ANT XXV/5, Weekly Report No. 3
Launch of a radiosonde at night. During the ascend of the probe meteorological data are transmitted to the ship. (© T. Hanschmann, IFM-GEOMAR)
Punta Arenas – Las Palmas – Bremerhaven
11 April – 24 May 2009
“The main goal of the WGL Pact Project OCEANET is the construction of an autonomous measurement system to fully describe the cycle of energy and matter between ocean and atmosphere. WGL stands for Wissenschaftsgemeinschaft Gottfried Wilhelm Leibniz e.V. We in the working group ‘clouds and radiation’ of Andreas Macke from the meteorological research unit of the Leibniz Institute of Marine Sciences IFM-GEOMAR in Kiel, are, amongst others, responsible for the capture of the atmospheric state and incoming radiation at ground level.
To fulfil this task we installed a wide range of measuring equipment on board. Part of it is well tested and established, however there are devices that are newly developed or whose performance at sea is still to be experienced. In detail there are pyrano- and pyrgeometers, a full sky imager for the optical recording of the cloud cover and type, a microwave radiometer as well as a very rapid measuring device for the determination of turbulent fluctuations in the atmosphere above the ocean surface.
Beside this instrumentation on board, we regularly measure the concentration of suspended particles in the atmosphere (aerosol optical thickness) for the ‘Maritime Aerosol Network’ (MAN) in the scope of OCEANET. These particles are produced for example by fossil burning and amongst other things do have an effect on the formation of clouds. It is the aim of the ‘AeroNet’ to describe the global distribution of aerosols.
With the help of an underwater camera and the irradiance measuring device RAMSES we determine the light intensity and fluctuation in the first 40 metres of the ocean. By surface waves, which act like lenses, the sunrays are focused. This effect leads to highly increased light intensities in vertical and horizontal concentrated spots. A part of these measurements have to be carried out free from the shadow of the ship. We use the zodiac regularly as soon as weather conditions allow it. Last but not least we do measurements for the Institute of medical climatology in Kiel. The skin harming amount of UV radiation is recorded by a spectroscope every three minutes during daylight hours.
While the first days were dedicated to the building up and starting of the numerous devices, we are now busy with keeping the autonomous measurements running and with optimizing the protocol of the manual measurements.”
So far, the interim report of T Hanschmann, M Schlundt and Y Zoll.
In the scope of our routine work plan we determine the thermocline depth with the CTD probe down to 200 metres daily at 1 P.M. The works at the northern end of the Vema Channel (Extension) were finished on 26 April. This week we listen to presentations of our engaged meteorologists about their work on board every other day. A sequence of <Nice Pictures> that was started last Sunday (South America for travellers) will be continued at the end of the week. We look forward to a presentation of rare images from the new German Antarctic Station and from King George Island.
All clocks had to be advanced four times by one hour since we left Punta Arenas. After reaching 23° W on a northeasterly course we now sail exactly northward to the equator. His Majesty King NEPTUN announced already its appearance via TELEX.
With best wishes, also in the name of all on board
Walter Zenk
30 April 2009
Comparison of temperature and humidity profiles between the sea surface and the troposphere. Profiles ere derived by microwave radiometry (blue) and by a radiosonde ascent (red). (© Yann Zoll, IFM-GEOMAR)
