Notes from the Field

NAAMES-II Expedition: May 12, 2016

May 12th, 2016 by Kristina Mojica

The R/V Atlantis doesn’t sail, as much as it moves the water out of its way. The waters so far have been calm, and progress is steady. We are still relatively close to land, as evident from a couple stowaways we picked up this morning, such as a summer tanager and 3 grey catbirds! Hopefully, these birds leave before we get too far out or they might be joining us the entire trip. I doubt Greenland is very hospitable this time of the year. Or any time of the year for these fellas and it would be a long trip home.

A stowaway summer tanager onboard the RV Atlantis. Photo: Susanne Mender

A stowaway summer tanager onboard the RV Atlantis. Photo: Susanne Mender


The scientists have largely gathered their sea legs and have already begun to work. This is relatively easy given the current calm weather conditions and clear skies. One part of the NAAMES project is understanding how particles in the air (aerosols) relate to cloud formation. Marine aerosols consist of a complex mixture of sea salt, non-sea-salt sulfate, and organic species formed through a variety of production pathways. The relative contribution of each aerosol type changes across the particle size distribution and exhibits a strong seasonal association with ocean biological activity. By sampling marine aerosols and associated particle size distributions during the several phases of the bloom we hope to get a better understanding of how changes in the burden and properties of atmospheric aerosols alter Earth’s radiation balance, and hence affect climate.
Calm seas and blue skies as we continue our transit to the NAAMES stations in the North Atlantic. Photo: Kristina Mojica

Calm seas and blue skies as we continue our transit to the NAAMES stations in the North Atlantic. Photo: Kristina Mojica


Generally, there is some background concentration of particles in the air at any given time, even on clear days like today. You breathe them in, you breathe them out, and you are not even aware of it. Most of these particles are too small to been seen with the naked eye, these are in the size range of ten to a few hundred nanometers. Visible light is about 400-700 nm, which means that these particles are smaller than a wavelength of visible light, and therefore your eye can’t discern them. They exist in a suspended state for two reasons, first is because they are so small and small particles fall slowly, and the atmosphere has many updrafts available to keep them from reaching the ground, and second is they are too large to move over great distances through diffusion like air molecules such as oxygen. This makes them ripe for cloud making.

If you could ask only one question about the water drops in a cloud, you would ask “How many?” Solar absorption, chemical processing, and even a little precipitation can be gleaned from this question. If you could ask two questions about water droplets in clouds, you would next ask, “What size?” Knowing both number and size reveals significant information about cloud lifetimes, and dynamic processes like rain formation. This is information we can obtain from using radar and lidar technologies.

Our group focuses on the third question, “What are they made of?” The chemical composition of particles near the earth surface can provide information about how many particles will form into cloud droplets, and ultimately how many will be returned by rain. Our instrument exposes particles to water vapor concentrations typically found in clouds, and can count directly the number of aerosol that have cloud forming potential. Obviously, we cannot walk the instrument out to the middle of the Atlantic Ocean, hence the expedition.

Sea life is a lot like lab life, except now the lab moves a little, and there is potential for hurricanes and icebergs. I am consistently surprised by the lack of complaining from the group. Measurements at 04:00 don’t seem to bother anybody because these are THEIR projects. They specifically wanted to do this, and here we are. I still stumble into walls from time to time, but the food is good and so are the people. In life, what more can you ask for?

Written by Joseph Niehaus

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