MALIHEH AREKHI - Academia.edu (original) (raw)

Papers by MALIHEH AREKHI

Environment, Development and Sustainability, 2019

Investigating agricultural drought is very important in semiarid areas, and it has a significant ... more Investigating agricultural drought is very important in semiarid areas, and it has a significant impact on people's livelihood, which depends on farming. This research tried to examine the capability of six Landsat surface reflectance bands, vegetation indices (VIs), and drought indices (DIs) for drought monitoring in the agricultural lands of Bandar-e-Turkmen and Gomishan cities in 1986 and 2015. Statistical analysis, Pearson correlation analysis, and correlation matrices between the VIs and DIs with land surface temperature (LST) were monitored separately for each date. In addition, the spatial and temporal drought extents using the Standardized Evapotranspiration Precipitation Index (SPEI) and the Vegetation Health Index (VHI) approaches were determined and compared for both study periods. The correlations between the LST and VIs were negative and significant in both study periods. The range of VI values decreased with increasing temperature in 2015 compared to 1986. The mean surface reflectance of the visible bands (blue, green, red), NIR (near-infrared), SWIR (shortwave infrared), and MWIR (mid-wave infrared) increased in 2015 compared to 1986. A higher spectral reflectance of the visible bands indicated a reduction in vegetation cover or increase in stress in 2015 compared to 1986. Meanwhile, the SWIR and MWIR bands showed that the average surface reflectance increased in 2015, while they showed a lower reflectance in 1986. The results of the Water Supplying Vegetation Index (WSVI) implied that the crop water stress in 2015 was more than that in 1986. The VHIs were separately compared with the NDVI and LST in each period of study. The maximum LST increased from 38 °C in 1986 to 44 °C in 2015. The moderate drought extent was 65% in 2015, while the study area did not experience any drought in 1986. The SPEI maps showed that the entire study area experienced moderate drought in 2015, while no drought was observed in 1986. The results showed that the DIs and VIs and the visible, SWIR and MWIR surface reflectance bands can be effectively used by sampling plots in future drought assessment studies. The present study also emphasizes that there is a similarity between traditional and remote sensing methods and indicates that remote sensing data can be effectively used instead of traditional approaches when there is no meteorological station. The results would be useful in food security and sustainable agriculture management plans.

Journal of the Indian Society of Remote Sensing, 2019

This research arose from concerns generated throughout my academic and professional experience wi... more This research arose from concerns generated throughout my academic and professional experience with adolescents who committed infraction acts. The question of childhood and adolescence was not always considered an important agenda to society and to State, there being for this part of population a series of violations of rights, mainly what refers to legislation. From social movements, who fought for guarantee children and adolescents' rights, was made and approved in 1990 the Child and Adolescent Statute that, besides regulating what is established in the Federal Constitution about human rights, defines rules to juridical accountability of adolescents who commit infractions, specified by socio-educational measures. Associated with this legislation, more recently, was approved the National System of Socio-Educational Attendance, which establishes the regulation of this attendance, as defined by the Statute, in addition to supervising and guiding the proper execution of the measures. Although we have a specific law to treat juvenile infraction, it was verified that both the Statute and the National System of Socio-Educational Attendance do not elucidate how adolescent author of an infraction act takes responsibility beyond the compliance with the socio-educational measure. In face of that, this dissertative study aimed to analyze the meanings about juvenile accountability produced by adolescents undergoing social-educational measure. To this, the methodological path of this research had a qualitative character, using the procedure of narrative interview (Brunner, 2013) with adolescents who were undergoing socio-educational measure in the Center of Specialized Reference of Social Assistance. Were interviewed, in total, six adolescents undergoing social-educational measure in the said institution and also a thematic workshop was made. The analysis of the corpus of the research was made under a Cultural-Historical perspective, from an interpretative analysis that allowed us to understand the meaning produced by the adolescents who participated in the research about the process of juvenile accountability, besides it made possible a new elaboration of the meanings and senses that they produced about this experience. The meaning of accountability produced by young people was linked to punitive processes, where institutional violence proved to be one of the main interventions disguised as accountability. The final considerations demonstrate that the process of juvenile accountability is not something given in the legislation; it should be constructed with the adolescent in the moment he is undergoing socio-educational measure. For this, it is necessary that the socio-educational system offers a space where the subject can position himself before his experiences in a conscious way so as to elaborate reflections that strengthen his citizenship.

Environmental monitoring and assessment, Jan 28, 2017

The diversity of forest trees as an indicator of ecosystem health can be assessed using the spect... more The diversity of forest trees as an indicator of ecosystem health can be assessed using the spectral characteristics of plant communities through remote sensing data. The objectives of this study were to investigate alpha and beta tree diversity using Landsat data for six dates in the Gönen dam watershed of Turkey. We used richness and the Shannon and Simpson diversity indices to calculate tree alpha diversity. We also represented the relationship between beta diversity and remotely sensed data using species composition similarity and spectral distance similarity of sampling plots via quantile regression. A total of 99 sampling units, each 20 m × 20 m, were selected using geographically stratified random sampling method. Within each plot, the tree species were identified, and all of the trees with a diameter at breast height (dbh) larger than 7 cm were measured. Presence/absence and abundance data (tree species number and tree species basal area) of tree species were used to determi...

