New sources of wind information for NWP.
Wind information is fundamental to initialize Numerical Weather Prediction (NWP) models and to follow the dynamical evolution of mesoscale structures. Meteorological analyses over the oceans are very relevant for climate monitoring and for lots of economical activities such as fishery, wind farms installation, marine transportation, etc. Unfortunately, they are very poor due to lack of wind observations in open oceans. In particular, an adequately high temporal sampling of ocean surface winds plays a key role in improving weather forecasts, especially at medium and small scales such as convective phenomena and/or dynamical conditions such as high winds regimes, polar lows, typhoons, etc.
This research project aims at exploiting the Global Navigation Satellite System (GNSS) ocean reflections (see Fig. 1) in order to increase the wind temporal sampling over oceans, following the user requirements of the World Meteorological Organization (WMO OSCAR. GNSS Reflectometry (GNSS-R) is at a primordial stage, therefore, the interpretation of the measured bi-static normalized radar cross section (BNRCS) and its dependency on the geophysical parameters of interest and on the acquisition geometry should be further investigated and tested.
The data from the TechDemoSat and Cyclone GNSS satellite missions will be used to reduce this knowledge gap. The most important aim of the CYGNSS mission is the improvement of hurricane forecasting (see Fig. 2).
The main final objectives of this project are the development of an observation operator and the evaluation of the impact of the retrieved winds on NWP models.
This project will be carried on mainly at KNMI, within the active satellite remote sensing group and with the support of the NWP SAF, which have a long and consolidate experience in the development observation operators for scatterometer winds. The KNMI active remote sensing group has a 30-years experience in retrieval, assimilation and validation of wind fields. Among many other activities, it is co-organizer of the International Ocean Vector Winds Science Team (IOVWST).
Furthermore, a strong collaboration with the ROM SAF (http://www.romsaf.org/) based at the Institut D'Estudis Espacials de Catalunya (IEEC) and the Institut de Ciencias del Mar, which have consolidate experience in the occultation part of the GNSS-R technique, will take place. A continuous collaboration and discussion with the CYGNSS and TDS science teams will go on.