News and notifications

Dear users,

The Metop ASCAT Soil Moisture products currently generated at the EUMETSAT Central Facility, and distributed on EUMETCast, will be replaced by new, upgraded soil moisture products generated by the H SAF, as follows:

• H16 (Large-scale surface soil moisture by radar scatterometer) and H104 (Metop-C ASCAT NRT SSM orbit geometry 12.5km sampling) will be replaced by H29 (Metop ASCAT Surface Soil Moisture Near Real-Time 12.5km sampling V2).
• H103 (Metop-B ASCAT NRT soil moisture 25km sampling) and H105 (Metop-C ASCAT NRT SSM orbit geometry 25km sampling) will be replaced by H122 (Metop ASCAT Surface Soil Moisture Near Real Time 6.25km sampling).

Main changes introduced with the new products include:

• Projection on to a fixed Earth grid (6.25km for H122, 12.5km for H29) using the ASCAT Level 1b full resolution backscatter product as input. As well as dropping the coarse resolution ASCAT SSM product (25km sampling) and introducing a better spatial resolution (6.25km sampling), one of the key differences is that there is no sampling of data using swath orbit nodes. The new fixed Earth grid makes it easy to build time series without applying any resampling procedure beforehand. In addition, individual backscatter echoes provided in the ASCAT Level 1b full resolution backscatter product allow for more accurate filtering of signals coming from areas not sensitive to soil moisture changes (eg, open water, cities).
• The underlying core soil moisture retrieval algorithm — a semi-empirical change detection method — will not change. However, the estimation of the model parameters (slope/curvature, dry/wet backscatter reference) has evolved (Hahn et al., 2017, Hahn et al. 2020), and is based on a much longer backscatter time series (2007–2023) than before. The retrieval method itself is not changing, but the updated model parameters have a significant impact on the dynamics of soil moisture and its extremes, rendering the old ASCAT SSM NRT product inconsistent with the upcoming SSM NRT product.
• A more adaptive vegetation correction has been introduced by using spatially varying cross-over angles instead of static angles. In addition, the computation of the slope and curvature climatology is now based on a kernel smoother function. Moreover, long-term land cover changes are introducing trends in backscatter, eg, in areas affected by urban growth. In order to mitigate those effects, the dry/wet backscatter reference is now estimated on a yearly basis, taking data from neighbouring years into account.

Main characteristics of ASCAT SSM 6.25km (H122) and ASCAT SSM 12.5km (H29):

• Variable: Soil moisture content in the surface layer (< 5cm)
• Unit: Degree of saturation (0–100%)
• Spatial sampling/resolution: 6.25km/15x15km2 or 12.5km/25x25km2
• Spatial coverage: Global (65°S, 180°W, 80°N, 180°E)
• Timeliness: 115 min (for the NRT product) Format: netCDF4 and BUFR

It is planned that the old products will be discontinued in Q2 2025. To ensure a smooth transition for users, the new products, H29 and H122, will be distributed on EUMETCast, in parallel to the old products for a few months. More information will be provided in due course. In the meantime, sample files of the new products are available on the H SAF FTP server: ftphsaf.meteoam.it (registration on the H SAF website is required).

Dear Users, due to technical issues the distribution of the new format for precipitation products: H60B (Blended SEVIRI / LEO MW precipitation), H61B (Accumulated Precipitation at ground by blended MW and IR), H63 (Precipitation rate at ground by GEO/IR supported by LEO/MW IODC) and H90 (Accumulated Precipitation at ground by blended MW and IR IODC); is postponed to the 6th of May.

Due to a permanent and unrecoverable damage of the 50 GHz channel, the DMSP18 satellite has been set out from the production of H01.

The last available orbit was 20241031_1219_DMSP18_77565

Dear users, we inform you that, product H120 SSM ASCAT DR2021 EXT TS12.5 has been updated and it now covers the period (2021-01-01 until 2024-08-31).

The Snow Water Equivalent by MW radiometry product H65 (SN-SWE-HH) has been released and it will now be avaulable on EUMETCast.
The H SAF H65 product (SN-SWE-HH) is gridded MW daily SWE observation for Northern Hemisphere. H65 is extension of H13 product to full Northern Hemisphere coverage with improved error estimates added.
The product is a merge between two approaches. For flatlands and forested areas snow depth data from weather stations are used to produce a first guess that is converted into MW brightness temperatures by an emission model.
An assimilation process is then used to force the first guess field to match MW brightness temperatures from SSMIS instrument aboard DMSP 18 satellite.
For mountainous areas, look up tables are used to fix any unrealistic snow density values retrieved from assimilating the satellite observations.
The H SAF H65 daily product is made available three days after each full Hemispheric coverage by SSMIS instument.
The product is offered in EASE2 equal area scalable earth grid, offering easy summation of liquid water volume over larger areas of interest.

The Snow Water Equivalent by MW radiometry product H65 (SN-SWE-HH) has been released and it will now be avaulable on EUMETCast.
The H SAF H65 product (SN-SWE-HH) is gridded MW daily SWE observation for Northern Hemisphere. H65 is extension of H13 product to full Northern Hemisphere coverage with improved error estimates added.
The product is a merge between two approaches. For flatlands and forested areas snow depth data from weather stations are used to produce a first guess that is converted into MW brightness temperatures by an emission model.
An assimilation process is then used to force the first guess field to match MW brightness temperatures from SSMIS instrument aboard DMSP 18 satellite.
For mountainous areas, look up tables are used to fix any unrealistic snow density values retrieved from assimilating the satellite observations.
The H SAF H65 daily product is made available three days after each full Hemispheric coverage by SSMIS instument.
The product is offered in EASE2 equal area scalable earth grid, offering easy summation of liquid water volume over larger areas of interest.