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2016

Changes in land surface reflectance measured by remote sensing data can be useful in climate chan... more Changes in land surface reflectance measured by remote sensing data can be useful in climate change studies. This study attempts to analyze the spatial-temporal extent change of vegetation greenness, Land Surface Temperature (LST), and Normalized Difference Snow Index (NDSI) in late spring at the Lar National Park of Iran using Landsat data. Vegetation indices (VIs), LST, and NDSI maps were calculated for each date (1985, 1994, 2010, and 2015). All VIs have shown an increasing trend from 1985 to 2015 which depicted increase of vegetation. Spectral reflectance of all bands is declining from 1985 to 2015 except in near-infrared (NIR) bands. High reflectance in NIR bands is due to increased vegetation greenness. The reduction was seen in the visible bands that show increased vegetation photosynthetic activity. In the short-wave infrared bands (SWIR) were observed reduced trend from 1985 to 2015 which is indicate increased vegetation. Also, in the mid-wave infrared (MWIR) bands were obs...

Forest Ecosystems, May 11, 2018

Background: Treeline dynamics have inevitable impacts on the forest treeline structure and compos... more Background: Treeline dynamics have inevitable impacts on the forest treeline structure and composition. The present research sought to estimate treeline movement and structural shifts in response to recent warming in Cehennemdere, Turkey. After implementing an atmospheric correction, the geo-shifting of images was performed to match images together for a per pixel trend analysis. We developed a new approach based on the NDVI, LST (land surface temperature) data, air temperature data, and forest stand maps for a 43-year period. The forest treeline border was mapped on the forest stand maps for 1970, 1992, 2002, and 2013 to identify shifts in the treeline altitudes, and then profile statistics were calculated for each period. Twenty sample plots (10 × 10 pixels) were selected to estimate the NDVI and LST shifts across the forest timberline using per-pixel trend analysis and non-parametric Spearman's correlation analysis. In addition, the spatial and temporal shifts in treeline tree species were computed within the selected plots for four time periods on the forest stand maps to determine the pioneer tree species. Results: A statistically significant increasing trend in all climate variables was observed, with the highest slope in the monthly average mean July temperature (tau = 0.62, ρ < 0.00). The resultant forest stand maps showed a geographical expansion of the treeline in both the highest altitudes (22 m-45 m) and the lowest altitudes (20 m-105 m) from 1970 to 2013. The per pixel trend analysis indicated an increasing trend in the NDVI and LST values within the selected plots. Moreover, increases in the LST were highly correlated with increases in the NDVI between 1984 and 2017 (r = 0.75, ρ < 0.05). Cedrus libani and Juniperus communis spp. were two pioneer tree species that expanded and grew consistently on open lands, primarily on rocks and soil-covered areas, from 1970 to 2013. Conclusion: The present study illustrated that forest treeline dynamics and treeline structural changes can be detected using two data sources. Additionally, the results will have a significant contribution to and implication for treeline movement studies and forest landscape change investigations attempting to project climate change impacts on tree species in response to climate warming. The results will assist forest managers in establishing some developmental adaptation strategies for forest treeline ecotones.

Advances in Remote Sensing and Geo Informatics Applications

Monitoring variations in the spectral reflectance of thermal bands of Landsat data provide land s... more Monitoring variations in the spectral reflectance of thermal bands of Landsat data provide land surface temperature information of earth’s surface features. This research tried to examine the variations of Land surface temperature (LST) from 1987 to 2017 at the Gomishan district and its soundings in Iran. Images preprocessing was conducted including the geo-shifting and atmospheric correction. NDVI and LST maps and their change map using a change detection technique were generated. Basic inferential statistics and spatial analysis were performed. The results show that LST mean reached approximately 42.5 °C with 9 °C increase, while it was 33.8 °C in 1987. However, comparing the statistical analysis of NDVI data did not show any differences between the two study dates. Land cover classes include water, urban, and rural covered areas had the lowest LST shifts between the two study periods. The LST of rangelands, wetlands, and bare lands with more than 10 °C increase have experienced considerable LST shifts between during the study periods. Interestingly, some parts of wetland areas had the highest increase approximately 13 °C from 1987 to 2017. This study emphasized that LST change detection approach and spatial analysis can be used successfully in LST monitoring investigations. The results can be used to identify regions that experienced LST shifts (change or no change) and also to identify the most critical and impacted areas. The obtained results can be used effectively in sustainable natural disaster management plans.

ISPRS International Journal of Geo-Information

This study aims to test the spectral and spatial consistency of Sentinel-2 and Landsat-8 OLI data... more This study aims to test the spectral and spatial consistency of Sentinel-2 and Landsat-8 OLI data for the potential of monitoring longos forests for four seasons in Igneada, Turkey. Vegetation indices, including Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and Normalized Difference Water Index (NDWI), were generated for the study area in addition to the five corresponding bands of Sentinel-2 and Landsat-8 OLI Images. Although the spectral consistency of the data was interpreted by cross-calibration analysis using the Pearson correlation coefficient, spatial consistency was evaluated by descriptive statistical analysis of investigated variables. In general, the highest correlation values were achieved for the images that were acquired in the spring season for almost all investigated variables. In the spring season, among the investigated variables, the Red band (B4), NDVI and EVI have the largest correlation coefficients of 0.94, 0.92 and 0.91, respe...

