Improved meteorological measurements from buoys and ships (IMET) : preliminary comparison of precipitation sensors

Rainfall data obtained from an optical rain gauge and a capacitive siphon rain gauge are analyzed and discussed. These sensors were developed for unattended use and are being considered for use at sea on ships and buoys.Funding was provided by the National Science Foundation under Grant No. OCE-87-0961

A compilation of moored current meter data and wind recorder data from the Severe Environment Surface Mooring (SESMOOR) volume XLIII

A Severe Environment Surface Mooring (SESMOOR) was designed to make long term meteorological and near surface oceanographic measurements in areas where harsh envionmental conditions prevail. SESMOOR was deployed in the North Atlantic Ocean approximately 300 km southeast of Halifax, Nova Scotia for 141 days during the winter of 1988-89. Meterological data were acquired from two Vector Averaging Wind Recorders (VAWR) located on top of a specially designed buoy mast and included air temperature, relative humidity, barometric pressure, wind velocity, solar and longwave radiation. Sea surface temperature was also acquired by the VAWR. Current velocities and sea temperatures were obtained from two Vector Measuring Current Meters (VMCM) at 20 and 50 meters below the sea surface. This report discusses instrument performance, data quality, pre-and post-deployment calibrations, data telemetry, data processing procedures. This report also presents the data in a variety of displays.Funding was provided by the Office of Naval Research under Contract No. N00014-84-C-0134, NR 083-400 and Grant No. N00014-90-J-1423

Improved meteorological measurements from buoys and ships (IMET) : preliminary report on barometric pressure sensors

Stability tests over periods ranging from 3 to 19 months have been carried out on Paroscientific models 215-AT and 760-15A, AIR DB-1A, Rosemount 1201F1B, Setra 270 and Heise 623 electronic barometers. The Paroscientific barometers had the highest accuracy, stability, and price, and the lowest power consumption. The Rosemount 1201FIB had excellent stability but high power consumption as well as price. The AIR DB-1A and Setra 270 have good stability and moderate power consumption and price. The tests are being expanded to include inexpensive sensors.Funding was provided by the National Science Foundation under Grant No. OCE-87-0961

Improved meteorological measurements from buoys and ships (IMET) : preliminary comparison of solar radiation air temperature shields

Several different types of solar radiation air temperature shields are evaluated for use at sea on ships and buoys. They include three types of static or Thaller shields, two vane oriented shields, and two fan ventilated shields. A preliminary data analysis is presented and discussed.Funding was provided by the National Science Foundation under Grant No. OCE-87-0961

Improved meteorological measurements from buoys and ships (IMET) : preliminary comparison of humidity sensors

Humidity sensors using various principles of operation are evaluated for the potential use at sea on buoys and ships. Thin film capacitive polymer sensors include the Vaisala Humicap HMP-14U (with WHOI electronics), Hy-Cal Engineerig Ultra-H (also with WHOI electronics), the new Vaisala HMP-35A, and the Rotronic MP-lOOF. Impedance sensors include the Thunder Scientific PC-2101, Phys-Chem PCRC-ll, and the General Eastern 850. The Hygrometrix 8503A is the only organically based cellulose crystallite sensor evaluated. Chilled mirror dew sensors include the EG&G 200M Dewtrak, which was used as a comparative standard, the General Eastern Dew-lO and the WHOI D10IQ Intelligent Dew Point Sensor. The IR-200 infrared optical hygrometer from Ophir is also included in this study. The performance of the EG&G 200M Dewtrak was quite disappointing. Errors of up to 2.5°C in air temperature were observed due to inadequate shielding from solar radiation.Funding was provided by the National Science Foundation under Grant No. OCE-87-09614

The VITROVAC Cavity for the TERA/PIMMS Medical Synchrotron

A proton and light-ion medical synchrotron is characterised by a large frequency swing for the RF between the injection and the top energy. For this purpose, a VITROVAC®-loaded RF cavity has been developed for the Proton-Ion Medical Machine Study (PIMMS) at CERN, and for TERA, the Italian project of a proton and light-ion synchrotron for cancer therapy, based on the PIMMS study. The main features are a large frequency swing, particularly extended to the low frequency range, a very large relative permeability and a low Q factor. The total power needed is less than 100 kW, while a very small bias power is required for the frequency tuning. The main mechanical characteristics are compactness (less than 1.5 m), and simplicity of construction. As a result, the requirements of the medical synchrotron are comfortably satisfied, namely: 0.4 to 3 MHz swing, 3 kV peak voltage at a repetition rate of less than 1 s