Sahel Mahdavi

• Doctor of Philosophy (PhD)
• Senior Remote Sensing Engineer at WSP in Canada

Marine ecosystems serve as vital indicators of biodiversity, providing habitats for diverse flora and fauna. Canada’s extensive coastal regions encompass a rich range of marine habitats, necessitating accurate mapping techniques utilizing advanced technologies, such as remote sensing (RS). This study focused on a study area in Pistolet Bay in Newfo...

Monitoring river ice in Canada is important for various applications, including assessing the danger of floods. For this purpose, satellites provide a valuable solution to reduce cost and improve safety. For example, all-weather day and night acquisition capability of Synthetic Aperture radar (SAR) systems facilitate frequent monitoring of river ic...

Progress toward habitat protection goals can effectively be performed using satellite imagery and machine-learning (ML) models at various spatial and temporal scales. In this regard, habitat types and landscape structures can be discriminated against using remote-sensing (RS) datasets. However, most existing research in three-dimensional (3D) habit...

Accurate ocean surface wind vector (OSWV) products are important for various offshore operations. Currently, different types of satellites provide OSWV data, using one of which alone does not yield a high accuracy, reasonable revisit time, and full coverage over large ocean environments. Moreover, the current OSWV products that were generated by fu...

Marine habitats provide various benefits to the environment and humans. In this regard, an accurate marine habitat map is an important component of effective marine management. Newfoundland’s coastal area is covered by different marine habitats, which should be correctly mapped using advanced technologies, such as remote sensing methods. In this s...

Oceans cover over 70% of the Earth’s surface and provide numerous services to humans and the environment. Therefore, it is crucial to monitor these valuable assets using advanced technologies. In this regard, Remote Sensing (RS) provides a great opportunity to study different oceanographic parameters using archived consistent multitemporal datasets...

As discussed in the first part of this review paper, Remote Sensing (RS) systems are great tools to study various oceanographic parameters. Part I of this study described different passive and active RS systems and six applications of RS in ocean studies, including Ocean Surface Wind (OSW), Ocean Surface Current (OSC), Ocean Wave Height (OWH), Sea...

Wetlands provide many benefits, such as water storage, flood control, transformation and retention of chemicals, and habitat for many species of plants and animals. The ongoing degradation of wetlands in the Great Lakes basin has been caused by a number of factors, including climate change, urbanization, and agriculture. Mapping and monitoring wetl...

Ocean Water Quality (OWQ) monitoring provides insights into the quality of water in marine and near-shore environments. OWQ measurements can contain the physical, chemical, and biological characteristics of oceanic waters, where low OWQ values indicate an unhealthy ecosystem. Many parameters of water can be estimated from Remote Sensing (RS) data....

River eelgrass has a vital role in the coastal ecosystem, which can be threatened by human activities and climate change. Accurate mapping of eelgrass habitats is important for sustainable eelgrass conservation and management. A large portion of the Shediac river in the province of New Brunswick, Canada is covered by eelgrass, which can be threaten...

Many geospatial applications rely on the extraction of spatial features, including road networks, from very high-resolution (VHR) satellite images. Researchers have developed many algorithms to achieve this goal, the majority of which are based on image fusion, fuzzy logic, and active contour models. The snake model is among the most widely used me...

Remote sensing datasets are great resources to map habitat types. In this study, 3D habitat maps were generated using high-resolution multispectral imagery and a LiDAR-derived digital surface model (DSM). Two study areas in the United Kingdom (UK) were selected to investigate the potential of the developed models in habitat classification. The over...

As discussed in the previous part of this review paper, Remote Sensing (RS) creates unprecedented opportunities by providing a variety of systems with different characteristics to study and monitor oceans. Part 1 of this review paper was dedicated to reviewing passive RS systems and their main applications in the ocean. Here, in part 2, seven activ...

Reliable, accurate, and timely information about oceans is important for many applications, including water resource management, hydrological cycle monitoring, environmental studies, agricultural and ecosystem health applications, economy, and the overall health of the environment. In this regard, Remote Sensing (RS) systems offer exceptional advan...

Iran is among the driest countries in the world, where many natural hazards, such as floods, frequently occur. This study introduces a straightforward flood hazard assessment approach using remote sensing datasets and Geographic Information Systems (GIS) environment in an area located in the western part of Iran. Multiple GIS and remote sensing dat...

Aquatic vegetation (AV) mapping is an important component of ecosystem-based management of coastal marine environments. A large portion of Newfoundland’s coastal areas is covered by different AV types, which should be correctly mapped using recent advanced technologies. In this regard, remote sensing (RS) datasets, such as those acquired by a light...