Changes in land surface reflectance measured by remote sensing data can be useful in climate chan... more Changes in land surface reflectance measured by remote sensing data can be useful in climate change studies. This study attempts to analyze the spatial-temporal extent change of vegetation greenness, Land Surface Temperature (LST), and Normalized Difference Snow Index (NDSI) in late spring at the Lar National Park of Iran using Landsat data. Vegetation indices (VIs), LST, and NDSI maps were calculated for each date (1985, 1994, 2010, and 2015). All VIs have shown an increasing trend from 1985 to 2015 which depicted increase of vegetation. Spectral reflectance of all bands is declining from 1985 to 2015 except in near-infrared (NIR) bands. High reflectance in NIR bands is due to increased vegetation greenness. The reduction was seen in the visible bands that show increased vegetation photosynthetic activity. In the shortwave infrared bands (SWIR) were observed reduced trend from 1985 to 2015 which is indicate increased vegetation. Also, in the mid-wave infrared (MWIR) bands were obse...

Forest Ecosystems

Background: Treeline dynamics have inevitable impacts on the forest treeline structure and compos... more Background: Treeline dynamics have inevitable impacts on the forest treeline structure and composition. The present research sought to estimate treeline movement and structural shifts in response to recent warming in Cehennemdere, Turkey. After implementing an atmospheric correction, the geo-shifting of images was performed to match images together for a per pixel trend analysis. We developed a new approach based on the NDVI, LST (land surface temperature) data, air temperature data, and forest stand maps for a 43-year period. The forest treeline border was mapped on the forest stand maps for 1970, 1992, 2002, and 2013 to identify shifts in the treeline altitudes, and then profile statistics were calculated for each period. Twenty sample plots (10 × 10 pixels) were selected to estimate the NDVI and LST shifts across the forest timberline using per-pixel trend analysis and non-parametric Spearman's correlation analysis. In addition, the spatial and temporal shifts in treeline tree species were computed within the selected plots for four time periods on the forest stand maps to determine the pioneer tree species. Results: A statistically significant increasing trend in all climate variables was observed, with the highest slope in the monthly average mean July temperature (tau = 0.62, ρ < 0.00). The resultant forest stand maps showed a geographical expansion of the treeline in both the highest altitudes (22 m-45 m) and the lowest altitudes (20 m-105 m) from 1970 to 2013. The per pixel trend analysis indicated an increasing trend in the NDVI and LST values within the selected plots. Moreover, increases in the LST were highly correlated with increases in the NDVI between 1984 and 2017 (r = 0.75, ρ < 0.05). Cedrus libani and Juniperus communis spp. were two pioneer tree species that expanded and grew consistently on open lands, primarily on rocks and soil-covered areas, from 1970 to 2013. Conclusion: The present study illustrated that forest treeline dynamics and treeline structural changes can be detected using two data sources. Additionally, the results will have a significant contribution to and implication for treeline movement studies and forest landscape change investigations attempting to project climate change impacts on tree species in response to climate warming. The results will assist forest managers in establishing some developmental adaptation strategies for forest treeline ecotones.

Forest Ecosystems, May 11, 2018

Background: Treeline dynamics have inevitable impacts on the forest treeline structure and compos... more Background: Treeline dynamics have inevitable impacts on the forest treeline structure and composition. The present research sought to estimate treeline movement and structural shifts in response to recent warming in Cehennemdere, Turkey. After implementing an atmospheric correction, the geo-shifting of images was performed to match images together for a per pixel trend analysis. We developed a new approach based on the NDVI, LST (land surface temperature) data, air temperature data, and forest stand maps for a 43-year period. The forest treeline border was mapped on the forest stand maps for 1970, 1992, 2002, and 2013 to identify shifts in the treeline altitudes, and then profile statistics were calculated for each period. Twenty sample plots (10 × 10 pixels) were selected to estimate the NDVI and LST shifts across the forest timberline using per-pixel trend analysis and non-parametric Spearman's correlation analysis. In addition, the spatial and temporal shifts in treeline tree species were computed within the selected plots for four time periods on the forest stand maps to determine the pioneer tree species. Results: A statistically significant increasing trend in all climate variables was observed, with the highest slope in the monthly average mean July temperature (tau = 0.62, ρ < 0.00). The resultant forest stand maps showed a geographical expansion of the treeline in both the highest altitudes (22 m-45 m) and the lowest altitudes (20 m-105 m) from 1970 to 2013. The per pixel trend analysis indicated an increasing trend in the NDVI and LST values within the selected plots. Moreover, increases in the LST were highly correlated with increases in the NDVI between 1984 and 2017 (r = 0.75, ρ < 0.05). Cedrus libani and Juniperus communis spp. were two pioneer tree species that expanded and grew consistently on open lands, primarily on rocks and soil-covered areas, from 1970 to 2013. Conclusion: The present study illustrated that forest treeline dynamics and treeline structural changes can be detected using two data sources. Additionally, the results will have a significant contribution to and implication for treeline movement studies and forest landscape change investigations attempting to project climate change impacts on tree species in response to climate warming. The results will assist forest managers in establishing some developmental adaptation strategies for forest treeline ecotones.

