Remote sensing refers to the acquisition and processing of information about an object or phenomenon, without making physical contact with the object, through the use of electromagnetic radiation intensity, frequency and polarization. These capabilities make the Remote Sensing technology one of the most suited candidate for the analysis of the landscape and environment towards the understanding and of natural phenomena, both in the prevention, management and mitigation of natural risks such as flooding and landslide, forest fires and volcanic eruption or earthquakes.
Optical Remote Sensing deals with those part of electromagnetic spectrum characterised by the wavelengths from the visible 0. In this range of frequencies data acquisition measurements, signals, images is realized with sensors that utilize for the radiation collection optical instruments such as lens for refraction or mirrors for reflection mechanism. News and Updates. Question: How many measurement scientists does it take to screw in an LED lightbulb? Answer: For researchers at the. Doctors use X-rays to see inside people, and scientists use neutrons to peer inside advanced materials and devices such.
Recommended For You
We see the world in reflection: Nearly all the light that enters our eyes has bounced off something first, bringing with. Projects and Programs. We maintain a suite of programs that can help calculate the optical properties of many solids throughout the electromagnetic spectrum. High performance optical radiometers with selected optical detectors are being designed, characterized, and calibrated in the Optical Radiation Group for the. The technical accuracy of LiDAR instruments may far exceed our ability to link point cloud data to forest attributes.
In this case, a further reduction of measurement error would not greatly improve the estimation of biophysical or biochemical attributes. This leaves some questions around the need for repetition in studies on the potential of LiDAR remote sensing in forestry. While being the cornerstone of science, the repetition with which the suitability of LiDAR for forest attribute retrieval has been established seems to some extent excessive, and one might even expect that the explosive drift to conduct and report LiDAR studies that we have seen over the years, has had something to do with the emphasis that has been put on publication metrics.
That said, significant research potential remains in exploring the use of LiDAR combined with other remote sensing technologies in studies that focus on the interaction between forest structure and physiological functions. For example, branching architecture can take on a range of angular form, planophile or erectophile or anywhere in between; canopies can be dense or sparse, and consist of mixed species or mono-cultures, and can be multilayered vertically.
Postdoctoral Fellow in Optical Remote Sensing for Biochemical Water Quality Parameter Retrieval
All of these traits have an impact on the radiation budget and hence, the photosynthetic and respiratory functioning of the canopy. While standard passive optical, multispectral, and hyperspectral remote sensing can provide coarse information about canopy structure, it can only generally do so for the upper layer s of dense canopies and requires empirical or process-based models to do so.
LiDAR and to some extent radar is the only method able to provide near-direct measures of structural information that are easy to interpret and work with. TLS allows trees to be scanned from multiple directions to increase the fidelity of the acquired data while reducing the effects of occlusion where multiple objects shadow one another.
TLS is characterized by a much higher point sampling density and smaller laser footprint that is often of the order of millimeters. This allows a near-continuous sampling of surface geometry from which solid geometry models can be derived through subsequent processing. This distinction can be important when the emphasis is placed on an accurate acquisition of canopy structure. The remainder of this chapter will explore the various uses of LiDAR remote sensing and reviews some of the potentials that it holds for forestry and tree physiology.
First, we discuss temporal and spatial domains in which LiDAR remote sensing offers new opportunities, ranging from the global scale to the stand and plot levels and further down to the scale of individual trees and tree crowns. Following this, we discuss matters of structural assessment as well as how canopy structural information can be used to study the radiation budget and impacts on physiological functions.
- Girl’s Night Out: Erotika Fantasy The Vampire Deception Series, Novella #1.
- Japan and the Pacific.
- Optical Remote Sensing: Science and Technology - CRC Press Book!
- ESA TRAINING COURSE ON RADAR AND OPTICAL REMOTE SENSING!
Finally, we present a brief review of potential synergies arising from a combination of LiDAR technology and other remote sensing technologies. With the current remote sensing technology developments, and in particular those at L-band 1. One of these new approaches is the combination of optical and passive microwave data based on a semiempirical approach derived from the general radiative transfer equation. The objective of this chapter is to present some applications of the combined optical-passive microwave approaches over several spatial scales and land cover types. Additionally, the influences of vegetation indexes such as the leaf area index or the normalized difference vegetation index are also described.
