Embracing the Unpredictable

By Kelly Schick

Winter in Antarctica isn’t always auroras and penguins – the chance for high winds, snow and rapidly changing conditions is a real factor that affects our day to day life on the ship. A fair portion of the science during PIPERS is weather condition limited. CTD casts and anything involving a crane, like a zodiac deployments, have wind speed cutoffs to ensure safety of equipment and crew. On ice operations require good visibility in addition to reasonable wind speeds. To complete the desired science, the PIPERS team needs to have a good idea of what weather will be happening and where there might be conditions more conducive to science.

 

Most sea faring vessels receive a once daily weather condition update that gives estimates of conditions for the next twenty-four to thirty-six hours in the vessels intended operational region. The source of these forecasts varies depending on where the ship is. The Palmer presently receives hers as a SPAWAR report from the forecasting team in McMurdo. The challenge in forecasting for the Palmer is that the vessel is constantly changing position to achieve the scientific goals of PIPERS, and the weather can change dramatically over short distances in space and time. Add in the fact that one of PIPERS goals is study ice production as a result of katabatic wind events (where pools of cool air rush down from higher to lower elevation creating an intense and localized jet) and the weather situation on board the Palmer becomes more intricate.

 

Dramatic wind speed changes during the peak of a katabatic event as illustrated by the ship’s on board measurement system. PC: Bettina Sohst.

Dramatic wind speed changes during the peak of a katabatic event as illustrated by the ship’s on board measurement system. PC: Bettina Sohst.

 

 

Enter the PIPERS forecasting team – John Cassano, based in Boulder at the University of Colorado, and myself, Kelly Schick, also of University of Colorado but presently based on the vessel. We’ve worked out a system where John will email in his review of the latest AMPS (Antarctic Mesoscale Prediction System) model run so that his forecast typically arrives before we begin day shift operations. I’m up early in the morning to assess current conditions and prepare a weather briefing to the bridge. Of course, during PIPERS there are operations ongoing twenty-four hours a day. That means that in addition to an update at the nightly science planning meeting I’ll prepare a second briefing for the science groups and the bridge.

 

While we were in Terra Nova Bay, I would pull down automatic weather station (AWS) data from a network supported by the University of Wisconsin. This enabled us to have a better idea of the timing of katabatic wind events and help communicate their strength to the science team and crew. While I wasn’t brought on board to be “the weather girl”, it’s a role that has become part of my daily routine – and an enjoyable one at that. Through my interactions with the bridge crew I’ve had the opportunity to learn about ship operations, ice characteristics and past experiences in the region while also having some funny moments to lighten up the mood.

 

Weather in Antarctic is a large branch of an incredibly dynamic system. While the forecast models we use (primarily AMPS – the Antarctic Mesoscale Prediction System) do an incredible job, there are processes that can’t be resolved in the model due to their small spatial scale. Our experience in the katabatic winds drove home the importance of being aware of the weather as well as emphasizing how quickly conditions can change.

 

The ship has her own set of meteorological information that streams constantly on the screens in the main lab that allows the changes to be quantified and recorded on a local scale. Due the remoteness of the region we are studying, meteorological data is scarce. In the States, there are multiple radiosonde (weather balloon) launches performed nationwide two or more times per day, along with extensive automatic weather station networks even in relatively remote areas to provide continuous data for live information on conditions and to use for initialization in forecasting models. While there are a few automatic weather stations in Antarctica they tend to be clustered in coastal regions near the main bases. We are very fortunate to have the AMPS models to place our observations in context and hope to understand how weather conditions will develop. The added challenge of piecing together bits of data, different interpretations and watching the science happen in real time makes it more of an adventure.

 

1 comment for “Embracing the Unpredictable

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