Agriculture and Biology Journal of North America, 2010

Several regions around the world are currently under rapid, wide-ranging changes of land cover. S... more Several regions around the world are currently under rapid, wide-ranging changes of land cover. Satellite remote sensing techniques have proven to be cost efficient in extensive land cover changes. This study illustrates the effect of land use/cover change in Neka river of Iran using topographic maps and multi-temporal remotely sensed data from 1975 to 2001. The Maximum likelihood supervised classification technique was used to extract information from satellite data, and post-classification change detection method was employed to detect land use/cover change. Post-classification change detection technique was used to produce an image through
cross-tabulation. Changes among different land use/cover classes were assessed. The overall accuracy of land cover change maps, generated from Landsat data 1975 and 2001, ranged from 99.44% and 97.08% with Kappa statistics of 85% and 83%, respectively. The analysis indicated that the urban and agricultural land expansion of Neka river was increased resulted in the considerable reduction of forest area. The maps showed that between 1987 and 2001 the agricultural land and built-up areas increased approximately 59.86km2 (9.16%) and 7.35(1.13%), respectively. While forest decreased 67.91 km2 (10.29%). The study quantified the patterns of land use/cover change for the last 13 years for Neka river that forms valuable resources for urban planners and decision makers to devise sustainable land use and environmental planning.

Changes in land surface reflectance measured by remote sensing data can be useful in climate chan... more Changes in land surface reflectance measured by remote sensing data can be useful in climate change studies. This study attempts to analyze the spatial-temporal extent change of vegetation greenness, Land Surface Temperature (LST), and Normalized Difference Snow Index (NDSI) in late spring at the Lar National Park of Iran using Landsat data. Vegetation indices (VIs), LST, and NDSI maps were calculated for each date (1985, 1994, 2010, and 2015). All VIs have shown an increasing trend from 1985 to 2015 which depicted increase of vegetation. Spectral reflectance of all bands is declining from 1985 to 2015 except in near-infrared (NIR) bands. High reflectance in NIR bands is due to increased vegetation greenness. The reduction was seen in the visible bands that show increased vegetation photosynthetic activity. In the shortwave infrared bands (SWIR) were observed reduced trend from 1985 to 2015 which is indicate increased vegetation. Also, in the mid-wave infrared (MWIR) bands were observed a declining trend which is the result of decreasing soil fraction from 1985 to 2015. LST has increased from 23.27 °C in 1985 to 27.45 °C in 2015. Snow patches were decreased over the study period. In conclusion, VIs and surface reflectance bands are considered the main tool to display vegetation change. Also, high VIs values showed healthy and dense vegetation. The results of our study will provide valuable information in preliminary climate change studies.

The diversity of forest trees as an indicator of ecosystem health can be assessed using the spect... more The diversity of forest trees as an indicator of ecosystem health can be assessed using the spectral characteristics of plant communities through remote sensing data. The objectives of this study were to investigate alpha and beta tree diversity using Landsat data for six dates in the Gönen dam watershed of Turkey. We used richness and the Shannon and Simpson diversity indices to calculate tree alpha diversity. We also represented the relationship between beta diversity and remotely sensed data using species composition similarity and spectral distance similarity of sampling plots via quantile regression. A total of 99 sampling units, each 20 m × 20 m, were selected using geographically stratified random sampling method. Within each plot, the tree species were identified, and all of the trees with a diameter at breast height (dbh) larger than 7 cm were measured. Presence/absence and abundance data (tree species number and tree species basal area) of tree species were used to determine the relationship between richness and the Shannon and Simpson diversity indices, which were computed with ground field data, and spectral variables derived (2 × 2 pixels and 3 × 3 pixels) from Landsat 8 OLI data. The Shannon-Weiner index had the highest correlation. For all six dates, NDVI (normalized difference vegetation index) was the spectral variable most strongly correlated with the Shannon index and the tree diversity variables. The Ratio of green to red (VI) was the spectral variable least correlated with the tree diversity variables and the Shannon basal area. In both beta diversity curves, the slope of the OLS regression was low, while in the upper quantile, it was approximately twice the lower quantiles. The Jaccard index is closed to one with little difference in both two beta diversity approaches. This result is due to increasing the similarity between the sampling plots when they are located close to each other. The intercept differences between two investigated beta diversity were strongly related to the development stage of a number of sampling plots in the tree species basal area method. To obtain beta diversity, the tree basal area method indicates better result than the tree species number method at representing similarity of regions which are located close together. In conclusion, NDVI is helpful for estimating the alpha diversity of trees over large areas when the vegetation is at the maximum growing season. Beta diversity could be obtained with the spectral heterogeneity of Landsat data. Future tree diversity studies using remote sensing data should select data sets when vegetation is at the maximum growing season. Also, forest tree diversity investigations can be identified by using higher-resolution remote sensing data such as ESA Sentinel 2 data which is freely available since June 2015.