Finally, as a future perspective of the possible use of thermal infrared information such as land surface temperature or land surface emissivity rather than vegetation indexes is also commented on. The application of remote-sensing technology, over the years, has shown its immense utility for large-scale geological mapping related to steep slopes, straight valley segments, abrupt changes in vegetation coverage and sudden bends along river courses. Remote sensing has the advantage of providing synoptic overviews of the region and thus it can provide information on structural geological features extending over large areas.
The availability of multispectral and high-resolution data as well as the various digital image-processing techniques in generating enhanced images further widens the scope of remote-sensing studies in delineating the lithological contacts and geological structure with more detail and better accuracy. Faults which are observed as either linear or curvilinear features on the earth surface can be easily demarcated as linears through remote-sensing studies.
These linear zones of different contrast are commonly referred to as lineaments and this may range from a few meters to tens of kilometers in length. The lithological boundaries, boundaries between different land uses, drainage lines, etc. The interpretation of lineaments is based on the spatial correlation of remotely sensed images of geological objects as well as on the density of the available geological—geophysical data. In comparison to fieldwork investigations, remote-sensing techniques are quicker and more cost effective for fault detection.
Adrien Michez, The first technological developments took place in the early s, but its use on an operational basis has only been going on since the s, particularly in support of national forest inventory projects in Canada, Finland, etc. In forestry, LiDAR technology is generally used for the estimation of dendrometric variables heights, basal areas, timber volume, biomass… but also for more qualitative characterizations species composition, ecological integrity of forest ecosystems, health condition….
LiDAR makes it possible to estimate the biomass in tropical forests, where there are significant standing stocks, without the saturation phenomenon typically observed using traditional remote sensing data. The costs of acquisition represent the main limitation to the development of the large-scale use of LiDAR in forestry. Wong, S.
The estimation of AGB using remote sensing technology relies heavily on the selection of an allometric equation of AGB. Many allometric equations have been proposed that have been developed in different types of forest and growth environments and can be categorized into generic models eg, Brown, ; Pearson et al. The AGB can be influenced by forest changes and species composition eg, Culmsee et al. Thus, it is recommended to evaluate the estimation error of each allometric equation if there are two or more applicable equations that are available eg, Hirata et al.
The allometric equation for Southeast Asia was developed as early as the s Yamakura et al. Because of the highly diverse forest type along with the degradation and plantation type in the Southeast Asia region, there has been continuous development of allometric equations eg, Kenzo et al. Yuen et al. Despite the high number of allometric equations available, the review concluded that there is a pressing need to address the insufficient number of allometric equations.
However, optimizing the specific allometric equation will require a good data set of vegetation class at first. Rodell, in Climate Vulnerability , Satellite gravimetry is the only remote sensing technology currently available for measuring water stored below the first few centimeters of the soil column or the total liquid and frozen water storage.
Remote Sensing Technology
GRACE has endured well beyond its designed 5-year mission lifetime, and there is no set end date. Depending on battery and instrument health and fuel consumption for orbital adjustments, the mission might continue into the middle of the s. This could be achieved by replacing the microwave ranging system with a laser interferometer, flying at a lower altitude in atmospheric-drag-free spacecraft NRC , and possibly maintaining multiple satellite pairs in orbit simultaneously Wiese and Nerem While the improved resolution would be valuable, the need for further downscaling via data assimilation would remain.
In the meantime, NASA has begun the development of a follow-on to GRACE with a nearly identical mission design, which would provide continuity in the data record while affording some improvement in resolution because of basic technological advancements of the past 10 years Watkins et al.
Optical Remote Sensing : Science and Technology | Semantic Scholar
This mission could launch as soon as and enable gravimetry-based water availability monitoring into the next decade. Water is essential to life and vulnerable, for example, to overexploitation, pollution, and redistribution associated with any changes in precipitation and temperature. The information provided by GRACE and future satellite gravimetry missions has great potential to improve monitoring and understanding of freshwater availability, thereby helping to reduce environmental and social consequences.
The hydrology and other climate communities have been somewhat slow to embrace GRACE as a tool of the trade because of the unique and challenging aspects of the observations. However, success stories such as those described here are increasing awareness and building momentum for GRACE-enabled research and applications.
Extending the data record by maintaining GRACE and launching the GRACE follow-on mission will also reduce uncertainty in and improve the understanding of climatic and anthropogenic impacts on the water cycle that have begun to be revealed.