Real–Time Monitoring and Reporting
Real–Time Monitoring and Reporting
Real-time is a phrase that refers to the ability to respond to something so quickly that the response takes place almost as the event is occurring. In environmental science, computer programs and devices can sample environments and produce results in real-time.
This environmental monitoring can be qualitative in nature, such as detecting the presence or absence of a specific substance—or can be quantitative in nature, as in measuring the amount of a specific substance that is present. In real-time monitoring, the information gained can be relayed to its final destination in near real-time by telephone, a signal beamed to a satellite, or over the Internet.
This technology allows developing and potentially dangerous weather systems to be detected and monitored over time, and also allows scientists to monitor environments that are difficult or too dangerous for humans to reach (such as the air above a volcano or its eruption cloud). Moreover, the devices can operate independently and with no maintenance for weeks, months, and, in some cases, decades.
Real-time monitoring and reporting can be done by manually positioning probes in the environment being sampled or by sensors mounted on orbiting satellites. As well, robotic probes and instruments can be positioned in the environment to automatically sample and relay information for analysis. This has allowed, for example, the positioning of instruments on the sea floor to monitor various aspects of the ocean environment over time.
Historical Background and Scientific Foundations
Real-time reporting of environmental conditions dates back to the invention of the telegraph in the 1830s. Until then, weather reports and forecasts could only be transmitted manually, usually involving a train journey from one location to another. Use of the telegraph enabled weather reports and warnings to be sent almost instantaneously to the same locations.
Many real-time measurements are made using sensors. The first such sensor that was developed was the pH meter, a device that measures the quality of hydrogen ions in the solution being tested. It was constructed in 1934.
The principle of a pH meter is similar to that of sensors that measure other chemicals. A pH meter measures the electrical potential between a chamber that is separated from the external environment by a membrane (originally the membrane was glass). This measurement requires comparison with a reference chamber; pH meters now can incorporate the measurement and reference electrodes in to the same probe. As well, pH meters can now obtain measurements from very small volumes of liquid; indeed, measurement of pH from damp leather or concrete is possible.
The difference between internal and external environments are utilized by other sensors to detect and quantify parameters that include dissolved oxygen, temperature, and ions such as ammonium, bromide, calcium, chloride, and fluoride. Modern probes used for environmental monitoring are rugged and hard to break, and do not require frequent checking to make sure the measurement accuracy is acceptable. This allows the probes to be positioned in environments that are not easily accessible where they can be left for a long time.
As an example of the potential of real-time monitoring and reporting, in 2005 the University of Victoria in Canada positioned instrumentation packages on the seafloor in the Pacific Ocean. The VENUS (Victoria Experimental Network Under the Sea) initiative linked the instrument via fiber optic cable to create an undersea grid of monitoring stations. Each station is connected to the Internet and the data that are regularly updated on the web site are publicly accessible. Data on temperature, salinity, turbidity, dissolved gas concentration, current speed and direction; sounds; and both still and video images are collected and sent in real-time to labs, classrooms, science centers, and homes around the world. Another array will be deployed in 2008 or 2009.
Impacts and Issues
Real-time monitoring of the environment allows for measurements over weeks and months of river flow, air and water temperature, ocean chemistry and biology, wind speed and direction, and many other parameters. These individual measurements can be combined in a single probe, and can be simultaneously displayed as different windows in various software programs that have been developed. This allows for a more precise monitoring of environmental conditions and the linking of different environmental aspects (wind speed and temperature, for example) than used to be possible.
One result is that trends in weather are more evident. For example, meteorologists can track a weather system to see if it has the potential to develop into something more extreme and hazardous such as a tornado. If so, warnings can be issued.
The ability to send and receive real-time information using mobile devices such as cell phones and personal digital assistants has expanded the ability to monitor environmental conditions. Similarly, refinements in fiber optic technology now allow multiple measurement devices to be packaged in a fiber optic cable that can be deployed with unmanned robotic probes that are teth-
WORDS TO KNOW
MODEM: A device that permits information form a computer to be transmitted over a telephone line or cable.
pH: The measure of the amount of dissolved hydrogen ions in solution.
SENSOR: A device to detect or measure a parameter as it is occurring.
SOFTWARE: Computer programs or data.
ered to ocean-going research vessels. Such probes are being readied to explore the deepest regions of the ocean.
Wang, Zhendi, and Scott Stout. Oil Spill Environmental Forensics: Fingerprinting and Source Identification. New York: Academic, 2006.
University of Victoria. “VENUS: Victoria Experimental Network Under the Sea.” April 8, 2008. http://www.venus.uvic.ca/ (accessed April 15, 2008).