20 Jan

Hurrah! Today is January 20th. Happy Pre-EUREC4A 2019!

In 12 months — now we start counting in months, soon days — we will be suffering our way through the Northern Hemisphere winter by watching waves and clouds come lap the shores of Barbados … we hope those of you joining us in the field will be able to put up with the harsh winter conditions (see attached snapshot, the top panel is the radar and has a very unusual absence of clouds, it seems even the weather is waiting) … and sustain them for a month, bringing life to an experiment that many of us have been cooking for several years now, and dreaming about even longer.

So with that brief reflection on the meteorology, today’s email is more a status report to get everyone up to speed on where we stand with EUREC4A and what we have taken to calling the EUREC4A family of experiments. Hopefully future posts won’t be so long, but we were excited. So here is where we stand:

French and German aircraft are getting equipped, and certified, for the observation of clouds and of their environment:

HALO is acquiring a new dropsondes system (allowing us to get up to 8 dropsondes in air at the same time), a new radiometer to measure SST a thermal imager, and updates to its radars, 22 channels of microwave radiometery, and visible imagers — more on the latter in a separate post by Bernhard Mayer in a couple of weeks.

The ATR-42 is getting a new window that will allow for sidewise-looking lidar and radar measurements, Julien Delanoë is (as best we know) in his garage at this very moment working on one radar (RASTA) to make it even more sensitive, and with his free hand assembling another one (mini-BASTA); these two Doppler radars, as well as the Alias backscatter lidar, are being optimized to observe the shallow cumuli as well as possible. In parallel, broadband radiometers and instruments for in-situ measurements of water vapor, temperature, high-frequency winds (gust-probe), particle (cloud aerosol) counters and water stable isotopes are being prepared by the team at SAFIRE.

There is also the hope of also brining a very special autonomous airborne system also developed by SAFIRE… we are starting to fund-rase for this now.

The Barbados Cloud Observatory continues to be improved:

We have a new W-band lidar, and a group of engineers is on the island at the moment putting the final touches on a new Raman lidar system. The Raman system has considerably more power, might well be the coolest such lidar in the world, and is designed to help us look at water vapor on the edge of a cloud. The W-band lidar allows us to look up at clouds with now three doppler instruments (lidar, K-band and W-Band) and will be joined (hopefully) later this year by a big beautiful beauty of a C-Band radar called Poldirad, who will survey the seas. Another group, including Sabrina Schnitt a PhD student with Susanne Crewell in Bonn, will join them in a couple of weeks, for some sonde launches and investigations of water profiling capabilities.

Two German Research Vessels have been secured:

The participation of two German ships — each for a month — is now confirmed. One of them (the famous Meteor) is nominally focused on complementing atmospheric observations within the area of aircraft operations and performing some oceanographic measurement; the other one (the Maria S. Merian) will focus more of air-sea coupling and the characterization of the ocean mesoscale and sub-mesoscale and its possible importance for air-sea interaction. This in someways is the most rapidly growing part of the experiment and adds a very new dimension. Another novelty of the ships is the idea of using them to tether massive Kite-stabelized Helium Balloons and thus provide a whole new way of probing clouds and the underlying boundary layer (check out the image attached, and cross your fingers for a forthcoming post with more details from the Bondenschatz team in Göttingen)

Colleagues in France, the UK and the US are eagerly waiting for the result of their request for additional ship and/or an aircraft to join EUREC4A. Over the last year, the oceanographic community has developed great plans to use EUREC4A as an opportunity to develop an observational component aiming at elucidating the role of the mesoscale and sub-mesoscale (e.g. eddies and filaments) in air-sea interactions. Reports from a recent workshop are posted here:


This component is named EUREC4A-OA in Europe and ATOMIC in the US. A meeting to discuss the coordination of this, beginning with a refinement of plans for the German ships, is being organized by Stefan Kinne next month in Hamburg. Look on the EURECA web page here:


for more up-to-date info on forthcoming meetings. (Yes we are working on the website and the logo needs some ships, so comments and suggestions are welcome on this work in progress…. or for a cooler logo look also below)

Colleagues in Switzerland (Aemisegger), in Norway (Sodeman), in the US (Galewsky), and in France (just about everyone, many with yellow vests) are making plans to measure the isotopic composition of water in the boundary layer (aircraft measurements) and near the surface (ground-based and ship-based measurements), to help decipher the transit and exchanges of water between the ocean and the atmosphere..an initiative named EUREC4A-iso. In addition to the growing interest of the EUREC4A communities in issues related to the mesoscale organization of the atmosphere and of the ocean, and the way one might influence the other. A classification of the mesoscale organization of cloud patterns (categorized as 'fish', 'gravel', 'sugar' or 'flowers') is developing, you might remember some discussion of this from Pre-EUREC4A-2018. In this vein, a group of us visualized over nearly 40,000 images late last year and this is forming the basis for machine learning approaches. We hope that it will help us name the diversity of organizations that we will find next year off-shore of Barbados, and characterize the organizational context of our measurements. Modelling initiatives are also developing in the context of EUREC4A. Global storm resolving models, as well as large domain LES, and maybe even some DNS (Juan Pedro Mellado are you listening) models and climate models will be run over the area and time of the field experiment, some of them coupled to an interactive ocean with a commensurate representation of scales (Johnathan Gula, Peter Sullivan and others are hopefully sharpening their knives) Finally, and as mentioned in the pre-Pre-EUREC4A email; we intend to use this new (and last) Pre-EUREC4A season to be an opportunity to present these different initiatives (and much more!), and exchange about the scientific questions that we would like to address next year. So if you wish to reserve a day for a post, please let one of us know.

So, Happy Pre-EUREC4A 2019!

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