Overview

Four weather probes accompanying the '98 Mt. Everest expedition were made to monitor weather conditions on the mountain year-round. Climate information is for the climbers' benefit as well as for the benefit of geologists and those who analyze the climate/rainfall conditions that are important for 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 instruments to collect long-term weather data on the mountain. The weather data is relayed via satellite to an ARGOS ground station, which then forwards the data via e-mail to the MIT Media Lab, where it is then processed by a script which parses the data and posts it on the web site.

Some technical specifications of each probe

• dimensions = 5 in diameter, 15 inches long
• weight = 2.4 kg (~5.3 lbs) (mostly batteries)
• temperature sensor, +/- .5 degree C
• pressure sensor +/- 1KPa
• light level (0-255, 0=dark, 255=bright)
• rough wind speed (0-255, 0= no wind, 255= over 200 MPH)
• power: 8 D-cell Lithium Sulfer-Dioxide batteries, optimized for low-temperature operation
• transmitter: Toyocom, ARGOS transmitter, .5W
• photo of controller board
• photo of transmitter side of board
• photo of experimental satellite web cam

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 Weather Team

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.

Team Functions:

• Rich Fletcher -- project management, satellite com, wind speed
• Matt Reynolds -- custom electronics, rf wizardry
• Rehmi Post -- coding, camera electronics
• Jessey Darley -- mechanical design, construction
• Brad Geilfuss, Mathew Gray -- Web scripting

Most of the team are members of the Physics and Media Group at the MIT Media Lab, directed by Prof. Neil Gershenfeld.

Comments on the current generation of weather probes

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.

Special Thanks To:

• Gerry Williams, Clearwater Instrumentation, Watertown, MA --support for the satellite transmitters
• Dave Mencin -- climber and MIT grad student, Earth and Planetary Sciences Dept -- field deployment of probes;