Aquatic vegetation (AV) mapping is an important component of ecosystem-based management of coastal marine environments. A large portion of Newfoundland’s coastal areas is covered by different AV types, which should be correctly mapped using recent advanced technologies. In this regard, remote sensing (RS) datasets, such as those acquired by a light...

In this study, wetland trends in Alberta were investigated in the past four decades using Landsat satellite imagery to produce updated information about wetland changes and to prevent further degradation of these valuable natural resources. All the processing steps and analyses were conducted in Google Earth Engine (GEE) to produce 16 wetland maps...

- First comprehensive wetland change analysis in Alberta is provided - Four decades of Landsat datasets are processed in the GEE cloud platform - It is observed that 18 of the wetlands in Alberta was subjected to change - Limitations are discussed and suggestions for future works are provided

MODIS Land Surface Temperature (LST) product (MOD11A1) has been widely used in analysing spatiotemporal trends of LST. However, its applicability is limited, partially due to its coarse spatial resolution (i.e., 1-km). In this study, an Adaptive Random Forest Regression (ARFR) method was developed for LST downscaling at national scale. This study a...

Wildfires are major natural disasters negatively affecting human safety, natural ecosystems , and wildlife. Timely and accurate estimation of wildfire burn areas is particularly important for post-fire management and decision making. In this regard, Remote Sensing (RS) images are great resources due to their wide coverage, high spatial and temporal...

The first Canadian Wetland Inventory (CWI) map, which was based on Landsat data, was produced in 2019 using the Google Earth Engine (GEE) big data processing platform. The proposed GEE-based method to create the preliminary CWI map proved to be a cost-, time-, and computationally efficient approach. Although the initial effort to produce an CWI map...

Wood Environment & Infrastructure conducted research on marine fog formation, dissipation, and movement on the Grand Banks of Newfoundland & Labrador, Canada during the period 2014 to 2020. This research and development project included a multi-year assessment of marine fog predictability for this location that has dense marine advection fog as fre...

Fog is a hazardous weather event that can endanger navigation, aviation, and transportation. While human has several limitations in detecting and forecasting offshore fog, satellite Remote Sensing (RS) offers cost-effective images. In this study, a probability-based daytime sea fog detection algorithm, applied to GOES-16 satellite data over the Gra...

The ability of the Canadian agriculture sector to make better decisions and manage its operations more competitively in the long term is only as good as the information available to inform decision-making. At all levels of Government, a reliable flow of information between scientists, practitioners, policy-makers, and commodity groups is critical f...

Accurate information about the location, extent, and type of Land Cover (LC) is essential for various applications. The only recent available country-wide LC map of Iran was generated in 2016 by the Iranian Space Agency (ISA) using Moderate Resolution Imaging Spectroradiometer (MODIS) images with a considerably low accuracy. Therefore, the producti...

Remote Sensing (RS) systems have been collecting massive volumes of datasets for decades, managing and analyzing of which are not practical using common software packages and desktop computing resources. In this regard, Google has developed a cloud computing platform, called Google Earth Engine (GEE), to effectively address the challenges of big da...

Wetlands are among the most valuable natural resources, being highly beneficial to both the environment and humans. Therefore, it is very important to map and monitor wetlands. Although various remote sensing datasets, including optical, synthetic aperture radar (SAR), light detection and ranging (LiDAR) imagery, have been widely applied to classif...

Erosion is the continuous degradation of the soil surface mainly caused by water and/or wind. In the erosion process, the nutrients of the soil, including potassium, are eroded. Therefore, developing new models to estimate soil potassium contents prone to erosion is important for soil degradation monitoring. In this study, three different soil type...

Nitrogen is an important nutrient in the process of crop growth. The aim of this research was to develop several models to estimate the Soil Total Nitrogen Content (STNC) using soil reflectance values. For this, 138 samples for three different types of soil: loam, sandy loam, and silty loam with different nitrogen contents were prepared. After pre-...

Soil moisture content (SMC) is a crucial component in various environmental studies. Although many models have been proposed for SMC estimation, developing new models for accurate estimation of SMC is still an interesting subject. This study aimed to develop new models for SMC estimation using the water absorption bands in the spectral signatures o...

Wetlands are important natural resources due to their numerous ecological services. Consequently, identifying their locations and extents is imperative. The stability, repeatability, cost-effectiveness, multi-scale coverage, and proper spatial resolution imagery of satellites provide a valuable opportunity for their use in various large-scale appli...

