A new snow scheme for the European Centre for Medium-Range Weather Forecasts (ECMWF) land surface model has been tested and validated. The scheme includes a new parameterization of snow density, incorporating a liquid water reservoir, and revised formulations for the subgrid snow cover fraction and snow albedo. Offline validation (covering a wide range of spatial and temporal scales) includes s...

Integrated Water vapour (IWV) has been measured since 1994 by the TROWARA microwave radiometer in Bern, Switzerland. Homogenization techniques were used to identify and correct step changes in IWV related to instrument problems. IWV from radiosonde, GPS and sun photometer (SPM) was used in the homogenisation process as well as partial IWV columns between valley and mountain weather stations. Th...

The climatology of atmospheric horizontal wind and its vertical gradient, i.e. wind-shear, is characterized as a function of climate region. For a better representation of the average atmospheric wind and shear and their variabilities, high-resolution radiosonde wind profiles up to about 30 km altitude are compared with collocated operational ECMWF-model ShortRange Forecast winds. Statistics of...

The Netherlands is a highly urbanized area. In addition to flooding from the sea due to storm surges and high water discharges from rivers, flooding from major lakes is also a threat. Since 2011 there is a new system in operational use (24 hours per day, 7 days per week), for the prediction of flooding at Lake IJssel, Lake Marken, and the lakes bordering them. This system, RWsOS Meren (Genseber...

This paper reports preliminary results of a Limited area model Ensemble Prediction System (LEPS), based on RAMS, for eight case studies of moderate-intense precipitation over Calabria, the southernmost tip of the Italian peninsula. LEPS aims to transfer the benefits of a probabilistic forecast from global to regional scales in countries where local orographic forcing is a key factor to force co...

The work reports validation of numerical weather forecasts (NWF), QuikSCAT-based wind speed and AMSR-E sea surface temperature (SST) for the surface atmospheric boundary layer in the Indian sector of the Southern Ocean under the International Polar Year. The database consists of wind speed, air temperature, relative humidity, sea level pressure collected along the ship route from Durban (32.4°S...