The research aircraft DO-128, call sign D-IBUF, of the IFF (TU Braunschweig) measures numerous meteorological and chemical variables to get a better understanding of the atmospheric processes which cause the development of precipitation. The aircraft starts from the Baden Airpark and flys among different flight pattern which are described in the flight protocols. The meteorological variables are static pressure and dynamic pressure at the nose boom, surface temperature, humidity mixing ratio by a lyman-alpha sensor, dewpoint temperature by a dewpoint-mirror, relative humidity by an aerodata-humicap, air temperature by a PT-100 sensor, vertical and horizontal wind components by a five-hole probe and GPS, turbulence (100 Hz), shortwave (pyranometer) and longwave (pyrgeometer) radiance in upper und lower half space. The chemical variables are mole fractions of ozone, carbon dioxide, carbon monoxide, nitrogen dioxide, nitrogen monoxide and nitric oxides (NOx). There are also a few variables for the position and the velocity of the aircraft stored in the data file. Additionally to the measurements by the aircraft, up to 30 drop-sondes can be dropped out of the aircraft. By using these sondes, vertical profiles of temperature, pressure, humidity and wind can be detected (see also the meta data describing the drop-sonde data). Special events are also marked in the data files by the event counter (e.g. dropping times of the drop-sondes, marks concerning the flight patterns etc.). The specific action or flight manoeuvre indicated by the event_number can be identified in the flight protocol.

The geographical distribution of the EARLINET stations is particularlysuitable for dust observation, with stations located all around the Mediterranean(from the Iberian Peninsula in the West to the Greece and Bulgaria and Romania in the East) and in the center of the Mediterranean (Italian stations) where dust intrusions are frequent, and with several stations in the central Europe where dust penetrates occasionally. A suitable observing methodology has been established within the network, based on Saharan dust alerts distributed to all EARLINET stations. The dust alert is based on the operational outputs (aerosol dust load) of the SDS-WAS (Sand and Dust Storm- Warning and Advisory System of WMO), and the Skiron models. The alerts are diffused 24 to 36 hours prior to the arrival of dust aerosols over the EARLINET sites. Runs of measurements longer than 3-hour observations, typical for the EARLINET climatological measurements are performed at the EARLINET stations in order to investigate the temporal evolution of the dust events. All aerosol backscatter and extinction profiles related to observations of Saharan dust layers are collected in the "Saharan dust" category of the EARLINET database.

The Sodar/RASS device installed at Fussbach consisted of a DSDPA.90/64-Sodar and a DSDR3x7-1290MHz-RASS extension by METEK GmbH. It operated with an averaging period of 10 min. The minimum measurement height was 40 m and the maximum measurement height 700 m with a step width of 20 m in between.

Dropsondes (mobile radiosondes) were launched by 5 mobile radiosonde teams. The launching sites were different from IOP to IOP. The positions are identical with the positions of the meteorological towers (imkmt1 to imkmt4). There have been no more than 4 teams operational on each IOP. The dropsondes are radiosonde-like systems. The maximum height is 12050 m above MSL. At this height, the sondes are separated from the balloon and then glide to the ground. Drop points are up to 70 kilometres apart from launching sites. For detailed information about the sites see supplement file and map.

The energy balance stations run by FZK/IMK-TRO measured high-frequency (20 Hz or 32 Hz) eddy-covariance raw data with either a Solent R1012 (Gill Instruments Ltd.) sonic anemometer or a Young 81000 (R. M. Young Company) sonic anemometer and a LI-7500 (LI-COR Biosciences) hygrometer above different target land use types. The measuring set-up was continuously running during the entire COPS measurement period in order to provide a complete time series of the turbulent fluxes of momentum, sensible and latent heat as well as carbon dioxide. Post-processing was performed using the software package TK2 (developed by the Department of Micrometeorology, University of Bayreuth) which produces quality assured turbulent flux data with an averaging interval of 30 min. The documentation and instruction manual of TK2 (see entry cops_nebt_ubt_info_1) and additional references about the applied flux corrections and post-field data quality control (see entry cops_nebt_ubt_info_2) as well as a document about the general handling of the flux data can be found in supplementary pdf-files within the energy balance and turbulence network (NEBT) experiment of the data base. The turbulent flux data in this data set are flagged according to their quality and checked for an impact of possible internal boundary layers. Additionally, the flux contribution from the target land use type intended to be observed to the total flux measured was calculated applying footprint modeling. Information and references about the internal boundary layer evaluation procedure and the footprint analysis are also given in the additional pdf-files. Pictures of the footprint climatology of the station as related to the land use and to the spatial distribution of the quality flags are included in the corresponding additional info pdf-files.

