Ligurian Sea

Temperature of the water column; Skin temperature of the water column; Solar Radiation; Visible waveband radiance and irradiance measurements in the atmosphere

Meteorological packages

Radiation budget data were collected during two hydrographic cruises in the Ligurian Sea during two different periods of year. Measurements were made from the CNR oceanographic vessel Minerva. The measurements were carried out continuously when the ship was either under way or when she was at a hydrographic station or anchored for shelter in the lee of small islands. The only rejected data were those collected in the ports. The R/V Minerva was equipped to measure the incoming irradiance (shortwave and long-wave) continuously and the sea surface temperature. Shortwave irradiance was measured using two Eppley PSP pyranometers. Long-wave irradiance was measured by two Eppley Precision Infrared Radiometers (PIR). To overcome the difficulties in making measurements of incident radiation on board, an experimental solution was ad hoc developed, based on the use of a couple of sensors for each measured term, as well as an analytical method to control the quality of the data. These four upward-looking hemispheric radiometers were mounted on the upper deck of the R/V Minerva, about 12 m above the sea level. The instrument locations were carefully selected to minimize the influence of the ship's structure on the measurements (i.e., avoiding having two sensors of the same kind simultaneously in the shadow of the ship's superstructure). The data were collected on a PC via an ADC card and recorded on the hard disk with a sampling time of 1 Hz. The sea surface temperature was measured by a Minarad RS-20. The thermometer was mounted on a boom over the bow of R/V Minerva, about 6 m above the sea level. The sea surface temperature was measured in the absence of breaking waves because in such instances the foam wetted the dome of the instrument invalidating the readings. The data were collected on a PC via an ADC card and recorded on the hard disk with a sampling time of 1 Hz. Long-wave upward radiation was computed from the sea surface temperature using the Stefan Boltzmann Law, while the reflected shortwave radiation using the Payne's table. Therefore the radiation budget was estimated. Hourly observations of the principal meteorological parameters were also carried out. An Assmann psychrometer was used to make measurements of air temperature and humidity, pressure values were obtained from the ship's barometer and the fractional cloud cover was visually estimated. All these observations were carried out from the main deck of the R/V Minerva, about 8 m above sea level. The navigation data were collected from the LORAN of the ship and recorded on a PC. The data set provides a continuous time series of 1-min average values of: solar radiation, atmospheric radiation, sea surface temperature, infrared radiation from the sea, radiation budget, latitude and longitude data. Moreover, data set of hourly values of the above parameters and air temperature, humidity, vapour pressure, atmospheric pressure are also available.

CNR, National Research Council, Institute of Atmospheric Sciences and Climate (Rome)
Via Fosso del Cavaliere, 100
Rome

00133
Italy