Land cover classification is important for various environmental assessments. The opportunity of imaging the Earth’s surface makes remote sensing techniques efficient approaches for land cover classification. The only country-wide land cover map of Iran was produced by the Iranian Space Agency (ISA) using low spatial resolution Moderate Resolution...

Change detection using Remote Sensing (RS) techniques is valuable in numerous applications, including environmental management and hazard monitoring. Synthetic Aperture Radar (SAR) images have proven to be even more effective in this regard because of their all-weather, day and night acquisition capabilities. In this study, a polarimetric index bas...

Applying numerous features is common for complex land cover classification, which makes feature selection necessary. Although the selected feature subsets may yield high overall accuracies in the case of spectrally similar classes such as wetlands, several individual accuracies are often low. A reason is that one set of features used to separate on...

Accurately classifying and monitoring wetlands using new technologies is important because of many services that wetlands provide to the environment. In this regard, Synthetic Aperture Radar (SAR) systems provide valuable data to separate different wetland classes. Using large amount of field samples collected over three years, 78 SAR features extr...

Although wetlands provide valuable services to humans and the environment and cover a large portion of Canada, there is currently no Canada-wide wetland inventory based on the specifications defined by the Canadian Wetland Classification System (CWCS). The most practical approach for creating the Canadian Wetland Inventory (CWI) is to develop a rem...

Wetlands are valuable natural resources that provide many benefits to the environment, and thus, mapping wetlands is crucially important. We have developed land cover and wetland classification algorithms that have general applicability to different geographical locations. We also want a high level of classification accuracy (i.e., more than 90%)....

The difference between an image pair acquired in crossing orbits of Synthetic Aperture Radar (SAR) sensors is of great importance. In this study, this difference was investigated in terms of back-scatter and scattering mechanisms for several classes, including the Ground Vegetation (Gv), Water (Wtr), and Trees. Two RADARSAT-2 image pairs were used,...

The separability of wetland types using different spectral bands is an important subject, which has not yet been well studied in most countries. This is particularly of interest in Canada because it contains approximately one-fourth of the total global wetlands. In this study, the spectral separability of five wetland classes, namely Bog, Fen, Mars...

There are currently various classification algorithms, each with its own advantages and limitations. It is expected that fusing different classifiers in a way that the advantages of each are selected can boost the accuracy in the classification of complex land covers , such as wetlands, compared to using a single classifier. Classification of wetla...

Wetlands provide a wide variety of environmental services globally and detailed wetland inventory maps are always necessary to determine the conservation strategies and effectively monitor these productive ecosystems. During the last two decades, satellite remote sensing data have been extensively used for wetland mapping and monitoring worldwide....

The potential of the red-NIR spectral space has been frequently investigated for the sole estimation of the Leaf Area Index (LAI) or Soil Moisture (SM) values. However, the applicability of the space for simultaneous prediction of the LAI and SM has not yet been studied. In this study, a general model was first proposed for the contemporaneous esti...

Wetlands are valuable natural resources that provide many benefits to the environment. Therefore, mapping wetlands is crucially important. Several review papers on remote sensing (RS) of wetlands have been published thus far. However, there is no recent review paper that contains an inclusive description of the importance of wetlands, the urgent ne...

While 18 percent of Newfoundland and Labrador (NL) is covered by wetlands, efforts to classify and monitor these valuable landscapes using new technologies have not been seriously addressed so far. The purpose of this study was to develop new and advanced remote sensing methods to classify wetlands in NL with efficient applicability in national Can...

Despite the fact that vast portions of Newfoundland and Labrador (NL) are covered by wetlands, currently there is no provincial inventory of wetlands in the province. In this study, we analyzed multi-temporal SAR data for wetland classification at four pilot sites across NL. Object Based Image Analysis (OBIA) using a segmentation method based on op...

Land cover classification is a common application of Remote Sensing, which often yields reasonable results. However , when the target classes are spectrally similar to each other, this task becomes quite challenging. In this paper, a method is proposed which attempts to alleviate this issue. In the proposed method, not all the objects are given a l...

Environmental conditions have considerable effects on synthetic aperture radar (SAR) imagery. Therefore, assessing these effects is important for obtaining accurate and reliable results. In this study, three series of RADARSAT-2 SAR images were evaluated. In each of these series, the sensor configuration was fixed, but the environmental conditions...

Newfoundland and Labrador (NL) is the only province in Atlantic Canada that does not have a wetland inventory system. As a consequence, both classifying and monitoring wetland areas are necessary for wetland conservation and human services in the province. In this study, wetlands in 5 pilot sites, distributed across NL, were classified using multi-...

