Land
Gaëlle Kerdraon presents the algorithm of snow/ice detection in the cloud mask and cloud type products of the NWC-SAF and shows some examples.
The first step of the cloud detection during day, is the snow/ice detection on the ground or at the sea surface. The talk will give details of the flag snow/ice in the cloud mask and in the cloud type. The algorithm will then be presented and illustrated by a recent example. The importance of this snow/ice detection will be pointed out for a good cloud detection. Finally, we will explain the limitations of this flag snow/ice.
Niilo Siljamo investigates the quality of H-SAF snow products.
H-SAF satellite snow extent products can be used for many meteorological and hydrological applications, for example as inputs for weather models. What are these products? How good are they? Especially, MSG/SEVIRI (H31) and Metop/AVHRR (H32) products are described with examples and validation results.
Rudolf Kaltenböck speaks about the challenges detecting snow from Radar data.
Weather radar data offers high spatial and temporal structures of three dimensional precipitation fields and can be well used for warning and nowcasting of adverse winter weather. Radar reflectivity, Doppler velocity products and polarized radar moments de liver insights into cloud microphysics and dynamical properties, such as the discrimination between different types of hydrometeors, quantitative precipitation estimation, icing conditions or areas of strong shear. Beside aeronautical nowcasting application, also the limitations of using weather radar in a cold winter weather environment will be addressed.
Ivan Smiljanić talks about the future possibilities detecting snow and ice from MTG data.
Detection of snow, but also its classification (depth, crystal size, age) depends mostly on the spectral and spatial resolution of geostationary satellites. Having better spatial resolution and more spectral channels, Meteosat Third Generation satellites (MTG) will be able to see snow better and tell more about its flavours, especially in the visible and near-IR spectral regions. Join if you are interested to know how the snow detection will be done with MTG and what is "the colour of the snow" with future data.
Mária Putsay discusses how single channels and RGB types can be effectively used for snow detection.
Single channels and RGB types will be discussed and compared from the snow detection point of view: how effectively they can be used for this purpose, which benefits and limitations they have. Physical background will be discussed and several examples will be shown.
Ideally an RGB type is usable for snow detection if the snow-covered cloud-free surface has good colour contrast against both now-free surface and clouds. Practically, one problem may cause difficulty: ice clouds and snowy land often appear similarly. Not surprising: their physical properties are similar as both consist of ice crystals. The presentation discusses which RGB types show snow and ice clouds less similarly. Forecasters usually look at animations, this also helps to distinguish snow covered area from moving ice clouds.
Craig D. Smith talks about automated observations of solid precipitation and snow cover that are still one of the most difficult meteorological measurements to make with any known level of uncertainty.
Automated observations of solid precipitation and snow cover are still one of the most difficult meteorological measurements to make with any known level of uncertainty. Many recommendations on best practices for measuring solid precipitation and snow cover emerged during and following the international Solid Precipitation Inter-Comparison Experiment (SPICE), including the development and application of transfer functions for adjusting precipitation gauge under-catch and techniques for minimizing errors in automated snow depth measurements. Following SPICE, work has continued on assessing and utilizing emerging technologies, such as optical and radar based present weather detectors, for improving the in situ measurement of solid precipitation. Furthermore, more effort is required to facilitate the transfer of techniques and best practices from research to application in operational networks.
In this presentation Tomaš Pučik and Christoph Gatzen explore different regimes under which ingredients come together and create marginal CAPE setups typical of winter
Forecasting deep-moist convection and lightning in winter is challenging, partly because it occurs outside the typical season and partly because it forms in the environments characterized by marginal buoyancy. Despite weak CAPE, winter time convective storms often pose a considerable severe weather risk given their frequent collocation with strong vertical wind shear. In this presentation we explore different regimes under which ingredients come together and create marginal CAPE setups typical of winter. These include synoptically strongly-forced situations, elevated storms and the lake-effect over the European seas.