Time is money: The value of opportunistic sampling

NOTE: This article is a reposting on one originally posted on the UNOLS Chief Scientist Workshop website (here) with slight modifications. Aboard the R/V Sikuliaq we often run around-the-clock operations and do our best to collect every last bit of data. Not only is our time limited, but ship time is valuable—really valuable. Even if you did manage to make the absolute most of the available ship time, there are inevitably gaps when the vessel is transiting from station to station, the equipment requires attention, or the weather limits safe science operations. This is where instruments that sample continuously come...

Learning to Drive the Boat: the Start of Chief Sci Training

For those of you who are unfamiliar with the terminology used for scientific, research cruises; a chief scientists is the de facto boss of the science party and coordinates the research plan with the captain and crew of the ship. This role often incorporates traits from other positions such as diplomate (between crew and science party), translater, and decision maker into one thankless role. Since this position requires skills outside of those which are traditionally taught in graduate programs, the National Science Foundation has sponsored a program to train young and advancing scientists. This Chief Scientists Training Cruise (CSW) involves seminars...

The benefits of interdisciplinarity: residence time

The so-called residence time of a system is both an immensely useful and highly intuitive conception which provides a relevant timescale for processes. For example, the residence time of nutrients flowing into a pond would be the average ‘lifetime’ of the nutrients before being taking up by the pond creatures. If it is a small number, then the nutrients are taken up very quickly compared to if is a large number. Here is the “traditional” formula for calculating residency time of a conservative tracer:     The more mass that’s in the system the longer the residence time becomes; and...

Call me Ishmael: Seahab

Living on a ship for three weeks means that you pick up a few tidbits of knowledge such as the difference between tieing a bend and a hitch, but a term that is rather unique to sailing on National Science Foundation (NSF) vessels is Seahab. All research vessels control the supply of alcohol on board, and thus the intake of alcohol while at sea (personal caches are not permitted). Many ships will serve a beer with dinner or provide a coupon for a drink at some other time. NSF has taken the extra step of making all of their vessels...

Call me Ishmael: Professional Insomnia

All professionals accept that there will be occasions when work gets in the way of sleep and that odd hours me be required to get the job done. Generally this interruption in sleep is temporary and isolated to project deadlines or mission critical tasks, but for scientists aboard research vessels this may be a de facto state. Now I must preface this discussion with the fact that every cruise is different, and the majority of such cruises have set, regular schedules–such as 12 on/12 off—which permit a normal sleep schedule. What I’ll be describing here is my own schedule during...

Daily Dose: Radiation Trouble

Update: See update section following the article for the latest. I recently described in general terms a new method that I’m developing which uses Yttrium to estimate the carbon export from the ocean’s photic zone, so today I saw it fitting to rant about an issue I’m currently facing. Assuming that you have either read that previous article or are familiar with the Thorium Disequilibrium method, then it should be no surprise that the “signal” for which we are attempting to measure from the radionuclide is the decay of the Y-90 into Zirconium. This decay, which results in the emission...

Quantifying Error

Being able to appropriately address uncertainty and error is fundamental to the pursuit of science. Without it, results and theory would never match up since theory usually involves a level of abstraction that permits simplification of the problem and observational results are never perfect and include all sorts of uncertainty. Recently I’ve been trying to quantify and approximate the error terms for the data that powers my model. (more…)

Spurious diapycnal mixing in z coordinate models

Introduction Diapycnal mixing is a natural process whereby water parcels of different temperature and/or salinity get mixed.  This process, as opposed to advection, is non-adiabatic (non-reversible) and is governed by diffusive mechanisms. The rate of diapycnal mixing is elevated in coastal waters relative to the open ocean and is responsible for the introduction of nutrients to plankton-containing waters at upwelling zones and within the mixed layer (nutricline/thermocline co-location). Resolution and management of diapycnal mixing was a major issue in all of the early global ocean models. Early work by Bryan (1987) as well as more recent research has found that...

End of the Semester

Believe it or not, but it is already the end of the semester for me and my peers. Somehow nearly four months have disappeared once again into that historical accident that we call the past. Since each of my three classes have required a project to be done for the final, I figure that I may as well adapt each of them here so I can share them with others. For the first entry, here is my Marine Primary Productivity final which includes aspects of both the presentation as well as the paper. (more…)

Remote Sensing Part 2

In a previous article I described a technique to determine the dye concentration from drone images, and I hope it sounded like a reasonable plan. Nevertheless, this plan did go ary when less than ideal conditions arose and the results got jumbled with the imperfections of the real world. So to make amends, I will layout a new pipeline that–with any luck–will work better in practice than the previous one. (more…)

Philosophy Monday: Einstein v Newton

The source for the tension between Newton’s view of the universe and of Einstein’s stems from each person’s respective choice of axioms. Newton choose to take the most concrete axioms for his mechanics: absolute nature of space and time. These intuitive assumptions mark and define the whole of Newtonian mechanics since all the other definitions and derivations are rooted in this foundation. Einstein decided to take a slightly divergent set of axioms (more…)