Aggregation of weather indicators

General description

The aggregation of grid weather towards administrative regions is executed for different input datasets. For each of the datasets the procedure is repeated using different weighing methods and different output resolutions. A dedicated software package called Aggregator is developed to do all calculations.

Input datasets

In the MCYFS several grid weather datasets are available: grid weather based on station observations (observed grid weather) and several ECMWF products (see acquisition). All sets are available in grid format. A selection of these datasets is aggregated to regions: observed grid weather (table WEATHER_OBS_GRID) and (re-)forecasted weather of the ERA5 and HIS/OPE model (table WEATHER_<MODEL>_GRID).

Weighing methods

Grid cells (or part of grid cells) that fall inside a region are used to calculate the aggregated value of a specific weather indicator. Besides using all grid cells in a region, the aggregation is repeated using different selections of grid cells in each region. The selection is based on landcover masks. In other words: the aggregated indicator emphasizes the phenomena that are most relevant for the selected mask while neglecting the phenomena not relevant for the selected mask.

Masks

For Europe weather data is aggregated to land cover types only:

• no mask (all mixed)
• agricultural areas
• non-irrigated arable land
• arable land
• pasture
• temporary forage
• rice

The masks are based on CORINE land cover and for countries, not covered by CORINE, the Globcover data set is used.

details on European masks
details on mask agricultural areas CORINE CLASSES GLOBCOVER CLASSES 211 116 212 241 244
details on mask non-irrigated arable land CORINE CLASSES GLOBCOVER CLASSES 211 116
details on mask arable land CORINE CLASSES GLOBCOVER CLASSES 211 116 212 241 242 243 244
details on mask pasture CORINE CLASSES GLOBCOVER CLASSES 231 113 244 CAPRI DYNASPAT: grass class (extra EU 27: GLC class 113)
details on mask temporary forage CORINE CLASSES GLOBCOVER CLASSES 211 116 CAPRI DYNASPAT: ofar class – fodder areas on arable land, only EU
details on mask rice CORINE CLASSES GLOBCOVER CLASSES 213

For the other regional windows weather data is aggregated to land cover types and a few crop types, the latter based on crop specific areas available at regional level.

RUK CHN no mask, all mixed no mask, all mixed irrigated cropland irrigated cropland rain fed cropland rain fed cropland arable Land (irr+rainfed) arable Land (irr+rainfed) agricultural areas (arable + mosaic > 50%) agricultural areas (arable + mosaic > 50%) arable land custom arable land custom winter wheat irrigated wheat spring wheat rain fed wheat grain maize rice

Output resolutions

The output is calculated for different types of regions.

In case of Europe:

• 4 levels of administrative regions (NUTS0-3)

In case of other regional windows like Russia and Kazakhstan (RUK):

• 3-4 levels of administrative regions (RUK has a specific sub national level grouping level 1 regions)

The results are written to the tables

• WEATHER_OBS_REGIONCOVER
• WEATHER_<MODEL>_REGIONCOVER

Replace <MODEL> with one of the model abbreviations for which aggregated indicators are calculated (ERA5, HIS/OPE).