The MICROWAT activity is funded by the ESA Support To Science Element (STSE) under the 2008/9 work plan [available at URL-4] that aims to reinforce the scientific component of the ESA Living Planet programme [URL-5] specifically addressing the exploratory action line calling for future missions. STSE is a programmatic element of the 3rd period of the Earth Observation Envelope Programme (EOEP-3), an optional programme of the European Space Agency.
Study Presentation
The activities in this ESA study, contracted by Astrium SAS, are part of an STSE future mission exploratory action. The study will consolidate scientific requirements and perform a preliminary analysis of different observational principles and concepts to measure contemporaneously and through clouds high resolution Sea Surface Temperature (SST) and Ocean Vector Winds (OVW). One optimal mission concept will then be defined and elaborated that will provide through-cloud SST and contemporaneous measurements of OVW at high resolution (5-15 km) over the global ocean including coastal and ice infested areas.
Mission Objectives
Accurate knowledge of the contemporaneous global OVW and SST distribution and temporal variation at finer spatial resolution [RD-2, RD-20] are needed as a key input to atmospheric and oceanic forecasting and prediction systems. The positive impact of using daily high resolution SST and OVW on operational NWP has been demonstrated at ECMWF [RD-20] and such measurements are also used for validating ocean and coupled ocean-atmosphere models
Sea Surface Temperature (SST) and Ocean Vector Winds (OVW) are fundamental variables for understanding, monitoring and predicting the general circulation of the ocean and atmosphere. OVW drive ocean currents and ocean vorticity through the transfer of energy to the ocean as frictional coupling at the atmosphere-ocean interface (the momentum flux expressed as drag force per unit area) [RD-13, RD-14]. The dynamic patterns of SST and OVW are important predictors of global climate [RD-21] with far reaching consequences for the global economy and security of life and property. For example, they directly influence the dynamics of large persistent features such as El Nino/La Nina (ENSO) in the Tropical Pacific Ocean which has a direct impact on global weather and climate patterns [RD-13, RD-14]. Changes in the patterns of SST reveal the dynamic structure of surface currents and other OVW driven features such as Tropical instability waves [RD-17] and the magnificent western boundary currents of the global ocean.
Contemporaneous high resolution SST and OVW are essential [RD-7] to understanding the interactions between the variability of ocean dynamics, thermohaline circulation, sea level and climate, the first ocean challenge of the ESA Living Planet Programme [RD-40].
The SST and OVW interaction has been demonstrated by measurements. The following plot shows simultaneous AVHRR SST measurement and ASCAT Wind measurements over an Artic "warm spot" dated 02/07/2008 :
Eastwood et al.
The aim of this study is to explore different options and define an optimal mission concept that will provide through-cloud SST and contemporaneous measurements of OVW at high resolution (5-15 km) over the global ocean including coastal and ice infested areas. The objectives of this study are:
- To analyze and consolidate MICROWAT mission user requirements for global SST and OWV observations.
- To identify, define and analyze measurement concepts that address these requirements including at least one real-aperture and one synthetic aperture measurement concepts. The Bidder may optionally consider intermediate hybrid combination concepts that would be considered optimum for meeting the MICROWAT requirements.
- To justify, select and develop a preliminary design of one MICROWAT mission concept and analyse the feasibility and risks of implementation including the scientific capability to retrieve contemporaneous OVW and SST. The analysis shall address accommodation difficulties in dedicated and multi-instrument platforms.
- To recommend further areas of research and development that could lead to instruments that are more affordable, easier to accommodate while still providing improvements in accuracy, coverage and resolution.
The study outputs will provide the Agency with a review of concepts and potential technologies (including an assessment of options) for all weather high resolution SST and contemporaneous OVW measurements from space.