November 17, 1999

First Detailed Survey of the Wisconsin LTER Sites

Between 9 and 12 November, 1999, I traveled to Wisconsin, taking Mike Willett our Senior Technical Assistant, to accomplish three things.

First to become familiar with the Researchers, staff, facilities, and research activities at the Center for Limnology, University of Wisconsin - Madison, which supports the North Temperate Lakes LTER at its two locations - Lake Mendota Lab and Trout Lake Station. (

Secondly to make the first inquiry into what research we might be able to support, wirelessly, at Mendota Lake.

Thirdly, we needed to do the Site survey of the principle lakes being studied from the Trout Lake Station, 200 miles north of Madison, and determine the first work to be done installing radios to connect their data logger instruments back to the servers and thence to the Internet at the Station.

Center for Limnology

We got a good tour of the Center by Dave Harring - its labs, boats, and ability to fabricate tools necessary to support the research on several close-by lakes, the main one being Mendota Lake that is quite large, fronting Madison, Wisconsin, the University, and on which the Center sits, with the boat dock inside the Center. So this site is right on the water itself.

The attached map shows part of Madison, the location of the University and Center for Limnology with respect to Mendota Lake: click here for Mendota Lake LTER Map

We first met with Paul Hanson, graduate student and chief Center administrator for for the Limnology Center, and several of his associates and assistants.

A major project that Paul Hanson is heading up, which was enabled by the most recent NSF grant, involves adapting a large ($100,000) floating platform - a buoy - with solar panels providing power to devices on the float, one major one of which will be a Carbon Dioxide measuring system that has to deal with a column of water below. Stimulated by discussions and a conference call I had on my first visit to Wisconsin last March, already (early November), Hanson has purchased and tested a pair of Aironet Spread Spectrum radios. In fact, he notes, that when he put up the base radio at he Center, and crossed the lake with the other radio, the link worked flawlessly all the way, 5 miles, across the lake. The only time it did not was when their boat went behind something that would block line of sight back to the Center and its radio. This, of course, is to be expected, for the Aironet radio family operates at 2.4 to 2.483 Ghz of frequency, with only 100 milliwatts of power.

So, together with a graduate student who is a computer science major, Hanson hopes to use the radio link to connect up the devices on the buoy back to the center, to afford real-time data collection. They will attempt to interface an Aironet PCMCIA card (PCMCIA 4800 model) to a special device, rather than mount a complete laptop on the raft. This will conserve power. But it will require a pretty technical fabrication of such an interface.

Thus, already, the Center is plunging into wireless, and other than offer them advice, we do not need to be much involved with this project unless they need our expertise.

An Interesting Challenge

We met the new Director of the LTER, Steve Carpenter, who is taking over those responsibilities from John Magnuson, who will be retiring. Dr. Carpenter described a problem which grabbed my attention, for I thought there could be a way to solve it with a novel use of wireless.

The LTER project has some sort of arrangement that provides for satellite mapping photography to be produced every two weeks - as the satellite passes overhead and looks down on Madison and the four close-in lakes. The photographic maps are, of course, color coded to represent a range of conditions - such as temperature - at the moment the satellite passes over.

A problem is, however, how to 'calibrate' the satellite imagery so that its colors and overlays perfectly match the corresponding condition on the lakes. The way this is done now is very labor intensive, according to Dr. E Carpenter. When they desire to get accurate, calibrated maps from the passover, they deploy up to 60 people in up to 15 teams in boats to reach all portions of the lakes over just a few total hours time, to fetch samples from the water, which are then taken back to the lab to be analyzed, and then the results of all the 'points' fed into the mapped imagery data, in order to 'calibrate' the image code to the actual conditions at that time. Thus producing maps, in which the concentration of chlorophyll, for example, is represented accurately on the map, from the sampling at many points taken over a very short period of time.

It immediately occurred to me that it should be possible, and economically enough to consider, to deploy the same number of chlorophyll (or multiple-function) sensors that are lightly anchored to the bottom of the somewhat shallow lakes, that are equipped with very small, minimum-data communicating, devices, perhaps even interfaced, battery powered pager-like devices, which can send data on command to pager satellites which cover most of the US. The amount of data may be, as frequently is the case for current data loggers used by biological scientists, very small - just bursts of number sequences. Thus pager technology might be able to handle the rate.

Then, having deployed the floats, pager-data devices, sensors, anchors and connecting lines, at the time the imagerying satellite passed over the pager-data devices could be commanded to communicate their readings at one point in time. Thus permitting calibration of the images.

The floats could be put out by one or two boat crews in the days proceeding the Passover schedule of the imagery satellites.

The questions, of course, would be, are there economical enough sensors to permit deployments of large enough numbers. Paging devices certainly are.

What would it take to interface the sensors to the pagers, and protect them in the water.

An alternative, if multiple 'chlorophyll' sensors, for example, are too costly, the linking of the pagers to an 'open and close on command' water sample containers might work. Where the satellite delivered command would tell the sensors to open the container, then close it, and await manual retrieval.

Much to think about.

LTER Science Meeting

One of the reasons we visited Madison, was to attend a meeting of LTER researchers gathering to discuss some longer term research strategies. In particular about a set of NSF initiatives that can be called the 'Era of Scientific Observatories.' We also were asked to make a brief presentation ourselves to acquaint the researchers and Limnology Center staff with this NSF 'Biology by Wireless' project and why were there in Wisconsin.

The hour and a half meeting covered several subjects. First was a presentation by Dr. Frost, recently assigned to the NSF in Washington, on the concept of Science Observatories - by which is meant not a singular astronomy-like observatory, but a complex of observation sites, which may be substantially funded by the NSF, with specific, one-observatory-a-budget-year, approval by Congress.

Then Dr. Triplett explained his Microbial Observatory plan, with a focus on biological organisms.

The buoy Project was laid out by Paul Hanson.

I presented the details on this Wireless Project, and how it came to be, and what we expected to accomplish.

Dr. Tim Kratz, of the Trout Lake site then took the floor and explained activities going on at the Trout Lake site called NEON. This melded into the general discussion about large science issues and questions which will have to be crystallized before thinking about applying for a competitive Observatory grant. The topics also covered the places that might be included in such a set of studies, the kinds of instruments needed, and the intellectual centers and people the LTER would want to partner with.

Then Mike Willett and I left for the 4 hour drive (faster than making air connections) to Trout Lake, northwest of Rhinlander, Wisconsin, and the middle of the lake region of Northern Wisconsin.

That part of the trip is discussed in the next Progress Report.


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