The aim of nowcasting is to gain the best available estimates for various meteorological fields in a very short forecast lead time (0-3h). Often the in-situ measurements are used for validation of Nowcasting Models (NM) . Additionally, satellite measurements complement or replace information on the incoming shortwave flux over the areas with limited measurements. We will show below how LSA SAF Total and Diffuse Downward Surface Shortwave Flux (MDSSFTD, LSA-207) product was included in the validation of NM forecasts. Satellite measurements are based on the SEVIRI instrument on-board the MSG satellite.
For understanding the climate processes at the Earth-atmosphere interface, an accurate knowledge of the spatio-temporal distribution of downwelling solar radiation and of its diffuse component at the surface are essential. LSA SAF MSG Total and Diffuse Downward Surface Shortwave Flux (MDSSFTD, LSA-207) product is updated every 15 minutes and provides information of total (DSSF) and fraction of diffuse (FD) surface solar flux measurements on MSG disk area. Thin layers of clouds are still difficult to detect from satellites especially over areas with high albedo. In such cases ground measurements can be used to improve MDSSFTD product. In this presentation we will show how we can use DSSF and ground measurements to detect fog.
Example of the Impact of Vegetation Shadows on the Ground Measurements in Gačnik, Slovenia
Values of incoming solar radiation are important parameters in climate and meteorological models. LSA SAF product MSG Total and Diffuse Downward Surface Shortwave Flux (MDSSFTD, LSA-207) is updated every 15 minutes and provides information of total (DSSF) and fraction of diffuse (FD) surface solar flux measurements over the MSG disk area. Additionally, it provides some auxiliary quantities - aerosol optical depth (AOD), opacity index (OI), quality flag (QF) and clearness index (Kt). Satellite data for MDSSFTD have a good agreement with ground measurements. Here we will present how a long time period comparison between station and satellite total and diffuse down-welling surface flux can provide valuable information about homogeneity of the ground measurements. We used the data for two years, 2017 - 2018.
Monthly evapotranspiration variability in May 2019 and May 2020 over Europe
Evapotranspiration (ET) accounts for the flux of water evaporated at the Earth-atmosphere interface (soil + vegetation + water bodies) and transpired by vegetation through stomata in its leaves as a consequence of photosynthetic processes. ET plays a crucial role in the recycling of precipitation, in soil water availability and in modelling the hydrological cycle components, especially in arid regions.
LSA SAF Derived Land Surface Temperatures (DLST; LSA-003) are obtained every ten days from all available 15 minute Meteosat LST (LSA-001) within that period. Temporal compositing and modelling of the diurnal temperature cycle results in representative and spatially continuous maps of LST, which are a very helpful indicator of past weather conditions, e.g. allowing to identify regions affected by heat waves and droughts.
Improved Monitoring in Specific Synoptic Situations by LSA SAF LST
A case of temperature inversion in complex terrain
In winter cold-air pools in the lowest layers of the atmosphere are frequently formed due to night-time cooling. This can result in significant temperature inversion in valleys and basins. A typical weather situation with a pronounced temperature inversion developed in late December over Slovenia.
Several factors (e.g. urban areas have different thermal characteristics than surrounding non-urban areas and district heating in the winter) contribute that urban heat islands occur inside cities, i.e., part of the city with higher land surface temperature than its outlying areas.