Speckle degrades the radiometric quality of a Synthetic Aperture Radar (SAR) image. Previous methods for speckle reduction have used a fixed-size window for filtering the entire image. This, however, may not be effective for the entire image, as land covers of different sizes require different filtering windows. In this paper, a novel method is pro...

While Soil Moisture (SM) can be used as a direct indicator of dryness, the Land Surface Temperature (LST) and vegetation status are indirectly related to SM, and consequently, affect the degree of dryness. Each of these three variables has been individually used to assess the dryness. Furthermore, a combination of the LST and vegetation information...

A vast portion of Newfoundland and Labrador (NL) is covered by wetland areas. Notably, it is the only province in Atlantic Canada that does not have a wetland inventory system. Wetlands are important areas of research because they play a pivotal role in ecological conservation and impact human activities in the province. Therefore, classifying wetl...

Wetlands play a key role in providing food, water, and shelter to a multitude of plants and animals. While much of Island of Newfoundland, which is located within Canada, is covered by wetlands, they have not been studied sufficiently in the province. Therefore, the study of these wetlands' characteristics is an important task in the province. In t...

Wetlands are important natural resources which provide numerous advantages to the environment. They play a pivotal role in purifying water, controlling natural hazards, and conserving soil and water. Remote Sensing (RS) is a cost-effective and timely tool which has been long applied for wetland mapping/ monitoring. Furthermore, since the advent of...

A vast portion of Newfoundland and Labrador is covered by wetland areas. Notably, it is the only province in Atlantic Canada that does not have a wetland inventory system. Wetlands are important areas of research because they play a pivotal role in ecological conservation and impact human activities in the province. Therefore, classifying wetland t...

Much of Newfoundland and Labrador is covered by wetlands. Notably, it is the only province in Atlantic Canada that does not have a wetland inventory system. As a consequence, classifying and monitoring wetland areas are necessary for ecological conservation and human services in the province. In this regard, remote sensing satellites with different...

Wetlands provide many advantages to the environment and hence their monitoring is of crucial importance. Newfoundland and Labrador (NL) in Canada, is a province rich in wetlands. However, despite their importance, wetlands have been poorly understood in NL and there is not a wetland inventory for the province, unlike other provinces in Atlantic Can...

Wetlands play a key role in providing food, water, and shelter to multitude of plants and animals. Wetlands occupy a large portion of Newfoundland and Labrador. Over the last decades, agricultural activities, urbanization, and industrialization have posed a serious threat to wetlands in this province. Therefore, coordinated actions providing inform...

Speckle degrades the radiometric quality of a Synthetic Aperture Radar (SAR) image and makes its visual interpretation difficult. The approaches proposed previously for speckle filtering of SAR images exploit a window of fixed size for this purpose. But a fixed size window is not sufficient as the size of objects may vary throughout the image. In t...

Wetlands have significant roles in filtering nature’s water, reducing downstream flooding and erosion, collecting and storing runoff, as well as providing food, water, and shelter to thousands of animals. Most parts of Newfoundland and Labrador are covered by wetland areas. Therefore, monitoring and classifying these areas are important in terms of...

Both Synthetic Aperture RADAR (SAR) and optical imagery play a pivotal role in many applications. Thus it is desirable to fuse the two independent sources of data congruously. Many of the fusion methods, however, fail to consider the different nature of SAR and optical data. Moreover, it is not straightforward to adjust the contribution of the two...

ch01: Introduction, ch02: The principles of a SAR system, ch03: Data acquisition by SAR systems, ch04: Speckle, ch05: Interpretation of SAR images, ch06: The principles of Polarimetric SAR, ch07: Interferometric SAR, ch08: The applications of SAR Remote Sensing, ch09: SAR platforms.

Speckle degrades the radiometric resolution of the image and complicates the visual interpretation of RADAR data. Speckle reduction is an important topic within radar remote sensing community and significant amount of research has been conducted on it. One strategy for speckle reduction is to apply the decomposition to the image followed by filteri...

Although wetlands contribute significant values to society, wetlands in boreal systems remain poorly understood. The need for wetland inventory in Newfoundland and Labrador has been identified for over 30 years. However, despite most of the other Canadian provinces which have a wetland inventory, a comprehensive wetland inventory identifying priori...

A method was presented for soil moisture retrieval which is based on considering different kinds of interaction of ra-dar electromagnetic waves in different frequencies. A vegetation index was defined and a relationship was developed between the index and C-HH backscatter. Then, the effect of vegetation from L-band backscatter in HH and VV po-lariz...