature than the Siah Tagh salt dome. From a structural point of veiw, the higher temperature of the Gach salt dome can be related to the rooting of this dome and its relationship with the basement salt column. While the lower temperature of the Siah Tagh salt dome can be due to the lack of connection between the salt dome and the salt source of Hormuz Series. Temperature anomaly maps show the different temperature pattern in these two salt domes. Spatial pattern of temperature anomaly in the Siah Tagh dome show the linear trend in the eastern part of the dome. This temperature linear pattern in the Siah Tagh dome probably is related to the morning sunshine in the eastern slope of this dome. According to the resulting LST map, the highest temperature in the Gach salt dome is 41.87 °C and 36.7 °C in the Siah Tagh salt dome.

In this research, a deterministic forecast of 24, 48 and 72 hours of 10-meter wind speed has been produced over Iran, using BMA and EMOS methods for post-processing of raw output of ensemble systems. The main purpose of this article is to compare the deterministic forecasts obtained by using these two methods with each raw ensemble members and the mean of the raw ensemble members. The used ensemble system consists of eight different physical configurations, with changes in the boundary layer scheme of the WRF model. Other physical models in ensemble system are the same for all ensemble members. Each ensemble member includes 24, 48 and 72-hour forecasts of 10-meter wind speed with a resolution of 21 kilometers over Iran. GFS forecasts are used for the initial and boundary conditions, and the forecast start time is 12 UTC per day. Observation data of 31 synoptic meteorological stations located in the provincial capitals have been used and the corresponding values of the predictions on these stations have been interpolated by bilinear method. The model is run from 1 March to 31 August 2017, and the results from 11 April to 31 August 2017 are considered as the test period. After calculating the forecast errors with different training periods, 30 days are considered as the length of training period for prediction in both BMA and EMOS methods. Verification was performed by different methods (accuracy: PC, TS and OR; reliability and resolution: FAR, POFD and POD; skill: CSS, HSS, PSS, GSS and Q; statistical errors: RMSE and MAE) for 10-meter wind speed thresholds less than 3 and more than 5, 10 and 15 m/s for both methods in all forecast ages. The results show a 3 times improvement in accuracy scores, 2.2 times improvement in reliability and resolution scores, 3.4 times improvement in skill scores and 24% reduction in statistical error scores relative to the mean of ensemble members. Furthermore, the verification results for different climatic regions (cold, semi-arid, hot-dry, hot-humid and moderate-rainy climate) in the country separately showed that in all climates, RMSE measurement has the best performance for BMA and EMOS methods and reduces the error by 21% and 23% ,respectively. In hot and humid climates, compared to the mean of ensemble members errors, these two methods were more powerful to improve the prediction system. They reduced the error by 44% and 46%, respectively.

Glaciers influenced by climatic factors and therefore as an important indicator in the study of climate change are studied. Although morphometric analyzes of glaciers based on the analysis of optical satellite data can provide an opportunity to measure ice outcrops, but the identification and determination of the buried glaciers underneath the Supraglacial moraines (accumulated debris on top of the glacial ice) and, consequently, the determination of the actual glacial body and their parameters, including the level and volume of the glaciers, are not possible based on optical satellite imagery. On the other hand, the existence of an ice cooling source underneath the glacial debris, which leads to a significant reduction in the surface temperature of the glacial debris, is a distinguishing feature for the separation of covered glaciers.
The over 2000 km long NW-SE trending Zagros Mountain belt extends from eastern Turkey to the Makran Mountains, forming a morphological boundary between the Iranian plateau and the Mesopotamian and Persian Gulf basins. The Zardkuh Mountain lies along the central Zagros Mountain Range (32°14'-32°38' N; 49°50'-50°15' E) in Chahar-Mahal and Bakhtiari province, Iran. The highest summit of this mountain chain is 4220 m a.s.l altitude. Small glaciers (mostly cirque glaciers) were first reported on the northern slopes of Zardkuh during August 1933. Other research has pointed to some glacial cirques on Zardkuh which have altitude about 3000m and located in small valleys on the N faces of the Zardkuh. Some new researches on the active glaciers of Zardkuh show the greatest glacier concentration around 1) Joft-zarde and Shahe Shahidan (Zarkuh) summits 2) around Sirdan summit and 3) Haft-tanan (Iluk) region. Based on the latest study, the current size of Zardkuh’s glaciers have estimated about 7.1 km2.
In this research, the expansion of natural glaciers of Zardkuh Mountain has been determined by the combined analysis of thermal (Thermal Infrared Sensor (TIRS) of Landsat 8), optical data (Operational Land Imager (OLI) of Landsat 8 and Quickbird image) and digital elevation data, based on Split Window Algorithm. For this purpose, the following steps are carried out: 1) Preparation of Landsat 8 TIRS and OLI images, Quickbird image and Digital Elevation Model with 10 m resolution 2) Radiometric correction and rectification of images to WGS-1984-UTM-Zone_39N 3) Detection of exposed ice of active glaciers using by short wavelength infrared and green spectral bands of Landsat and optical images 4) Creation of 3D model of active glacier by combination of DEM and Quickbird images / Landsat images 5) Estimation of Land Surface Temperature (LST) using by Normalized Difference Vegetation Index (NDVI) and Land Surface Emissivity (LSE) based on the Single Window Algorithm. The NDVI is calculated as a ratio between measured reflectivity in the red and near infrared portions of the electromagnetic spectrum. The land surface emissivity (LSE (𝜀)) is calculated based on the Proportion of vegetation (Pv) and NDVI. 6) Supervised classification of LST layer based on the sampling of ice and supraglacial deposits temperatures for each glacier (the presence of ice under sediments has already been confirmed in field visits) 7) Area calculation of ​​the glaciers based on the classified LST layer.
In this study, Land Surface Temperature (LST) layer were calculated for Zardkuh Mountain based on the single method algorithm. Furthermore, Land Surface Emissivity (LSE), Proportion of vegetation (Pv) and normalised difference vegetation index (NDVI) layers were calculated for the study area. The surface area of exposed ice of Zardkuh glaciers is detected by using the short wavelength infrared and green spectral bands by making RGB753 color composite which its spatial resolution has improved with Panchromatic band to 15 m and 3D model of glaciers. Based on the results of this study, the area of the exposed ice of glaciers were 123 hectares. The surface area of exposed ice and buried glaciers underneath the Supraglacial moraines of Zardkuh glaciers based on the described methodology, were measured about 201 hectares in August 2017. The area of ​​the Haftanan, Joftzarde, Kuhrang3 and Khersan glaciers has decreased and reached to 32, 31, 30 and 29 hectares, respectively.
In this paper, potential of remote sensing to study the actual extent of Zardkuh glaciers in Zagrous Mountains in Iran by estimating LST distribution with the help of Landsat 8 OLI and TIRS sensor bands provided. Remote Sensing technology data such as Landsat 8 TIRS proved as an efficient one to estimate LST. Single window algorithm methods are applied to calculate the LST from TIRS data. Based on the results of this study, the area of the glaciers (surface and buried ice) in comparison with previous studies, shows a significant decrease in the past decade.

