International Data Centre on Hydrology of Lakes and Reservoirs HYDROLARE - established in 2009 by Roshydromet at the State Hydrological Institute under aegis of the World Meteorological Organization (WMO); - together with other data centers enters the system "Global Terrestrial Network-Hydrology" (GTN-H); - provides data on hydrology of world lakes and reservoirs (nearly 879 water bodies). - the Centre operates on the basis of free dissemination of information (used for non-commercial purposes) for governmental, scientific, educational public and commercial institutions. www.hydrolare.net

The objective of the HYDROLARE is: the establishment, development and regular update of international database on hydrological regime of lakes and reservoirs in order to: stimulate the development of the global monitoring system on lakes and reservoirs for rational use, preservation and management of their water resources; improve the knowledge of lateral fluxes transformation within lakes and reservoirs; supply data for scientific and educational purposes, modelling, development of different global and regional projects/programmes.

HYDROLARE: ∙  contributes important information for decision-making on regional and global scales concerning water resources of inland lakes and reservoirs; ∙  assists WMO Members in the analysis and improving of monitoring systems on lakes and reservoirs; ∙  improves data collection, processing, analysis and monitoring; ∙  supports the exchange of information.

The special HYDROLARE search and explore tool helps users to search information about main database content through Google Maps API. Regularly updated information on the status of the database content is available on the web site at: www.hydrolare.net

Cross links between pages of LEGOS (Hydroweb) and HYDROLARE websites Within HYDROLARE – LEGOIS (France) cooperation activities were implemented aimed at integration of in-situ and satellite data available at HYDROLARE and LEGOS respectively. Direct access from HYDROLARE to Hydroweb web-site was enabled for acquiring information on availability of satellite data for selected lakes on Hydroweb and vice versa. Now at the HYDROLARE database there is satellite data on lake water level for 48 lakes in 32 countries together with related metadata. Cross links between pages of LEGOS (Hydroweb) and HYDROLARE websites

Informing users about availability of data on water temperature Until 2015 the only type of data in the database was in-situ and remote sensing water levels of lakes and reservoirs. In 2016 HYDROLARE started updating its database with in-situ water temperature data. Plans for 2017 include adding ice thickness data on lakes and reservoirs. Informing users about availability of data on water temperature

Annual newsletters in Russian and English are regularly prepared providing information about HYDROLARE activities including results obtained by LEGOS/CNES in the framework of the mutual cooperation.

This is a sheme of the functioning of the new service: Two partners (in fact 3 with CNES), the Legos which works on product quality assessment and research and development of new products and improvement on the data processing, and a private company which operates the system for operationnal uses. All of this will be hosted by a big platform of multi usage (not only lakes and rivers) called THEIA and which belong to the CNES, with support devices for users, and interfaces between product centers (CLS and Legos) and the users.

This is a table of comparison for ~20 lakes of different sizes and locations between satellite and in situ. Message is here simple: For big lakes in general the accuracy is very good (less than 10 cm) but then there is no real rules and one may have quite good accuracy for small lakes (Aydarkul or Argentino) while it can be serverely degraded for big but narrow reservoirs like the Mead, the Powell or the Bratsk. Second message is that this kind of comparison is very important, and maintainance of in situ data base and altimetry on the same lakes are essential in the quality check process, and is part of the cooperation between legos and SHI

This is a map with the location of the lake included in the GTN-L (official one). Currently 53 among the 79 lakes of this list can be monitored with satellite and in 2016/2017 when some new satellites like the sentinel-3A and Sentinel 3B will be launched, then quite all of the lakes of the GTN-L will be covered. In 2020 with SWOT satellite, all of the lakes will be monitored

What needs to be done in future? Try to project ourselves in a double framework program: The CCI+ from ESA The preparation of the SWOT missions For CCI+, and ECVs on lakes, we will need to investigate for each of the already defined ECVs by GCOS (water level, extent temperature and ice duration) how this may be measured globally, continuously and accurately by remote sensing. The aim of this project is here: remote sensing application to ECVs for lakes. Secondly we will have to propose new ECVs to GCOS: immediately it can be thought on the water color, and on the distribution changes of lakes worldwide. In SWOT science development we strongly need to have a full investigation on the broad range of applications in limnology. Particularly, if one scientific objective as defined in the science requirement document is to study the processes that are linked to lakes and their inter-action with CC, quite nothing has been concretely done yet. The Surface Water and Ocean Topography mission (SWOT) is a satellite mission recommended by the US National Research Council 2007 Decadal Survey that will provide a quantum improvement oceanography and hydrology. SWOT Performance Requirements: Lakes Inundated area: 15% accuracy for lakes larger than 250 m. (baseline). 15% accuracy for lakes larger that 1 km (Threshold). Lake water surface height: 10 cm accuracy for lakes larger that 1 km. 25 cm accuracy for lakes between 1 km and 250 m. (baseline). 11 cm accuracy for lakes larger than 1 km. (threshold). That’s why, a working group needs to be created on this topic: what and how SWOT will inform us on these lakes issues? I would add, how to best as possible use SWOT in synergy with other missions for lakes study.

Steps: Create a consortium to answer to forthcoming open call of ESA (CCI+; which should be opened In spring for deadline around next summer). Organize a symposium (March or April in Toulouse) to prepare the answer to this ESA call and the SWOT sciences application for lakes. Create a working group to discuss what and how SWOT will help to make an investigation on the broad range of applications in limnology. Discuss of a connection between the consortium and a working group which needs to be set up within specifically the SWOP project.

For more information about HYDROLARE Data Base, Partners, News visit : www.hydrolare.net