The field experiments ALKOR 2000 (consisting of three cruises: ALKOR 4/2000, 6/2000, 10/2000) and ALKOR 2001 (4/2001, 6/2001, 10/2001) took place in the central Baltic Sea. The six cruises of the German Research Vessel Alkor with duration of about seven days each led to a point of the Baltic Sea which is most remote from the adjacent lands and additionally a grid point of regional climate model REMO. The ALKOR experiments as well as BASIS 1998 and BASIS 2001 are part of the research compound BALTIMOS (BALTic sea Integrated MOdel System). BALTIMOS in turn is part of the Baltic Sea Experiment (BALTEX). The overall objective of all eight field experiments (ALKOR and BASIS) was to collect a comprehensive data set suited to validate the coupled model system BALTIMOS for the Baltic Sea region. The observations mainly focus on: - the atmospheric boundary layer structure and processes and the air-sea-ice interaction over areas with inhomogeneous sea ice cover - the atmospheric boundary layer structure over open water under different synoptic conditions such as cold-air advection, warm-air advection or frontal passages. In addition to the published datasets several other measurements were performed during the experiment. Corresonding datasets will be published in the near future and are available on request. Details about all used platforms and sensors and all performed measurements are listed in the fieldreport. The following datasets are available on request: ground data at RV Alkor

Surface layer scintillometer data derived from a Optical Energy Balance Measurement System OEBMS1 with a Scintillometer SLS20 system by Scintec AG at station UV1EG (Deckenpfronn). The system operated at a measurement height of 1.75 m and with a path length of 117 m over the target land use type meadow.

The positions of the meteorological towers (IMKMT1 to IMKMT4) are identical with the positions of the launching sites of the drop-up-sondes (IMKRS1 to IMKRS5). There have been no more than 4 teams operating on each IOP. For detailed information about the sites (including a map) and operating days see supplement pdf-file (cops_rsdu_imk_info_1). The parameters are: air_pressure: measured at about 1.8 m GND by a barometric pressure sensor that has a gill pressure port, 60s mean. air_temperature_at_1.8m: measured at about 1.8 m GND by a HYGROMER meteorology probe MP 400a, 60s mean. relative_humidity_at_1.8m: measured at about 1.8 m GND by a HYGROMER meteorology probe MP 400a, 60s mean. precipitation_amount: measured by a tipping bucket rain gauge (catchment area: 200 cm**2), 60s accumulated. wind_speed_at_4.5m, wind_from_direction_at_4.5m, virtual_temperature_at_4.5m: measured at about 4.5 m by a Young 3-D Sonic Anemometer, 60s mean.

The geographical distribution of the EARLINET stations is particularly suitable for dust observation, with stations located all around the Mediterranean (from the Iberian Peninsula in the West to the Greece and Bulgaria and Romania in the East) and in the center of the Mediterranean (Italian stations) where dust intrusions are frequent, and with several stations in the central Europe where dust penetrates occasionally. A suitable observing methodology has been established within the network, based on Saharan dust alerts distributed to all EARLINET stations. The dust alert is based on the operational outputs (aerosol dust load) of the DREAM (Dust REgional Atmospheric Model), and the Skiron models. The alerts are diffused 24 to 36 hours prior to the arrival of dust aerosols over the EARLINET sites. Runs of measurements longer than 3-hour observations, typical for the EARLINET climatological measurements are performed at the EARLINET stations in order to investigate the temporal evolution of the dust events. All aerosol backscatter and extinction profiles related to observations of Saharan dust layers are collected in the "Saharan dust" category of the EARLINET database.

Since the beginning of CALIPSO observations in June 2006 EARLINET has performed correlative measurements during nearby overpasses of the satellite at individual stations following a dedicated observational strategy. The EARLINET-CALIPSO correlative measurement plan considers the criteria established in the CALIPSO validation plan (http://calipsovalidation.hamptonu.edu). Participating EARLINET stations perform measurements, as close in time as possible and for a period of at least 30 min up to several hours, when CALIPSO overpasses their location within a horizontal radius of 100 km. Within the 16-day observational cycle of CALIPSO each station is overpassed within this distance 1-2 times during daytime (typically between 1100 and 1400 UTC) and 1-2 times during night time (typically between 0000 and 0300 UTC). Additional measurements are performed, mainly on a non-regular basis, when CALIPSO overpasses a neighboring station in order to study the horizontal variability of the aerosol distribution. The time schedule for correlative observations is calculated starting from the high-resolution ground-track data provided by NASA, and is updated and distributed to whole network weekly. The EARLINET-CALIPSO correlative dataset represents a statistically significant data set to be used for the validation and full exploitation of the CALIPSO mission, for studying the representativeness of cross sections along an orbit against network observations on a continental scale, and for supporting the continuous, harmonized observation of aerosol and clouds with remote-sensing techniques from space over long time periods.