Aquatic vegetation is an important component of wetland and coastal ecosystems, playing a key role in the ecological functions of these environments. Surveys of macrophyte communities are commonly hindered by logistic problems, and remote sensing represents a powerful alternative, allowing comprehensive assessment and monitoring. Also, many vegetation characteristics can be estimated from reflectance measurements, such as species composition, vegetation structure, biomass, and plant physiological parameters. However, proper use of these methods requires an understanding of the physical processes behind the interaction between electromagnetic radiation and vegetation, and remote sensing of aquatic plants have some particular difficulties that have to be properly addressed in order to obtain successful results. The present paper reviews the theoretical background and possible applications of remote sensing techniques to the study of aquatic vegetation.

Remote sensing of aquatic vegetation: theory and applications

Remote sensing of submerged aquatic vegetation in lower chesapeake bay: A comparison of Landsat MSS to TM imagery

A compilation of approximately three hundred publications concerning the brown alga Sargassum mulicum (Yendo) Fensholt is given. This seaweed has attracted considerable attention amongst the phycological fraternity, because of recent large-scale changes in its geographical distribution and feared consequences of the alga's presence in invaded habitats.

A Bibliography of the Invasive Alga Sargassum muticum (Yendo) Fensholt (Fucales; Sargassaceae)

The main aim of this study was to assess the potential of Landsat TM for detecting and quantifying marine habitat changes on the Fasht Al-Adham reef complex of the east coast of Bahrain. The raw data comprized several digital TM images acquired between 1985 and 1992 during different tidal conditions. Following pre-processing and registration to a digitized UTM marine chart, the image processing proceeded in two parts. In the first part, visual interpretation was employed using a combination of principal component and false color composites (FCCs) of the multi-temporal images to identify the changed areas. Then, and in conjunction with extensive field data, the changed areas between the two dates were identified.

Monitoring marine ecological changes on the east coast of Bahrain with Landsat TM

A review, with literature citations, of current remote sensing technology, applications, and costs for wildland resource management, including collection, interpretation, and processing of data gathered through photographic and nonphotographic techniques for classification and mapping, interpretive information for specific applications, measurement of resource parameters, and observations and counts of occurrences. INTRODUCTION Remote sensing is a tool to aid gathering information about land cover with a minimum of ground verification. How much information is extracted from remotely sensed data is dependent upon the type of sensor and the portion of the electromagnetic spectrum (EMS) used, the quality of the data recorded , and certain physical limitations including platform altitude, topography, variations in solar angle and solar altitude, and atmospheric interference. There are other limiting factors involved in processing the data once they have been collected (i.e., regardless of how well data are gathered, improperly processed and/or interpreted data will yield poor information, preventing realization of the full capabilities of remote sensing). The " state " of something is the sum of the qualities involved in its existence at a particular time and place. The qualities of remote sensing as defined here include the data as well as the data collection, interpretation , and/or data processing. The end result must be cost-effective information useful to resource managers for land use planning and solving wild-land management problems. Remote sensing as reviewed in this paper covers both photographic and nonphotographic data including microwave, radar, thermal infrared (thermal JR), ultraviolet (UV), as well as multispectral scanner (MSS) data. Nonimaging radiometers and spectrometers, however, are not included. Remotely sensed data may be interpreted manually (photo interpretation), by automatic data processing (ADP), or by a combination of the two. TERMINOLOGY It would be difficult to discuss the state of remote sensing without reference to several basic technical Forest Service, for their helpful reviews of this paper. Their comments and suggestions lead to many improvements in the manner of presentation as well as content. terms. These terms are defined here to avoid confusion and the need for repetition later in the review. A more complete glossary of remote sensing is found in appendix A. Ground resolution.—For this review, ground resolution refers to the smallest detectable or measureable detail on a remotely sensed image. In aerial photography, ground resolution is a function of scale (camera lens focal length and flying height above ground) and the resolving power of a system. …

https://www.fs.fed.us/rm/pubs_rm/rm_gtr071.pdf

Remote sensing of wildland resources: A state-of-the-art review

A parallel electro-optical input spectroradiometer system with 500 channels and operating in the 400-1100 nm wavelength region has been designed and fabricated for use in a light aircraft. The airborne system was conceived for determining the high-spectral-resolution properties of various ground targets of interest in remote sensing. Spectral radiance data at 4-digit resolution are generated on a 9-track tape in computer compatible format. At a survey altitude of 600 m and 200 km/hr ground speed, a ground resolution element is 18 meters square. The data acquisition rate is 2.5 spectra per second of 500 channels each. Absolute radiometric calibration is achieved with a standard lamp that is calibrated against an NBS secondary standard source. The linearity of instrument response to intensity change is 1 percent. The rapid data acquisition in parallel input channels is essential for obtaining good quality spectral data at 2 nm or better wavelength resolution and high sensitivity under airborne operating conditions. These data have yielded spectral information valuable to basic remote sensing research in the areas of detecting geologic zones of alteration, monitoring the condition of vegetation canopies, and determining the spectral properties of water bodies. /Author/

R Adams

Papers

Aerial color and color infrared survey of marine plant resources