Environment, Development and Sustainability, 2019

Investigating agricultural drought is very important in semiarid areas, and it has a significant ... more Investigating agricultural drought is very important in semiarid areas, and it has a significant impact on people's livelihood, which depends on farming. This research tried to examine the capability of six Landsat surface reflectance bands, vegetation indices (VIs), and drought indices (DIs) for drought monitoring in the agricultural lands of Bandar-e-Turkmen and Gomishan cities in 1986 and 2015. Statistical analysis, Pearson correlation analysis, and correlation matrices between the VIs and DIs with land surface temperature (LST) were monitored separately for each date. In addition, the spatial and temporal drought extents using the Standardized Evapotranspiration Precipitation Index (SPEI) and the Vegetation Health Index (VHI) approaches were determined and compared for both study periods. The correlations between the LST and VIs were negative and significant in both study periods. The range of VI values decreased with increasing temperature in 2015 compared to 1986. The mean surface reflectance of the visible bands (blue, green, red), NIR (near-infrared), SWIR (shortwave infrared), and MWIR (mid-wave infrared) increased in 2015 compared to 1986. A higher spectral reflectance of the visible bands indicated a reduction in vegetation cover or increase in stress in 2015 compared to 1986. Meanwhile, the SWIR and MWIR bands showed that the average surface reflectance increased in 2015, while they showed a lower reflectance in 1986. The results of the Water Supplying Vegetation Index (WSVI) implied that the crop water stress in 2015 was more than that in 1986. The VHIs were separately compared with the NDVI and LST in each period of study. The maximum LST increased from 38 °C in 1986 to 44 °C in 2015. The moderate drought extent was 65% in 2015, while the study area did not experience any drought in 1986. The SPEI maps showed that the entire study area experienced moderate drought in 2015, while no drought was observed in 1986. The results showed that the DIs and VIs and the visible, SWIR and MWIR surface reflectance bands can be effectively used by sampling plots in future drought assessment studies. The present study also emphasizes that there is a similarity between traditional and remote sensing methods and indicates that remote sensing data can be effectively used instead of traditional approaches when there is no meteorological station. The results would be useful in food security and sustainable agriculture management plans.

Journal of the Indian Society of Remote Sensing, 2019

This research arose from concerns generated throughout my academic and professional experience wi... more This research arose from concerns generated throughout my academic and professional experience with adolescents who committed infraction acts. The question of childhood and adolescence was not always considered an important agenda to society and to State, there being for this part of population a series of violations of rights, mainly what refers to legislation. From social movements, who fought for guarantee children and adolescents' rights, was made and approved in 1990 the Child and Adolescent Statute that, besides regulating what is established in the Federal Constitution about human rights, defines rules to juridical accountability of adolescents who commit infractions, specified by socio-educational measures. Associated with this legislation, more recently, was approved the National System of Socio-Educational Attendance, which establishes the regulation of this attendance, as defined by the Statute, in addition to supervising and guiding the proper execution of the measures. Although we have a specific law to treat juvenile infraction, it was verified that both the Statute and the National System of Socio-Educational Attendance do not elucidate how adolescent author of an infraction act takes responsibility beyond the compliance with the socio-educational measure. In face of that, this dissertative study aimed to analyze the meanings about juvenile accountability produced by adolescents undergoing social-educational measure. To this, the methodological path of this research had a qualitative character, using the procedure of narrative interview (Brunner, 2013) with adolescents who were undergoing socio-educational measure in the Center of Specialized Reference of Social Assistance. Were interviewed, in total, six adolescents undergoing social-educational measure in the said institution and also a thematic workshop was made. The analysis of the corpus of the research was made under a Cultural-Historical perspective, from an interpretative analysis that allowed us to understand the meaning produced by the adolescents who participated in the research about the process of juvenile accountability, besides it made possible a new elaboration of the meanings and senses that they produced about this experience. The meaning of accountability produced by young people was linked to punitive processes, where institutional violence proved to be one of the main interventions disguised as accountability. The final considerations demonstrate that the process of juvenile accountability is not something given in the legislation; it should be constructed with the adolescent in the moment he is undergoing socio-educational measure. For this, it is necessary that the socio-educational system offers a space where the subject can position himself before his experiences in a conscious way so as to elaborate reflections that strengthen his citizenship.

Environmental monitoring and assessment, Jan 28, 2017

The diversity of forest trees as an indicator of ecosystem health can be assessed using the spect... more The diversity of forest trees as an indicator of ecosystem health can be assessed using the spectral characteristics of plant communities through remote sensing data. The objectives of this study were to investigate alpha and beta tree diversity using Landsat data for six dates in the Gönen dam watershed of Turkey. We used richness and the Shannon and Simpson diversity indices to calculate tree alpha diversity. We also represented the relationship between beta diversity and remotely sensed data using species composition similarity and spectral distance similarity of sampling plots via quantile regression. A total of 99 sampling units, each 20 m × 20 m, were selected using geographically stratified random sampling method. Within each plot, the tree species were identified, and all of the trees with a diameter at breast height (dbh) larger than 7 cm were measured. Presence/absence and abundance data (tree species number and tree species basal area) of tree species were used to determi...

