Sunday, June 19, 2011

Fieldwork Preparations

Fieldwork at Quelccaya is most efficiently done during the dry season, now well underway. Predominantly clear skies result in low temperatures at night and abundant solar radiation during the day. This year we will visit the glacier in early July to recover meteorological measurements, service the instruments, spend time in snowpits measuring density and temperature profiles, and investigate changes in glacier thickness and marginal position.

Preparing for fieldwork in such a remote location is rather painstaking, to insure that the work goes smoothly on site. That requires attention to nitty-gritty details; there are no hardware stores anywhere near Quelccaya, and time spent modifying anything is essentially wasted. This image illustrates just some of the components required for increasing the weather station tower height. Gathering them together is bad enough, but that isn't the whole story. Some parts, such as those on the right, must be custom made on a metal lathe in the UMass Geosciences machine shop. Ace machinist John Sweeney produces these with precision suitable for a NASA mission. Even standard structural fittings (e.g., crosses at top of image) are inspected closely and molding burrs are filed off to prevent problems during assembly. They are then washed with detergent to help keep smudges off equipment such as radiometer domes.

Countless other tasks also require attention. An unexpected aspect of the forthcoming trip will be changing the GOES satellite transmitter, as telemetry suddenly ceased with the 4:46 am transmission on 24 May. Detective work at the Climate Center in conjunction with Doug Neff at Campbell Scientific suggests likely failure of the existing transmitter's GPS time-keeping function. Accompanying the new transmitter on this trip will be an assortment of other parts, some for regular replacement or recalibration and others just in case they are needed. Deciding exactly what to bring is always tricky, requiring a balance between the probability of their being needing against their weight and cost.

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