Summary: In this study, satellite images, and aeromagnetic and ground magnetic data were analyzed to explore the geothermal potential in Sirch-Golbaf area in Kerman province. Thermal anomalies and apparent thermal inertia images were studied using MODIS, Landsat and ASTER images. As a result, two thermal anomalies were obtained; one in the southeastern part of the study area and the other one in Jooshan location. Magnetic investigations also detected two anomalies; a deep magnetic anomaly in the southern part of the area and another magnetic anomaly near Jooshan hot spring in the northeastern part. These magnetic anomalies were correlated with thermal anomalies.
Remote sensing techniques are helpful reconnaissance tools for detecting surface temperature anomalies and identifying geothermal indicators (Calvin et al., 2005). Lu et al. (2008) used Landsat ETM thermal images to detect thermal anomalies strongly correlated with faults in certain scales in the Jiangshan-Shaoxing fault in the Zhejiang Province, China. They defined thermal anomalies as areas having temperatures higher than the temperature of the spatial background. In a geothermal resource exploration in Akita and Iwate prefectures, northern Japan, Noorollahi et al. (2007) showed that 95% of the production wells were located in a zone within 6000 m to the active faults and 4000 m to hot springs. Magnetic measurements are also generally used in geothermal exploration programs to locate hidden intrusive bodies and possibly estimate their depths. Moreover, they can be used to trace buried dykes and faults, and also to detect areas of reduced magnetization due to thermal activity (Georgeson, 2009). A variety of magnetic studies in geothermal exploration projects having different objectives can be found in the literature (e.g. Hojat et al., 2016; Gailler et al., 2014; Georgsson, 2009; Hunt, 1989; Palmason, 1975). The aim of this study is to analyze remote sensing and magnetic data (airborne and ground measurements) for evaluating the geothermal potential zones in an area east of Kerman Province.
Methodology and Approaches: The input data in this research include MODIS, MOD11_L2 005 (day and night) reflectance and LST products, for the year 2015, ASTER L1T night-time image on November 10, 2015, Landsat ETM day-time image on November 14, 2015, aeromagnetic data collected by Houston Texas Co., USA, in 1975-1977, and geomagnetic total intensity contour map of Gowk area having 1:50000 scale, which surveyed by Atomic Energy Organization of Iran. Ground magnetic survey is also carried out in an area around Joshan hot spring. A comparison of the day-time and night-time images can reveal surface thermal differences for detecting geothermal anomalies. Land surface temperature was calculated using generalized split-window algorithm for MODIS sensor (Wan and Dozier, 1996), emissivity normalization method for ASTER (Coll et al., 2007; Banerjee et al., 2014), and LST calculation method for Landsat sensor (Barsi et al., 2003; Barsi et al., 2005; Coll et al., 2010). Apparent thermal inertia of the three sensors was calculated using albedo and LST difference of day and night (Sabol et al., 2006; Scheidt et al., 2010; Chang et al., 2012; Qin et al., 2013). After removal of noise from the observed magnetic data, processing steps including main field removal using IGRF model of the proper period, reduction to the pole, and upward continuation were applied on the magnetic data. The processed magnetic data were finally interpreted in order to locate the hidden intrusive bodies and faults.
Results and Two thermal anomalies were detected on the maps and charts obtained for the average temperature difference (day and night) and apparent thermal inertia. One anomaly was located in the Jooshan area and the other one was situated in the western part of Gowk fault and continues along it to the southeastern side. Gowk fault is an active fault with Jooshan (45 C) hot spring, and most earthquakes larger than magnitude 5 have occurred in this part. These might be evidences of a thermal anomaly. The results of magnetic interpretations confirmed thermal anomalies showing a deep magnetic anomaly in the southern part of the study area and another magnetic anomaly in the Jooshan hot spring.