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2016

Changes in land surface reflectance measured by remote sensing data can be useful in climate chan... more Changes in land surface reflectance measured by remote sensing data can be useful in climate change studies. This study attempts to analyze the spatial-temporal extent change of vegetation greenness, Land Surface Temperature (LST), and Normalized Difference Snow Index (NDSI) in late spring at the Lar National Park of Iran using Landsat data. Vegetation indices (VIs), LST, and NDSI maps were calculated for each date (1985, 1994, 2010, and 2015). All VIs have shown an increasing trend from 1985 to 2015 which depicted increase of vegetation. Spectral reflectance of all bands is declining from 1985 to 2015 except in near-infrared (NIR) bands. High reflectance in NIR bands is due to increased vegetation greenness. The reduction was seen in the visible bands that show increased vegetation photosynthetic activity. In the short-wave infrared bands (SWIR) were observed reduced trend from 1985 to 2015 which is indicate increased vegetation. Also, in the mid-wave infrared (MWIR) bands were obs...

Forest Ecosystems, May 11, 2018

Background: Treeline dynamics have inevitable impacts on the forest treeline structure and compos... more Background: Treeline dynamics have inevitable impacts on the forest treeline structure and composition. The present research sought to estimate treeline movement and structural shifts in response to recent warming in Cehennemdere, Turkey. After implementing an atmospheric correction, the geo-shifting of images was performed to match images together for a per pixel trend analysis. We developed a new approach based on the NDVI, LST (land surface temperature) data, air temperature data, and forest stand maps for a 43-year period. The forest treeline border was mapped on the forest stand maps for 1970, 1992, 2002, and 2013 to identify shifts in the treeline altitudes, and then profile statistics were calculated for each period. Twenty sample plots (10 × 10 pixels) were selected to estimate the NDVI and LST shifts across the forest timberline using per-pixel trend analysis and non-parametric Spearman's correlation analysis. In addition, the spatial and temporal shifts in treeline tree species were computed within the selected plots for four time periods on the forest stand maps to determine the pioneer tree species. Results: A statistically significant increasing trend in all climate variables was observed, with the highest slope in the monthly average mean July temperature (tau = 0.62, ρ < 0.00). The resultant forest stand maps showed a geographical expansion of the treeline in both the highest altitudes (22 m-45 m) and the lowest altitudes (20 m-105 m) from 1970 to 2013. The per pixel trend analysis indicated an increasing trend in the NDVI and LST values within the selected plots. Moreover, increases in the LST were highly correlated with increases in the NDVI between 1984 and 2017 (r = 0.75, ρ < 0.05). Cedrus libani and Juniperus communis spp. were two pioneer tree species that expanded and grew consistently on open lands, primarily on rocks and soil-covered areas, from 1970 to 2013. Conclusion: The present study illustrated that forest treeline dynamics and treeline structural changes can be detected using two data sources. Additionally, the results will have a significant contribution to and implication for treeline movement studies and forest landscape change investigations attempting to project climate change impacts on tree species in response to climate warming. The results will assist forest managers in establishing some developmental adaptation strategies for forest treeline ecotones.

Advances in Remote Sensing and Geo Informatics Applications

Monitoring variations in the spectral reflectance of thermal bands of Landsat data provide land s... more Monitoring variations in the spectral reflectance of thermal bands of Landsat data provide land surface temperature information of earth’s surface features. This research tried to examine the variations of Land surface temperature (LST) from 1987 to 2017 at the Gomishan district and its soundings in Iran. Images preprocessing was conducted including the geo-shifting and atmospheric correction. NDVI and LST maps and their change map using a change detection technique were generated. Basic inferential statistics and spatial analysis were performed. The results show that LST mean reached approximately 42.5 °C with 9 °C increase, while it was 33.8 °C in 1987. However, comparing the statistical analysis of NDVI data did not show any differences between the two study dates. Land cover classes include water, urban, and rural covered areas had the lowest LST shifts between the two study periods. The LST of rangelands, wetlands, and bare lands with more than 10 °C increase have experienced considerable LST shifts between during the study periods. Interestingly, some parts of wetland areas had the highest increase approximately 13 °C from 1987 to 2017. This study emphasized that LST change detection approach and spatial analysis can be used successfully in LST monitoring investigations. The results can be used to identify regions that experienced LST shifts (change or no change) and also to identify the most critical and impacted areas. The obtained results can be used effectively in sustainable natural disaster management plans.

ISPRS International Journal of Geo-Information

This study aims to test the spectral and spatial consistency of Sentinel-2 and Landsat-8 OLI data... more This study aims to test the spectral and spatial consistency of Sentinel-2 and Landsat-8 OLI data for the potential of monitoring longos forests for four seasons in Igneada, Turkey. Vegetation indices, including Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and Normalized Difference Water Index (NDWI), were generated for the study area in addition to the five corresponding bands of Sentinel-2 and Landsat-8 OLI Images. Although the spectral consistency of the data was interpreted by cross-calibration analysis using the Pearson correlation coefficient, spatial consistency was evaluated by descriptive statistical analysis of investigated variables. In general, the highest correlation values were achieved for the images that were acquired in the spring season for almost all investigated variables. In the spring season, among the investigated variables, the Red band (B4), NDVI and EVI have the largest correlation coefficients of 0.94, 0.92 and 0.91, respe...

