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Call for tenders' details

Title:
Pan European High Resolution Snow and Ice Monitoring of the Copernicus Land Moni...
Contracting authority:
European Environment Agency (EEA)
TED publication date:
21/12/2018
Time limit for receipt of tenders:
11/02/2019
Status:
Closed
Status
21/01/2019
25/01/2019
English (en)
Question details
Clarification of “permanent snow line” for EEA tender for the “Pan European high resolution Snow & Ice Monitoring of the Copernicus Land Monitoring Service – production of basic products”
Date: 21.01.2019 In the Annex I – Tender Specifications for the “Pan European high resolution Snow & Ice Monitoring of the Copernicus Land Monitoring Service – production of basic products”, one of the specified products to be provided is called “permanent snow line”. This parameter is further defined as the “yearly minimum extent of snow covered area”, to be derived from the fractional snow cover product, which should be based on the normalized difference snow index (NDSI). As the minimum snow extent per year in Europe is usually the snow remaining at the accumulation areas on glaciers, could you please clarify what exactly is meant by the “permanent snow line”? Does it refer to: A) the permanent snow AND ice areas, i.e. glacier areas, excluding debris covered glacier parts? B) Or the snow remaining at the end of the summer season on glaciers, i.e. that a separation of snow and ice areas on glaciers is requested? And if so, what exactly is defined as “snow”? o Is it only the snow from the last winter season? o Or the snow from the last winter season AND – if present – firn (snow from previous winter seasons)? The identification snow AND ice areas (option A) could be derived from NDSI based FSC maps. The identification of minimum snow areas only, so only snow remaining on glaciers at the end of the summer season (option B), and in particular the separation of seasonal snow from last winter and firn requires a different processing of the satellite data, but cannot be derived from NDSI based FSC maps, as the NDSI values for snow, firn and ice are too similar for a differentiation.
25/01/2019
In relation to task 2 in the tender specifications, Permanent Snow Line shall be understood as (B) 'the snow remaining at the end of the summer season on glaciers', and the separation of snow and ice areas on glaciers is requested. As far as firn is concerned, and whether it shall be considered either as glacier or as snow (to the extent feasible), this is something that should be discussed with the user community in an early project phase. A possible method separating snow and ice is described by Paul et al. 2016 (https://www.mdpi.com/2072-4292/8/7/575 chapter 3.4.), although the method described therein does not separate out firn. The glacier area shall be based on the ‘glaciers extent’ produced by C3S (https://cds.climate.copernicus.eu/cdsapp#!/dataset/insitu-glaciers-extent?tab=overview). Within this AoI the NDSI only approach is not expected to meet the accuracy requirements. (The graphical ‘seed concept’ in figure 2, p. 9 of the tender specifications is meant as a rough illustration of the processing flow only.)