Photo of a probe at base camp.
The purpose of the MIT weather probes for the Mt. Everest expeditions is to monitor weather conditions on the mountain year-round. For the 1998 Everest Expedition, weather data included: Temperature, barometric pressure, and light level (to determine the sun radiation and sun position). Climate information meets the immediate needs of the climbers planning their ascent. However, the weather information has a long-term benefit to geologists and to those who analyze the climate/rainfall conditions which is crucially important to the living of the local people. Since Mt. Everest is only humanly accessible for only a few weeks per year, very little is known about the yearly weather on Mt. Everest. To the best of our knowledge, our probes are the first on-site instruments to have collected continuous long-term weather data on the mountain. The weather data from our probes is relayed via satellite to an ARGOS service ground station, which then forwards the data via e-mail to the MIT Media Lab. At MIT, the incoming e-mail is automatically received and parsed by a software script which automatically posts it onto the web site for the project.
After the 1998 Everest Expedition, 2 of the probes were left on Mt. Everest. One probe is at the South Col (altitude 27,000 ft) and the other probe is at a local Sherpa village lower on the mountain (<16,000 ft). Data from the probes was recieved daily until the batteries ran out in late August 1998. This data can be viewed here.
Each probe is made to be mounted on a pole, both on the summit and at South Col (alt. 27,000 ft). Data from the weather probes is collected approximately once every 2 hours by an ARGOS receiver mounted on one of 3 polar-orbiting NOAA satellites. During each satellite pass, 4-6 32-byte packets of data are uploaded to the satellite by each probe. The probes are programmed to transmit in a pseudo-random sequence so as to minimize data collisions during transmit.
The 4 sleepless members of the weather team (left to right): Jessey Darley, Matt Reynolds, Rehmi Post, and Rich Fletcher. Jessey looked the freshest, despite having run the Boston Marathon in 2hr29min the day before.
Most of the team are members of the Physics and Media Group at the MIT Media Lab, directed by Prof. Neil Gershenfeld.
The Everest weather probes, along with the custom controller board, were designed and built over a period of 6 weeks, so time was definitely a serious constraint. Since we did not choose to incorporate solar power on this version of the probes, battery life was critical. (note: solar panels are a commodity in Nepal; the solar panel for a previous weather probe left on the mountain last year was stolen). Matt Reynolds was successful in designing a custom controller board which consumes <2uA @ 5V in it's quiescent state. We hope that the batteries will last at least a couple months. Also being tested on this expedition is an Everest WebCam, designed by Rehmi Post. The camera board captures one gray-scale picture per day, compresses it, and sends little bits of image to the controller board to be relayed back to MIT over the course of many satellite passes. The wind speed sensor on each probe designed by Rich Fletcher is basically a low-power microphone, which is pulsed ON periodically for 10 ms to sample the sound pressure due to the wind. There are many improvements we would like to make to the probes, including better calibrations; however, given the amount of time we had to work on it (which we did aside from our regular lab research and schoolwork), we are pretty happy with it. We hope that we will have other opportunities to build better systems for future expeditions.