Changes in land surface reflectance measured by remote sensing data can be useful in climate chan... more Changes in land surface reflectance measured by remote sensing data can be useful in climate change studies. This study attempts to analyze the spatial-temporal extent change of vegetation greenness, Land Surface Temperature (LST), and Normalized Difference Snow Index (NDSI) in late spring at the Lar National Park of Iran using Landsat data. Vegetation indices (VIs), LST, and NDSI maps were calculated for each date (1985, 1994, 2010, and 2015). All VIs have shown an increasing trend from 1985 to 2015 which depicted increase of vegetation. Spectral reflectance of all bands is declining from 1985 to 2015 except in near-infrared (NIR) bands. High reflectance in NIR bands is due to increased vegetation greenness. The reduction was seen in the visible bands that show increased vegetation photosynthetic activity. In the shortwave infrared bands (SWIR) were observed reduced trend from 1985 to 2015 which is indicate increased vegetation. Also, in the mid-wave infrared (MWIR) bands were obse...

Forest Ecosystems

Background: Treeline dynamics have inevitable impacts on the forest treeline structure and compos... more Background: Treeline dynamics have inevitable impacts on the forest treeline structure and composition. The present research sought to estimate treeline movement and structural shifts in response to recent warming in Cehennemdere, Turkey. After implementing an atmospheric correction, the geo-shifting of images was performed to match images together for a per pixel trend analysis. We developed a new approach based on the NDVI, LST (land surface temperature) data, air temperature data, and forest stand maps for a 43-year period. The forest treeline border was mapped on the forest stand maps for 1970, 1992, 2002, and 2013 to identify shifts in the treeline altitudes, and then profile statistics were calculated for each period. Twenty sample plots (10 × 10 pixels) were selected to estimate the NDVI and LST shifts across the forest timberline using per-pixel trend analysis and non-parametric Spearman's correlation analysis. In addition, the spatial and temporal shifts in treeline tree species were computed within the selected plots for four time periods on the forest stand maps to determine the pioneer tree species. Results: A statistically significant increasing trend in all climate variables was observed, with the highest slope in the monthly average mean July temperature (tau = 0.62, ρ < 0.00). The resultant forest stand maps showed a geographical expansion of the treeline in both the highest altitudes (22 m-45 m) and the lowest altitudes (20 m-105 m) from 1970 to 2013. The per pixel trend analysis indicated an increasing trend in the NDVI and LST values within the selected plots. Moreover, increases in the LST were highly correlated with increases in the NDVI between 1984 and 2017 (r = 0.75, ρ < 0.05). Cedrus libani and Juniperus communis spp. were two pioneer tree species that expanded and grew consistently on open lands, primarily on rocks and soil-covered areas, from 1970 to 2013. Conclusion: The present study illustrated that forest treeline dynamics and treeline structural changes can be detected using two data sources. Additionally, the results will have a significant contribution to and implication for treeline movement studies and forest landscape change investigations attempting to project climate change impacts on tree species in response to climate warming. The results will assist forest managers in establishing some developmental adaptation strategies for forest treeline ecotones.

Forest Ecosystems, May 11, 2018

Background: Treeline dynamics have inevitable impacts on the forest treeline structure and compos... more Background: Treeline dynamics have inevitable impacts on the forest treeline structure and composition. The present research sought to estimate treeline movement and structural shifts in response to recent warming in Cehennemdere, Turkey. After implementing an atmospheric correction, the geo-shifting of images was performed to match images together for a per pixel trend analysis. We developed a new approach based on the NDVI, LST (land surface temperature) data, air temperature data, and forest stand maps for a 43-year period. The forest treeline border was mapped on the forest stand maps for 1970, 1992, 2002, and 2013 to identify shifts in the treeline altitudes, and then profile statistics were calculated for each period. Twenty sample plots (10 × 10 pixels) were selected to estimate the NDVI and LST shifts across the forest timberline using per-pixel trend analysis and non-parametric Spearman's correlation analysis. In addition, the spatial and temporal shifts in treeline tree species were computed within the selected plots for four time periods on the forest stand maps to determine the pioneer tree species. Results: A statistically significant increasing trend in all climate variables was observed, with the highest slope in the monthly average mean July temperature (tau = 0.62, ρ < 0.00). The resultant forest stand maps showed a geographical expansion of the treeline in both the highest altitudes (22 m-45 m) and the lowest altitudes (20 m-105 m) from 1970 to 2013. The per pixel trend analysis indicated an increasing trend in the NDVI and LST values within the selected plots. Moreover, increases in the LST were highly correlated with increases in the NDVI between 1984 and 2017 (r = 0.75, ρ < 0.05). Cedrus libani and Juniperus communis spp. were two pioneer tree species that expanded and grew consistently on open lands, primarily on rocks and soil-covered areas, from 1970 to 2013. Conclusion: The present study illustrated that forest treeline dynamics and treeline structural changes can be detected using two data sources. Additionally, the results will have a significant contribution to and implication for treeline movement studies and forest landscape change investigations attempting to project climate change impacts on tree species in response to climate warming. The results will assist forest managers in establishing some developmental adaptation strategies for forest treeline ecotones.

