# On-Board Wind Scatterometry
###### Abstract
However, similar application chains can only meet regional coverage. For far open ocean regions that ground stations cannot reach, support information is unable to be provided without extra support from communication satellites, and 30 min is longer than many small scale events that can be observed by scatterometers but are difficult to be predicted by NWP, e.g., convections in the tropical region [21]. The real-time (RT) information of such events is useful for applications like disaster alarms for ships and airlines. With the fast development of satellite remote sensing methods, on-board hardware types and capabilities, an innovative application mode involving generating and distributing higher levels of products with extracted information rather than original observations has come out [22; 23]. Current applications concentrate on on-board feature extraction to relieve transmissions of large amounts of observations from sensors, such as SAR and optical cameras [24; 25]. The advent of micro-nano satellites, accompanying burst developments of neural network hardware components, has propelled this processing mode to the experimental stage with affirmative results [26]. The new generation of communication satellites has provided the possibility of a data downlink routine for RT transportation, as well as the possibility of solving downlink obstacles for on-board processing for countries who lack suitable ground station sites [27; 28]. Off-line ground processing chains of scatterometer data are already well-established. If integrated to an established on-board environment, the RT processing and direct broadcast of retrieved winds with high accuracy can be realized for RT applications with a communication-remote-sensing mode [29; 30]. This research demonstrates the whole procedure. An on-board processing environment is simulated with processors and systems that can be applied to satellites. Steps of traditional processing are modified for the on-board environment and RT processing requirements. Validation is achieved with application to CFOSCAT real data. First, the on-board environment is established, and reasons for its applicability to the spaceborne environment are provided. The method to distribute processed results, such as on-board wind products are also presented. Then scatterometer processes that are adjusted for on-board applications, including procedures from return power to wind product generation, are described with modifications to the proposed data product forms. Changes made to traditional procedures are described. After that, CFOSCAT data for the validation of the new processing chain and environment are introduced, followed by experiment results. Differences in accuracy with the traditional off-line processing chain are provided. For the validated on-board processing chain especially, the relationship bewteen accuracy and processing time changes due to the information involved in processing is analyzed and provided. It is concluded that on-board scatterometer winds can be realized with the accuracies needed to meet application requirements. This can be achieved as an extra parallel working mode of existing scatterometers, complementing their wind producing chains. This research is the first discussion on on-board wind scatterometry for satellites. The proposed method can fill the blank of stable far sea RT winds in future scatterometer missions. This can benefit sailing routing optimizing systems, especially for scientific research ships that go into rare regions of oceans. Conclusions can also be valuable as part of future intelligent observation systems in terms of locating possible disaster regions with RT winds in order to give alarms and for further highlight monitoring. The proposed method's RT capability also provides well-established inputs for future NWP application schemes described in [31] and contributes to improving short-term forecasts.