Real-time climate monitoring using an AVHRR-based vegetation index

A normalized difference vegetation index (NDVI) has been produced and archived on a 1° latitude by 1° longitude grid between 55°S and 75°N. The many sources of data errors in the NDVI include cloud contamination, scan angle biases, changes in solar zenith angle, and sensor degradation. Week-to-week variability, primarily caused by cloud contamination and scan angle biases, can be minimized by temporally filtering the data. Orbital drift and sensor degradation introduces interannual variability into the dataset. These trends make the usefulness of a long-term climatology uncertain and limit the usefulness of the NDVI. Elimination of these problems should produce an index that can be used for climate monitoring.

Ecological monitoring of trawling grounds

The development of mechanized fishing in India is traced to point out the harmful effects of trawling by way of disturbing the ecological balance of the ecosystem, of which the fish stocks are a part. It may cause the disappearance of some demersal species from the catches as brought out poignantly in the case of a marine catfish namely, Arius tenuispinis. History of trawling has been the same all over the world showing that depletion of demersal fish stocks is not only due to excessive harvesting but also due to the damage done to the ecological balance of the trawling grounds. The need for ecological monitoring of the trawling grounds is pointed out.

Dynamic condition monitoring of buried gas pipes

This paper describes a device which can be used to detect variation in the integrity of the surrounding medium which supports buried gas pipes. The method is also applicable to other kinds of pipe. Variation in pipe support condition leads to increased likelihood of pipe damage under vehicle loading. A vibrating 'pig' has been developed and tested on buried pipelines in Britain and the measured data obtained is compared with theoretical models. Certain features, such as voids, hard spots and joints, display characteristic responses to vibration and a library of such characteristics has been constructed both experimentally and from the theoretical models.

Fibre optic distributed sensor system for condition monitoring of synthetic ropes

Reliability of the measuring devices is very important problem. Optical fibre sensors are very efficient. The use of optical fibre sensors for monitoring the physical and chemical parameters has been expanding over resent years. These sensors are applied for monitoring the structural integrity of long, parallel lay synthetic ropes. Such ropes are corrosion free, however, their operational lifetime under cyclic load is not well understood and premature failure can occur due to slippage and breakage of yarns within the rope. The monitoring system has been proposed which is based on acoustic detection of yarn breakage. Monitoring the strain and temperature is performed using the array of fibre gratings distributed along the rope length.