Agriculture and Biology Journal of North America, 2010

Several regions around the world are currently under rapid, wide-ranging changes of land cover. S... more Several regions around the world are currently under rapid, wide-ranging changes of land cover. Satellite remote sensing techniques have proven to be cost efficient in extensive land cover changes. This study illustrates the effect of land use/cover change in Neka river of Iran using topographic maps and multi-temporal remotely sensed data from 1975 to 2001. The Maximum likelihood supervised classification technique was used to extract information from satellite data, and post-classification change detection method was employed to detect land use/cover change. Post-classification change detection technique was used to produce an image through
cross-tabulation. Changes among different land use/cover classes were assessed. The overall accuracy of land cover change maps, generated from Landsat data 1975 and 2001, ranged from 99.44% and 97.08% with Kappa statistics of 85% and 83%, respectively. The analysis indicated that the urban and agricultural land expansion of Neka river was increased resulted in the considerable reduction of forest area. The maps showed that between 1987 and 2001 the agricultural land and built-up areas increased approximately 59.86km2 (9.16%) and 7.35(1.13%), respectively. While forest decreased 67.91 km2 (10.29%). The study quantified the patterns of land use/cover change for the last 13 years for Neka river that forms valuable resources for urban planners and decision makers to devise sustainable land use and environmental planning.

Changes in land surface reflectance measured by remote sensing data can be useful in climate chan... more Changes in land surface reflectance measured by remote sensing data can be useful in climate change studies. This study attempts to analyze the spatial-temporal extent change of vegetation greenness, Land Surface Temperature (LST), and Normalized Difference Snow Index (NDSI) in late spring at the Lar National Park of Iran using Landsat data. Vegetation indices (VIs), LST, and NDSI maps were calculated for each date (1985, 1994, 2010, and 2015). All VIs have shown an increasing trend from 1985 to 2015 which depicted increase of vegetation. Spectral reflectance of all bands is declining from 1985 to 2015 except in near-infrared (NIR) bands. High reflectance in NIR bands is due to increased vegetation greenness. The reduction was seen in the visible bands that show increased vegetation photosynthetic activity. In the shortwave infrared bands (SWIR) were observed reduced trend from 1985 to 2015 which is indicate increased vegetation. Also, in the mid-wave infrared (MWIR) bands were observed a declining trend which is the result of decreasing soil fraction from 1985 to 2015. LST has increased from 23.27 °C in 1985 to 27.45 °C in 2015. Snow patches were decreased over the study period. In conclusion, VIs and surface reflectance bands are considered the main tool to display vegetation change. Also, high VIs values showed healthy and dense vegetation. The results of our study will provide valuable information in preliminary climate change studies.

The diversity of forest trees as an indicator of ecosystem health can be assessed using the spect... more The diversity of forest trees as an indicator of ecosystem health can be assessed using the spectral characteristics of plant communities through remote sensing data. The objectives of this study were to investigate alpha and beta tree diversity using Landsat data for six dates in the Gönen dam watershed of Turkey. We used richness and the Shannon and Simpson diversity indices to calculate tree alpha diversity. We also represented the relationship between beta diversity and remotely sensed data using species composition similarity and spectral distance similarity of sampling plots via quantile regression. A total of 99 sampling units, each 20 m × 20 m, were selected using geographically stratified random sampling method. Within each plot, the tree species were identified, and all of the trees with a diameter at breast height (dbh) larger than 7 cm were measured. Presence/absence and abundance data (tree species number and tree species basal area) of tree species were used to determine the relationship between richness and the Shannon and Simpson diversity indices, which were computed with ground field data, and spectral variables derived (2 × 2 pixels and 3 × 3 pixels) from Landsat 8 OLI data. The Shannon-Weiner index had the highest correlation. For all six dates, NDVI (normalized difference vegetation index) was the spectral variable most strongly correlated with the Shannon index and the tree diversity variables. The Ratio of green to red (VI) was the spectral variable least correlated with the tree diversity variables and the Shannon basal area. In both beta diversity curves, the slope of the OLS regression was low, while in the upper quantile, it was approximately twice the lower quantiles. The Jaccard index is closed to one with little difference in both two beta diversity approaches. This result is due to increasing the similarity between the sampling plots when they are located close to each other. The intercept differences between two investigated beta diversity were strongly related to the development stage of a number of sampling plots in the tree species basal area method. To obtain beta diversity, the tree basal area method indicates better result than the tree species number method at representing similarity of regions which are located close together. In conclusion, NDVI is helpful for estimating the alpha diversity of trees over large areas when the vegetation is at the maximum growing season. Beta diversity could be obtained with the spectral heterogeneity of Landsat data. Future tree diversity studies using remote sensing data should select data sets when vegetation is at the maximum growing season. Also, forest tree diversity investigations can be identified by using higher-resolution remote sensing data such as ESA Sentinel 2 data which is freely available since June 2015.